ALBERT

Description: The number of input-output assessments focused on energy has grown considerably in the last years. Many of these assessments combine data from multi-regional input-output (MRIO) databases with energy extensions that completely or partially depict the different stages through which energy products are supplied or used in the economy. The improper use of some energy extensions can lead to double accounting of some energy flows, but the frequency with which this happens and the potential impact on the results are unknown. Based on a literature review, we estimate that around a quarter of the MRIO-based energy assessments reviewed incurred into double accounting. Using the EXIOBASE MRIO database, we also analyse the effects of double accounting in the absolute values and rankings of different countries' and products' energy footprints. Building on the insights provided by our analysis, we offer a set of key recommendations to MRIO users to avoid the double accounting problem in the future. Likewise, we conclude that the harmonisation of the energy data across MRIO databases led by experts could simplify the choices of the data users until the provision of official energy extensions by statistical offices becomes a widespread practice.

Description: By use of macro-economic model EXIOMOD, the expected impacts of actions described in the Strategic Research and Innovation Agenda (SRIA) have been analyzed. The results of this analysis show that the R&I actions described in the SRIA contribute to decoupling economic growth from resource use. The actions are expected to cause an increasing gross domestic product and a decreasing raw material demand. This results in an increasing extracted resource productivity, a measure used to show the decoupling of economic growth and resource use. It can however be questioned whether the actions in the SRIA - or the measures implemented in the model - assume a strong enough pace for decoupling economic growth and material use. The actions contribute to the climate goals of the European Commission, by showing a pathway through which the emissions of greenhouse gas can be reduced.

Description: Despite Germany's Paris Agreement pledge and coal exit legislation, the political debate around carbon-intensive coal remains heated. Coal power and mining have played an important, yet changing role in the history of German politics. In this paper, we analyze the entire parliamentary debate on coal in the German parliament (Bundestag) from its inception in 1949 to 2019. For this purpose we extract the more than 870,000 parliamentary speeches from all protocols in the history of the Bundestag. We identify the 9167 speeches mentioning coal and apply dynamic topic modeling – an unsupervised machine learning technique that reveals the changing thematic structure of large document collections over time - to analyze changes in parliamentary debates on coal over the past 70 years. The trends in topics and their varying internal structure reflect how energy policy was discussed and legitimized over time: Initially, coal was framed as a driver of economic prosperity and guarantee of energy security. In recent years, the debate evolved towards energy transition, coal phase-out and renewable energy expansion. Germany’s smaller and younger parties, the Greens and the Left Party, debate coal more often in the context of the energy transition and climate protection than other parties. Our results reflect trends in other countries and other fields of energy policy. Methodologically, our study illustrates the potential of and need for computational methods to analyze vast corpora of text and to complement traditional social science methods.

Description: Digitalisation is disrupting business practices worldwide and transforming consumption patterns. While a global increase in wealth is leading to higher consumption rates, consumption-related decisions are increasingly based on digital information and marketing; furthermore, shopping increasingly takes place online and products and services are more and more digitalised. The transformative character of digitalisation calls for political action in order to ensure sustainable consumption in a new and dynamically changing context. Focusing on consumption is imperative in combatting many global challenges. Take climate change: consumption-based emissions (i.e. emissions from domestic final consumption and emissions caused by the production of imported goods) are rising more rapidly than production-based emissions in high-income countries. Meanwhile most political measures target production-based emissions (i.e. territorial emissions). The German council for sustainable development (Rat für Nachhaltige Entwicklung) has called for the §principle of sustainable development [to] serve as the political framework for digital transformation" as "digitalisation has the potential to engender disruptive developments in the business world as well as society as a whole that carry both great opportunities and significant risks". Thus, to implement the 2030 Agenda, in particular SDG 12, and the National Program Sustainable Consumption, it is key to seize the opportunities that digitalisation presents for sustainable consumption and tackle the challenges. This assessment report thus examines the following key question: "What are the implications of the digital transformation of consumption patterns for the implementation of the German sustainability strategy in, by and with Germany?"

Description: The transition from today's "take, make, waste" economic paradigm to a circular economy requires a joint effort from actors on all levels: governments, business, and civil society. While companies are among the drivers of the circular transformation, they find it hard to achieve a circular economy on their own. Hence, cross-industry collaboration is one of the imperatives for scaling a circular economy. Against this background, econsense, together with Accenture and the Wuppertal Institute, launched its study "Germany's Transition to a Circular Economy - How to Unlock the Potential of Cross-Industry Collaboration". Based on a survey and expert interviews within the econsense community, the study finds that companies are yet to unlock the full potential of cross-industry collaboration. While two thirds of analysed industry collaborations have a high potential for scaling the circular economy, only 43 per cent of those already show a high degree of interaction. The study provides concrete guidance for companies to get started with circularity and identify the right partners for cross-industry collaboration. Specifically, the report recommends companies: 1) Understand what circularity is about and map it on their own operations and processes. 2) Understand the different circular business models and identify the ones relevant to each business. 3) Discover areas where collaboration can help to create the needed foundation and to execute circular actions.

Description: Digitalisation is taking place at a fast pace in all European countries and it is transforming the economies, societies, communication, jobs and the necessary skills for the workplace and everyday life. The Covid-19 pandemic is also accelerating digitalisation at many levels. To address the great challenges resulting from this, the European Commission has launched the Green Deal, a long-term transformation strategy towards an innovative and sustainable society. Three important initiatives under the Green Deal are the New Circular Economy Action Plan, the Biodiversity Strategy for 2030 and the Zero Pollution Action Plan. The various strategies and action plans draw up a large portfolio of measures, instruments and milestones that are always linked to digital technologies. Ideally, these are eco-innovative and sustainable and contribute to improving living conditions in Europe. The EIO Biennial Report 2020, which looks at a different topic every two years, considers digitalisation a major opportunity to accelerate the transition to a circular Europe. In the current report, the authors provide an overview of eco-innovation trends, illustrated by digital technology and policy practices that can further drive the circular economy.

Description: For achieving a transition towards sustainable development, central importance is attached to science and education, and especially higher education. Suitable formats are needed for empowering students to perform transformative research. On the basis of transdisciplinary and transformative real-world laboratory research and futures studies, we develop encompassing learning and teaching module: the Transformative Innovation Lab (til). The lab builds on insights into five key competencies and three types of knowledge needed for developing socially robust sustainability innovations. In this paper, the main features of this experiential and reflexive format are presented and linked to a handbook for facilitating the lab. Central learnings for implementing the format in existing study programmes from two test runs at two German universities are shared and discussed.

Description: Para lograr una transición hacia el desarrollo sostenible son fundamentales la ciencia y la educación, especialmente la educación superior. Se necesitan formatos educativos para capacitar a los estudiantes en la realización de investigaciones transformadoras. Con base en la investigación transdisciplinaria y transformadora en laboratorios del mundo real y estudios del futuro, desarrollamos un módulo de aprendizaje y enseñanza integral: el Laboratorio de Innovación Transformadora (lit). El laboratorio desarrolla cinco competencias clave y tres tipos de conocimiento necesarios para impulsar innovaciones en sostenibilidad socialmente robustas. En este artículo se presentan las principales características de este formato vivencial y reflexivo, además de un manual para facilitar el laboratorio. También se comparten y discuten los aprendizajes centrales de la implementación de este formato en programas de estudio existentes a partir de dos pruebas realizadas en dos universidades alemanas.

Description: In current German debates on sustainable urbanisation and urbanism, new urban actors reviving buildings, brownfields or whole neighbourhoods are discussed as potential drivers of urban transformation towards sustainability as well as potential co-producers for conventional actors in urban development and planning. These actor's projects can be understood as spatially confined niches for experimentation with (built) urban space itself. Building upon the concepts of niche entrepreneurship (Pesch et al., 2017) and the framework of strategic action field theory (Fligstein & McAdam, 2011; 2015), we ask how these actors secure support for their projects and how these projects in turn are altered in this process. Based upon a case study from Wuppertal, Germany, we show that in struggling for support of powerful actors, these actors often have to significantly compromise, and that these compromises can be understood as contextualisation in the project's spatial and institutional environment.

Description: Consumption by private households in various areas of demand - housing, mobility, nutrition, services and products - contributes to around 10 % of total emissions in Germany. Of this, higher-income households are responsible for a disproportionate share. At the same time, many households often lack the knowledge, time, or motivation to deal with their own energy-relevant and climate-impacting behaviours. In this context, energy advice services play an important role for raising awareness, activating consumers and imparting knowledge about available options for action. However, conventional energy advice services are mostly limited to the topics of building and appliance energy efficiency - especially for middle- and high-income households - without considering private consumption behaviour and the related social practices as a whole. In practice, there has been little differentiation to date in addressing target groups in a way that takes into account different lifestyles and realities and the underlying values and motivations in a pluralistic society. The present paper presents a methodological approach to develop targeted energy advice approaches in urban environments that are oriented towards the motivations of different types of households with medium and high incomes. It proposes a three-step approach consisting of 1) a microdata-based population analysis to identify and categorize target subgroups, 2) an inventory of existing advice offers with regard to their coverage and approach and 3) a gap analysis based on the results of the preceding steps. Applied to a large city in Germany, the analysis finds that gaps are rarely found with regard to communicated facts but rather the way in which information is conveyed. Accordingly, recommendations relate to more effectively use windows of opportunity and framing of measures to match target group motivations.

Description: The Paris Agreement combines collective goals with individual countries' contributions. This hybrid approach does not guarantee that the individual contributions add up to what is required to meet the collective goals. The Paris Agreement therefore established the Global Stocktake. Its task is to "assess collective progress" towards achieving the long-term goals of the agreement as of 2023 and every five years thereafter. Corresponding to this role, this report addresses three questions: What should an effective Global Stocktake look like? What information and data are needed? Is it possible to execute an effective Global Stocktake within the mandate of the Paris Agreement?

Description: On the pathway to climate neutrality, EU member states are obliged to submit national energy and climate plans (NECPs) with planned policies and measures for decarbonization until 2030 and long-term strategies (LTSs) for further decarbonization until 2050. We analysed the 27 NECPs and 15 LTSs submitted by October 2020 using an interrater method. This paper focuses on energy sufficiency policies and measures in the transport sector. We found a total of 236 sufficiency policy measures with more than half of them (53 %) in the transport/mobility sector. Additionally, we found 41 measures that address two or more sectors (cross-sectoral measures). From the explicit sufficiency measures within the transport sector, 82 % aim at modal shift. A reduction of transport volumes is much less addressed. Countries plan to use mainly fiscal and economic instruments. Those are in many cases investments in infrastructure of low-carbon transport modes and taxation instruments. Plans on decarbonisation measures are also frequently mentioned. The majority of cross-sectoral measures are carbon taxes or tax reforms, also economic instruments. On the one hand it is encouraging that Member States strongly emphasize the transport sector in their NECPs and LTSs - at least quantitatively and concerning sufficiency measures - because this sector has been the worst-performing in climate mitigation so far. On the other hand, the measures described seem not sufficient to reach ambitious climate targets, and we doubt that the presented set of policy instruments will get the transport sector on track to mitigate greenhouse gas emissions in the necessary extent.

Description: A clear understanding of socio-technical interdependencies and a structured vision are prerequisites for fostering and steering a transition to a fully renewables-based energy system. To facilitate such understanding, a phase model for the renewable energy transition in MENA countries has been developed and applied to the country case of Algeria. It is designed to support the strategy development and governance of the energy transition and to serve as a guide for decision makers. The analysis shows that Algeria has already taken first steps towards a renewable energy transition. According to the MENA phase model, Algeria can be classified as entering the "Take-Off Renewables" phase. Nevertheless, fossil fuels still play a dominant role in the Algerian energy sector and in the economy as a whole. To support the renewables take-off, strong support is therefore needed at all levels. Only then can the necessary framework conditions be created to encourage participation and to attract investment from the private sector. To this end, a long-term energy strategy should to be developed that takes into account the renewable energy potential to support an efficient transformation of the Algerian energy supply and enables a smooth transition.

Description: The unprecedented challenge of reaching carbon neutrality before mid-century and a large share of it within 2030 in order to keep under the 1.5 or 2 °C carbon budgets, requires broad and deep changes in production and consumption patterns which, together with a shift to renewables and reinforced efficiency, need to be addressed through energy sufficiency. However, inadequate representations and obstacles to characterising and identifying sufficiency potentials often lead to an underrepresentation of sufficiency in models, scenarios and policies. One way to tackle this issue is to work on the development of sufficiency assumptions at a concrete level where various implications such as social consequences, environmental co-benefits, conditions for implementation can be discussed. This approach has been developed as the backbone of a collaborative project, gathering partners in 20 European countries at present, aiming for the integration of harmonised national scenarios into an ambitious net-zero European vision. The approach combines a qualitative discussion on the role of energy sufficiency in a "systemic" merit order for global sustainability, and a quantitative discussion of the level of sufficiency to be set to contribute to meeting 100 % renewables supply and net-zero emissions goals by 2050 at the latest. The latter is based on the use of a dashboard, which serves as a common descriptive framework for all national scenario trajectories and their comparison, with a view to harmonising and strengthening them through an iterative process. A set of key sufficiency-related indicators have been selected to be included in the dashboard, while various interrelated infrastructural, economic, environmental, social or legal factors or drivers have been identified and mapped. This paves the way for strengthening assumptions through the elaboration of "sufficiency corridors" defining a convergent, acceptable and sustainable level of energy services in Europe. The process will eventually inform the potential for sufficiency policies through a better identification of leverages, impacts and co-benefits.

Description: The basic materials industries are a cornerstone of Europe's economic prosperity, increasing gross value added and providing around 2 million high-quality jobs. But they are also a major source of greenhouse gas emissions. Despite efficiency improvements, emissions from these industries were mostly constant for several years prior to the Covid-19 crisis and today account for 20 per cent of the EU's total greenhouse gas emissions. A central question is therefore: How can the basic material industries in the EU become climate-neutral by 2050 while maintaining a strong position in a highly competitive global market? And how can these industries help the EU reach the higher 2030 climate target - a reduction of greenhouse gas emissions of at least 55 per cent relative to 1990 levels? In the EU policy debate on the European Green Deal, many suppose that the basic materials industries can do little to achieve deep cuts in emissions by 2030. Beyond improvements to the efficiency of existing technologies, they assume that no further innovations will be feasible within that period. This study takes a different view. It shows that a more ambitious approach involving the early implementation of key low-carbon technologies and a Clean Industry Package is not just possible, but in fact necessary to safeguard global competitiveness.

Description: The aim of this study is to contribute to a learning process about innovative and successful approaches to overcoming problems and challenges of urban environmental protection. To this end, a detailed overview of the importance of environmental challenges, political priorities and successful solutions in selected countries and cities is given. Based on this, the study analyzes specific success factors and discusses the extent to which these can be transferred and replicated to other cities. Finally, recommendations are made for cities, countries and the international community on how environmental protection at the urban level can be further strengthened. The role of German cities and institutions will also be discussed. The case studies analyzed include Belo Horizonte in Brazil, Moscow in Russia, Kochi in India, Beijing in China, Cape Town in South Africa and Jakarta in Indonesia. These cities were selected because they have already implemented successful policies, measures and other initiatives in the past. For each city, the study analyzes relevant policy documents in order to present the respective challenges and political priorities. The analysis aims to understand the effectiveness of the plans and instruments taking into account the national political environment. Despite the cross-sectoral approach, the analysis of each case study focuses on specific sectors in order to produce well-founded results. The success factors that are worked out based on this sectoral analysis are placed in a holistic context in order to be able to make generalizable statements about success factors.

Description: Especially in the arid areas of the Middle East and North Africa (MENA), water availability plays an important role in the expansion planning of industrial-scale solar power plants. Although power plants may account for only a very small portion of local water demand, competition for water with other sectors is expected to increase when water resources are insufficient for meeting local needs. This can lead to conflicts between different users (such as communities, farmers, tourism, businesses and utilities). Despite the increasing attention on the water-energy nexus, comprehensive studies analysing the interdependencies and potential conflicts between energy and water at the local level are absent. To examine the linkages between water resources and energy technologies at the local level, this case study was selected because Morocco is one of the countries most affected by water scarcity and, at the same time, it is also one of the most promising countries in North Africa for the development of renewable energies and offers excellent conditions for solar and wind power plants. Nevertheless, the country's electricity system is still largely based on conventional energy sources, and the country is more than 95% dependent on energy imports. To strengthen the country's energy security and reduce the financial burden associated with energy imports, Morocco is pursuing an ambitious renewable energy expansion strategy: by 2020, around 42% of the national electricity demand should be met by renewable energies. In view of Morocco's ambitious plans, it is particularly important to identify the potential conflicts and synergies resulting from the expansion of renewable energies in relation to the water sector.

Description: The energy sector today accounts for about 10% to 15% of global freshwater withdrawal. Most water in the energy sector is used for generating electricity, especially for cooling processes in thermal power plants. At the same time the demand for electricity is expected to increase significantly due to population growth and economic development in emerging and developing economies. Growing demand is also driven by electrification strategies pursued by industrialized countries to decarbonize their economies. With the global demand for electricity expected to increase significantly in the coming decades also the water demand in the power sector is expected to rise. However, due to the on-going global energy transition, the future structure of the power supply - and hence future water demand for power generation - is subject to high levels of uncertainty because the volume of water required for electricity generation varies significantly depending on both the generation technology and cooling system. In light of these challenges the objective of this analysis is to provide more systematic and robust answers in terms of the impacts of different decarbonization strategies in the electricity sector on water demand at global and regional level. The focus is on operational water use for electricity generation.

Description: This report was prepared by the Wuppertal Institute in cooperation with the German Economic Institute as part of the SCI4climate.NRW project. The report aims to shed light on the possible phenomenon that the availability and costs of "green" energy sources may become a relevant location factor for basic materials produced in a climate-neutral manner in the future. For this purpose, we introduce the term "Renewables Pull". We define Renewables Pull as the initially hypothetical phenomenon of a shift of industrial production from one region to another as a result of different marginal costs of renewable energies (or of secondary energy sources or feedstocks based on renewable energies). Shifts in industrial production in the sense of Renewables Pull can in principle be caused by differences in the stringency of climate policies in different countries, as in the case of Carbon Leakage. Unlike Carbon Leakage, however, Renewables Pull can also occur if similarly ambitious climate policies are implemented in different countries. This is because Renewables Pull is primarily determined by differences in the costs and availability of renewable energies. In addition, Renewables Pull can also be triggered by cost reductions of renewable energies and by changing preferences on the demand side towards climate-friendly products. Another important difference to Carbon Leakage is that the Renewables Pull effect does not necessarily counteract climate policy. Similar to Carbon Leakage, it is to be expected that Renewables Pull could become relevant primarily for very energy-intensive products in basic materials industries. In these sectors (e.g. in the steel or chemical industry), there is also the possibility that relocations of specific energy-intensive parts of the production process could trigger domino effects. As a result, large parts of the value chains previously existing in a country or region could also be subjected to an (indirect) Renewables Pull effect. For the federal state of NRW, in which the basic materials industry plays an important role, the possible emergence of Renewables Pull is associated with significant challenges as climate policy in Germany, the EU and also worldwide is expected to become more ambitious in the future. This report aims to enable and initiate a deeper analysis of the potential future developments and challenges associated with the Renewables Pull effect. Thus, in the final chapter of the report, several research questions are formulated that can be answered in the further course of the SCI4climate.NRW project as well as in other research projects.

Description: Two thirds of today's world trade is based on global value chains and supply networks. Purely regional supply chains have become less important in recent decades. The effects of these globalised structures are manifold. On the one hand, they promote employment and generate prosperity. On the other hand, they are beset by extreme social, ecological and economic imbalances. The COVID-19 pandemic has demonstrated the fragility of existing supply chain systems. The lockdown continues to disrupt complex supply chains and many problems of existing production and consumption continue to worsen. COVID-19 is one example of the crises that can shake globally networked supply chains in the short term. Other crises, such as climate change, develop more insidiously and are less immediately recognisable. Different as they are, such crises have one thing in common: they highlight the vulnerability of global social and economic structures and illustrate the impact of global trade on the regions and people of the world. This is precisely where global sustainability strategy comes in - it aims to fundamentally reduce differences and inequalities in opportunities and quality of life. The COVID-19 pandemic has forced the entire world into upheaval, creating an opportunity to make sustainability a central political resilience strategy. In the wake of the Corona pandemic, the discussion about resilient communities has flared up. In order to guarantee supply in the face of such crises, these should be more strongly regional and circular in their economic approach and global and sustainable in their perspective. The aim should be sustainable, transparent, non-exploitative supply chains that guarantee the security of supply to cover basic needs and public services despite sudden changes and crises. This discussion paper draws a future scenario of globally cooperative, circular regional economies that fundamentally reduce global inequalities in opportunities and quality of life, while at the same time permanently preserving the natural foundations of life.

Description: An important instrument to enhance the market uptake of energy-efficient new buildings and the energy-efficient renovation of existing buildings in the European Union (EU) are the Energy Performance Certificates (EPC). However, their implementation and use has varied between EU Member States. The European Commission has therefore provided funding to a number of Horizon2020 projects to develop next-generation EPC schemes. One of these is the QualDeEPC project, aiming to both improve quality and cross-EU convergence of EPC schemes, and particularly the link between EPCs and deep renovation. The objective of the project is to improve the practical implementation of the assessment, issuance, design, and use of EPCs as well as their renovation recommendations, in the participating countries and beyond. This paper presents the policy proposals and concepts for tools that the QualDeEPC project has developed as priorities for enhanced EPC schemes: - Improving the recommendations for renovation, which are provided on the EPCs, towards deep energy renovation - An online tool for comparing EPC recommendations to deep energy renovation recommendations - Creating Deep Renovation Network Platforms (One-stop Shops plus networking and joint communication of supply-side actors) - Regular mandatory EPC assessor training (on assessment and renovation recommendations) required for certification/accreditation and registry - Achieving a high user-friendliness of the EPC - Voluntary/mandatory advertising guidelines for EPCs - Improving compliance with the mandatory use of EPCs in real estate advertisements The paper will focus on the aspects related to improving the impact of EPCs for stimulating deep renovation. It will also present lessons learnt from the discussion with stakeholders at national and European workshops and from the testing of the proposals and tools in around 100 buildings, as well as from the first steps of their country-specific adaptation.

Description: The ambition to reach climate-neutral energy systems requires profound energy transitions. Various scenario studies exist which present different options to reach that goal. In this paper, key strategies for the transition to climate neutrality in Germany are identified through a meta-analysis of published studies, including scenarios which achieve at least a 95 % greenhouse gas emissions reduction by 2050 compared to 1990. It has been found that a reduction in energy demand, an expansion of domestic wind and solar energy, increased use of biomass as well as the importation of synthetic energy carriers are key strategies in the scenarios, with nuclear energy playing no role, and carbon capture and storage playing a very limited role. Demand-side solutions that reduce the energy demand have a very high potential to diminish the significant challenges of other strategies, which are all facing certain limitations regarding their sustainable potential. The level and and type of demand reductions differ significantly within the scenarios, especially regarding the options of reducing energy service demand.

Description: Staying within the 2 °C (preferably 1.5 °C) limit requires fast and fundamental system changes, also in urban passenger transport. Shifting car traffic to environmentally friendly transport modes is one central strategy to make urban transport more sustainable and climate friendly. However, in most cities car use remains high. Therefore, this paper analyzes what course change is needed regarding direction, scale and speed of change for urban sustainability and climate protection reasons. The paper analyzes the role of modal shift as a strategy in itself and in relation to land-use (avoid) and efficiency (improve) measures. The paper draws on insights from European frontrunning cities and explorative forecasting scenarios calculated with the sophisticated integrated land-use transport model "Ruhr Region 2050". The paper suggests that a significant reduction of urban car use is needed (direction) that roughly equals a fast halving of car use (scale), which has proven feasible under the current socio-political conditions by annual reduction rates of 0.5 to 1.5 percentage points of the trip-based modal share of car use (speed). Significantly reducing car use requires comprehensive and high-intensive measures that go far beyond usual practices. Modal shift measures need to play a crucial role in integrated approaches with land-use (avoid) and efficiency (improve) measures because they have the potential to significantly reduce car use and CO2 emissions and because they can produce comparatively fast effects - which makes modal shift measures first aid approaches to achieve a fast "bending of the curve" of excessive car use and growing CO2 emissions.

Description: A clear understanding of socio-technical interdependencies and a structured vision are prerequisites for fostering and steering a transition to a fully renewables-based energy system. To facilitate such understanding, a phase model for the renewable energy (RE) transition in the Middle East and North Africa (MENA) countries has been developed and applied to the country case of Tunisia. It is designed to support the strategy development and governance of the energy transition and to serve as a guide for decision makers. The analysis shows that Tunisia has already taken important steps towards a RE transition. According to the MENA phase model, Tunisia can be classified as being in the "Take-Off Renewables" phase. Nevertheless, natural gas still plays the dominant role in Tunisia's highly subsidised electricity generation. In addition to the elevated political uncertainty, there are numerous structural, political, social, and economic challenges within the energy sector that hinder progress in the transition to REs. Strong support at all levels is needed to promote the breakthrough of RE. This includes more detailed long-term planning and improving the regulatory framework, as well as reducing offtaker risks to improve the bankability of RE projects in order to attract private investment. Furthermore, institutional buy-in needs to be increased and the engagement of key non-state stakeholders must be strengthened. In light of the growing domestic energy demand and with the on-going global decarbonisation efforts in favour of sustainable fuels, Tunisia would be well advised to embark on a sustainable energy path sooner rather than later to seize economic opportunities that can arise from RE development.

Description: Urban development faces numerous challenges in the 21st century and a central task is the sustainable and liveable design of the city. Can the concept of a Smart City be a tool to making cities more liveable and sustainable? To find out, we chose a biographical method to analyse the steps towards a successful Smart City and to better understand the structures behind it. We combine the innovation biography method with a process model from sustainability governance research, namely Steurer's sustainability governance model and apply them to Vienna's Smart City, especially the preparation of the Vienna Smart City framework strategy (Steurer & Trattnigg, 2010). On the one hand, this article shows that a transfer of the innovation biography method to urban research can generate deeper insights on urban development processes in general. On the other hand, the approach chosen can show that Vienna integrates the sustainable urban design into the process of Smart City design. So the smart and sustainable city design, often called for in theoretical contributions, is practised in Vienna. Due to its reconstructive character, the biographical method has revealed that it is possible to govern sustainability by using Smart City as an umbrella strategy, as long as one manages it in an integrated and holistic way, recognises trends and is able to acquire and use research funds effectively and efficiently. The knowledge gained from the new method for urban and Smart City research is twofold. Firstly, the transfer of the method previously developed in the human sciences and subsequently for organisations, institutions and products and services also works in urban research. Second, the innovation biography provides in-depth insights into the process towards the Smart City and the stakeholders involved. The use of the biographical method highlights the relevance of good governance in terms of interdisciplinary cooperation on the one hand and high political commitment on the other through the micro-level perspective and is also sensitive enough to highlight the importance of an appropriate narrative in and for the process towards the Smart City.

Description: With increasing world population and an unsettling resource scarcity in the back, sustainble consumption has moved to the foreground of political, economical and social discussions. One major school-of-thought is Circular Economy (CE), an approach summarizing various sustainable consumption activites under one roof. However, quantitative studies on the consumer are rare, yet crucial for a transfer from linear to circular consumption. This dissertation adds to literature by providing pioneer insights into consumer behavior in CE as an overarching concept, instead limiting research on singular subconcepts. Namely, four consumer activities are studied: recycling, upcycling, renting and sharing. In order to identify relevant insights for both academics and practitioners in CE, the research question ("what drives participation in CE?") is broken down into sub-hypotheses, which are addressed by three empirical studies. Using the SOR-Model (adaption Belk 1975) as overarching logic, the three studies deal with (1) the consumer (and their motivation) and situational stimuli (both (2) offline and (3) online). Respectively, three data sets are consulted to assess the sub-hypotheses and to identify overarching insights on how to accelerate consumer participation in CE, The research methodology employed ranges from a structured equation model (SEM), a random allocation field experiment during Fashion Week in Berlin to a discrete-choice model with best-worst scaling. The dissertation succeeds in revealing that (1) different activities in CE can be summarized in one latent variable, proving CE as a wholesome concept in consumer-related activities; that (2) Trust has a leveraging effect on participation in CE activities. Further, Trust can be enhanced offline via face-to-face interaction and online via third-party online attributes.; and that (3) experience in CE activities affects perception of online attributes, implying the need for adapted measures when dealing with CE-unexperienced consumers as compared to consumers with prior experience in CE activities.

Description: 2020 was meant to be the year of climate ambition. Then the COVID-19 pandemic struck, the Glasgow conference was postponed to November 2021, and climate policy generally appeared to have been put on the backburner. But towards the end of the year prospects seemed to brighten with a series of zero-emission pledges and the election of Joe Biden as US President. This article analyses what the year of the pandemic achieved in terms of combating climate change. This article first summarizes the virtual events that were organised to substitute for the physical UNFCCC conferences and what progress was or was not made on the outstanding items of the "Paris rulebook", implementation of the Gender Action Plan, and other items. Subsequently, the article surveys the status of NDC updates and to what extent recovery programmes have been used to advance climate action. Finally, the article takes a closer look at the current dynamics among non-Party actors. In summary, while formal negotiations essentially stopped in the year of the pandemic, the conservation did not. However, implementation is still lagging far behind the ambitious targets that have been set. While implementation is mostly the domain of national policy, the international process has a number of options at its disposal to foster climate action.

Description: Deep hydrothermal Mo, W and base metal mineralization found in the Detroit City portal of the Sweet Home mine in the Alma district (Colorado Mineral Belt) was deposited in response to magmatic activity and the formation of Climax-type Mo deposits during the Oligocene. This study presents extensive geochemical analyses of fluid inclusions inminerals from early greisen-like vein mineralization to better understand the fluid system responsible for ore formation. Quartz and fluorite, which are associated with molybdenite, huebnerite and/or pyrite mineralization, precipitated from low- to medium-salinity (1.5-11.5 wt.% equiv. NaCl), CO2-bearing fluids at temperatures between 360 and 415°C and probably under a fluctuating pressure regime at depths of at least 3.5 km. The formation of greisen-like and base metal mineralization at the Detroit City portal of the Sweet Home mine is related to fluids of different origin. Early magmatic fluids were the principal source for mantle-derived volatiles (CO2, H2S/SO2, noble gases) and mixed with significant amounts of heated meteoric water. Fluid mixing of magmatic fluids with meteoric water is constrained by δ 2H-δ 18O relationships of fluid inclusion water in different minerals (Fig. 1). Whether molybdenum was derived from magmatic fluids remains unclear. Fluid inclusions in huebnerite suggest that W originated from source rocks that are enriched in organic matter rather than from magmatic fluids. The deep hydrothermal mineralization at the Detroit City portal of the Sweet Home mine shows features similar to deep hydrothermal vein mineralization found in Climax-type Mo deposits and their periphery, suggesting that fluid migration and the deposition of ore and gangue minerals in the Sweet Home mine was triggered by a deep-seated magmatic intrusion. The findings of this study are in good agreement with the results of previous fluid inclusion studies of the mineralization of the Sweet Home mine (Lüders et al., 2009) and from Climaxtype Mo porphyry deposits in the Colorado Mineral Belt (Hall et al., 1974).

Description: By means of 4 years of Challenging Minisatellite Payload (CHAMP) zonal wind observations and a Thermosphere-Ionosphere Electrodynamics General Circulation Model simulation, longitudinal and seasonal variations of thermospheric superrotation at magnetic equator are investigated first. The superrotation shows four- and three-peaked longitudinal patterns in March and September equinoxes, and a two-peaked variation during solstices. The superrotation is stronger in December than in June solstice, and stronger in March than in September equinox. The mean correlation between the zonal variation of superrotation and nighttime eastward wind is about 0.8, while it is 0.6 with daytime westward zonal wind. The interaction between the neutral wind and geomagnetic field plays a more important role in the superrotation, rather than the F-region electron density. The lower atmospheric tides tend to suppress the superrotation, but contribute to the longitudinal patterns of the superrotation. The viscous force is also important for the longitudinal modulation of the superrotation.

Description: We report the concurrent observations of F-region plasma changes and field-aligned currents (FACs) above isolated proton auroras (IPAs) associated with electromagnetic ion cyclotron Pc1 waves. Key events on March 19, 2020 and September 12, 2018 show that ground magnetometers and all-sky imagers detected concurrent Pc1 wave and IPA, during which NOAA POES observed precipitating energetic protons. In the ionospheric F-layer above the IPA zone, the Swarm satellites observed transverse Pc1 waves, which span wider latitudes than IPA. Around IPA, Swarm also detected the bipolar FAC and localized plasma density enhancement, which is occasionally surrounded by wide/shallow depletion. This indicates that wave-induced proton precipitation contributes to the energy transfer from the magnetosphere to the ionosphere.

Description: Tropical forests store 40–50 per cent of terrestrial vegetation carbon1. However, spatial variations in aboveground live tree biomass carbon (AGC) stocks remain poorly understood, in particular in tropical montane forests2. Owing to climatic and soil changes with increasing elevation3, AGC stocks are lower in tropical montane forests compared with lowland forests2. Here we assemble and analyse a dataset of structurally intact old-growth forests (AfriMont) spanning 44 montane sites in 12 African countries. We find that montane sites in the AfriMont plot network have a mean AGC stock of 149.4 megagrams of carbon per hectare (95% confidence interval 137.1–164.2), which is comparable to lowland forests in the African Tropical Rainforest Observation Network4 and about 70 per cent and 32 per cent higher than averages from plot networks in montane2,5,6 and lowland7 forests in the Neotropics, respectively. Notably, our results are two-thirds higher than the Intergovernmental Panel on Climate Change default values for these forests in Africa8. We find that the low stem density and high abundance of large trees of African lowland forests4 is mirrored in the montane forests sampled. This carbon store is endangered: we estimate that 0.8 million hectares of old-growth African montane forest have been lost since 2000. We provide country-specific montane forest AGC stock estimates modelled from our plot network to help to guide forest conservation and reforestation interventions. Our findings highlight the need for conserving these biodiverse9,10 and carbon-rich ecosystems.

Description: In this study, the effect of disturbance dynamo electric field (DDEF) induced by subauroral polarization streams (SAPS) on the variations of the equatorial electrojet (EEJ) and its counter electrojet (CEJ) during the geomagnetic storm on June 1, 2013 is analyzed in detail for the first time. Observations from ground-based magnetometers showed that the SAPS-induced EEJ flows westward and eastward in the daytime and dawn/dusk sectors, respectively. The effects of SAPS on EEJ are mainly associated with the changes of zonal ionospheric electric field, while the changes in the ionospheric conductivity play a secondary role. By using Thermosphere Ionosphere Electrodynamic General Circulation Model simulations, the zonal electric field induced by SAPS associated with the DDEF is examined. The results of the simulations show that the DDEF has a significant impact on the EEJ variability. The daytime westward EEJ at the dip equator is mainly driven by disturbance zonal wind, with secondary contributions from disturbance meridional wind. A similar mechanism can be observed in the dawn/dusk sector when the eastward EEJ is produced; however, it has a much weaker intensity than that during the daytime.

Description: CO2 release from particulate organic carbon (POC) oxidation during fluvial transit can influence climate over a range of timescales. Identifying the mechanistic controls on such carbon fluxes requires determining where POC oxidation occurs in river systems. While field data show POC oxidation and replacement moving downstream in lowland rivers, flume studies show that oxidation during active fluvial transport is limited. This suggests that most fluvial POC oxidation occurs during transient floodplain storage, but this idea has yet to be tested. Here, we isolate the influence of floodplain storage time on POC oxidation by exploiting a chronosequence of floodplain deposits above the modern groundwater table in the Rio Bermejo, Argentina. Measurements from 15 floodplain cores with depositional ages from 1 y to 20 ky show a progressive POC concentration decrease and 13C-enrichment with increasing time spent in floodplain storage. These results from the Rio Bermejo indicate that over 80% of fluvially-deposited POC can be oxidized over millennial timescales in aerated floodplains. Furthermore, POC in the oldest floodplain cores is more 14C-enriched than expected based on the independently-dated floodplain ages, indicating that a portion of this oxidized POC is replaced by autochthonous POC produced primarily by floodplain vegetation. We suggest floodplain storage timescales control the extent of oxidation of fluvially-deposited POC, and may play a prominent role in determining if rivers are significant atmospheric CO2 sources.

Description: Geochemical processes such as mineral dissolution and precipitation alter the microstructure of rocks, and thereby affect their hydraulic and mechanical behaviour. Quantifying these property changes and considering them in reservoir simulations is essential for a sustainable utilisation of the geological subsurface. Due to the lack of alternatives, analytical methods and empirical relations are currently applied to estimate evolving hydraulic and mechanical rock properties associated with chemical reactions. However, the predictive capabilities of analytical approaches remain limited, since they assume idealised microstructures, and thus are not able to reflect property evolution for dynamic processes. Hence, aim of the present thesis is to improve the prediction of permeability and stiffness changes resulting from pore space alterations of reservoir sandstones. A detailed representation of rock microstructure, including the morphology and connectivity of pores, is essential to accurately determine physical rock properties. For that purpose, three-dimensional pore-scale models of typical reservoir sandstones, obtained from highly resolved micro-computed tomography (micro-CT), are used to numerically calculate permeability and stiffness. In order to adequately depict characteristic distributions of secondary minerals, the virtual samples are systematically altered and resulting trends among the geometric, hydraulic, and mechanical rock properties are quantified. It is demonstrated that the geochemical reaction regime controls the location of mineral precipitation within the pore space, and thereby crucially affects the permeability evolution. This emphasises the requirement of determining distinctive porosity-permeability relationships by means of digital pore-scale models. By contrast, a substantial impact of spatial alterations patterns on the stiffness evolution of reservoir sandstones are only observed in case of certain microstructures, such as highly porous granular rocks or sandstones comprising framework-supporting cementations. In order to construct synthetic granular samples a process-based approach is proposed including grain deposition and diagenetic cementation. It is demonstrated that the generated samples reliably represent the microstructural complexity of natural sandstones. Thereby, general limitations of imaging techniques can be overcome and various realisations of granular rocks can be flexibly produced. These can be further altered by virtual experiments, offering a fast and cost-effective way to examine the impact of precipitation, dissolution or fracturing on various petrophysical correlations. The presented research work provides methodological principles to quantify trends in permeability and stiffness resulting from geochemical processes. The calculated physical property relations are directly linked to pore-scale alterations, and thus have a higher accuracy than commonly applied analytical approaches. This will considerably improve the predictive capabilities of reservoir models, and is further relevant to assess and reduce potential risks, such as productivity or injectivity losses as well as reservoir compaction or fault reactivation. Hence, the proposed method is of paramount importance for a wide range of natural and engineered subsurface applications, including geothermal energy systems, hydrocarbon reservoirs, CO2 and energy storage as well as hydrothermal deposit exploration

Description: Geochemische Lösungs- und Fällungsprozesse verändern die Struktur des Porenraums und können dadurch die hydraulischen und mechanischen Gesteinseigenschaften erheblich beeinflussen. Die Quantifizierung dieser Parameteränderung und ihre Berücksichtigung in Reservoirmodellen ist entscheidend für eine nachhaltige Nutzung des geologischen Untergrunds. Aufgrund fehlender Alternativen werden dafür bisher analytische Methoden genutzt. Da diese Ansätze eine idealisierte Mikrostruktur annehmen, können insbesondere Änderungen der Gesteinseigenschaften infolge von dynamischen Prozessen nicht zuverlässig abgebildet werden. Ziel der vorliegenden Doktorarbeit ist es deshalb, die Entwicklung von Gesteinspermeabilitäten und -steifigkeiten aufgrund von Porenraumveränderungen genauer vorherzusagen. Für die möglichst exakte Bestimmung physikalischer Gesteinsparameter ist eine detaillierte Darstellung der Mikrostruktur notwendig. Basierend auf mikro-computertomographischen Scans werden daher hochaufgelöste, dreidimensionale Modelle typischer Reservoirsandsteine erstellt und Gesteinspermeabilität und -steifigkeit numerisch berechnet. Um charakteristische Verteilungen von Sekundärmineralen abzubilden, wird der Porenraum dieser virtuellen Sandsteinproben systematisch verändert und die resultierenden Auswirkungen auf die granulometrischen, hydraulischen und elastischen Gesteinseigenschaften bestimmt. Die Ergebnisse zeigen deutlich, dass charakteristische Fällungsmuster unterschiedlicher geochemischer Reaktionsregime die Permeabilität erheblich beeinflussen. Folglich ist die Nutzung von porenskaligen Modellen zur Bestimmung der Porosität-Permeabilitätsbeziehungen unbedingt notwendig. Im Gegensatz dazu ist die Verteilung von Sekundärmineralen für die Gesteinssteifigkeit nur bei bestimmten Mikrostrukturen von Bedeutung, hierzu zählen hochporöse Sandsteine oder solche mit Korngerüst-stützenden Zementierungen. In der Arbeit wird außerdem ein Ansatz zur Konstruktion granularer Gesteine vorgestellt, welcher sowohl die Kornsedimentation als auch die diagenetische Verfestigung umfasst. Es wird gezeigt, dass die synthetischen Proben die mikrostrukturelle Komplexität natürlicher Reservoirsandsteine gut abbilden. Dadurch können generelle Limitationen von bildgebenden Verfahren überwunden und unterschiedlichste virtuelle Repräsentationen von granularen Gesteinen generiert werden. Die synthetischen Proben können zukünftig in virtuellen Experimenten verwendet werden, um die Auswirkungen von Lösungs- und Fällungsreaktionen auf verschiedene petrophysikalische Korrelationen zu untersuchen. Die vorgestellte Arbeit liefert methodische Grundlagen zur Quantifizierung von Permeabilitäts- und Steifigkeitsänderungen infolge geochemischer Prozesse. Die berechneten petrophysikalischen Beziehungen basieren direkt auf mikrostrukturellen Veränderungen des Porenraums. Daher bieten sie eine genauere Vorhersage der Gesteinseigenschaften als herkömmliche analytische Methoden, wodurch sich die Aussagekraft von Reservoirmodellen erheblich verbessert. Somit können Risiken, wie Produktivitäts- oder Injektivitätsverluste sowie Reservoirkompaktion oder Störungsreaktivierung, verringert werden. Die präsentierten Ergebnisse sind daher relevant für verschiedenste Bereiche der geologischen Untergrundnutzung wie CO2- oder Energiespeicherung, Geothermie, Kohlenwasserstoffgewinnung sowie die Erkundung hydrothermaler Lagerstätten.

Description: Monitoring and controlling of mineral precipitation is a major challenge in several industry segments such as oil and gas or geothermal energy. Especially at elevated pressures, temperatures, and salinities, these reactions are poorly understood and difficult to predict. Real-time monitoring under such conditions, however, is crucial for reduction or prevention of scaling as well as for process modelling. In this study, a novel fibre-optical method for monitoring the barite precipitation process at high pressures and high temperatures was developed and tested. The applicability of a fibre-optical sensor was demonstrated and kinetic data derived from experiments using synthetic fluids that were oversaturated with barite. The ionic strength was varied between 0 and 5 mol/l NaCl to simulate geothermal brines typically found in deep sedimentary reservoirs. Experiments were performed at 25 and 150 °C. For the studied variations it was found that the ionic strength had a strong impact on the barite precipitation rate whereas temperature had only a minor influence. The kinetic rate constants were decreasing with increasing salinity ranging from 9 to 0.4 l‧mol−1‧s−1 at 25 °C and from 8.6 to 0.66 l‧mol−1‧s−1 at 150 °C.

Description: Earth’s lowermost mantle displays complex geological phenomena that likely result from its heterogeneous physical interaction with the core. Geophysical models of core-mantle interaction rely on the thermal and electrical conductivities of appropriate geomaterials which, however, have never been probed at representative pressure and temperature (P-T) conditions. Here we report on the opacity of single crystalline bridgmanite and ferropericlase and link it to their radiative and electrical conductivities. Our results show that light absorption in the visible spectral range is enhanced upon heating in both minerals but the rate of change in opacity with temperature is a factor of six higher in ferropericlase. As a result, bridgmanite in the lowermost mantle is moderately transparent while ferropericlase is highly opaque. Our measurements support previous indirect estimates of low (〈 1 W/m/K) and largely temperature-independent radiative conductivity in the lowermost mantle. This implies that the radiative mechanism has not contributed significantly to cooling the Earth’s core throughout the geologic time. Opaque ferropericlase is electrically conducting and mediates strong core-mantle electromagnetic coupling, explaining the intradecadal oscillations in the length of day, low secular geomagnetic variations in Central Pacific, and the preferred paths of geomagnetic pole reversals.

Description: The SWATH‐D experiment involved the deployment of a dense temporary broadband seismic network in the Eastern Alps. Its primary purpose was enhanced seismic imaging of the crust and crust–mantle transition, as well as improved constraints on local event locations and focal mechanisms in a complex part of the Alpine orogen. The study region is a key area of the Alps, where European crust in the north is juxtaposed and partially interwoven with Adriatic crust in the south, and a significant jump in the Moho depth was observed by the 2002 TRANSALP north–south profile. Here, a flip in subduction polarity has been suggested to occur. This dense network encompasses 163 stations and complements the larger‐scale sparser AlpArray seismic network. The nominal station spacing in SWATH‐D is 15 km in a high alpine, yet densely populated and industrialized region. We present here the challenges resulting from operating a large broadband network under these conditions and summarize how we addressed them, including the way we planned, deployed, maintained, and operated the stations in the field. Finally, we present some recommendations based on our experiences.

Description: The project DARE proposes an integrated study of seismic site effects on the deep and elongated Messinian Rhône Canyon (French Rhône Valley). Lithological information from boreholes reaching the bedrock and preliminary geophysical campaigns indicate that the canyon can reach locally 〉500 m and may be deeply incised. The strong material contrast between the sedimentary filling and the substratum, as well as its expected confined geometry make this canyon a good candidate for generating various kinds of multi-dimensional site effects. Waveform data are available from the GEOFON data centre, under network code Y7.

Description: The temporary seismic array of MySCOLAR in northern Myanmar consists of 30 broadband stations. The overall scientific goals are to understand the transition from continental collision to oceanic subduction, to quantify the partitioning of deformation in the accretionary prism, in the Burma Plate and along the strike-slip Sagaing fault system and to image the subducting Indian Plate beneath Myanmar and southwest China. The seismological analysis methods applied to this dataset will include location of local earthquakes and determining their focal mechanisms, surface wave tomography from ambient noise and earthquake data, body wave tomography from local and teleseismic earthquakes, full waveform inversion for Earth structure, receiver functions, and shear wave splitting. A subset of the stations was transmitting data in real time, and these stations contributed to real-time earthquake analysis by the Department of Meteorology and Hydrology (DMH) in Myanmar and the GEOFON earthquake monitoring service. Waveform data are available from the GEOFON data centre, under network code 6C.

Description: The Villarrica Volcano is one of the most active volcanoes in South America and is located in a major tourism region. A dense seismological network is used to investigate the seismic characteristics of the volcano and its seismic structure tomographically with high spatial resolution. The network was in operation for 2 week from 01.03.2012 to 14.03.2012. It consisted of 30 3-component and 45 1-component short period seismographs covering an area of 2000 km*2. The covered area has a diameter of 45 km and includes the volcanic building.

Description: The main aim of this project is to investigate the crustal and mantle structure beneath the Longmenshan fault zone in China, based on a very dense passive seismology profile. The Longmenshan fault zone hosted the Wenchuan earthquake of May 2008 with a magnitude (Mw) of 7.9 and the Lushan earthquake of June 2013 with a magnitude (Mw) of 6.6. It is planned to mainly use the receiver-function method, to investigate the crustal and mantle structure beneath the Longmenshan fault zone. Waveform data are available from the GEOFON data center, under network code 4O under license CC BY-NC-ND 4.0, and are embargoed until February 2024.

Description: Irpinia seismic Array is part of the DEnse mulTi-paramEtriC observations and 4D high resoluTion imaging (DETECT) project focused on the acquisition of a unique multiparametric dataset and fosters collaboration among various institutions. The University of Naples Federico II (UniNa) and the German Research Centre for Geosciences (GFZ) are leading this effort carried out in collaboration with various local institutions and supported by the local municipalities. The DETECT project aims at exploiting very dense seismic networks deployed across a segmented fault system (Irpinia and Pergola-Melandro) to foster the development of scientific integrated methodologies for monitoring and imaging the fault behavior during the inter-seismic phase. The Irpinia seismic Array consists of a dense constellation of seismic antennas using more than 200 seismic stations deployed for one year. Each seismic antenna, with maximum aperture of ~2 km, uses one broad-band sensor, one short period sensor with 1 Hz and 8 with 4.5 Hz natural frequency. The antennas are deployed above and near the fault segments that generated during the last centuries many strong earthquakes in the southern Apennines. Waveform data are available from the GEOFON data centre, under network code ZK.

Description: The Villarrica Volcano is one of the most active volcanoes in South America and is located in a major tourism region. A dense temporal seismological network was installed to investigate the volcanic seismicity and the seismic structure of the edifice with seismic traveltime tomography at high spatial resolution. The network was in operation for 2 weeks from 01.03.2012 to 14.03.2012. It consisted of 30 three-component and 45 one-component short period seismographs covering an area of about 2000 km2. The covered area has a diameter of 45 km and includes the volcanic building.

Description: Study Region Vietnamese Mekong Delta. Study focus This study investigates the trends of groundwater levels (GWLs), the memory effect of alluvial aquifers, and the response times between surface water and groundwater across the Vietnamese Mekong Delta (VMD). Trend analysis, auto- and cross-correlation, and time-series decomposition were applied within a moving window approach to examine non-stationary behavior. New hydrological insights Our study revealed an effective connection between the shallowest aquifer unit (Holocene) and surface water, and a high potential for shallow groundwater recharge. However, low-permeable aquicludes separating the aquifers behave as low-pass filters that reduce the high‐frequency signals in the GWL variations, and limit the recharge to the deep groundwater. Declining GWLs (0.01−0.55 m/year) were detected for all aquifers throughout the 22 years of observation, indicating that the groundwater abstraction exceeds groundwater recharge. Stronger declining trends were detected for deeper groundwater. The dynamic trend analysis indicates that the decrease of GWLs accelerated continuously. The groundwater memory effect varied according to the geographical location, being shorter in shallow aquifers and flood-prone areas and longer in deep aquifers and coastal areas. Variation of the response time between the river and alluvial aquifers was controlled by groundwater depth and season. The response time was shorter during the flood season, indicating that the bulk of groundwater recharge occurred in the late flood season, particularly in the deep aquifers.

Description: Important aspects of geothermal exploration and exploitation are the assessment and mitigation of natural and/or induced seismicity, the imaging and resource assessment of a geothermal reservoir and the monitoring of the effects of the exploitation activities. With this thesis the analysis and application of various seismological tools for the planning, exploration, and monitoring of geothermal fields are given. The methods explored and further developed include survey design for microseismic network construction and assessment, local earthquake tomography, ambient noise tomography, and coda wave interferometry. These techniques were applied to study Los Humeros (Mexico), Theistareykir (Iceland) and Reykjanes (Iceland) geothermal fields. The geometry of seismological arrays is essential for high quality seismic event retrieval and minimal location errors. A sequential survey design algorithm that uses a quality measure based on the D-criterion was applied to extend the seismic network at Theistareykir and to qualify the geometry of the Reykjanes network. Assuming mean picking errors of tp =0.2 s and ts = 0.4 s, the extended Theistareykir network presented an improvement of ∼0.2 km for the computed hypocentral components of seismic events located within the new network. Conversely, we estimated that the Reykjanes network could spare up to 18 of its station locations and obtain comparable location errors nonetheless. This study showed thei mportance of prior survey design experiments to optimize the expenses for a geothermal project (required number of sensors) while obtaining good location estimates of expected seismic events (benefit/cost relations). To characterize the seismic structures at Los Humeros and Theistareykir geothermal fields, a local earthquake tomography and an ambient noise tomography were computed at both locations, respectively. A local earthquake tomography is feasible in areas with high seismicity and good ray coverage (earthquake/station geometries). On the other hand, an ambient noise tomography depends on a good and sufficiently dense station distribution. With the results of these studies, the seismic structures and the dynamics of these two producing fields were obtained for the first time. The seismicity distribution at Los Humeros was used to characterize structures and potential permeability enhancements in some of the existing faults. The retrieved Vp model was combined with available well log data and ultrasonic pulse measurements of collected rock samples to estimate the boundaries of different geologic units. The Vp/Vs model was then used in combination with resistivity data and surface CO2 measurements to deduce the geometry of the conductive clay cap (Vp/Vs ≤ 1.65 and resistivities ≤ 10 Ωm), to identify fluid (Vp reduction, Vp/Vs ≥ 1.71, and resistivities between ∼ 10-60 Ωm), and to locate gas bearing regions (Vp/Vs ≤ 1.55 and high surface CO2 concentrations). A similar study was carried out at Theistareykir, where the Vs model was combined with resistivity data to identify magmatic and/or hydrothermal bodies (Vs ≤ -7 %, resistivities ≤ 30 Ωm). An important conclusion from these studies is that the combination of seismic properties with additional geological and/or geophysical data avoids ambiguities and provides robust interpretations of the dynamics and structure of a geothermal reservoir. Finally, a coda wave interferometry technique (stretching method) was applied to two years of ambient noise records at the Theistareykir geothermal field with the aim to monitor possible velocity changes due to the exploitation activities. Here, the effects of the injection and production changes were very small on the computed Δv/v ratio and only a small long-term velocity reduction (possibly due to production) was detected (-0.05 %/year at the producing field compared to a regional -0.04 %/year). Such observations are also very relevant for the safe long-term continuation of exploitation activities. Although not yet a standard practice, the computation of these changes is very useful to control aseismic processes prior to potentially triggered/induced large seismic events and is complementary to microseismic monitoring. With these results, this thesis contributes to the efforts of the International Energy Agency to develop and increase the use of geothermal energy.

Description: Wichtige Aspekte der geothermischen Exploration und Nutzung sind die Bewertung und Reduzierung der natürlichen und/oder induzierten Seismizität, die Abbildung und Ressourcenbewertung eines geothermischen Reservoirs, sowie die Überwachung der Auswirkungen der Explorationsaktivitäten. In dieser Arbeit werden die Analysen und Anwendungen verschiedener seismologischer Methoden zur Planung, Erkundung und Überwachung geothermischer Felder vorgestellt. Die untersuchten und hier weiterentwickelten Methoden umfassen das Design für den Aufbau und die Bewertung mikroseismischer Netzwerke, die lokale Erdbebentomographie, die Ambient-Noise-Tomographie und die Coda-Wellen-Interferometrie. Diese Techniken werden angewendet, um die geothermischen Felder Los Humeros (Mexiko), Theistareykir (Island) und Reykjanes (Island) zu untersuchen. Die Geometrie seismologischer Arrays ist essentiell für eine gute Bestimmung seismischer Ereignisse mit kleinen Lokationsungenauigkeiten. Ein sequenzieller Algorithmus zum Design des Arrays, der eine Qualitätskennzahl auf der Grundlage des D-Kriteriums verwendet, wurde benutzt, um das seismische Netzwerk in Theistareykir zu erweitern und die Geometrie des Reykjanes-Netzwerks zu testen. Unter der Annahme von mittleren Ablesefehlern von tp = 0.2 s und ts = 0.4 s für P- und S- Wellen verbessert das erweiterte Theistareykir-Netzwerk die berechneten Hypo-Zentren um 0.2 km innerhalb des neuen Netzes. Das Reykjanes-Netz könnte andererseits um bis zu 18 Stationsstandorte reduziert werden und dennoch vergleichbare Lokationsgenauigkeiten erzielen. Diese Studie zeigte die Wichtigkeit vor den eigentlichen Feld-Experimenten Tests möglicher Array-Designs durchzuführen um die Kosten für ein geothermisches Projekt (erforderliche Anzahl von Sensoren) zu optimieren und gleichzeitig gute Lokationen für erwartete seismische Ereignisse zu erhalten (Nutzen/Kostenverhältniss). Um die seismischen Strukturen der geothermischen Felder Los Humeros und Theistareykir zu charakterisieren, wurden an beiden Standorten eine lokale Erdbebentomographie und eine Ambient-Noise-Tomographie berechnet. Eine lokale Erdbebentomographie ist in Gebieten mit hoher Seismizität und guter Strahlenabdeckung (Erdbeben/Stationsgeometrie) möglich. Eine Ambient-Noise-Tomographie hängt nur von einer guten und ausreichend dichten Stationsverteilung ab. Mit den Ergebnissen dieser Studien wurden dann erstmals die seismischen Strukturen und die Dynamik dieser beiden produzierenden Felder ermittelt. Die Seismizitätsverteilung in Los Humeros wurde verwendet, um Strukturen und potenzielle Verbesserungen in der Durchlässigkeit einiger Störungszonen zu charakterisieren. Das abgeleitete Vp-Modell wurde mit Bohrloch-Daten und Ultraschall-Messungen an Gesteinsproben kombiniert, um die Grenzen verschiedener geologischer Einheiten abzuschätzen. Das Vp/Vs-Modell wurde dann in Kombination mit Widerstandsdaten und Oberflächen-CO2-Messungen verwendet, um die Geometrie der leitfähigen Tonkappe abzuleiten (Vp/Vs ≤ 1.65 und Widerstand ≤ 10 Ωm), um Fluide zu identifizieren (reduzierte Vp Werte, Vp/Vs ≥ 1.71 und Widerstände zwischen 10-60 Ωm) und um gasführende Bereiche zu lokalisieren (Vp/Vs ≤ 1.55 und hohe CO2-Konzentrationen). Eine ähnliche Studie wurde in Theistareykir durchgeführt, wo das Vs-Modell mit Widerstandsdaten kombiniert wurde, um magmatische und/oder hydrothermale Körper zu identifizieren (Vs ≤ -7 %, Widerstände ≤ 30 Ωm). Eine wichtige Schlussfolgerung aus diesen Studien ist, dass die Kombination von seismischen Eigenschaften mit zusätzlichen geologischen und/oder geophysikalischen Daten Mehrdeutigkeiten vermeidet und robuste Interpretationen der Dynamik und Struktur eines geothermischen Reservoirs liefert. Weiterhin wurde eine Coda-Wellen-Interferometrie-Technik (Dehnungsmethode) auf zwei Jahre Ambient-Noise-Daten im Geothermiefeld Theistareykir angewendet, um mögliche Geschwindigkeitsänderungen aufgrund der Nutzung des Feldes zu überwachen. Hier waren die Auswirkungen der Injektions- und Produktionsveränderungen auf das Δv/v-Verhältnis sehr gering und nur eine kleine, möglicherweise produktionsbedingte, langfristige Geschwindigkeitsreduktion wurde festgestellt (-0.05 %/Jahr innerhalb des Produktionsbereichs im Vergleich zum regionalen Wert von -0.04 %/Jahr). Solche Beobachtungen sind für die sichere langfristige Ausbeutung von geothermischen Feldern von großer Bedeutung. Obwohl es noch keine Standardpraxis ist, ist die Berechnung dieser Änderungen weiterhin sehr nützlich, um aseismische Prozesse vor potenziell ausgelösten/induzierten großen seismischen Ereignissen zu steuern, sie ergänzen weiterhin die mikroseismische Überwachung. Mit diesen Ergebnissen trägt die vorgelegte Arbeit zu den Bemühungen der Internationalen Energieagentur bei, die Nutzung von Geothermie zu entwickeln und zu erhöhen.

Description: The Caribbean and South American tectonic plates bound the north-eastwards expulsion of the North Andean Block in western Venezuela. This complicated geodynamic setting resulted in the formation of major strike-slip fault systems and sizeable mountain chains. The 100 km wide Mérida Andes extend from the Colombian/Venezuelan border to the Coastal Cordillera. To the north and south, the Mérida Andes are bound by hydrocarbon-rich sedimentary basins. Knowledge of lithospheric structures, related to the formation of the Mérida Andes, is limited though, due to a lack of deep geophysical data. This thesis presents the results of the first broadband magnetotelluric profile crossing the Mérida Andes and the Maracaibo and Barinas-Apure foreland basins spanning a distance of 240 km. The MT dataset consists of 72 stations installed during March and April 2015 with a minimum recording period of 3 days per station. Geoelectrical strike and dimensionality analyses are consistent with one- or two- dimensional subsurface structures for the sedimentary basins yet also indicate a strong three- dimensional setting for the Mérida Andes. Even more significantly, these analyses showed the presence of off-profile features that influenced the data considerably, particularly at long periods. Therefore, a combination of 2D and 3D modelling was necessary for analysing the geoelectrical structures associated with this dataset. Off-profile structures can significantly affect the outcome of a 2D inversion. Thus, the systematic examination of the influence of 3D structures on 2D inversions was necessary to support the obtained result. Synthetic data sets derived from 3D modelling allowed identification and quantification of spurious off-profile features as well as smoothing artefacts due to limited areal station coverage of data collected along a profile. In general, structures in the 2D inversion are affected by the projection and rotation of the data resulting in sub-horizontal anomalies to reproduce the oblique extent of the fault systems and sedimentary basins. Moreover, a profile distributed dataset can limit the lateral resolution of a 3D inversion considerably. Hence, the effect of data distribution on a 3D inversion was carefully studied to determine the areas of the models that can be confidently explained by the data. To this end, several synthetic datasets were derived from 3D models with varying levels of complexity. The analysis of the synthetic datasets allows determination of the lateral resolution of the 3D models and identification of spurious shallow and deep features considered artefacts related to off-profile features. Furthermore, the inversion of synthetic models provided support to the geological interpretation of the recovered anomalies for the 2D and 3D modelling. The 2D and 3D inversion models were similar above the sedimentary basins and showed marked differences above the Mérida Andes, due to the 3D nature of this section. The inversion models show electrically conductive basins with depths of 2 to 5 km for the Barinas-Apure and 2 to 9 km for the Maracaibo basins. Many resistive bodies within the Maracaibo basin could be related to active deformation causing juxtaposition of older geological formations and younger basin sediments. A conductive zone under the Maracaibo Basin correlates spatially with the location of a Bouguer anomaly low and seem to describe the SE tilt of the Maracaibo Triangular Block under the Mérida Andes. This conductive zone is limited towards the mountain by the north-western thrust system, whose fault plane may function as a detachment surface reaching depth larger than 30 km in the 3D inversion models. The most prominent fault systems of the area, the Boconó and Valera Faults, cross-cut the Mérida Andes in NE-SW direction along its strike with a length 400 km and N-S direction at its centre with a length 60 km, respectively. Both faults are associated with sub-vertical zones of high electrical conductivity and sensitivity tests suggest that the Valera fault reach depths of up to 12 km. The Boconó fault can be considered a crustal structure with a depth up to 35 km. The observed anomalies seem to show a deep connection of the fault planes, possibly related to the formation of the fault systems in a transpressive regime. Conductive anomalies to the south of the Boconó Fault seem to represent a considerable back thrust structure well constrained between 3 and 10 km depth. The high conductivity of these structures is possibly related to weathering water from the surface and the accumulation of clay minerals in the fault gauges. However, fluids related to the flat and shallow subduction of the Caribbean Plate in north-western Venezuela could better explain the low resistivity of the deep structures (〉 15 km). A sizeable conductor at 50 km depth, which appears consistently in the 2D sections, could be identified as an inversion artefact caused by a conductor east of the profile. The 3D inversion places this structure 10 km to the east at 15 km deep. This model also shows depth connection (12 km depth) of the anomalies related to the Valera and Boconó faults with the off-profile conductor. The observed anomalies in the 2D and 3D inversion related to these conductors were tested and reproduced employing synthetic datasets, leading to the speculation that the high conductivity associated with the off-profile conductor may be related to the detachment of the Trujillo Block. The models obtained confirm the shape and distribution of the known geological structures related to the complicated geodynamic settings responsible for the formation of the Mérida Andes. These results partially support the "floating orogen hypothesis" developed to explain the geodynamic evolution of western Venezuela, and they highlight the relevance of the Trujillo Block in this process. However, they also show that features of known structures such as the Boconó fault system maximum depth, the back-thrusting in the Mérida Andes, and the relevance of the escape of the Trujillo Block in the tectonic processes need to be adjusted to the current knowledge.

Description: Die Karibische und Südamerikanische tektonischen Platten begrenzten die nordöstliche Abschiebung des Nord-Anden-Blocks im Westen Venezuelas. Diese komplizierte geodynamische Umgebung führte zur Bildung großer Blattverschiebungen-Verwerfungssysteme und beträchtlicher Gebirgsketten. Die 100 km breiten Mérida-Andes erstrecken sich von der Grenze zwischen Kolumbien und Venezuela bis zum Coastal Cordillera. Im Norden und Süden sind die Mérida-Anden von kohlenwasserstoffreichen Sedimentbecken umgeben. Das Wissen über lithosphärische Strukturen im Zusammenhang mit der Bildung der Mérida-Anden ist jedoch aufgrund des Mangels an tiefen geophysikalischen Daten begrenzt. Diese Arbeit präsentiert die Ergebnisse des ersten breitbandigen magnetotellurischen Profils, das die Mérida-Anden und die Vorlandbecken Maracaibo und Barinas-Apure über eine Entfernung von 240 km quert. Der MT-Datensatz besteht aus 72 Stationen, die im März und April 2015 mit einer Mindestaufzeichnungsdauer von 3 Tagen pro Station installiert wurden. Geoelektrische Streich- und Dimensionalitätsanalysen stimmen mit ein- oder zweidimensionalen Untergrundstrukturen für die Sedimentbecken überein, weisen jedoch auch auf eine starke dreidimensionale Strukturen in der Umgebung der Mérida-Andes hin.. Noch wichtiger ist, dass diese Analysen das Vorhandensein von Merkmalen außerhalb des Profils zeigten, die die Daten insbesondere für lange Perioden erheblich beeinflussen. Daher war eine Kombination aus 2D- und 3D-Modellierung erforderlich, um Störungssysteme und Sedimentbecken quer zum Profil zu reproduzieren. Off-Profile-Strukturen können das Ergebnis einer 2D-Inversion erheblich beeinflussen. Daher war die systematische Untersuchung des Einflusses von 3D-Strukturen auf 2D-Inversionen erforderlich, um das erhaltene Ergebnis zu verifizieren. Synthetische Datensätze, die aus der 3D-Modellierung abgeleitet wurden, ermöglichten die Identifizierung und Quantifizierung von störenden Strukturen außerhalb des Profils sowie die Glättung von Artefakten aufgrund der begrenzten Stationsüberdeckung der entlang eines Profils gesammelten Daten. Im Allgemeinen werden Strukturen in der 2D-Inversion durch die Projektion und Rotation der Daten beeinflusst, was zu flach stehenden Anomalien führt, um die schräge Ausdehnung der Verwerfungssysteme und Sedimentbecken zu reproduzieren. Darüber hinaus kann ein Datensatz entlang eines Profils die laterale Auflösung einer 3D-Inversion erheblich einschränken. Daher wurde die Auswirkung der Datenverteilung auf eine 3D-Inversion sorgfältig untersucht, um die Bereiche der Modelle zu bestimmen, die durch die Daten sicher erklärt werden können. Zu diesem Zweck wurden mehrere synthetische Datensätze aus 3D-Modellen mit unterschiedlicher Komplexität abgeleitet. Die Analyse der synthetischen Datensätze ermöglicht die Bestimmung der lateralen Auflösung der 3D-Modelle und die Identifizierung von störenden oberflächennahen und tiefen Merkmalen, die als Artefakte im Zusammenhang mit Strukturen außerhalb des Profils betrachtet werden. Darüber hinaus unterstützte die Inversion synthetischer Modelle die geologische Interpretation der reproduzierten Anomalien für die 2D- und 3D-Modellierung. Die 2D- und 3D-Inversionsmodelle stimmen über den Sedimentbecken überein. Aufgrund der 3D Strukturen über den MA ergaben sich jedoch deutliche unterschiede. Die Inversionsmodelle zeigen elektrisch leitende Becken mit Tiefen von 2 bis 5 km für das Barinas-Apure und 2 bis 9 km für das Maracaibo-Becken. Viele Gebiete höheren Widerstands im Maracaibo-Becken könnten mit einer aktiven Deformation zusammenhängen, die ein Nebeneinander älterer geologischer Formationen und jüngerer Beckensedimente verursacht. Eine besserleitende Zone unter dem Maracaibo-Becken korreliert räumlich mit der Lage einer Bouguer-Anomalie und scheint die SE-Neigung des Maracaibo-Dreiecksblocks unter den Mérida-Anden zu markieren. Diese leitende Zone ist in Richtung des Gebirges durch das nordwestliche Schubsystem begrenzt, dessen Störungsebene als Ablösefläche fungieren kann, die in den 3D-Inversionsmodellen eine Tiefe von mehr als 30 km erreicht. Die bekanntesten Störungssysteme des Gebiets, die Verwerfungen Boconó und Valera, kreuzen die Mérida-Anden in Nordost-Südwest-Richtung entlang ihres Streichens mit einer Länge von 400 km und die N-S-Richtung in ihrer Mitte mit einer Länge von 60 km. Beide Störungen sind durch steil stehende Zonen hoher elektrischer Leitfähigkeit verbunden. Sensitivitätsstudien legen nahe, dass die Valera-Störung Tiefen von bis zu 12 km erreicht. Die Boconó-Verwerfung kann als Krustenstruktur mit einer Tiefe von bis zu 35 km angesehen werden. Die beobachteten Anomalien scheinen eine tiefe Verbindung der Verwerfungsebenen zu zeigen, möglicherweise im Zusammenhang mit der Bildung der Verwerfungssysteme in einem transpressiven Regime. Leitfähige Anomalien südlich der Boconó-Verwerfung scheinen eine beträchtliche Rückschubstruktur darzustellen, die zwischen 3 und 10 km Tiefe gut lokalisiert ist. Die hohe Leitfähigkeit dieser Strukturen hängt möglicherweise mitWasser aus Verwitterungsprozessen nahe der Erdoberfläche und der Ansammlung von Tonmineralien in den Störungszonen zusammen. Alte Fluide im Zusammenhang mit flach stehenden und oberflächenahen Subduktion der Karibikplatte im Nordwesten Venezuelas könnten jedoch den geringen spezifischen Widerstand der tiefen Strukturen (〉 15 km) besser erklären. Ein beträchtlicher Leiter in einer Tiefe von 50 km, der in den 2D-Schnitten konsistent erscheint, konnte als Inversionsartefakt identifiziert werden, der durch einen Leiter östlich des Profils verursacht wird. Durch die 3D-Inversion wird diese Struktur 10 km östlich in 15 km Tiefe platziert. Dieses Modell zeigt auch die Tiefenverbindung (12 km Tiefe) der Anomalien im Zusammenhang mit den Störungen von Valera und Boconó mit dem Leiter außerhalb des Profils. Die beobachteten Anomalien in der 2D- und 3D-Inversion in Bezug auf diese Leiter wurden unter Verwendung synthetischer Datensätze getestet und reproduziert. Daher kann man annehmen das die mit dem Leiter abseits des Profils verbundene Leitfähigkeit mit der Ablösung des Trujilo Blocks zusammenhängt. Die erhaltenen Modelle bestätigen die Form und Verteilung der bekannten geologischen Strukturen im Zusammenhang mit dem komplizierten geodynamischen Millieu, welches für die Bildung der Mérida-Andes verantwortlich ist. Diese Ergebnisse stützen teilweise die "schwimmende Orogenhypothese", die entwickelt wurde, um die geodynamische Entwicklung West-Venezuelas zu erklären, und sie unterstreichen die Relevanz des Trujillo-Blocks in diesem Prozess. Sie zeigen jedoch auch, dass Merkmale bekannter Strukturen wie die maximale Tiefe des Boconó-Verwerfungssystems, das Zurückschieben in den Mérida-Anden und die Relevanz des Entweichens des Trujillo-Blocks in den tektonischen Prozessen an den aktuellen Kenntnisstand angepasst werden müssen.

Description: This dataset provides friction and elasticity data from ring shear and axial tests, respectively, on rock analogue materials used at the University Roma Tre (Rome, IT) in “Foamquake”, a novel seismotectonic analog model mimicking the megathrust seismic cycle (Mastella et al., under review). Two granular materials (quartz sand and Jasmine rice) have been characterized by means of internal friction coefficients µ and cohesions C. An elastic material (foam rubber) have been characterized by means of Young’s modulus E and Poisson’s ratio v. According to our analysis the granular materials show Mohr-Coulomb behaviour characterized by linear failure envelopes in the shear stress vs. normal load Mohr space. Peak, dynamic and reactivation friction coefficients of the quartz sand are µP = 0.69, µD = 0.56 and µR = 0.64, respectively. Cohesion ranges between 50 and 100 Pa. Rate-dependency of friction in quartz sand seems insignificant. Peak, dynamic and reactivation friction coefficients of the Jasmine rice are µP = 0.70, µD = 0.59 and µR = 0.61, respectively. Cohesion ranges between 30 and 50 Pa. Rate-weakening of Jasmine rice is c. 6% per tenfold change in shear velocity v. The Young’s modulus of the foam rubber has been constrained to 30 kPa, its Poisson’s ratio is v=0.1.

Description: This dataset includes particle image correlation data from 26 experiments performed with Foamquake, a novel analog seismotectonic model reproducing the megathrust seismic cycle. The seismotectonic model has been monitored by the means of a high-resolution top-view monitoring camera. The dataset presented here represents the particle image velocimetry surface velocity field extracted during the experimental model through the cross-correlation between consecutive images. This dataset is supplementary to Mastella et al. (2021) where detailed descriptions of models and experimental results can be found.

Description: Understanding how resilient rangelands are to climatic disturbances such as drought is of major importance to land managers. The resilience of ecosystems can be reduced by livestock grazing and by environmental conditions. Most studies quantifying resilience are based on model simulations. However, natural time series from satellite data offer the possibility to infer aspects of resilience from real systems. The objective of this study was to investigate two aspects of ecological resilience, namely resistance to climate variability and recovery from drought, by applying a change detection method (Breaks For Additive Seasonal and Trend; BFAST) spatially on a 28-year Landsat NDVI time series in a dry rangeland in southern Cyprus. First, we used the number of breakpoints fitted by the BFAST model as an inverted proxy for long-term vegetation resistance to climate variability (the ability to withstand change during a disturbance reduces the likelihood to trigger a breakpoint in the time series). Second, we used the linear slope of the BFAST model after a known drought as a proxy of the recovery rate of the vegetation. This information was then used to analyse the spatial distribution of the total number of breakpoints and of the NDVI recovery trend in relation to grazing and environmental properties. Our results show that high NDVI and a northern orientation (i.e. favourable environmental conditions) were associated with a highly resilient system, due to high resistance to climate variability and fast recovery after drought. Intermediate conditions were associated with low resistance. Unfavourable conditions and high grazing intensities were associated with an unresponsive ecosystem state characterised by high resistance and slow recovery after a drought event. Low grazing intensities positively affected the NDVI recovery trend, but did not improve resistance. On northern slopes, terrain slope had a positive effect on the NDVI recovery trend, while on southern slopes it had a negative effect. Our satellite-driven approach has a strong potential for resilience monitoring, because it can be applied on broad spatial and temporal scales in areas with low availability of field data. Moreover, it allows to jointly extract two important components of resilience: resistance and recovery rate.

Description: Earthquakes are generally known to alter the stress field near seismogenic faults. Observations using YRY-four-gauge borehole strainmeters within Yushu (YSH) borehole near the Ganzi-Yushu fault in eastern Tibetan Plateau shows that the azimuth variation of maximum horizontal stress (SH) first decreased and then increased substantially when the earthquakes occurred during the measurement period from January 1, 2009 to December 31, 2018. In this period, 38 earthquakes (M ≥ 3) were detected near the fault and the SH orientation showed a drastic change after the 2010 Ms 7.3 Yushu mainshock. We present a discrete element modelling using Particle Flow Code 2D (PFC2D) to simulate a dynamic fault rupturing process and to use the modelling results for interpretation of the stress reorientation. The modelling reveals that dilatation and compression quadrants are formed around a fault rupturing in strike-slip model, resulting in different spatiotemporal changes of the orientation of maximum horizontal stress (Δθ). The value of Δθ in the compression quadrants shows a sharp drop at the time of coseismic slip, then approaches slowly to an asymptotic value. In the dilatation quadrants, Δθ drops by coseismic slip, then increases sharply and finally reaches a stable value. The modelled Δθ by coseismic fault slip agrees with in-situ observations at YSH borehole during 2010 Ms 7.3 Yushu mainshock. It is also found that, the value of Δθ decreases with increasing distance from the rupturing source. We modelled the effect of fault geometry and host rock properties on the Δθ, and found that structural complexity and off-fault damage by coseismic fault slip have significant impact on the stress field alteration near the rupturing source.

Description: At the Decatur carbon capture and storage site (IL, USA) CO2 has been injected from 2011–2014 and from 2017 to present near the base of the Lower Mt. Simon Sandstone saline reservoir, resulting in microseismicity. Microseismicity is mainly located in the basement and distributed in distinct spatial clusters. The lack of significant impedance contrasts within the basement makes the interpretation of active-source seismic reflection data challenging, however, recent reprocessing allowed to resolve faults above and at the top of the basement. These faults generally do not coincide with the location of microseismic events and their continuation to the general depth of the seismic events cannot be assumed. This paper shows how the interpretation of the microseismicity can complement structural interpretations of active-source seismic reflection data. In particular, we analyze clusters and bursts (abrupt increases) of microseismicity, identify unresolved, smaller-scale weaknesses and extract statistical parameters. These parameters allow comparisons with the interpreted faults, and with fracture sets intercepted by boreholes. During injection at the Decatur site, the injection pressure was kept far below fracture pressure, nevertheless, seismic events were induced and spread far beyond the expected extent of the CO2 plume. We argue that local stress transfers related to the CO2 injection reactivated pre-existing fractures within the critically stressed basement. Finally, we conducted a slip tendency analysis for faults interpreted from active seismic, selected cluster, bursts and nodal planes from focal mechanisms to determine if the interpreted structures are optimally oriented with respect to the stress regime. Our results suggest that the orientation of fractures close to the injection well, generally shows slight deviations from the optimal orientation for slip. This might indicate either slight local deviations of the maximum horizontal stress azimuth from the average direction used in the analysis, or the lack of optimally oriented fractures at this location.

Description: This work presents a study of an unusual synthetic diamond sample, where calcite is the main phase in addition to diamond. Using Raman spectroscopy it can be shown that in addition to diamond carbon forms four different generations: highly ordered graphite-II, lower ordered graphite-I as spandrel between different mineral grains, weakly-ordered carbonaceous material as graphite-III and the hexagonal diamond lonsdaleite (here graphite-IV) as last formation in calcite. Graphite-III can be found mainly in the calcite body. According to the fine dispersion of this carbonaceous material and the arrangement on grain boundaries, we assume that carbon was dissolved in the calcite melt, and that by the activated state of carbon in the calcite melt the formation of diamond is favored near 1760°C, and 6.8 GPa. Lonsdaleite as minor phase may have been formed as an longlived intermediate state under standard conditions between graphite and diamond. Evidence shows that there are two different lonsdaleite phases (possibly hexagonal and monocline) present. The prevailing diamond is characterized by the first-order Raman line at 1333 cm-1. However, there are also present diamonds with the first-order Raman line down to 1310.6 cm-1, corresponding to 13C = 0.511. Significantly there is the strong decrease of the optical damage threshold with increase of the 13C content.

Description: While there has been a lot of work focusing on improving our understanding of divergent and convergent plate boundaries, the intricate nature of back-arc extension, where subduction and large-scale extension occur and interact in close, is yet to be explored properly. It has long been proposed that the strength of the subduction interface, which depends among others on the amount of subducted sediments, plays a pivotal role in subduction dynamics. Here, we investigate the role of back-arc rheology and subduction interface strength on the deformation style of the overriding plate. Using two-dimensional thermomechanical model experiments, we demonstrate, that the presence of a weak mantle–lithospheric domain in the overriding plate can result in back-arc breakup even during the subduction of narrow, land-locked oceanic basins such as those found in the Mediterranean region. The thinning of the back-arc mantle–lithosphere results in a weaker overriding plate, hence a lower slab-pull force is sufficient to initiate back-arc extension. Convective thinning at the subduction interface also reduces the length of the interface, reducing the portion of slab-pull lost as energy dissipation. A weak plate interface, can also reduce the energy dissipated along the subduction zone, leading to earlier extension. A detailed analysis of the forces shaping the overriding plate stress field shows that transmission of slab-pull force has a predominant role while viscous basal drag has a negligible effect in our experiments. Our results compare favorably with large-scale characteristics of land-locked Mediterranean back-arc basins such as the North Tyrrhenian basin and the Pannonian basin.

Description: Located in the middle of Shanxi Province, northern China, Taiyuan basin is a dry and water-short region. This region is reaching alarming levels of aquifer depletion due to decades of groundwater overexploitation, which has caused severe land subsidence in the basin. The Wanjiazhai Water Diversion Project (WWDP) was designed to ease water scarcity by transporting water from the Yellow River to the Taiyuan basin through 452.4 km-long canals. By the end of 2018, the WWDP had supplied 2.87 billion m3 of water to Shanxi Province, which replenish the basin’s surface water body as well as the underground aquifer. The groundwater levels have continued to rise since 2003, with rising levels of more than 70 meters by 2018 in comparison with its low stand in 2000. In this study, we use 2007-2010 ENVISAT, ALOS-1 data, and 2017-2020 Sentinel-1 data to study the response of the basin’s aquifer to the groundwater rebound against the background of the water transfer project. We addressed the issue of tropospheric delay and its impact on the seasonal deformation by combing GACOS (Generic Atmospheric Correction Online Service) and a common-point stacking method. The accuracy improvement of deformation by this correction method was validated with measurements from seven continuous GPS stations in the basin. Groundwater rebound triggers ground uplift, which was identified in five areas by InSAR with a rate up to 25 mm/yr. The uplifting displacement time series are well correlated with groundwater level recovery. The land subsidence in the south of the basin continues but the rates decreased significantly in 2017-2020 detected from Sentinel-1 as compared to that in period 2007-2010 from ENVISAT and ALOS-1. All these uplifting signals and the decreasing rates of land subsidence found in Taiyuan city provide the indication that water management practices are successful in mitigating further subsidence. We found a significant seasonal displacement concentrated within the central region of the basin corresponding to the main irrigated areas in the Taiyuan basin. The maximum peak-to-peak amplitude is 43 mm observed from ENVISAT and decreases to 20 mm observed from Sentinel-1. The seasonal amplitudes change rapidly across faults, indicating that the fault is an effective barrier to across-fault fluid flow. To further quantify the causal relationships between water level and ground displacement, groundwater levels and ground displacement at three wells located near the area affected by significant seasonal land subsidence are analyzed by Cross Wavelet Transform (XWT) method. We found the time lags of about one month between land subsidence and the forcing groundwater level declines. Such a cross wavelet analysis with high spatial-temporal resolution therefore enables tracking the health of the aquifer system and highlights the system’s sustainability in aiding water resources allocation against the background of the water diversion project.

Description: We explore nonlinear site effects in the new Japanese ground-motion dataset compiled by Bahrampouri et al. (2020). Following the approach of Seyhan and Stewart (2014), we evaluate the decrease of soil amplification according to the increasing and corresponding ground motion on surface rock (VS30 760 m=s). To better predict the rock ground motion associated with each record, we take into account the between-event variability of the ground motion, and to better evaluate the impact of nonlinearity, we correct observed ground motion on soil by the site-specific linear amplification. Instead of grouping the stations by site-response proxy, we focus on individual stations with several strong-motion records. We develop a framework to test recently published nonlinear site amplification models against a linear site amplification model and compare the results with recent building codes that include nonlinearity. The results show that the site response varies greatly from site to site, indicating that conventional site proxies, such as VS30, are not sufficient to characterize nonlinear site response. Out of all of the Kiban–Kyoshin network stations, 20 stations are selected as having recorded sufficient data to be used in the test. Out of these 20 stations, five stations show signs of nonlinearity, that is, the nonlinear models performed better than the linear-amplification model for all periods T. For most sites, however, the linear site amplification models get the best score. This suggest that, for the range of predicted rock motion considered in this study (peak ground acceleration 〈0:2g), nonlinearity may not have a sufficiently large impact on soil ground motion to justify the use of nonlinear site terms in ground-motion functional forms and seismic building codes for such moderate-level shaking.

Description: Archaeomagnetic data are fundamental for our understanding of the evolution of Earth's magnetic field on centennial to millennial timescales. From the earliest studies of the Thelliers, Aitken, Nagata and others in the 1950s and 1960s, archaeomagnetic data have been vital for extending our knowledge of the field to times prior to observational measurements. Today, many thousands of archaeomagnetic data allow us to explore the geomagnetic field in more detail than ever before. Both regional time series of archaeomagnetic data and the inclusion of archaeomagnetic data in time-varying global spherical harmonic field models have revealed a range of newly discovered field behaviour. More sophisticated approaches to developing regional curves and global models have allowed us to resolve the field in certain regions more robustly and with greater resolution than previously possible. In this review we give an overview of the widely used global archaeomagnetic database GEOMAGIA50, discuss the methods used to obtain archaeomagnetic data, their challenges, and explore progress over the past twenty years in developing regional secular variation curves and global spherical harmonic models of the archaeomagnetic field. We end the review by covering what we see as the “grand challenges” in archaeomagnetism, including which regions of the world should be focussed on with regards to data acquisition.

Description: The Earth is rotating around its rotation axis in an irregular manner. The Earth rotation axis and its orientation in space vary with respect to the reference system (both the terrestrial and the celestial) due to the wide range of processes that contribute to the rotation excitation. Therefore, the study of the Earth rotation can provide essential information concerning the Earth system. Spaceborne geodetic sensors can determine Earth orientation parameters (EOP), which fully describe Earth’s behaviour in space. The EOP are needed for several fields and applications such as fundamental astronomical and geodetic reference systems, precise satellite orbit determination, space navigation, and disaster prevention.\\ Over the past three decades, climate change has caused undesirable alterations in living organisms, human activities, and socio-economic aspects. Climate change is fluctuating and alters weather patterns such as precipitation patterns and sea and ocean levels. It also threatens the biodiversity of ecosystems, food security, and human health, and exacerbates natural disasters. The intensity and frequency of natural hazards are increasing with erratic distribution due to changes in the climate. Also, the level of vulnerability and zonation of risk are changed. Analysis of natural hazards, such as atmospheric and hydrological events, can help improve crisis management. Therefore, satellite observation data and simulated data derived from different atmospheric models are needed in order to model different types of hazards and risks, which can help early warning and prediction systems. Even though continuous sensor measurements and archive data (historical data/climate) are used for weather forecasting in developed countries, deadly flooding happened close to Stuttgart in southern Germany in May 2016, which might be avoided by a precise weather warning system. Therefore, real-time space geodetic technique data estimation is necessary to use as input data in weather prediction models. For the analysis of space geodetic techniques in (near) real-time, predictions of the EOP are required. EOP are made available by the International Earth Rotation and Reference Systems Service (IERS) Rapid Service Prediction Centre at USNO, Washington D.C., with a delay of hours to days. Accordingly, in the past, several methods were developed and applied for the EOP prediction. However, the accuracy of EOP prediction is still unsatisfactory, even for prediction of just a few days in the future.\\ To improve the EOP prediction accuracy, this study investigates the consistency between Earth rotation’s theories and observations. Moreover, the potentials of different geophysical phenomena are examined to better understand the interaction of different processes that affect the Earth rotation excitation with the time. Most of the Earth’s rotation theories and solutions are based on the location of the Earth’s principal axes of inertia (PAI). That location is defined by the second-degree Stokes coefficients of the geopotential, which are accurately observed by the Gravity Recovery and Climate Experiment (GRACE) and satellite laser ranging (SLR). In this study, the evolution of the Earth’s axes of inertia is analyzed for the first time. The presented results are remarkable, as the inertia axes do not move around a mean position fixed to a given terrestrial reference frame in the study period, but drift away from their initial location in a non-negligible manner.\\ Moreover, this study proposes a novel hybrid approach to predict EOP. There is a well-introduced stochastic method called copula-based analysis, and I combined it with singular spectrum analysis (SSA) for EOP prediction. I analyzed the potential of copula-based methods for predicting Earth rotation parameters that are derived from the combination of different satellite geodetic sensors and from other geophysical parameters like effective angular momentums. The copula is a statistical method that exploits linear and non-linear relationships between two or more variables by fitting a theoretical copula function into an empirical bivariate or multivariate distribution function. I introduced a hybrid prediction method that can be applied to other geophysical parameters is introduced in this thesis.\\ In this study, the interconnection between the celestial pole motion (CPM) and geomagnetic field (GMF) is investigated to improve the current CPM prediction methods. During the last decade, several investigations have been conducted in order to discuss a possible interconnection of polar motion and geomagnetic jerks, which are rapid changes in GMF secular variations. However, less attention has been paid to the impact of the GMF changes on the CPM, e.g., the interrelation of the geomagnetic jerks, geomagnetic dipole moment, geomagnetic field elements, and CPM variations. In this study, I use the CPM time series obtained from very long baseline interferometry (VLBI) observations and the latest GMF data to explore the correlation between CPM and the GMF. Our preliminary results revealed some impressive common features in the CPM and GMF variations, which show the potential to improve our understanding of the GMF’s contribution to the Earth’s rotation. All in all, the results mathematically illustrate the coherency between the GMF parameters and CPM, which helps improve EOP products.

Description: Die Erde dreht sich um ihre Rotationsachse auf unregelmäßige Art und Weise. Die Erdrotationsachse und ihre Orientierung im Raum variieren in Bezug auf das Referenzsystem (sowohl im terrestrischen wie auch im zälestischen System) aufgrund des breiten Spektrums von Prozessen, die zur Rotationsanregung beitragen. Daher kann die Untersuchung der Erdrotation wesentliche Informationen über das Erdsystem liefern. Weltraumgestützte geodätische Sensoren liefern Informationen über erdgebundene Orientierungsparameter (EOP), die das Verhalten der Erde im Weltraum vollständig beschreiben. EOP werden für verschiedene Bereiche und Anwendungen, wie beispielsweise für grundlegende astronomische und geodätische Referenzsysteme, benötigt. Des Weiteren sind sie auch für die präzise Bestimmung von Satellitenorbits und die weltraumgestützten Navigation, bis hin zu Anwendungen im Katastrophenschutz von Bedeutung.\\ In den letzten drei Jahrzehnten zeigen sich bereits die negativen Auswirkungen des Klimawandels auf Biosphäre, menschliche Aktivitäten und sozioökonomische Aspekte. Der Klimawandel unterliegt Fluktuationen und verändert die Wettermuster, wie z.B. die Niederschlagsverteilung, sowie Meeres- und Ozeanspiegel. Er bedroht aber auch die biologische Vielfalt der Ökosysteme, die Ernährungssicherheit, die menschliche Gesundheit und verschlimmert Naturkatastrophen. Die Intensität und Häufigkeit von Naturgefahren werden zunehmen, hierbei ist ihre Verteilung aufgrund von Klimaveränderungen allerdings unregelmäßig; auch der Grad von Schadensanfälligkeiten und die Einteilung von Risikozonen werden sich zukünftig ändern.\\ Die Analyse von Naturgefahren, wie atmosphärische und hydrologische Ereignisse, kann zur Verbesserung des Krisenmanagements beitragen. Daher werden Satellitenbeobachtungen und simulierte Daten, die von verschiedenen atmosphärischen Modellen abgeleitet werden, für die Gefahr- und Risikomodellierung benötigt; dies kann Frühwarn- und Vorhersagesysteme unterstützen. Obwohl kontinuierliche Sensormessungen und Archivdaten (historische Daten/Klimadaten) für die Wettervorhersage in entwickelten Ländern zur Verfügung stehen, kamen es im Mai 2016 in der Nähe von Stuttgart in Süddeutschland bei einer katastrophalen Überschwemmung zu Verlusten von Menschenleben, die möglicherweise durch ein präzises Wetterwarnsystem vermeidbar gewesen wären. \\ Eine Echtzeitschätzung der geodätischen Weltraumtechnik wäre notwendig, um sie als Eingangsdaten in Wettervorhersagemodellen zu verwenden. Für die Analyse von raumgeodätischen Techniken in (nahezu) Echtzeit sind Vorhersagen der EOP unerlässlich. EOP werden durch das Rapid Service Prediction Centre des International Earth Rotation and Reference Systems Service (IERS) am USNO, Washington D.C., mit einer Verzögerung von Stunden bis Tagen zur Verfügung gestellt. Demzufolge wurden in der Vergangenheit mehrere Methoden für die EOP-Vorhersage entwickelt und angewendet. Die Genauigkeit dieser EOP-Vorhersagen ist jedoch nach wie vor - selbst für einen Vorhersagezeitraum von nur wenigen Tagen - unbefriedigend.\\ Um die Genauigkeit der EOP-Vorhersage zu verbessern, beschäftigt sich die vorliegende Studie mit der Untersuchung von der Vereinbarkeit von Erdrotationstheorien mit Beobachtungen. Darüber hinaus wird das Potenzial verschiedener geophysikalischer Phänomene analysiert, um die Wechselwirkungen verschiedener Prozesse, die die zeitabhängige Anregung der Erdrotation beeinflussen, besser zu verstehen.\\ Die meisten Theorien und Lösungen zur Erdrotation basieren auf der Lage der Hauptträgheitsachsen der Erde (PAI). Diese Position wird durch die Stokes-Koeffizienten zweiten Grades des Geopotentials, das mit Hilfe der Satellitenmission Gravity Recovery and Climate Experiment (GRACE) und der Satelliten-Laser-Entfernungsmessung (SLR) genau beobachtet wird, definiert. In dieser Studie wird zum ersten Mal die Entwicklung der Trägheitsachsen der Erde analysiert. Bemerkenswert an den vorgestellten Ergebnissen ist, daß sich die Trägheitsachsen während der Untersuchungsperiode nicht um eine mittlere Position, die in einem bestimmten terrestrischen Bezugsrahmen festgelegt ist, bewegen, sondern sich in nicht zu vernachlässigender Weise von ihrem ursprünglichen Position entfernen.\\ Darüber hinaus schlägt diese Studie einen neuartigen hybriden Ansatz zur EOP-Vorhersage vor. Es gibt eine gut eingeführte stochastische Methode, die “kopula-basierte Analyse”, die wir mit der “Singulär-Spektrum-Analyse” (SSA) für die EOP-Vorhersage kombiniert haben . Wir analysierten das Potenzial kopula-basierter Methoden zur Vorhersage von Erdrotationsparametern, die aus der Kombination verschiedener geodätischer Satellitensensoren und aus anderen geophysikalischen Parametern, wie z.B effektiven Drehimpulsen, abgeleitet werden. Die Kopula ist eine statistische Methode, die lineare und nicht-lineare Beziehungen zwischen zwei oder mehreren Variablen nutzt, indem eine theoretische Kopula-Funktion an eine empirische, bivariate oder multivariate Verteilungsfunktion angepasst wird. Wir haben eine hybride Vorhersagemethode entwickelt, die auch auf andere geophysikalische Parameter angewendet werden kann.\\ In dieser Studie wird der Zusammenhang zwischen der Bewegung des Himmelspols (CPM) und dem geomagnetischen Feld (GMF) untersucht, um die derzeitigen CPM-Vorhersagemethoden zu verbessern. Während des letzten Jahrzehnts wurden mehrere Untersuchungen durchgeführt, um eine mögliche Verbindung zwischen polaren Bewegungen und geomagnetischen Ausbrüten - hierbei handelt es sich um rasche Veränderungen der säkularen Variationen des GMF - zu erörtern. Weniger Aufmerksamkeit wurde jedoch den Auswirkungen der GMF-Änderungen auf die CPM, z.B. der Wechselbeziehung der geomagnetischen Ausbrüte, des geomagnetischen Dipolmoments, der geomagnetischen Feldelemente und der CPM-Variationen, gewidmet. In dieser Studie verwenden wir CPM-Zeitreihen, die aus Beobachtungen der Very Long Baseline Interferometry (VLBI) gewonnen wurden und aktuelle GMF-Daten, um die Korrelation zwischen CPM und GMF zu untersuchen. Unsere vorläufigen Ergebnisse zeigen einige auffallente Gemeinsamkeiten in den CPM- und GMF-Variationen, die das Potenzial besitzen, unser Verständnis des GMF-Beitrags zur Erdrotation zu verbessern. Alles in allem veranschaulichen die Ergebnisse mathematisch die Kohärenz zwischen den GMF-Parametern und der CPM und weisen damit perspektivisch den Weg für eine Verbesserung der EOP-Produkte.

Description: Our planet is in crisis! The latest report of the United Nations Intergovernmental Panel on Climate Change (IPCC AR6) confirms that human influence is causing widespread, rapid, and intensifying changes in our weather and climate that are affecting every region on Earth in multiple ways. With every additional ton of carbon we emit, the frequency and intensity of storms, floods, droughts, and fires become greater and the effects on the environment and on human health and civilization become more severe. As geoscientists and journal editors, most of us have been accustomed to being on the leading edge of human knowledge and understanding of climate change, where we deal in objectivity, uncertainty, and debate, but now we find ourselves at the core of this climate crisis. It is no longer scientific discoveries at stake, but also humanity itself. This is an uncomfortable place for many of us. We are trained to be dispassionate observers and cautious thinkers, yet the alarming rate of recent climate change impels us to turn our attention directly toward mitigating this impending crisis. We are making a plea for collective action: we must make the switch to a green economy, put a just and effective price on carbon now, and consider a portfolio of other equitable public investments in climate solutions. These actions will ensure that the true costs and risks of burning fossil fuels are accounted for and global carbon emissions are rapidly reduced. Rich countries must lead the way in making drastic cuts to carbon emissions and in helping low- and middle-income countries to develop sustainably. We are running out of time. For decades, American Geophysical Union (AGU) journals have been at the forefront of documenting human-caused climate change and warning of a worsening climate crisis. Over 2,000 publications from AGU journals are cited in the new IPCC AR6 report. But we too can do more than just document and scientifically explain the ongoing crisis—our profession must help lead the way to solutions. Finding solutions and adapting to change have become not only necessary, but essential in ensuring safe, sustainable, and healthy human communities in the future. The geosciences have an essential role to play in these efforts by pivoting toward more cross-sector, solution-based science. To help lead this vision, the AGU is adding a new publication forum for community science in partnership with associations outside the geosciences. This forum will enhance interactions among AGU's existing, more disciplinary journals and give local communities a voice in leading solutions to global challenges. We are scientists, but we also have families and loved ones alongside our fellow citizens on this planet. The time to bridge the divide between scientist and citizen, head and heart, is now. The lead-up to the 2021 UN Climate Change Conference, COP26, being held in Glasgow in November, is our “last best chance” to urge world leaders to come together and commit to keeping climate change and its devastating impacts in check.

Description: This study presents an enhancement to the Global Navigation Satellite Systems (GNSS) by integrating low Earth orbiters (LEOs) to a joint precise orbit determination (POD) processing. The Global Position System (GPS) operated by the United States is studied as a representative of all GNSS. The LEOs equipped with GNSS receivers supplement the receivers of the ground stations, especially for regions with a limited number of employed stations, which can be caused by various reasons. Due to the altitude and high velocity of LEOs, they not only contribute with additional observations, but also with a rapidly-changing observation geometry. Moreover, space-based observations have additional advantages over ground-based observations, e.g., signals are received without the impact of the troposphere. LEOs not only act as kinematic stations for GNSS satellites, but also bring additional orbit dynamics to the integrated system. The constraints caused by these orbit dynamics have an important impact on the determination of the orbits of the GNSS satellites and other parameters beyond that. In this thesis, the following topics are presented: 1) Background information and the basic principles related to the POD of GNSS satellites and LEOs, 2) the separated POD of GNSS satellites and LEOs, 3) the integrated POD, 4) the determination of the antenna phase center offsets (PCOs) of the GPS satellites and other geodetic parameters in the integrated POD. The orbit modeling and processing configuration used in this study for GNSS satellites and LEOs are verified to be compatible with state-of-the-art studies by the separated POD. The orbits of the GNSS satellites and LEOs reach an accuracy of a few centimeters and are comparable with the state-of-art studies. A more efficient outlier detection method has been developed to improve the position determined by using pseudo-range observations. In the study about the enhancement of the GPS orbits by integrating LEOs, a 26-station ground network in a global and sparse distribution is supplemented by different subsets of seven LEOs including GRACE-A/B, OSTM/Jason-2, Jason-3 and, Swarm-A/B/C. A 34% improvement of the GPS orbit in 1D-mean RMS (from 37.5 mm to 23.9 mm) is achieved by including the seven LEOs. Both the number of space-based observations and the LEOs' orbital geometry affect the GPS orbits where the orbital geometry is shown to be more important. The estimated GPS PCOs are also improved by including LEOs. For the x- and y-components of the GPS PCOs, the formal error is reduced significantly due to the additional observations and expanded nadir angle coverage brought by the LEOs during the periods of large solar-elevation angle. The z-component of the GPS PCOs (z-PCO) are strongly correlated with the scale of the terrestrial reference frame. By introducing the orbit dynamics of the seven LEOs to the processing without applying a no-net-scale constraint, the correlation coefficients between the GPS z-PCOs and the scale are reduced from 0.85 to 0.30. Consequently, the GPS z-PCOs can be estimated independently from the a-priori scale and a purely GNSS-based scale can be determined as well. A system-specific -25.5 cm offset of the GPS z-PCOs relative to the values offered by the International GNSS Service (IGS) is computed based on the seven-LEO-integrated solution. Another approach based on Galileo also solves this problem. The GPS satellites, multi-GNSS stations, and Galileo satellites with ground calibrated PCOs are processed jointly to calibrate the GPS z-PCOs and simultaneously determine a Galileo-based scale simultaneously. Based on the comparison and cross-check, a good agreement is shown between the LEO-based and Galileo-based methods. There is a slight improvement in the geocenter when including three Swarm satellites to the processing with about 80 ground stations over a half year. Based on the analysis in theory and the results derived from real data, an obvious enhancement to various aspects of GNSS by the integrated processing with LEOs is shown. More LEOs equipped with GNSS receivers and carefully calibrated PCOs are expected for further missions or even the next generation of GNSS.

Description: In dieser Arbeit wird eine Verbesserung der globalen Satellitennavigationssysteme (GNSS) durch die Einbindung von Satelliten in niedrigen Erdumlaufbahnen (LEOs) in eine gemeinsame präzise Bahnbestimmung (POD) vorgestellt. Das von den Vereinigten Staaten betriebene Global Positioning System (GPS) wird stellvertretend für alle GNSS untersucht. Die mit GNSS-Empfängern ausgestatteten LEOs ergänzen die Empfänger der Bodenstationen, vor allem in Regionen, in denen aus verschiedenen Gründen nur wenige Stationen verfügbar sind. Aufgrund der Orbithöhe und schnellen Bewegung der LEOs tragen diese nicht nur mit zusätzlichen Beobachtungen bei, sondern auch mit einer sich schnell verändernden Beobachtungsgeometrie. Darüber hinaus haben weltraumgestützte Beobachtungen zusätzliche Vorteile gegenüber bodengestützten Beobachtungen, z. B. werden Signale ohne den Einfluss der Troposphäre empfangen. LEOs stellen nicht nur kinematische Stationen für die GNSS-Satelliten dar, sondern bringen auch eine zusätzliche Bahndynamik in das integrierte System ein. Die durch diese Bahndynamik gegebenen Beschränkungen sind sowohl für die Bahnbestimmung der GNSS Satelliten als auch für weitere Parameter äußerst relevant. In dieser Arbeit werden die folgenden Themen behandelt: 1) Hintergrundinformationen und Grundprinzipien der POD von GNSS-Satelliten und LEOs, 2) eine separate POD von GNSS-Satelliten und LEOs, 3) eine integrierte POD, 4) die Schätzung der Antennen-Phasenzentrumsversätze (PCOs) der GPS-Satelliten und anderer geodätischer Parameter in der integrierten POD. Die separaten PODs bestätigen, dass die in dieser Studie verwendete Bahnmodellierungs- und Prozessierungskonfiguration der GNSS-Satelliten und LEOs mit dem aktuellen Stand der Forschung kompatibel ist. Die Bahnen der GNSS-Satelliten und LEOs erreichen eine Genauigkeit von wenigen Zentimetern. Es wurde eine effizientere Methode zur Erkennung von Ausreißern entwickelt, um die mit Hilfe von Pseudo-Range-Beobachtungen ermittelte Position zu verbessern. Ein Bodennetz mit 26 global dünn verteilten Stationen wird verwendet, um die Verbesserung der GPS-Bahnen durch die Integration von verschiedenen Teilgruppen der sieben LEOs GRACE-A/B, OSTM/Jason-2, Jason-3 und Swarm-A/B/C zu untersuchen. Bei der Einbeziehung aller sieben LEOs ergibt sich eine Verbesserung des 1D RMS Mittelwertes der GPS-Orbits von 34 % (von 37,5 mm auf 23,9 mm). Sowohl die Anzahl der weltraumgestützten Beobachtungen als auch die Geometrie der Bahnen der LEOs beeinflussen die GPS-Bahnen, wobei die Orbitgeometrie sich als der wichtigere Faktor erweist. Die geschätzten GPS PCOs werden durch die Einbeziehung von LEOs ebenfalls verbessert. Der formale Fehler der x- und y-Komponenten der GPS PCOs wird durch die zusätzlichen Beobachtungen und die größere Abdeckung des Nadirwinkels, den die LEOs während Perioden eines großen Sonnenstandswinkels mit sich bringen, erheblich reduziert. Die z-Komponente der GPS PCOs (z-PCO) ist mit dem Maßstabsfaktor des terrestrischen Referenzrahmens stark korreliert. Durch die Berücksichtigung der Bahndynamik der sieben LEOs in der Prozessierung werden ohne Fixierung des Maßstabes (d.h. ohne eine No-Net-Scale Bedingung) die Korrelationskoeffizienten zwischen den GPS z-PCOs und dem Maßstabsfaktor von 0,85 auf 0,30 reduziert. Folglich können zum einen die GPS z-PCOs unabhängig von einem externen Maßstab geschätzt werden und zum anderen kann ein rein GNSS-basierter Maßstabsfaktor bestimmt werden. Mit der integrierten Lösung mit sieben LEOs ergibt sich ein systemspezifischer Versatz der GPS z-PCOs von -25,5 cm relativ zu den vom International GNSS Service (IGS) veröffentlichten Werten. Ein anderer Ansatz basierend auf Galileo löst dieses Problem ebenfalls. Die GPS Satelliten, Multi-GNSS Bodenstationen und Galileo Satelliten mit bodenkalibrierten PCOs werden gemeinsam prozessiert, um die GPS z-PCOs zu kalibrieren und gleichzeitig einen Galileo-basierten Maßstabsfaktor zu bestimmen. Ein Vergleich zur Überprüfung zeigt eine hohe Übereinstimmung der LEO- und Galileo-basierten Methoden. Die Einbeziehung von drei Swarm Satelliten in eine Prozessierung mit etwa 80 Bodenstationen über ein halbes Jahr hinweg zeigt eine leichte Verbesserung des Geozentrums. Auf der Grundlage der theoretischen Analyse und der aus realen Daten abgeleiteten Ergebnisse zeigt sich eine deutliche Verbesserung verschiedener Aspekte der GNSS durch die Integration von LEOs. Es ist zu erwarten, dass mehr LEOs, ausgestattet mit GNSS-Empfängern und sorgfältig kalibrierten PCOs, für künftige Missionen oder sogar die nächste GNSS Generation eingesetzt werden.

Description: Water reinjection into the formation is an indispensable operation in many energy engineering practices. This operation involves a complex hydromechanical (HM) coupling process and sometimes even causes unpredictable disasters, such as induced seismicity. It is acknowledged that the relative magnitude and direction of the principal stresses significantly influence the HM behaviors of rocks during injection. However, due to the limitations of current testing techniques, it is still difficult to comprehensively conduct laboratory injection tests under various stress conditions, such as in triaxial extension stress states. To this end, a numerical study of HM changes in rocks during injection under different stress states is conducted. In this model, the saturated rock is first loaded to the target stress state under drainage conditions, and then the stress state is maintained and water is injected from the top to simulate the formation injection operation. Particular attention is given to the difference in HM changes under triaxial compression and extension stresses. This includes the differences in the pore pressure propagation, mean effective stress, volumetric strain, and stress-induced permeability. The numerical results demonstrate that the differential stress will significantly affect the HM behaviors of rocks, but the degree of influence is different under the two triaxial stress states. The HM changes caused by the triaxial compression stress states are generally greater than those of extension, but the differences decrease with increasing differential stress, indicating that the increase in the differential stress will weaken the impact of the stress state on the HM response. In addition, the shear failure p otential of fracture planes with various inclination angles is analyzed and summarized under different stress states. It is recommended that engineers could design suitable injection schemes according to different tectonic stress fields versus fault occurrence to reduce the risk of injection-induced seismicity.

Description: Subduction initiation induced by a hot and buoyant mantle plume head is unique among proposed subduction initiation mechanisms because it does not require pre-existing weak zones or other forces for lithospheric collapse. Since recognition of the first evidence of subduction nucleation induced by a mantle plume in the Late Cretaceous Caribbean realm, the number of studies focusing on other natural examples has grown. Here, we review numerical and physical modeling and geological-geochemical studies which have been carried out thus far to investigate onset of a new subduction zone caused by impingement of a mantle plume head. As geological-geochemical data suggests that plume-lithosphere interactions have long been important - spanning from the Archean to the present - modeling studies provide valuable information on the spatial and temporal variations in lithospheric deformation induced by these interactions. Numerical and physical modeling studies, ranging from regional to global scales, illustrate the key role of plume buoyancy, lithospheric strength and magmatic weakening above the plume head on plume-lithosphere interactions. Lithospheric/crustal heterogeneities, pre-existing lithospheric weak zones and external compressional/extensional forces may also change the deformation regime caused by plume-lithosphere interaction.

Description: The detection of transient events related to slow earthquakes in GNSS positional time series is key to understanding seismogenic processes in subduction zones. Here, we present a novel Principal and Independent Components Correlation Analysis (PICCA) method that allows for the temporal and spatial detection of transient signals. The PICCA is based on an optimal combination of the principal (PCA) and independent component analysis (ICA) of positional time series of a GNSS network. We assume that the transient signal is mostly contained in one of the principal or independent components. To detect the transient, we applied a method where correlations between sliding windows of each PCA/ICA component and each time series are calculated, obtaining the stations affected by the slow slip event and the onset time from the resulting correlation peaks. We first tested and calibrated the method using synthetic signals from slow earthquakes of different magnitudes and durations and modelled their effect in the network of GNSS stations in Chile. Then, we analyzed three transient events related to slow earthquakes recorded in Chile, in the areas of Iquique, Copiapó, and Valparaíso. For synthetic data, a 150 days event was detected using the PCA-based method, while a 3 days event was detected using the ICA-based method. For the real data, a long-term transient was detected by PCA, while a 16 days transient was detected by ICA. It is concluded that simultaneous use of both signal separation methods (PICCA) is more effective when searching for transient events. The PCA method is more useful for long-term events, while the ICA method is better suited to recognize events of short duration. PICCA is a promising tool to detect transients of different characteristics in GNSS time series, which will be used in a next stage to generate a catalog of SSEs in Chile.

Description: This paper describes the concept of an innovative, interdisciplinary, user-oriented earthquake warning and rapid response system coupled with a structural health monitoring system (SHM), capable to detect structural damages in real time. The novel system is based on interconnected decentralized seismic and structural health monitoring sensors. It is developed and will be exemplarily applied on critical infrastructures in Lower Rhine Region, in particular on a road bridge and within a chemical industrial facility. A communication network is responsible to exchange information between sensors and forward warnings and status reports about infrastructures’ health condition to the concerned recipients (e.g., facility operators, local authorities). Safety measures such as emergency shutdowns are activated to mitigate structural damages and damage propagation. Local monitoring systems of the infrastructures are integrated in BIM models. The visualization of sensor data and the graphic representation of the detected damages provide spatial content to sensors data and serve as a useful and effective tool for the decision-making processes after an earthquake in the region under consideration.

Description: The equatorial electrojet (EEJ) represents a ribbon of intense electric current flowing in the ionospheric E region on the dayside along the dip-equator. The primary reason for the high current density is the geometry of the geomagnetic field with its horizontal field lines at these latitudes. This enables a greatly enhanced electrical conductivity in the ionospheric E layer over a latitudinal width of about 600 km. Any low-latitude electric field in that region will give rise to significant currents in that channel. In this chapter we will first present some historical observations that lead to the discovery and early characterization of the EEJ. In those years, most of the studies were based on magnetic signatures observed on ground. Significant progress in understanding the EEJ could be made when measurements from low-Earth orbiting satellites became routinely available. Subsequently, we describe the electrodynamics that governs the EEJ properties. These can be used for predicting important EEJ features. Besides the physics-based models, an empirical model based on a large observational data set is presented. From this model, the main climatological characteristics of the EEJ can be deduced, such as diurnal, annual and longitudinal variations, as well as dependencies on solar and magnetic activities. The tidal modulation plays an important role for the temporal and spatial variation of the EEJ intensity. We describe both the influences of solar and lunar tides. At times the commonly eastward EEJ current reverses to westward. Here the most important processes are described that cause the counter equatorial electrojet. In the end, the prime features of the EEJ are summarized and remaining open issues are presented.

Description: The LEXIS project (Large-scale EXecution for Industry & Society, H2020 GA825532) provides a platform for optimised execution of Cloud-HPC workflows, reducing computation time and increasing energy efficiency. The system will rely on advanced, distributed orchestration solutions (Atos YSTIA Suite, with Alien4Cloud and Yorc, based on TOSCA), the High-End Application Execution Middleware HEAppE, and new hardware capabilities for maximising efficiency in data processing, analysis and transfer (e.g. Burst Buffers with GPU- and FPGA-based data reprocessing). LEXIS handles computation tasks and data from three Pilots, based on representative and demanding HPC/Cloud-Computing use cases in Industry (SMEs) and Science: i) Simulations of complex turbomachinery and gearbox systems in Aeronautics, ii) Tsunami simulations and earthquake loss assessments which are time-constrained to enable immediate warnings and to support well-informed decisions, and iii) Weather and Climate simulations where massive amounts of in-situ data are assimilated to improve forecasts. A user-friendly LEXIS web portal, as a unique entry point, will provide access to data as well as workflow-handling and remote visualisation functionality. As part of its back-end, LEXIS builds an elaborate system for the handling of input, intermediate and result data. At its core, a Distributed Data Infrastructure (DDI) ensures the availability of LEXIS data at all participating HPC sites, which will be federated with a common LEXIS Authentication and Authorisation Infrastructure (with unified security model, user database and policies). The DDI leverages best of breed data-management solutions from EUDAT, such as B2SAFE (based on iRODS) and B2HANDLE. REST APIs on top of it will ensure a smooth interaction with LEXIS workflows and the orchestration layer. Last, but not least, the DDI will provide functionalities for Research Data Management following the FAIR principles (“Findable, Interoperable, Accessible, Reusable”), e.g. DOI acquisition, which helps to publish and disseminate open data products.

Description: The determination of seismic risk is the foundation for risk mitigation decision-making and a key step in risk management. Large corporations and other enterprises (e.g., local governments) analyze their 'portfolio' of properties, to determine how to best allocate limited funds for structural strengthening of buildings, or other risk reduction measures such as emergency planning. When assessing the seismic vulnerability of buildings, it is essential to first establish the project objectives, before subsequently choosing the most appropriate strategy and tools necessary for building assessment and fulfillment of these objectives. It is also extremely important to understand the difference between the detailed approaches used for individual building assessment and those methods most efficient for larger scale analysis, pursued for city center assessment. While the latter results can be used as a general measure of seismic risk for different types of buildings, the actual seismic risk for any individual building may vary considerably and will depend upon its exact configuration and condition. In this study, some historical masonry buildings located in Alsace France are considered and the dynamic characteristics of these structures were estimated by the analysis of seismic noise recordings by sensors installed at each floor of the buildings under study. The estimated dynamic properties for small amplitude vibrations of these historical structures were used to derive fragility curves through vulnerability models with different level of complexity and accuracy. These fragility curves have been calculated using incremental dynamic analysis for the seismic demands generally imposed upon linear and slightly nonlinear models of single and multiple degrees of freedom, which is the case for the effects of induced seismicity. Considering the latter case of induced seismicity, the vulnerability assessment requires the expected damage to refer to non-structural components. The conclusions through comparison of the results of this study in terms of refinement of the verified structural models will prove useful for both local end-users and industrial stakeholders, with a clear perspective for a better understanding of the risk related to induced and triggered seismicity and its sound management.

Description: In order to systematically and thoroughly study the crust-mantle structure and deep geodynamic processes of basins, mountains and plateaus of western China, we proposed and led the implementation of the ANTILOPE Project (Array Network of Tibetan International Lithospheric Observation and Probe Experiments) in 2003. So far, we have completed four 2D broadband arrays, ANTILOPE-I to ANTILOPE-IV, on the Tibetan Plateau, and deployed two 3D broadband arrays, ANTILOPE-V and ANTILOPE-VI, at the eastern and western Himalayan syntaxis, respectively. In addition, we included in our study framework nine comprehensive geophysical observation profiles previously obtained from the Junggar Basin, Tienshan Orogenic Belt, Tarim Basin, Altyn Orogenic Belt, and Qaidam Basin. Through the implementation of the ANTILOPE Project, we collected a large amount of high-quality, comprehensive first-hand observational data from western China (including the basin-mountain system surrounding the Tibetan Plateau in the northwest and the Tibetan Plateau in the southwest). The fine crust-mantle structure systematically reveals the deep geodynamic processes of the basin-mountain-plateau geosystem in western China. The up-to-date main research progress can be summarized as follows. The structure and properties of the basement of the Junggar Basin have been determined, and the basement structural framework has been optimized. A new intracontinental orogenic model of lithospheric subduction with crustal interlayer intrusion in the Tienshan Orogenic Belt has been established, which reveals the fate of the 44% shortened Tienshan lithosphere after the India-Eurasia collision and the conversion mechanism from ocean-continent subduction to continent-continent collision and subduction. Our results reveal the basin-mountain contact relationship between the Tarim Basin, Altyn Orogenic Belt and Qaidam Basin. We have obtained the deep geometric, kinematic and geodynamic evidence for the clockwise rotation of the Tarim Basin, and determined the collision boundary between the Indian and the Eurasian Plates under the Tibetan Plateau. We also found that the current Tibetan Plateau consists of the Indian Plate in the south, the Eurasian Plate in the north, and the giant crush zone-also called the "Tibetan Plate"-between them. For the first time, the respective lithospheric bottom boundaries are determined; two end-member models of plateau deformation are corrected; and the constraints of deep structures on the surface topography are established. Our result systematically reveals the changing pattern and controlling factors of the horizontal advancing distance and the subduction angle of the Indian Plate along the Himalayan Orogenic Belt. By combining a huge observation network with comprehensive geophysical detection technologies, the ANTILOPE Project adopts different methods, including geophysical, geological and geochemical methods, to reveal the subduction of the Indian continent, the development of the giant crush zone in Tibet, the clockwise rotation of the Tarim Block, the accelerated closure of the western water vapor channel, and the advance of aridification and desertification in northwest China and their constraints on surface topography, oil and gas resources, and environmental variations. The above results have promoted the development of the Earth system theory in the Tibetan Plateau. © 2021, Editorial Office of Earth Science Frontiers. All right reserved.

Description: Yield penetration occurs from the critical section towards both the shear span and the support of reinforced concrete columns; physically it refers to the extent of the nonlinear region and determines the pullout slip measured at the critical section. Contrary to the fixed design values adopted by codes of assessment, the yield penetration length is actually the only consistent definition of the notion of the plastic hinge length, whereas the latter determines the contribution of pullout rotation to column drift and column stiffness. Yield penetration in the anchored reinforcing bar inside the shear span of the column where it occurs, destroys interfacial bond between bar and concrete and reduces the strain development capacity of the reinforcement. This affects the plastic rotation of the member by increasing the contribution of bar slippage. Results obtained from the analytical procedures introduced in this paper are compared with experimental evidence from tests conducted on circular reinforced concrete bridge piers under cyclic loading designed and detailed according with Eurocode 8-II (2005). It can be seen that the produced monotonic envelope for applied shear load versus the slip of the extreme tensile reinforcing bar of the circular section of the bridge piers under study is in good agreement with the experimental results.

Description: Spatiotemporal variations of pressure, temperature, water vapour content in the atmosphere lead to significant delays in interferometric synthetic aperture radar (InSAR) measurements of deformations in the ground. One of the key challenges in increasing the accuracy of ground deformation measurements using InSAR is to produce robust estimates of the tropospheric delay. Tropospheric models like ERA-Interim can be used to estimate the total tropospheric delay in interferograms in remote areas. The problem with using ERA-Interim model for interferogram correction is that after the tropospheric correction, there are still some residuals left in the interferograms, which can be mainly attributed to turbulent troposphere. In this study, we propose a Generative Adversarial Network (GAN) based approach to mitigate the phase delay caused by troposphere. In this method, we implement a noise to noise model, where the network is trained only with the interferograms corrupted by tropospheric noise. We applied the technique over 116 large scale 800 km long interfergrams formed from Sentinel-1 acquisitions covering a period from 25th October, 2014 to 2nd November, 2017 from descending track numbered 108 over Iran. Our approach reduces the root mean square of the phase values of the interferogram 64% compared to those of the original interferogram and by 55% in comparison to the corresponding ERA-Interim corrected version. © 2021 Copernicus GmbH. All rights reserved.

Description: The Environmental Mapping and Analysis Program (EnMAP) is a spaceborne German hyperspectral satellite mission that aims at monitoring and characterizing the Earth’s environment on a global scale. This paper presents an update of the mission status with developments from the space and the ground segment. © 2021 The Author (s).

Description: Many areas across Iran are subject to land subsidence, a sign of exceeding stress due to the over-extraction of groundwater during the past decades. This paper uses a huge dataset of Sentinel-1, acquired since 2014 in 66 image frames of 250×250km, to identify and monitor land subsidence across Iran. Using a two-step time series analysis, we first identify subsidence zones at a medium scale of 100m across the country. For the first time, our results provide a comprehensive nationwide map of subsidence in Iran and recognize its spatial distribution and magnitude. Then, in the second step of analysis, we quantify the deformation time series at the highest possible resolution to study its impact on civil infrastructure. The results spots the hazard posed by land subsidence to different infrastructure. Examples of road and railways affected by land subsidence hazard in Tehran and Mashhad, two of the most populated cities in Iran, are presented in this study. © 2021 International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. All rights reserved.

Description: The idea of near real-time deformation analysis using Synthetic Aperture Radar (SAR) data as a response to natural and anthropogenic disasters has been an interesting topic in the last years. A major limiting factor for this purpose has been the non-availability of both spatially and temporally homogeneous SAR datasets. This has now been resolved thanks to the SAR data provided by the Sentinel-1A/B missions, freely available at a global scale via the Copernicus program of the European Space Agency (ESA). Efficient InSAR analysis in the era of Sentinel demands working with cloud-based platforms to tackle problems posed by large volumes of data. In this study, we explore a variety of existing cloud-based platforms for Multioral Interferometric SAR (MTI) analysis and discuss their opportunities and limitations. © 2021 International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives. All rights reserved.

Description: The following authors were omitted from the original version of this Data Descriptor: Markus Reichstein and Nicolas Vuichard. Both contributed to the code development and N. Vuichard contributed to the processing of the ERA-Interim data downscaling. Furthermore, the contribution of the co-author Frank Tiedemann was re-evaluated relative to the colleague Corinna Rebmann, both working at the same sites, and based on this re-evaluation a substitution in the co-author list is implemented (with Rebmann replacing Tiedemann). Finally, two affiliations were listed incorrectly and are corrected here (entries 190 and 193). The author list and affiliations have been amended to address these omissions in both the HTML and PDF versions. © 2021, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.

Description: The MW7.1 Anchorage earthquake is the most destructive earthquake since the 1964 MW9.2 great Alaska earthquake in the United States. In this study, high-rate GPS data and near-field broadband seismograms are used in separate and joint inversions by the generalized Cut-and-Paste (gCAP) method to estimate the focal mechanism. In order to investigate the influence of crustal velocity structure on the focal mechanism inversion results, two velocity models (Crust1.0 and Alaska Earthquake Center (AEC)) are used for detailed comparison and analysis. The results show that: (1) The two nodal planes of the optimal double-couple solution are nearly north-south striking, with dip angles of about 30° and 60°respectively, and the centroid focal depth is 54–55 km, which is an intraplate normal fault event. (2) The inversion results for the two types of data and the two velocity models are consistent with some previous studies, which indicates that the results are stable and reliable. The more accurate velocity structure model is helpful for focal mechanism inversion of the complex earthquake. (3) The inclusion of high-rate GPS data in joint inversion provides a more effective constraint on centroid depth. © 2021 The Authors

Description: The data result from a sedimentological and geochemical multiproxy approach to study a Holocene palaeolake record north of Tayma, NW Saudi Arabia. The lacustrine, partly varved record was analysed in the frame of the DFG founded project CLEAR “Holocene climatic events in Northern Arabia - Environmental changes and human response”. The Tayma palaeolake record comprises continuous lacustrine sediments covering the early to mid-Holocene. The dataset allows detailed palaeoenvironmental and palaeoclimate interpretations from the early Holocene humid period and subsequent dryer conditions during the mid-Holocene. The dataset is part of the supplementary material to “Neugebauer et al. (submitted)” where further details about the locality, core composite, age model, sampling and analytical methods and data processing are given. The data are provided in individual xlsx-files per type of data. The different files include sedimentological and geochemical data determined on the ca. 6 m long master core from the sediment cores (Tay 220/221 and Tay 253/254/255/256): (i) sediment core microfacies data, (ii) bulk total organic carbon (TOC) and carbonate delta13C_carb and delta18O_carb data, (iii) single aragonite laminae delta13C_arag and delta18O_arag data, (iv) concentrations of n-alkanes n-C29 and n-C31 and hydrogen isotope composition deltaD, (v) XRF core scanning data. All data are provided on composite depths and age scales (based on Bayesian age modelling of radiocarbon dates, varve counting and one tephrochronological anchor; see details in the Supplementary material of Neugebauer et al., submitted).

Description: We present an extensive dataset of highly accurate absolute travel times and travel-time residuals of teleseismic P waves recorded by the AlpArray Seismic Network and complementary field experiments in the years from 2015 to 2019. The dataset is intended to serve as the basis for teleseismic travel-time tomography of the upper mantle below the greater Alpine region. In addition, the data may be used as constraints in full-waveform inversion of AlpArray recordings. The dataset comprises about 170 000 onsets derived from records filtered to an upper-corner frequency of 0.5 Hz and 214 000 onsets from records filtered to an upper-corner frequency of 0.1 Hz. The high accuracy of absolute and residual travel times was obtained by applying a specially designed combination of automatic picking, waveform cross-correlation and beamforming. Taking travel-time data for individual events, we are able to visualise in detail the wave fronts of teleseismic P waves as they propagate across AlpArray. Variations of distances between isochrons indicate structural perturbations in the mantle below. Travel-time residuals for individual events exhibit spatially coherent patterns that prove to be stable if events of similar epicentral distance and azimuth are considered. When residuals for all available events are stacked, conspicuous areas of negative residuals emerge that indicate the lateral location of subducting slabs beneath the Apennines and the western, central and eastern Alps. Stacking residuals for events from 90∘ wide azimuthal sectors results in lateral distributions of negative and positive residuals that are generally consistent but differ in detail due to the differing direction of illumination of mantle structures by the incident P waves. Uncertainties of travel-time residuals are estimated from the peak width of the cross-correlation function and its maximum value. The median uncertainty is 0.15 s at 0.5 Hz and 0.18 s at 0.1 Hz, which is more than 10 times lower than the typical travel-time residuals of up to ±2 s. Uncertainties display a regional dependence caused by quality differences between temporary and permanent stations as well as site-specific noise conditions.

Description: The Alpine orogeny is characterized by tectonic sequences of subduction and collision accompanied by break-off events and possibly preceded by a flip of subduction polarity. The tectonic evolution of the transition to the Eastern Alps has thus been under debate. The dense SWATH-D seismic network as a complementary experiment to the AlpArray seismic network provides unprecedented lateral resolution to address this ongoing discussion. We analyze the shear-wave splitting of this data set including stations of the AlpArray backbone in the region to obtain new insights into the deformation at depth from seismic anisotropy. Previous studies indicate two-layer anisotropy in the Eastern Alps. This is supported by the azimuthal pattern of the measured fast axis direction across all analyzed stations. However, the temporary character of the deployment requires a joint analysis of multiple stations to increase the number of events adding complementary information of the anisotropic properties of the mantle. We, therefore, perform a cluster analysis based on a correlation of energy tensors between all stations. The energy tensors are assembled from the remaining transverse energy after the trial correction of the splitting effect from two consecutive anisotropic layers. This leads to two main groups of different two-layer properties, separated approximately at 13°E. We identify a layer with a constant fast axis direction (measured clockwise with respect to north) of about 60° over the whole area, with a possible dip from west to east. The lower layer in the west shows N–S fast direction and the upper layer in the east shows a fast axis of about 115°. We propose two likely scenarios, both accompanied by a slab break-off in the eastern part. The continuous layer can either be interpreted as frozen-in anisotropy with a lithospheric origin or as an asthenospheric flow evading the retreat of the European slab that would precede the break-off event. In both scenarios, the upper layer in the east is a result of a flow through the gap formed in the slab break-off. The N–S direction can be interpreted as an asthenospheric flow driven by the retreating European slab but might also result from a deep-reaching fault-related anisotropy.

Description: We perform a teleseismic P-wave travel-time tomography to examine the geometry and structure of subducted lithosphere in the upper mantle beneath the Alpine orogen. The tomography is based on waveforms recorded at over 600 temporary and permanent broadband stations of the dense AlpArray Seismic Network deployed by 24 different European institutions in the greater Alpine region, reaching from the Massif Central to the Pannonian Basin and from the Po Plain to the river Main. Teleseismic travel times and travel-time residuals of direct teleseismic P waves from 331 teleseismic events of magnitude 5.5 and higher recorded between 2015 and 2019 by the AlpArray Seismic Network are extracted from the recorded waveforms using a combination of automatic picking, beamforming and cross-correlation. The resulting database contains over 162 000 highly accurate absolute P-wave travel times and travel-time residuals. For tomographic inversion, we define a model domain encompassing the entire Alpine region down to a depth of 600 km. Predictions of travel times are computed in a hybrid way applying a fast TauP method outside the model domain and continuing the wave fronts into the model domain using a fast marching method. We iteratively invert demeaned travel-time residuals for P-wave velocities in the model domain using a regular discretization with an average lateral spacing of about 25 km and a vertical spacing of 15 km. The inversion is regularized towards an initial model constructed from a 3D a priori model of the crust and uppermost mantle and a 1D standard earth model beneath. The resulting model provides a detailed image of slab configuration beneath the Alpine and Apenninic orogens. Major features are a partly overturned Adriatic slab beneath the Apennines reaching down to 400 km depth still attached in its northern part to the crust but exhibiting detachment towards the southeast. A fast anomaly beneath the western Alps indicates a short western Alpine slab whose easternmost end is located at about 100 km depth beneath the Penninic front. Further to the east and following the arcuate shape of the western Periadriatic Fault System, a deep-reaching coherent fast anomaly with complex internal structure generally dipping to the SE down to about 400 km suggests a slab of European origin limited to the east by the Giudicarie fault in the upper 200 km but extending beyond this fault at greater depths. In its eastern part it is detached from overlying lithosphere. Further to the east, well-separated in the upper 200 km from the slab beneath the central Alps but merging with it below, another deep-reaching, nearly vertically dipping high-velocity anomaly suggests the existence of a slab beneath the eastern Alps of presumably the same origin which is completely detached from the orogenic root. Our image of this slab does not require a polarity switch because of its nearly vertical dip and full detachment from the overlying lithosphere. Fast anomalies beneath the Dinarides are weak and concentrated to the northernmost part and shallow depths. Low-velocity regions surrounding the fast anomalies beneath the Alps to the west and northwest follow the same dipping trend as the overlying fast ones, indicating a kinematically coherent thick subducting lithosphere in this region. Alternatively, these regions may signify the presence of seismic anisotropy with a horizontal fast axis parallel to the Alpine belt due to asthenospheric flow around the Alpine slabs. In contrast, low-velocity anomalies to the east suggest asthenospheric upwelling presumably driven by retreat of the Carpathian slab and extrusion of eastern Alpine lithosphere towards the east while low velocities to the south are presumably evidence of asthenospheric upwelling and mantle hydration due to their position above the European slab.

Description: In this study, we analyzed a large seismological dataset from temporary and permanent networks in the southern and eastern Alps to establish high-precision hypocenters and 1-D VP and VP/VS models. The waveform data of a subset of local earthquakes with magnitudes in the range of 1–4.2 ML were recorded by the dense, temporary SWATH-D network and selected stations of the AlpArray network between September 2017 and the end of 2018. The first arrival times of P and S waves of earthquakes are determined by a semi-automatic procedure. We applied a Markov chain Monte Carlo inversion method to simultaneously calculate robust hypocenters, a 1-D velocity model, and station corrections without prior assumptions, such as initial velocity models or earthquake locations. A further advantage of this method is the derivation of the model parameter uncertainties and noise levels of the data. The precision estimates of the localization procedure is checked by inverting a synthetic travel time dataset from a complex 3-D velocity model and by using the real stations and earthquakes geometry. The location accuracy is further investigated by a quarry blast test. The average uncertainties of the locations of the earthquakes are below 500 m in their epicenter and ∼ 1.7 km in depth. The earthquake distribution reveals seismicity in the upper crust (0–20 km), which is characterized by pronounced clusters along the Alpine frontal thrust, e.g., the Friuli-Venetia (FV) region, the Giudicarie–Lessini (GL) and Schio-Vicenza domains, the Austroalpine nappes, and the Inntal area. Some seismicity also occurs along the Periadriatic Fault. The general pattern of seismicity reflects head-on convergence of the Adriatic indenter with the Alpine orogenic crust. The seismicity in the FV and GL regions is deeper than the modeled frontal thrusts, which we interpret as indication for southward propagation of the southern Alpine deformation front (blind thrusts).

Description: The Alpine Fault zone in New Zealand marks a major transpressional plate boundary that is late in its typical earthquake cycle. Understanding the subsurface structures is crucial to understand the tectonic processes taking place. A unique seismic survey including 2D lines, a 3D array, and borehole recordings, has been performed in the Whataroa Valley and provides new insights into the Alpine Fault zone down to ∼2 km depth at the location of the Deep Fault Drilling Project (DFDP)-2 drill site. Seismic images are obtained by focusing prestack depth migration approaches. Despite the challenging conditions for seismic imaging within a sediment filled glacial valley and steeply dipping valley flanks, several structures related to the valley itself as well as the tectonic fault system are imaged. A set of several reflectors dipping 40°–56° to the southeast are identified in a ∼600 m wide zone that is interpreted to be the minimum extent of the damage zone. Different approaches image one distinct reflector dipping at ∼40°, which is interpreted to be the main Alpine Fault reflector located only ∼100 m beneath the maximum drilled depth of the DFDP-2B borehole. At shallower depths (z 〈 0.5 km), additional reflectors are identified as fault segments with generally steeper dips up to 56°. Additionally, a glacially over-deepened trough with nearly horizontally layered sediments and a major fault (z 〈 0.5 km) are identified 0.5–1 km south of the DFDP-2B borehole. Thus, a complex structural environment is seismically imaged and shows the complexity of the Alpine Fault at Whataroa.

Description: This dataset was collected during field-based monitoring in the Kali Gandaki River catchment be-tween the years 2013 and 2017. The monitoring aims to understand the hydrological fluxes and feedback with weathering and erosion processes across the mountain range. The Kali Gandaki River sources its water in the North and traverses through the Himalayan Mountain Range, along a north-south transect. The field-based monitoring comprises targeted field campaigns to revisit locations at different years and seasons in order to constrain the annual and intra-annual variability. This is complemented by permanent installations and routine river and rain sampling at two loca-tions, Lete and Purtighat. Lete is situated at the orographic barrier, at ~2500 m asl. and the up-stream catchment integrates the northern part of the Himalayan Range as well as some of the southern edge of the Tibetan Plateau. Purtighat is located further south and integrates the north-ern part as well as south-facing flanks of the Higher and Lower Himalayas. At both locations, auto-mated river monitoring is installed as well as a trained station ward for daily routine sampling. At Lete, rainfall samples are obtained on a daily resolution during the monsoon. This sampling was not feasible at Purtighat for logistic reasons. Instead, rain was sampled daily in Kathmandu. This dataset contains five tables of stable water isotope analysis. One containing grab samples from the Kali Gandaki river in its vicinities and 4 tables with time series sampling from the Kali Gandaki River and from rainfall.

Description: The Alpine mountains in central Europe are characterized by a heterogeneous crust accumulating different tectonic units and blocks in close proximity to sedimentary foreland basins. Centroid moment tensor inversion provides insight into the faulting mechanisms of earthquakes and related tectonic processes but is significantly aggravated in such an environment. Thanks to the dense AlpArray seismic network and our flexible bootstrap-based inversion tool Grond, we are able to test different setups with respect to the uncertainties of the obtained moment tensors and centroid locations. We evaluate the influence of frequency bands, azimuthal gaps, input data types, and distance ranges and study the occurrence and reliability of non-double-couple (DC) components. We infer that for most earthquakes (Mw≥3.3) a combination of time domain full waveforms and frequency domain amplitude spectra in a frequency band of 0.02–0.07 Hz is suitable. Relying on the results of our methodological tests, we perform deviatoric moment tensor (MT) inversions for events with Mw〉3.0. Here, we present 75 solutions for earthquakes between January 2016 and December 2019 and analyze our results in the seismotectonic context of historical earthquakes, seismic activity of the last 3 decades, and GNSS deformation data. We study regions of comparably high seismic activity during the last decades, namely the Western Alps, the region around Lake Garda, and the eastern Southern Alps, as well as clusters further from the study region, i.e., in the northern Dinarides and the Apennines. Seismicity is particularly low in the Eastern Alps and in parts of the Central Alps. We apply a clustering algorithm to focal mechanisms, considering additional mechanisms from existing catalogs. Related to the N–S compressional regime, E–W-to-ENE–WSW-striking thrust faulting is mainly observed in the Friuli area in the eastern Southern Alps. Strike-slip faulting with a similarly oriented pressure axis is observed along the northern margin of the Central Alps and in the northern Dinarides. NW–SE-striking normal faulting is observed in the NW Alps, showing a similar strike direction to normal faulting earthquakes in the Apennines. Both our centroid depths and hypocentral depths in existing catalogs indicate that Alpine seismicity is predominantly very shallow; about 80 % of the studied events have depths shallower than 10 km.

Description: This deliverable summarises the methodology and results of the data collection for the European Fluid Atlas by the REFLECT project partners.

Description: We have performed a combined experimental and theoretical study of ethane and methane at high pressures up to 120 GPa at 300 K using x-ray diffraction and Raman spectroscopy and the USPEX ab-initio evolutionary structural search algorithm, respectively. For ethane, we have determined the crystallization point, for room temperature, at 2.7 GPa and also the low pressure crystal structure (Phase A). This crystal structure is orientationally disordered (plastic phase) and deviates from the known crystal structures for ethane at low temperatures. Moreover, a pressure induced phase transition has been identified, for the first time, at 13.6 GPa to a monoclinic phase B, the structure of which is solved based on a good agreement of the experimental results and theoretical predictions. For methane, our x-ray diffraction (XRD) measurements are in agreement with the previously reported high-pressure structures and equation of state (EOS). We have determined the EOSs of ethane and methane, which provides a solid basis for the discussion of their relative stability at high pressures.

Description: The effects of ion irradiation on the surface and the subsurface of synthetic diamonds were characterized by using optical microscopy, atomic force microscopy, Raman spectroscopy, x-ray reflectivity, electron backscatter diffraction, and resistivity measurements. Irradiation experiments with 14 MeV Au6+ ions with fluences up to 2,4 x 10 15 ions/cm2 were carried out on synthetic single crystal diamonds, grown either at high pressure or by chemical vapor deposition, and on polycrystalline samples with high boron concentrations. We show that the ion irradiation-induced changes to the surface and subsurface of diamonds are rather complex and, especially in the first few nanometers, more severe than generally considered. We establish a model describing the changes in density, defect concentration, topology, crystallinity, and bonding from the surface down to the first few micrometers of the irradiated diamond.

Description: The tropical Northern Andes of Colombia are one the world's most biodiverse places, offering an ideal location for unraveling the linkages between the geodynamic forces that build topography and the evolution of the biota that inhabit it. In this study, we utilize geomorphic analysis to characterize the topography of the Western and Central Cordilleras of the Northern Andes to identify what drives landscape evolution in the region. We supplement our topographic analysis with erosion rate estimates based on gauged suspended sediment loads and river incision rates from volcanic sequences. In the northern Central Cordillera, an elevated low-relief surface (2500 m in elevation, ~40 × 110 km in size) with quasi-uniform lithology and surrounded by knickpoints, indicates a recent increase in rock and surface uplift rate. Whereas the southern segment of the Central Cordillera shows substantially higher local relief and mostly well graded river profiles consistent with longer term uplift-rate stability. We also identify several areas of major drainage reorganization, including captures and divide migrations. These changes in the topography coincide with the proposed location of a slab tear and flat slab subduction under the northern Central Cordillera, as well as with a major transition in the channel slope of the Cauca River. We identify slab flattening as the most likely cause of strong and recent uplift in the Northern Andes leading to ~2 km of surface uplift since 8–4 Ma. Large scale drainage reorganization of major rivers is likely driven by changes in upper plate deformation in relation to development of the flat slab subduction geometry; however, south of the slab tear other factors, such as emplacement of volcanic rocks, also play an important role. Several biologic observations above the area of slab flattening suggest that surface uplift isolated former lowland species on the high elevation plateaus, and drainage reorganization may have influenced the distribution of aquatic species.

Description: The main objective of the work package 2 of the REFLECT project is to characterise relevant fluid properties and their reactions for saline fluids (type C). One of the specific goals was to collect fluid samples from several saline fluids from geothermal sites across Europe, determine their properties, and thus contribute to the Fluid Atlas (WP3). Additionally, the REFLECT team will compare those field data with data from lab experiments performed at near natural conditions. Samples of type C fluids were taken from several sites in Germany, Austria, Belgium and the Netherlands. The samples were analysed for major and minor ions, dissolved gases and isotopes.

Description: In the present study, the structure of sedimentary basins in the eastern Asia Arctic zone is analysed by employing the approach based on decompensative gravity anomalies. Two obtained models, differing in their initial conditions, provide thickness and density of sediments in the study area. They demonstrate essentially new details on the structure, shape, and density of the sedimentary basins. Significant changes in the sedimentary thickness and the depo-centre location have been found for the Anadyr Basin in its continental part. Also, new details on the sedimentary thickness distribution have been revealed for the central part of the Penzhin and Pustorets basins; for the latter, the new location of the depo-centre has been identified. The new model agrees well with the seismic data on the sedimentary thickness for the offshore part of the Chauna Basin confirming that the method is robust. The most significant lateral redistribution of the thickness has been found for the Lower Cretaceous coal-bearing strata in the northern part of the Zyryanka Basin, where the connection of two coal-bearing zones, which was not previously mapped, has been identified. Also, the new details on the sedimentary thickness distribution have been discovered for the Primorsk Basin. Therefore, the new results substantially improve our knowledge about the region, since previous geological and geophysical studies were unsystematic, sparse, and limited in depth. Thus, the implementation of the decompensative gravity anomalies approach provides a better understanding of the evolution of the sedimentary basins and the obtained results can be used for planning future detailed studies in the area.

Description: Der Vergleich der neuen Erdbebengefährdungskarten für die Schweiz, Deutschland, Österreich und für Frankreich, die für die Nationalen Anhänge zum Eurocode 8 entwickelt wurden, ist Gegenstand dieser Studie. Die vorgestellte gemeinsame Karte überdeckt den südlichen Teil Deutschlands samt angrenzender Gebiete der genannten Nachbarländer. Die Parametrisierung der Karte erfolgt für die Spitzenbodenbeschleunigung, für eine mittlere Wiederholungsperiode von 475 Jahren, für MedianWerte und für einen Untergrund mit einer mittleren Scherwellengeschwindigkeit der obersten 30 m von 800 m/s. Entlang des Grenzverlaufs zwischen Deutschland und den südlichen Nachbarländern zeigen die Konturlinien der unabhängig voneinander berechneten Erdbebengefährdungskarten insgesamt eine erstaunlich gute Übereinstimmung. Das gilt insbesondere für Gebiete relativ erhöhter Erdbebengefährdung. Diese gute bis sehr gute Übereinstimmung kann als Indiz für die Belastbarkeit der Einschätzungen angesehen werden.

Description: Knowledge of pressure-dependent static and dynamic moduli of porous reservoir rocks is of key importance for evaluating geological setting of a reservoir in geo-energy applications. We examined experimentally the evolution of static and dynamic bulk moduli for porous Bentheim sandstone with increasing confining pressure up to about 190 MPa under dry and water-saturated conditions. The static bulk moduli (Ks) were estimated from stress–volumetric strain curves while dynamic bulk moduli (Kd) were derived from the changes in ultrasonic P- and S- wave velocities (~ 1 MHz) along different traces, which were monitored simultaneously during the entire deformation. In conjunction with published data of other porous sandstones (Berea, Navajo and Weber sandstones), our results reveal that the ratio between dynamic and static bulk moduli (Kd/Ks) reduces rapidly from about 1.5 − 2.0 at ambient pressure to about 1.1 at high pressure under dry conditions and from about 2.0 − 4.0 to about 1.5 under water-saturated conditions, respectively. We interpret such a pressure-dependent reduction by closure of narrow (compliant) cracks, highlighting that Kd/Ks is positively correlated with the amount of narrow cracks. Above the crack closure pressure, where equant (stiff) pores dominate the void space, Kd/Ks is almost constant. The enhanced difference between dynamic and static bulk moduli under water saturation compared to dry conditions is possibly caused by high pore pressure that is locally maintained if measured using high-frequency ultrasonic wave velocities. In our experiments, the pressure dependence of dynamic bulk modulus of water-saturated Bentheim sandstone at effective pressures above 5 MPa can be roughly predicted by both the effective medium theory (Mori–Tanaka scheme) and the squirt-flow model. Static bulk moduli are found to be more sensitive to narrow cracks than dynamic bulk moduli for porous sandstones under dry and water-saturated conditions.

Description: The potential of vegetation recovery through resprouting of plant tissue from buds after the removal of aboveground biomass is a key resilience strategy for populations under abrupt environmental change. Resprouting leads to fast regeneration, particularly after the implementation of mechanical mowing as part of active management for promoting open habitats. We investigated whether recovery dynamics of resprouting and the threat of habitat conversion can be predicted by optical and structural stand traits derived from drone imagery in a protected heathland area. We conducted multivariate regression for variable selection and random forest regression for predictive modeling using 50 spectral predictors, textural features and height parameters to quantify Calluna resprouting and grass invasion in before-mowing images that were related to vegetation recovery in after-mowing imagery. The study reveals that Calluna resprouting can be explained by significant optical predictors of mainly green reflectance in parental individuals. In contrast, grass encroachment is identified by structural canopy properties that indicate before-mowing grass interpenetration as starting points for after-mowing dispersal. We prove the concept of trait propagation through time providing significant derivates for a low-cost drone system. It can be utilized to build drone-based decision support systems for evaluating consequences and requirements of habitat management practice.

Description: The relationship between River Ammer flood frequency variability, extreme summer climate over Europe, and solar forcing is investigated. First, we used observational data to evaluate extreme weather and climate anomaly patterns associated with flood and solar forcing as well as the possible dynamical mechanisms behind them. Then, the annual resolution flood layer record from the Lake Ammer sediments is analysed to evaluate millennial‐scale variability of floods and possible related extreme climate patterns back to 5,500 years BP. A composite analysis reveals that observed River Ammer flood frequency variability at interannual to multidecadal time scales is connected to large‐scale extreme precipitation and temperature patterns. From a synoptic‐scale perspective, the extreme precipitation pattern associated with floods is related to an increase in the frequency of high upper‐level potential vorticity (PV) events over western Europe and a decrease over eastern Europe and western Russia. Increased (decreased) frequency of upper‐level high PV events is related to more (less) surface extreme precipitation occurrence. Furthermore, we show that increased frequency of upper‐level high PV events over western Europe is associated with enhanced blocking activity over eastern Europe. Therefore, the out of phase interannual to millennial‐scale variations of River Ammer flood frequency and solar irradiance, as presented in previous studies, can be explained by a solar modulation of eastern European‐western Russia summer blocking and associated upstream upper‐level wave breaking activity. In addition, we identify two distinct quasi‐periodic signals in both frequency of Lake Ammer flood layer and solar irradiance records with periods of ~900 years and ~2,300 years. We argue that similar cycles should dominate millennial‐scale variations of blocking activity in eastern Europe‐western Russia as well as extreme precipitation and flood frequency variability over central and western Europe during the last ~5,500 years.