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  • Articles  (8,809)
  • Data  (348)
  • 2020-2023  (9,157)
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  • 1
    Publication Date: 2022-08-15
    Description: Ocean acidification (OA) has been identified as one of the major climate-change related threats, mainly due to its significant impacts on marine calcifiers. Among those are the calcareous green algae of the genus Halimeda that are known to be major carbonate producers in shallow tropical and subtropical seas. Hence, any negative OA impacts on these organisms may translate into significant declines in regional and global carbonate production. In this study, we compiled the available information regarding Halimeda spp. responses to OA (experimental, in situ), with special focus on the calcification responses, one of the most studied response parameters in this group. Furthermore, among the compiled studies (n = 31), we selected those reporting quantitative data of OA effects on algal net calcification in an attempt to identify potential general patterns of species- and/or regional-specific OA responses and hence, impacts on carbonate production. While obtaining general patterns was largely hampered by the often scarce number of studies on individual species and/or regions, the currently available information indicates species-specific susceptibility to OA, seemingly unrelated to evolutionary lineages (and associated differences in morphology), that is often accompanied by differences in a species� response across different regions. Thus, for projections of future declines in Halimeda-associated carbonate production, we used available regional reports of species-specific carbonate production in conjunction with experimental OA responses for the respective species and regions. Based on the available information, declines can be expected worldwide, though some regions harbouring more sensitive species might be more impacted than others.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , NonPeerReviewed
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  • 2
    Publication Date: 2022-12-05
    Description: The EUREF Permanent GNSS Network (EPN) provides a unique atmospheric dataset over Europe in the form of Zenith Total Delay (ZTD) time series. These ZTD time series are estimated independently by different analysis centers, but a combined solution is also provided. Previous studies showed that changes in the processing strategy do not affect trends and seasonal amplitudes. However, its effect on the temporal and spatial variations of the stochastic component of ZTD time series has not yet been investigated. This study analyses the temporal and spatial correlations of the ZTD residuals obtained from four different datasets: one solution provided by ASI (Agenzia Spaziale Italiana Centro di Geodesia Spaziale, Italy), two solutions provided by GOP (Geodetic Observatory Pecny, Czech Republic), and one combined solution resulting from the EPN’s second reprocessing campaign. We find that the ZTD residuals obtained from the three individual solutions can be modeled using a first-order autoregressive stochastic process, which is less significant and must be completed by an additional white noise process in the combined solution. Although the combination procedure changes the temporal correlation in the ZTD residuals, it neither affects its spatial correlation structure nor its time-variability, for which an annual modulation is observed for stations up to 1,000 km apart. The main spatial patterns in the ZTD residuals also remain identical. Finally, we compare two GOP solutions, one of which only differs in the modeling of non-tidal atmospheric loading at the observation level, and conclude that its modeling has a negligible effect on ZTD values.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 3
    Publication Date: 2022-12-02
    Description: Temporal aliasing errors resulting from the undersampling of non-tidal atmospheric as well as oceanic mass variations constitute the largest limitation towards the retrieval of monthly gravity solutions based on GRACE and GRACE-FO satellite gravity missions. Their mitigation is thus a primary goal of current research. Unfortunately, the two-step co-parametrization approach proposed for application in Bender-type gravity retrieval scenario in Wiese et al. yields no added value for a single satellite pair. A detailed study of this parametrization strategy is carried out and it is shown that the reason for this is the flawed central assumption of the proposed method, that is that signals of different spatial wavelengths can be perfectly captured and separated with respect to their temporal extent. Based on this finding, we derive a multi-step self-de-aliasing approach (DMD) which aims to rectify the shortcoming of the Wiese et al. method specifically for the single-pair case while retaining its independence from background-model-based de-aliasing of non-tidal atmosphere and ocean (AO) signal components. The functionality and added value of this novel approach is validated within a set of numerical closed-loop simulations as well as in real GRACE and GRACE-FO data processing. The simulation results show that the DMD may improve the gravity retrieval performance in the high-degree spectrum by more than one order of magnitude if one aims to retrieve the full AOHIS (i.e. atmosphere, ocean, hydrology, ice, solid earth) signal, and by at least a factor 5 if a priori AO de-aliasing is applied. Simultaneously, the DMD is shown to degrade the retrieval of the low degrees, but it is also demonstrated that this issue can be mitigated by introducing a constraint into the processing scheme. The simulation results are widely confirmed by results obtained from applying the DMD to real GRACE/GRACE-FO data of the test years 2007, 2014 and 2019. The applicability of the DMD is further shown for Bender-type gravity retrieval. It is demonstrated that in case of a double-pair-based gravity retrieval this approach is at least equivalent to the Wiese et al. method.
    Type: info:eu-repo/semantics/article
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  • 4
    Publication Date: 2022-11-14
    Description: The Pan-African belts of Malawi contain a largely unexplored endowment of gem bearing pegmatites. We present U–Pb in zircon (LA-ICPMS) and Rb–Sr mineral isochron geochronological and isotope data from pegmatites across Malawi. The pegmatites contain tourmaline, beryl, aquamarine, zircon, amethyst and sunstone as gemstone species. Two zircon bearing pegmatites in southern Malawi intruded early in the Pan-African orogenic cycle at 719 ± 5 Ma and 729 ± 4 Ma and are associated with the emplacement of alkaline rocks that formed during an intra-continental rifting episode in the eastern part of former Rodinia. One further zircon pegmatite containing inherited zircon of a similar age (746 ± 44 Ma) was emplaced at 598 ± 15 Ma, after the assembly of Western and Eastern Gondwana and the formation of the East African Orogen (EAO). The majority of the analysed pegmatites, however, are significantly younger. The ∼550 Ma pegmatites were emplaced during the Kuunga Orogeny, correlating with the collision of northern and southern Gondwana cratonic entities. During a prolonged post-collisional period, possibly related to crustal collapse and extension, further gem-mineralised pegmatites formed at ∼520 ± 6 Ma and ∼500–485 Ma. The youngest pegmatite intruded in the southern Malawian Ntcheu area in the Middle Ordovician at ∼460 Ma. A large spread in 87Sr/86Sr initial isotopic ratios between 0.70556 and 0.79018 suggests a variety of magma sources for the Kuunga-related pegmatites with a variably strong crustal affinity.
    Language: English
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  • 5
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    In:  Marine Analytical Chemistry
    Publication Date: 2022-11-17
    Type: info:eu-repo/semantics/bookPart
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  • 6
    Publication Date: 2022-12-14
    Description: Ilmenite and olivine megacrysts from the 89 Ma Monastery kimberlite (Kaapvaal Craton, South Africa) captured abundant and large melt inclusions containing quenched Si-Mg-rich melt, calcite, spinel, perovskite, phlogopite, and serpentine. Textural observations and 3D X-ray tomography of ilmenite and olivine megacrysts show melt inclusion shapes, sizes and distribution patterns indicative of melt capture during primary crystal growth near the base of the subcontinental lithospheric mantle (SCLM). Patterns supporting secondary melt injection along fractures or veins, such as planar arrays of melt inclusions, are absent. Melt inclusions in olivine, in some examples reaching the dimension of centimetres, likely were captured in skeletal voids forming in fast growing, up to decimetre-sized olivine megacrysts. These large melt inclusions commonly decrepitated, forming apophyses, radial fractures, and veins, along which residual volatile- and Si-Mg-rich melt was extracted. We attribute the decrepitation of melt inclusions in olivine to the rapidly increasing difference between the melt pressure in the inclusions, captured at mantle depth, and the decreasing confining stress to which the host olivines were exposed during magma ascent and after emplacement. In ilmenite, melt inclusions up to ∼ 6 mm in diameter remained commonly intact during the kimberlite ascent from its mantle source to the shallow crust. The quenched silicate melt in olivine- and ilmenite-hosted melt inclusions, in some places preserved as unaltered hydrous and CO3-bearing glass, shows systematic major element compositional variations that suggest that this melt formed by similar fractionation and depletion processes, irrespective of the hosting megacryst phase. Apparent modal variations in quenched silicate melt, calcite, and oxide contents suggest that the melt batches captured as inclusions in ilmenite and olivine either record different evolution stages in the megacryst magma, or document compositional heterogeneities in this magma at the time of megacryst growth.
    Language: English
    Type: info:eu-repo/semantics/article
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  • 7
    Publication Date: 2022-01-11
    Description: Abstract
    Description: Stress maps show the orientation of the current maximum horizontal stress (SHmax) in the earth's crust. Assuming that the vertical stress (SV) is a principal stress, SHmax defines the orientation of the 3D stress tensor; the minimum horizontal stress Shmin is than perpendicular to SHmax. In stress maps SHmax orientations are represented as lines of different lengths. The length of the line is a measure of the quality of data and the symbol shows the stress indicator and the color the stress regime. The stress data are freely available and part of the World Stress Map (WSM) project. For more information about the data and criteria of data analysis and quality mapping are plotted along the WSM website at http://www.world-stress-map.org. The stress map of Taiwan 2022 is based on the WSM database release 2016. However, all data records have been checked and we added a large number of new data from earthquake focal mechanisms from the national earthquake catalog and from publications. The total number of data records has increased from n=401 in the WSM 2016 to n=6,498 (4,234 with A-C quality) in the stress map of Taiwan 2022 The update with earthquake focal mechanims is even larger since another 1313 earthquake focal mechanism data records beyond the scale of this map have been added to the WSM database. The digital version of the stress map is a layered pdf file generated with GMT (Wessel et al., 2019). It also provide estimates of the mean SHmax orientation on a regular 0.1° grid using the tool stress2grid (Ziegler and Heidbach, 2019). Two mean SHmax orientations are estimated with search radii of r=25 and 50 km, respectively, and with weights according to distance and data quality. The stress map and data are available on the landing page at https://doi.org/10.5880/WSM.Taiwan2022 where further information is provided. The earthquake focal mechanism that are used for this stress map are provided by the Taiwan Earthquake Research Center (TEC) available at the TEC Data Center (https://tec.earth.sinica.edu.tw).
    Description: Other
    Description: The World Stress Map (WSM) is a global compilation of information on the crustal present-day stress field. It is a collaborative project between academia and industry that aims to characterize the stress pattern and to understand the stress sources. It commenced in 1986 as a project of the International Lithosphere Program under the leadership of Mary-Lou Zoback. From 1995-2008 it was a project of the Heidelberg Academy of Sciences and Humanities headed first by Karl Fuchs and then by Friedemann Wenzel. Since 2009 the WSM is maintained at the GFZ German Research Centre for Geosciences and since 2012 the WSM is a member of the ICSU World Data System. All stress information is analysed and compiled in a standardized format and quality-ranked for reliability and comparability on a global scale.
    Type: Other , Other
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  • 8
    Publication Date: 2022-01-17
    Description: Abstract
    Description: Analysis of prehistoric lithic artefacts helps to answer a wide array of questions concerning archaeological contexts and prehistoric human behaviour. Typological studies allow for a chronological and partly also cultural attribution of the sites, while the analysis of raw materials used is fundamental for the reconstruction of mobility patterns, communication networks and land use of Stone Age communities. Within the framework of two projects funded by the German Research Foundation, and a regional initiative of Werner Schön, it was possible to determine the origin of the raw materials of 32 inventories from the Late Glacial and Early Holocene in northwest and southern Germany. The petrographic analysis was conducted by the geologist and petro-archaeologist Jehanne Affolter. In addition, data of more than 60 Stone Age assemblages from Switzerland as well as western and southern Germany were recorded, that had already been published elsewhere. The origin of the flint raw materials from most of these inventories was determined using the micro-facial method. Some inventories, where the raw material sources were determined exclusively macroscopically, are also tentatively mapped to complement the chronological sequence. GIS-based maps of the raw material sources from the aforementioned regions are compiled and raw material catchment areas of the Stone Age sites are mapped. The area calculations of the raw material catchments revealed a diachronic alternation of larger and smaller areas, which above all suggest culturally determined cycles in the range of mobility and communication networks.
    Keywords: Late and Final Palaeolithic ; Mesolithic ; Switzerland ; central europe ; lithic raw material catchments ; lithic raw material sources ; neolithic ; south-eastern France ; south-western Germany ; western germany
    Type: Dataset , dataset
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  • 9
    Publication Date: 2022-01-18
    Description: Abstract
    Description: The DFG Priority Program 1803 “EarthShape” (www.earthshape.net) investigates Earth surface shaping by biota. As part of this project, we present Light Detection and Ranging (LiDAR) data of land surface areas for the four core research sites of the project. The research sites are located along a latitudinal gradient between ~26 °S and ~38 °S in the Chilean Coastal Cordillera. From north to south, the names of these sites are: National Park Pan de Azúcar; Private Reserve Santa Gracia; National Park La Campana; and National Park Nahuelbuta. The three datasets contain raw 3D point cloud data captured from an airborne LiDAR system, and the following derivative products: a) digital terrain models (DTM, sometimes also referred to as DEM [digital elevation model]) which are (2.5D) raster datasets created by rendering only the LiDAR returns which are assumed to be ground/bare-earth returns and b) digital surface models (DSM) which are also 2.5D raster datasets produced by rendering all the returns from the top of the Earth’s surface, including all objects and structures (e.g. buildings and vegetation). The LiDAR data were acquired in 2008 (southernmost Nahuelbuta [NAB] catchment), 2016 (central La Campana [LC] catchment) and 2020 (central Santa Gracia [SGA] catchment). Except for Nahuelbuta (data already was available from the data provider from a previous project), the flights were carried out as part of the "EarthShape" project. The LiDAR raw data (point cloud/ *.las files) were compressed, merged (as *.laz files) and projected using UTM 19 S (UTM 18 S for the southernmost Nahuelbuta catchment, respectively) and WGS84 as coordinate reference system. A complementary fourth dataset for the northernmost site in the National Park Pan de Azúcar, derived from Uncrewed Aerial Vehicle (UAV) flights and Structure from Motion (SfM) photogrammetry, is expected to be obtained during the first half of 2022 and will be added to the above data set.
    Description: Other
    Description: The DFG Priority Program 1803 "EarthShape - Earth Surface Shaping by Biota" (2016-2022) explored between scientific disciplines and includes geoscientists and biologists to study from different viewpoints the complex question how microorganisms, animals, and plants influence the shape and development of the Earth’s surface over time scales from the present-day to the young geologic past. All study sites are located in the north-to-south trending Coastal Cordillera mountains of Chile, South America. These sites span from the Atacama Desert in the north to the Araucaria forests approximately 1300 km to the south. The site selection contains a large ecological and climate gradient ranging from very dry to humid climate conditions. For more information visit: www.earthshape.net
    Keywords: 3D point cloud ; LiDAR scanner ; Elevation Models ; EarthShape ; Chile ; Coastal Cordillera ; Private Reserve Santa Gracia ; National Park La Campana ; National Park Nahuelbuta ; Earth Remote Sensing Instruments 〉 Active Remote Sensing 〉 Altimeters 〉 Lidar/Laser Altimeters 〉 AIRBORNE LASER SCANNER ; EARTH SCIENCE 〉 LAND SURFACE 〉 TOPOGRAPHY 〉 TERRAIN ELEVATION ; EARTH SCIENCE 〉 LAND SURFACE 〉 TOPOGRAPHY 〉 TOPOGRAPHICAL RELIEF ; EARTH SCIENCE 〉 SPECTRAL/ENGINEERING 〉 LIDAR ; EARTH SCIENCE SERVICES 〉 MODELS 〉 LAND SURFACE MODELS ; Models/Analyses 〉 DEM ; radiation 〉 laser
    Type: Dataset , Dataset
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  • 10
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    GFZ Data Services
    Publication Date: 2022-01-28
    Description: Abstract
    Description: PDToolbox is a collection of methods helpful for doing probability distribution computations in Python. The aim of the PDToolbox Python module is to provide a set of features, based on simple probability distributions, that are not available from the scipy.stats module. This includes fast batch computations of (weighted) maximum likelihood estimates, computation of critical empirical distribution statistics, and more niche probability distributions or related code in the pdtoolbox.special module. The module contains code that is described in (ADD citations of the two articles).
    Description: Other
    Description: LICENSE: GNU General Public License, Version 3, 29 June 2007 Copyright © 2021 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany PDToolbox is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. PDToolbox is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see 〈http://www.gnu.org/licenses/〉.
    Keywords: goodness-of-fit ; Anderson-Darling ; Lilliefors ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOTHERMAL DYNAMICS 〉 GEOTHERMAL ENERGY 〉 ENERGY DISTRIBUTION ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION 〉 STATISTICAL APPLICATIONS
    Type: Software , Software
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  • 11
    Publication Date: 2022-02-01
    Description: Abstract
    Description: The River Plume Workflow is part of the Flood Event Explorer (FEE, Eggert et al., 2022), developed at the GFZ German Research Centre for Geosciences in close collaboration with Helmholtz-Zentrum Hereon. It is funded by the Initiative and Networking Fund of the Helmholtz Association through the Digital Earth project (https://www.digitalearth-hgf.de/). The focus of the River Plume Workflow is the impact of riverine flood events on the marine environment. At the end of a flood event chain, an unusual amount of nutrients and pollutants is washed into the North Sea, which can have consequences, such as increased algae blooms. The workflow aims to enable users to detect a river plume in the North Sea and to determine its spatio-temporal extent. Identifying river plume candidates can either happen manually in the visual interface or also through an automatic anomaly detection algorithm, using Gaussian regression. In both cases a combination of observational data, namely FerryBox transects and satellite data, and model data are used. Once a river plume candidate is found, a statistical analysis supplies additional detail on the anomaly and helps to compare the suspected river plume to the surrounding data. Simulated trajectories of particles starting on the FerryBox transect at the time of the original observation and modelled backwards and forwards in time help to verify the origin of the river plume and allow users to follow the anomaly across the North Sea. An interactive map enables users to load additional observational data into the workflow, such as ocean colour satellite maps, and provides them with an overview of the flood impacts and the river plume’s development on its way through the North Sea. In addition, the workflow offers the functionality to assemble satellite-based chlorophyll observations along model trajectories as a time series. They allow scientists to understand processes inside the river plume and to determine the timescales on which these developments happen. For example, chlorophyll degradation rates in the Elbe river plume are currently investigated using these time series. The workflow's added value lies in the ease with which users can combine observational FerryBox data with relevant model data and other datasets of their choice. Furthermore, the workflow allows users to visually explore the combined data and contains methods to find and highlight anomalies. The workflow’s functionalities also enable users to map the spatio-temporal extent of the river plume and investigate the changes in productivity that occur in the plume. All in all, the River Plume Workflow simplifies the investigation and monitoring of flood events and their impacts in marine environments.
    Description: TechnicalInfo
    Description: Copyright 2022 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany / DE Flood Event Explorer Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: Digital Earth ; Flood ; DASF ; Workflow ; river plume ; ferrybox ; impact ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 FLOODS ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION
    Type: Software , Software
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  • 12
    Publication Date: 2022-02-01
    Description: Abstract
    Description: The Socio-Economic Flood Impacts Workflow is part of the Flood Event Explorer (FEE, Eggert et al., 2022), developed at the GFZ German Research Centre for Geosciences . It is funded by the Initiative and Networking Fund of the Helmholtz Association through the Digital Earth project (https://www.digitalearth-hgf.de/). The Socio-Economic Flood Impacts Workflow aims to support the identification of relevant controls and useful indicators for the assessment of flood impacts. It should support answering the question What are useful indicators to assess socio-economic flood impacts?. Floods impact individuals and communities and may have significant social, economic and environmental consequences. These impacts result from the interplay of hazard - the meteo-hydrological processes leading to high water levels and inundation of usually dry land, exposure - the elements affected by flooding such as people, build environment or infrastructure, and vulnerability - the susceptibility of exposed elements to be harmed by flooding. In view of the complex interactions of hazard and impact processes a broad range of data from disparate sources need to be compiled and analysed across the boundaries of climate and atmosphere, catchment and river network, and socio-economic domains. The workflow approaches this problem and supports scientists to integrate observations, model outputs and other datasets for further analysis in the region of interest. The workflow provides functionalities to select the region of interest, access hazard, exposure and vulnerability related data from different sources, identifying flood periods as relevant time ranges, and calculate defined indices. The integrated input data set is further filtered for the relevant flood event periods in the region of interest to obtain a new comprehensive flood data set. This spatio-temporal dataset is analysed using data-science methods such as clustering, classification or correlation algorithms to explore and identify useful indicators for flood impacts. For instance, the importance of different factors or the interrelationships among multiple variables to shape flood impacts can be explored. The added value of the Socio-Economic Flood Impacts Workflow is twofold. First, it integrates scattered data from disparate sources and makes it accessible for further analysis. As such, the effort to compile, harmonize and combine a broad range of spatio-temporal data is clearly reduced. Also, the integration of new datasets from additional sources is much more straightforward. Second, it enables a flexible analysis of multivariate data and by reusing algorithms from other workflows it fosters a more efficient scientific work that can focus on data analysis instead of tedious data wrangling.
    Description: TechnicalInfo
    Description: Copyright 2022 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany / DE Flood Event Explorer Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: Digital Earth ; Flood ; DASF ; Workflow ; hydrometeorological controls ; indicators ; impact assessment ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 FLOODS ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION
    Type: Software , Software
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  • 13
    Publication Date: 2022-02-01
    Description: Abstract
    Description: The Flood Similarity Workflow is part of the Flood Event Explorer (FEE, Eggert et al., 2022), developed at the GFZ German Research Centre for Geosciences . It is funded by the Initiative and Networking Fund of the Helmholtz Association through the Digital Earth project (https://www.digitalearth-hgf.de/). River floods and associated adverse consequences are caused by complex interactions of hydro-meteorological and socio-economic pre-conditions and event characteristics. The Flood Similarity Workflow supports the identification, assessment and comparison of hydro-meteorological controls of flood events. The analysis of flood events requires the exploration of discharge time series data for hundreds of gauging stations and their auxiliary data. Data availability and accessibility and standard processing techniques are common challenges in that application and addressed by this workflow. The Flood Similarity Workflow allows the assessment and comparison of arbitrary flood events. The workflow includes around 500 gauging stations in Germany comprising discharge data and the associated extreme value statistics as well as precipitation and soil moisture data. This provides the basis to identify and compare flood events based on antecedent catchment conditions, catchment precipitation, discharge hydrographs, and inundation maps. The workflow also enables the analysis of multidimensional flood characteristics including aggregated indicators (in space and time), spatial patterns and time series signatures. The added value of the Flood Event Explorer comprises two major points. First, scientist work on a common, homogenized database of flood events and their hydro-meteorological controls for a large spatial and temporal domain , with fast and standardized interfaces to access the data. Second, the standardized computation of common flood indicators allows a consistent comparison and exploration of flood events.
    Description: TechnicalInfo
    Description: Copyright 2022 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany / DE Flood Event Explorer Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: Digital Earth ; Flood ; DASF ; Workflow ; hydrometeorological controls ; compare ; assess ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 FLOODS ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION
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  • 14
    Publication Date: 2022-02-01
    Description: Abstract
    Description: The Smart Monitoring Workflow (Tocap) is part of the Flood Event Explorer (FEE, Eggert et al., 2022), developed at the GFZ German Research Centre for Geosciences in close collaboration with the Helmholtz-Centre for Environmental Research UFZ Leipzig. It is funded by the Initiative and Networking Fund of the Helmholtz Association through the Digital Earth project (https://www.digitalearth-hgf.de/). A deeper understanding of the Earth system as a whole and its interacting sub-systems depends not only on accurate mathematical approximations of the physical processes but also on the availability of environmental data across time and spatial scales. Even though advanced numerical simulations and satellite-based remote sensing in conjunction with sophisticated algorithms such as machine learning tools can provide 4D environmental datasets, local and mesoscale measurements continue to be the backbone in many disciplines such as hydrology. Considering the limitations of human and technical resources, monitoring strategies for these types of measurements should be well designed to increase the information gain provided. One helpful set of tools to address these tasks are data exploration frameworks providing qualified data from different sources and tailoring available computational and visual methods to explore and analyse multi-parameter datasets. In this context, we developed a Smart Monitoring Workflow to determine the most suitable time and location for event-driven, ad-hoc monitoring in hydrology using soil moisture measurements as our target variable. The Smart Monitoring Workflow consists of three main steps. First is the identification of the region of interest, either via user selection or recommendation based on spatial environmental parameters provided by the user. Statistical filters and different color schemes can be applied to highlight different regions. The second step is accessing time-dependent environmental parameters (e.g., rainfall and soil moisture estimates of the recent past, weather predictions from numerical weather models and swath forecasts from Earth observation satellites) for the region of interest and visualizing the results. Lastly, a detailed assessment of the region of interest is conducted by applying filter and weight functions in combination with multiple linear regressions on selected input parameters. Depending on the measurement objective (e.g highest/lowest values, highest/lowest change), most suitable areas for monitoring will subsequently be visually highlighted. In combination with the provided background map, an efficient route for monitoring can be planned directly in the exploration environment. The added value of the Smart Monitoring Workflow is multifold. The workflow gives the user a set of tools to visualize and process their data on a background map and in combination with data from public environmental datasets. For raster data from public databases, tailor-made routines are provided to access the data in the spatial-temporal limits required by the user. Aiming to facilitate the design of terrestrial monitoring campaigns, the platform and device-independent approach of the workflow gives the user the flexibility to design a campaign at the desktop computer first and to refine it later in the field using mobile devices. In this context, the ability of the workflow to plot time-series of forecast data for the region of interest empowers the user to react quickly to changing conditions, e.g thunderstorm showers, by adapting the monitoring strategy, if necessary. Finally, the integrated routing algorithm assists to calculate the duration of a planned campaign as well as the optimal driving route between often scattered monitoring locations.
    Description: TechnicalInfo
    Description: Copyright 2022 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany / DE Flood Event Explorer Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: Digital Earth ; Flood ; DASF ; Workflow ; smart monitoring ; campaign planning ; tocap ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 FLOODS ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION
    Type: Software , Software
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  • 15
    Publication Date: 2022-02-01
    Description: Abstract
    Description: The Climate Change Workflow is part of the Flood Event Explorer (FEE, Eggert et al., 2022), developed at the GFZ German Research Centre for Geosciences in close collaboration with Helmholtz-Zentrum Hereon , Climate Service Center Germany. It is funded by the Initiative and Networking Fund of the Helmholtz Association through the Digital Earth project (https://www.digitalearth-hgf.de/). The goal of the Climate Change Workflow is to support the analysis of climate-driven changes in flood-generating climate variables, such as precipitation or soil moisture, using regional climate model simulations from the Earth System Grid Federation (ESGF) data archive. It should support to answer the geoscientific question How does precipitation change over the course of the 21st century under different climate scenarios, compared to a 30-year reference period over a certain region? Extraction of locally relevant data over a region of interest (ROI) requires climate expert knowledge and data processing training to correctly process large ensembles of climate model simulations, the Climate Change Workflow tackles this problem. It supports scientists to define the regions of interest, customize their ensembles from the climate model simulations available on the Earth System Grid Federation (ESGF), define variables of interest, and relevant time ranges. The Climate Change Workflow provides: (1) a weighted mask of the ROI ; (2) weighted climate data of the ROI; (3) time series evolution of the climate over the ROI for each ensemble member; (4) ensemble statistics of the projected change; and lastly, (5) an interactive visualization of the region’s precipitation change projected by the ensemble of selected climate model simulations for different Representative Concentration Pathways (RCPs). The visualization includes the temporal evolution of precipitation change over the course of the 21st century and statistical characteristics of the ensembles for two selected 30 year time periods for the mid and the end of the 21st century (e.g. median and various percentiles). The added value of the Climate Change Workflow is threefold. First, there is a reduction in the number of different software programs necessary to extract locally relevant data. Second, the intuitive generation and access to the weighted mask allows for the further development of locally relevant climate indices. Third, by allowing access to the locally relevant data at different stages of the data processing chain, scientists can work with a vastly reduced data volume allowing for a greater number of climate model ensembles to be studied; which translates into greater scientific robustness. Thus, the Climate Change Workflow provides much easier access to an ensemble of high-resolution simulations of precipitation, over a given ROI, presenting the region’s projected precipitation change using standardized approaches and supporting the development of additional locally relevant climate indices.
    Description: TechnicalInfo
    Description: Copyright 2022 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany / DE Flood Event Explorer Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: Digital Earth ; Flood ; DASF ; Workflow ; Climate Change ; ESGF ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 FLOODS ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION
    Type: Software , Software
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  • 16
    Publication Date: 2022-02-01
    Description: Abstract
    Description: The Digital Earth Flood Event Explorer supports geoscientists and experts to analyse flood events along the process cascade event generation, evolution and impact across atmospheric, terrestrial, and marine disciplines. It applies the concept of scientific workflows and the component-based Data Analytics Software Framework (DASF, Eggert and Dransch, 2021) to an exemplary showcase. It aims at answering the following geoscientific questions: - How does precipitation change over the course of the 21st century under different climate scenarios over a certain region? - What are the main hydro-meteorological controls of a specific flood event? - What are useful indicators to assess socio-economic flood impacts? - How do flood events impact the marine environment? - What are the best monitoring sites for upcoming flood events? The Flood Event Explorer developed scientific workflows for each geoscientific question providing enhanced analysis methods from statistics, machine learning, and visual data exploration that are implemented in different languages and software environments, and that access data form a variety of distributed databases. The collaborating scientists are from different Helmholtz research centers and belong to different scientific fields such as hydrology, climate-, marine-, and environmental science, and computer- and data science. It is funded by the Initiative and Networking Fund of the Helmholtz Association through the Digital Earth project (https://www.digitalearth-hgf.de/).
    Description: TechnicalInfo
    Description: Copyright 2022 Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences, Potsdam, Germany / DE Flood Event Explorer Licensed under the Apache License, Version 2.0 (the "License"); you may not use these files except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: Digital Earth ; Flood ; DASF ; Workflows ; EARTH SCIENCE 〉 HUMAN DIMENSIONS 〉 NATURAL HAZARDS 〉 FLOODS ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION
    Type: Software , Software
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  • 17
    Publication Date: 2022-02-10
    Description: Abstract
    Description: Integrated water vapor above Iquique airport from March 2018 to March 2019 measured with Microwave radiometer HATPRO-FOGHAT. Retrieval is based on 20 Years of Radiosonde Data from Antofagasta. Radiosonde data has been preprocessed with a relative humidity threshold of 90% for cloud formation.
    Keywords: Climatology/Meteorology/Atmosphere ; Meteorology ; Remote Sensing ; Integrated water vapor (IWV)
    Type: Dataset , Dataset
    Format: NetCDF
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  • 18
    Publication Date: 2022-02-10
    Description: Abstract
    Description: Liquid water path above Iquique airport from March 2018 to March 2019 measured with Microwave radiometer HATPRO-FOGHAT. Retrieval is based on 20 Years of Radiosonde Data from Antofagasta. Radiosonde data has been preprocessed with a relative humidity threshold of 80% for cloud formation.
    Keywords: Climatology/Meteorology/Atmosphere ; Meteorology ; Remote Sensing ; Cloud liquid water path (LWP)
    Type: Dataset , Dataset
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  • 19
    Publication Date: 2022-02-10
    Description: Abstract
    Description: Liquid water path above Iquique airport from March 2018 to March 2019 measured with Microwave radiometer HATPRO-FOGHAT. Retrieval is based on 20 Years of Radiosonde Data from Antofagasta. Radiosonde data has been preprocessed with a relative humidity threshold of 85% for cloud formation.
    Keywords: Climatology/Meteorology/Atmosphere ; Meteorology ; Remote Sensing ; Cloud liquid water path (LWP)
    Type: Dataset , Dataset
    Format: NetCDF
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  • 20
    Publication Date: 2022-02-10
    Description: Abstract
    Description: Integrated water vapor above Iquique airport from March 2018 to March 2019 measured with Microwave radiometer HATPRO-FOGHAT. Retrieval is based on 20 Years of Radiosonde Data from Antofagasta. Radiosonde data has been preprocessed with a relative humidity threshold of 95% for cloud formation.
    Keywords: Climatology/Meteorology/Atmosphere ; Meteorology ; Remote Sensing ; Integrated water vapor (IWV)
    Type: Dataset , Dataset
    Format: NetCDF
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  • 21
    Publication Date: 2022-02-10
    Description: Abstract
    Description: Liquid water path above Iquique airport from March 2018 to March 2019 measured with Microwave radiometer HATPRO-FOGHAT. Retrieval is based on 20 Years of Radiosonde Data from Antofagasta. Radiosonde data has been preprocessed with a relative humidity threshold of 90% for cloud formation.
    Keywords: Climatology/Meteorology/Atmosphere ; Meteorology ; Remote Sensing ; Cloud liquid water path (LWP)
    Type: Dataset , Dataset
    Format: NetCDF
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  • 22
    Publication Date: 2022-02-10
    Description: Abstract
    Description: Liquid water path above Iquique airport from March 2018 to March 2019 measured with Microwave radiometer HATPRO-FOGHAT. Retrieval is based on 20 Years of Radiosonde Data from Antofagasta. Radiosonde data has been preprocessed with a relative humidity threshold of 95% for cloud formation.
    Keywords: Climatology/Meteorology/Atmosphere ; Meteorology ; Remote Sensing ; Cloud liquid water path (LWP)
    Type: Dataset , Dataset
    Format: NetCDF
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  • 23
    Publication Date: 2022-02-11
    Description: Abstract
    Description: This dataset provides friction data from ring-shear tests (RST) on twice broken rice used in the GEC Laboratory in CY Cergy Paris University in stick-slip experiments. They were obtained by Sarah Visage as part of her doctoral training (funded by the ANR DISRUPT programme) during an invitation at the Helmholtz Laboratory for Tectonic Modelling (HelTec) at the GFZ German Research Centre for Geosciences in Potsdam. Like any granular material, the twice broken rice is characterized by several internal friction coefficients μ and cohesions C, classicaly qualified as dynamic, static, and reactivation coefficients. In adition, since the rice exhibits a stick slip behaviour, the various shear - velocity or shear-displacement curves exhibit high frequency oscillations and we therefore define maximum, minimum, and mean values corresponding respectively to the curve peaks, curve troughs and smoothed curve.
    Keywords: EPOS ; Multiscale laboratories ; analogue models of geologic processes ; property data of analogue modelling materials ; analogue modelling results ; software tools ; Cohesion ; deformation 〉 fracturing ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES ; fault ; Flour 〉 Rice ; Force sensor ; Friction coefficient ; Matlab (Mathworks) ; Rate-state parameters ; Ring-shear tester
    Type: Dataset , Dataset
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  • 24
    Publication Date: 2022-02-17
    Description: Abstract
    Description: Volcanic projectiles are centimeter- to meter-sized clasts – both solid-to-molten rock fragments or lithic eroded from conduits – ejected during explosive volcanic eruptions that follow ballistic trajectories. Despite being ranked as less dangerous than large-scale processes such as pyroclastic density currents (hot avalanches of gas and pyroclasts), volcanic projectiles still represent a constant threat to life and properties in the vicinity of volcanic vents, and frequently cause fatal accidents on volcanoes. Mapping of their size, shape, and location in volcanic deposits can be combined to model possible trajectories of projectiles from the vent to their final position, and to estimate crucial source parameters of the driving eruption, such as ejection velocity and pressure differential at the vent. Moreover, size and spatial distributions of volcanic projectiles from past eruptions, coupled with ballistic modelling of their trajectory, are crucial to forecast their possible impact in future eruptions. The reliability of such models strongly depends on i) the appropriate physical functions and input parameters and ii) observational validations. In this study, we aimed to unravel intra-conduit processes that strongly control the dynamic of volcanic projectiles by combining numerical modelling and novel experimentally-determined source parameter. In particular, the multiphase ASHEE model (Cerminara 2016; Cerminara et al. 2016) suited for testing post-fragmentation conduit dynamics based on a robust shock tube experimental dataset. By exploding mixtures of pumice and dense lithic particles within a specially designed transparent autoclave, and by using a raft of pressure sensors, ultra-high-speed cameras and pre-sieved natural particles, we observed and quantified: i) kinematic data of the particles and of the gas front along the shock tube and outside, ii) pressure decay at 1GHz resolution. By feeding the ASHEE model with these datasets, and using initial and boundary conditions similar to that of the experiment, we defined domains composed by a pressurized shock tube and the outside chamber at ambient conditions, and tested particles particle motion according to a Lagrangian approach, as well as gas flow with a Eulerian approach (a 3D finite-volume numerical solver, compressible). The comparison between data and model yields estimate of the particle kinematic inside the tube, the pressure evolution at the top and the bottom of the tube, and the eruption source parameters at the tube exit.
    Description: Methods
    Description: We designed a series of rapid decompression experiments in which we systematically varied componentry, particle size, and packing arrangement of the initial samples. We also carried empty run experiments, where only the gas phase is decompressed. We used the pressure evolution and high-speed footage of these experiments to i) benchmark the expansion of the gas phase against the expansion of gas and particle mixture, and ii) develop 1D and 3D models of particle acceleration.
    Keywords: Eperimental volcanology ; ASHEE model ; Conduit dynamic ; Ejection behavior ; Numerical modelling ; EPOS ; multi-scale laboratories ; rock and melt physical properties ; analysis 〉 physicochemical analysis 〉 granulometry ; EARTH SCIENCE 〉 SOLID EARTH 〉 ROCKS/MINERALS/CRYSTALS 〉 IGNEOUS ROCKS 〉 IGNEOUS ROCK PHYSICAL/OPTICAL PROPERTIES ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 VOLCANIC ACTIVITY 〉 ERUPTION DYNAMICS 〉 PYROCLASTIC PARTICAL SIZE DISTRIBUTION ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 VOLCANIC ACTIVITY 〉 ERUPTION DYNAMICS 〉 PYROCLASTICS COMPOSITION/TEXTURE ; experiment 〉 test 〉 comparative test ; experiment 〉 test 〉 testing method 〉 calibration ; research 〉 scientific research 〉 experimental study ; science 〉 natural science 〉 earth science 〉 geology 〉 volcanology ; science 〉 physical science
    Type: Dataset , Dataset
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  • 25
    Publication Date: 2022-02-18
    Description: TechnicalInfo
    Description: This is a synthetic dataset. It was created from the outputs of the glacial isostatic adjustment model VILMA (Klemann et al. 2008). It consists of realtive sea level (RSL) data on a global regular grid. The resolution is 256 x 512 points (Lat x Lon). The tomporal range is from 123 ka BP until present day. Time steps vary between 2.5 kyrs at the beginning and 0.5 kyrs towards the end. The data were created for a specific configuration of the GIA model: lithosphere thickness = 60 km, lithosphere viscosity = 1.0E31 Pa s, upper mantle thickness = 610 km, upper mantle viscosity = 1.0E20 Pa s, lower mantle thickness = 3,221 km, lower mantle viscosity = 1.0E21 Pa s. The RSL data are accompanied by a observation locations mask. This mask was used to identify those locations in the global RSL dataset where real observations are available.
    Description: TechnicalInfo
    Description: The dataset consists of realtive sea level (RSL) data on a global regular grid. The resolution is 256 x 512 points (Lat x Lon). The temporal range is from 123 ka BP until present day. Time steps vary between 2.5 kyrs at the beginning and 0.5 kyrs towards the end. The data were created for a specific configuration of the GIA model: lithosphere thickness = 60 km, lithosphere viscosity = 1.0E31 Pa s, upper mantle thickness = 610 km, upper mantle viscosity = 1.0E20 Pa s, lower mantle thickness = 3,221 km, lower mantle viscosity = 1.0E21 Pa s. The RSL data are accompanied by observation locations masks. These masks were used to mark those locations in the global RSL dataset where real-life observations are available in order to restrict usage of the synthetic data to those locations.
    Keywords: Synthetic data ; Relative sea level ; EARTH SCIENCE 〉 OCEANS 〉 SEA SURFACE TOPOGRAPHY 〉 SEA SURFACE HEIGHT ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMORPHIC LANDFORMS/PROCESSES 〉 GLACIAL PROCESSES 〉 CRUST REBOUND ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOMORPHIC LANDFORMS/PROCESSES 〉 GLACIAL PROCESSES 〉 GLACIER CRUST SUBSIDENCE ; EARTH SCIENCE 〉 SOLID EARTH 〉 GRAVITY/GRAVITATIONAL FIELD 〉 CRUSTAL MOTION 〉 ISOSTATIC ADJUSTMENTS
    Type: Dataset , Dataset
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  • 26
    Publication Date: 2022-02-18
    Description: Sea level pressure is a fundamental weather and climate element and the very basis of everyday weather maps. Daily sea level pressure distributions provide information on the influence of high and low pressure systems, air flow, weather activity, and, hence, synoptic conditions. Using sea level pressure distributions from the NCEP/NCAR Reanalysis 1 (Kalnay et al., 1996) and a simplified variant of the weather-typing scheme by Jenkinson and Collison (1977) atmospheric circulation over the North Sea has been classified as to pattern and intensity on a daily basis starting in 1948. A full account of the original weather-typing scheme can be found in Loewe et al. (2005), while the variant scheme has been detailed in Loewe et al. (2006). The analysis has been carried out on the original 16-point grid. Though formally valid at its central point (55°N, 5°E), results are representative of the North Sea region between 50°N-60°N and 0°E-10°E. The modified scheme allows for six weather types, namely four directional (NE=Northeast, SE, SW, NW) and two rotational types (C=cyclonic and A=anticyclonic). The strength of the atmospheric circulation is classified by way of a peak-over-threshold technique, employing re-calibrated thresholds for the gale index G* of 28.3, 36.6, and 44.6 hPa for gale (G), severe gale (SG), and very severe gale (VSG), respectively (Loewe et al., 2013). Technically, the set of weather-typing and gale-classification rules is implemented as a lean FORTRAN code (lwtnssim.f), internally known as "Simple Lamb weather-typing scheme for the North Sea v1". The processing run was done on a Linux server under Debian 10 (Buster). Both, weather types and gale days, form a catalogue of more than 70 annual calendars since 1948 that is presented and continuously updated to the present day at https://www.bsh.de/EN/DATA/Climate-and-Sea/Weather-and-Gales/weather-and-gales_node.html. This catalogue concisely documents synoptic conditions in the North Sea region. Possible benefits are manifold. Special events and episodes in regional-scale atmospheric circulation are easily looked up and traced. Beyond that, the dataset is well suited for frequency, trend, persistence, transition, and extreme-value statistics.
    Type: experiment
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  • 27
    Publication Date: 2022-02-23
    Description: Abstract
    Description: This data set is Part 2 of the compiles whole-rock chemical data for late-Variscan low-F biotite and two-mica granites in the German Erzgebirge, in the Saxothuringian Zone of the Variscan Orogen. The group of F-poor biotite granites is represented by the composite massifs of Kirchberg and Niederbobritzsch, the Plohn Granite Suite (PGS), the Aue Granite Suite (AGS), and the subsurface granites of Beiersdorf und Bernsbach. For the group of two-mica granites, compositional data for the multi-stage Bergen massif and the granites from Lauter and Schwarzenberg are reported (Figure 1). Crystal-melt fractionation was the dominant process controlling the evolution of bulk composition in the course of massif/pluton formation. However, metasomatic and hydrothermal processes involving late-stage residual melts and high-T late- to post-magmatic fluids became increasingly more important in highly evolved units and have variably modified the abundances of mobile elements. Interaction with the various metamorphic country rocks and infiltration of meteoric low-T fluids have further disturbed the initial chemical patterns in the endocontact zones and zones influenced by surface weathering. The data set reports whole-rock geochemical analyses for enclaves, granites, aplites, endocontact rocks, and some facial varieties. The data are presented as Excel (xlsx) and machine-readable txt formats. The content of the excel sheet and further information on the granites and regional geology are provided in the data description file.
    Keywords: granite ; peraluminous granite ; aplite ; enclave ; fractional crystallization ; composite pluton ; alteration ; ore mineralization ; whole-rock geochemistry ; tungsten ; molybdenum ; uranium ; Kirchberg pluton ; Plohn granite suite ; Bergen pluton ; Aue-Schwarzenberg Granite Zone ; late Carboniferous ; Variscan orogen ; Saxothuringian Zone ; Erzgebirge ; Germany ; EARTH SCIENCE 〉 SOLID EARTH 〉 ROCKS/MINERALS/CRYSTALS 〉 ELEMENTS ; EARTH SCIENCE 〉 SOLID EARTH 〉 ROCKS/MINERALS/CRYSTALS 〉 IGNEOUS ROCKS ; EARTH SCIENCE 〉 SOLID EARTH 〉 ROCKS/MINERALS/CRYSTALS 〉 MINERALS
    Type: Dataset , Dataset
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  • 28
    Publication Date: 2022-03-01
    Description: Abstract
    Description: Fatbox - Fault Analysis Toolbox is a python module for the extraction and analysis of faults (and fractures) in raster data. We often observer faults in 2-D or 3-D raster data (e.g. geological maps, numerical models or seismic volumes), yet the extraction of these structures still requires large amounts of our time. The aim of this module is to reduce this time by providing a set of functions, which can perform many of the steps required for the extraction and analysis of fault systems. The basic idea of the module is to describe fault systems as graphs (or networks) consisting of nodes and edges, which allows us to define faults as components, i.e. sets of nodes connected by edges, of a graph. Nodes, which are not connected through edges, thus belong to different components (faults).
    Description: TechnicalInfo
    Description: Copyright [2022] Helmholtz Centre Potsdam GFZ German Research Centre for Geosciences Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.
    Keywords: clustering ; signal-processing ; image-processing ; network-analysis ; deformation ; faults ; Python 3 ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION ; EARTH SCIENCE SERVICES 〉 DATA ANALYSIS AND VISUALIZATION 〉 STATISTICAL APPLICATIONS ; EARTH SCIENCE SERVICES 〉 DATA MANAGEMENT/DATA HANDLING 〉 TRANSFORMATION/CONVERSION
    Type: Software , Software
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  • 29
    Publication Date: 2022-03-05
    Description: preindustrial Control experiment to be used in VolMIP analyses. The piControl experiment is the CMIP6-DECK piControl experiment described in Eyring et al. (2016). piControl provides initial climate states that are sampled to start most of VolMIP experiments (Zanchettin et al., 2016). The dataset contains monthly values of selected variables spatially averaged over four regions. These are the full globe (GL), the Northern Hemisphere extratropics (30°-90°N, NH), the tropics (30°S-30°N, TR), and the Southern Hemisphere (30°-90°S, hereafter SH). The considered variables have the following cmor names: hfls, hfss, pr, rlds, rldscs, rlus, rlut, rlutcs, rsds, rsdscs, rsdt, rsus, rsut, rsutcs, tas. Additionally, the climate indices NAO and Nino34 are part of the dataset. Considered models are CanESM5, IPSL-CM6A-LR, GISS-E2.1-G, MIROC-ES2L, MPI-ESM1.2-LR (named MPI-ESM-LR in the files of this dataset) and UKESM1. Considered experiments are piControl and volc-pinatubo-full, with initial date and final date as specified for each model in Zanchettin et al. (2021). Different realizations are considered for the participating models depending on availability.
    Type: experiment
    Format: netCDF.tar
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  • 30
    Publication Date: 2022-03-05
    Description: Idealized volcanic-forcing coupled climate model experiment using the 1991 Pinatubo forcing as used in the CMIP6 historical simulations. It is a Tier 1 (mandatory) VolMIP experiment based on a large ensemble of short-term “Pinatubo” climate simulations aimed at accurately estimating simulated responses to volcanic forcing that may be comparable to the amplitude of internal interannual climate variability. Initialization is based on equally distributed predefined states of ENSO (cold/neutral/warm states) and of the North Atlantic Oscillation (NAO, negative/neutral/positive states). Sampling of an eastern phase of the Quasi-Biennial Oscillation (QBO), as observed after the 1991 Pinatubo eruption, is preferred for those models that spontaneously generate such mode of stratospheric variability. VIRF diagnostics must be calculated for this experiment for the whole integration and for all ensemble members, as these are required for the “volc-pinatubo-strat”/“surf” experiments. A minimum length of integration of 3 years is requested. Details about the experiment are provided by Zanchettin et al. (2016). The dataset contains monthly values of selected variables spatially averaged over four regions. These are the full globe (GL), the Northern Hemisphere extratropics (30°-90°N, NH), the tropics (30°S-30°N, TR), and the Southern Hemisphere (30°-90°S, hereafter SH). The considered variables have the following cmor names: hfls, hfss, pr, rlds, rldscs, rlus, rlut, rlutcs, rsds, rsdscs, rsdt, rsus, rsut, rsutcs, tas. Additionally, the climate indices NAO and Nino34 are part of the dataset. Considered models are CanESM5, IPSL-CM6A-LR, GISS-E2.1-G, MIROC-ES2L, MPI-ESM1.2-LR (named MPI-ESM-LR in the files of this dataset) and UKESM1. Considered experiments are piControl and volc-pinatubo-full, with initial date and final date as specified for each model in Zanchettin et al. (2021). Different realizations are considered for the participating models depending on availability.
    Type: experiment
    Format: netCDF.tar
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  • 31
    Publication Date: 2022-03-09
    Description: Abstract
    Description: 1.Nature conservation is fostered through the expansion of protected areas. This is particularly evident in Sub-Saharan Africa (SSA), where conservation is intended to simultaneously promote the recovery of megafauna like elephants. Rising numbers of megaherbivores induce woody biomass losses but restore soil organic carbon (SOC). We hypothesized that increases of SOC under conservation with wildlife in SSA go directly along with increases in the preservation of plant residues in soil organic matter (SOM), traceable by plant biomarkers such as lignin and n-alkane. In contrast, intensification with agriculture leads to a reduction of them. To test this, we sampled topsoil (0-10 cm) and corresponding plant samples along different intensities of conservation and intensification in the Zambezi Region of Namibia, comprising a) conservation sites with low, medium and high elephant densities and b) adjacent intensification sites with rangeland and cropland. We found that lignin and n-alkane patterns of the above-ground vegetation were preserved in the soil. Confirming our hypothesis, increasing SOC contents with rising elephant densities went along with increasing accumulation of lignin-derived phenols. Under conservation, lignin concentrations were influenced by the input of woody debris into the soil, traced by carbon isotopes, clay, and total woody biomass. This could not be proved for n-alkanes. Under intensification, lignin derived phenols were lower than under conservation, but again, there was no clear pattern for n-alkanes. We showed that conservation with wildlife leads to an increase of SOC, which was accompanied by an accumulation of lignin-derived phenols in the soil organic matter. Increased input of woody debris, clay content and total biomass were important parameters for this lignin accumulation. In contrast, intensification with agriculture leads to a loss of lignin. Contrary, n- alkanes were not sensitive to detect effects of conservation or intensification. We conclude that increasing incorporation of woody residues into soil is a key mechanism controlling SOC accrual and to offset losses of aboveground biomass on SOC in sites under conservation with wildlife. The dataset contains raw data of lignin and n-alkanes and related soil properties. A third sheet contains a legend with information on abbreviations.
    Keywords: Ecology ; Environment ; Conservation ; Intensification ; Soil Organic Carbon ; Carbon Storage Dynamics ; Carbon Sequestration ; Biomarker ; Lignin ; n-Alkanes
    Type: Dataset , Microsoft excel file
    Format: MS Excel
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  • 32
    Publication Date: 2022-03-10
    Description: Abstract
    Description: Stress maps show the orientation of the current maximum horizontal stress (SHmax) in the earth's crust. Assuming that the vertical stress (SV) is a principal stress, SHmax defines the orientation of the 3D stress tensor; the minimum horizontal stress Shmin is than perpendicular to SHmax. In stress maps SHmax orientations are represented as lines of different lengths. The length of the line is a measure of the quality of data and the symbol shows the stress indicator and the color the stress regime. The stress data are freely available and part of the World Stress Map (WSM) project. For more information about the data and criteria of data analysis and quality mapping are plotted along the WSM website at http://www.world-stress-map.org. The stress map of Great Britain and Ireland 2022 is based on the WSM database release 2016. All data records have been checked and we added a number of new data from earthquake focal mechanisms from the national earthquake catalog and borehole data. The number of data records has increased from n=377 in the WSM 2016 to n=474 in this map. Some locations and assigned quality of WSM 2016 data were corrected due to new information. The digital version of the map is a layered pdf generated with GMT (Wessel et al., 2019) using the topography of Tozer et al. (2019). We also provide on a regular 0.1° grid values of the mean SHmax orientation which have a standard deviation 〈 25°. The mean SHmax orientation is estimated using the tool stress2grid of Ziegler and Heidbach (2019). For this estimation we used only data records with A-C quality and applied weights according to data quality and distance to the grid points. The stress map is available at the landing page of the GFZ Data Services at http://doi.org/10.5880/WSM.GreatBritainIreland2022 where further information is provided.
    Description: Other
    Description: The World Stress Map (WSM) is a global compilation of information on the crustal present-day stress field. It is a collaborative project between academia and industry that aims to characterize the stress pattern and to understand the stress sources. It commenced in 1986 as a project of the International Lithosphere Program under the leadership of Mary-Lou Zoback. From 1995-2008 it was a project of the Heidelberg Academy of Sciences and Humanities headed first by Karl Fuchs and then by Friedemann Wenzel. Since 2009 the WSM is maintained at the GFZ German Research Centre for Geosciences and since 2012 the WSM is a member of the ICSU World Data System. All stress information is analysed and compiled in a standardized format and quality-ranked for reliability and comparability on a global scale.
    Keywords: crustal stress ; in situ stress ; tectonic stress ; crustal stress pattern ; geophysics ; tectonics ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 NEOTECTONICS ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 PLATE TECTONICS 〉 FAULT MOVEMENT ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 PLATE TECTONICS 〉 STRESS
    Type: Dataset , Dataset
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  • 33
    Publication Date: 2022-03-14
    Description: Abstract
    Description: This data set is the source of my doctoral thesis and of three resulting publications. Through whole rock geochemistry of selected samples and microprobe and geochronological analyses of key minerals, formerly selected by extensive microscopical studies, standard geothermobarometry and modelling was applied. It has been shown that metamorphic rocks, in particular, the eclogites of the northern Kaghan Valley, Pakistan, were buried to depths of 140-100 km (36-30 kbar) at 790-640°C. Subsequently, cooling during decompression (exhumation) towards 40-35 km (17-10 kbar) and 630-580°C has been superseded by a phase of reheating to about 720-650°C at roughly the same depth before final exhumation has taken place. In the southern-most part of the Kaghan Valley, amphibolite facies assemblages with formation conditions similar to the deduced reheating phase indicate a juxtaposition of both areas after the eclogite facies stage and thus a stacking of Indian Plate units. Radiometric dating of zircon, titanite and rutile by U-Pb and amphibole and micas by Ar-Ar reveal peak pressure conditions at 47-48 Ma. With a maximum exhumation rate of 14 cm/a these rocks reached the crust-mantle boundary at 40-35 km within 1 Ma. Subsequent exhumation (46-41 Ma, 40-35 km) decelerated to ca. 1 mm/a at the base of the continental crust but rose again to about 2 mm/a in the period of 41-31 Ma, equivalent to 35-20 km. Apatite fission track (AFT) and (U-Th)/He ages from eclogites, amphibolites, micaschists and gneisses yielded moderate Oligocene to Miocene cooling rates of about 10°C/Ma in the high altitude northern parts of the Kaghan Valley using the mineral-pair method. AFT ages are of 24.5±3.8 to 15.6±2.1 Ma whereas apatite (U-Th)/He analyses yielded ages between 21.0±0.6 and 5.3±0.2 Ma. The southern-most part of the Valley is dominated by younger late Miocene to Pliocene apatite fission track ages of 7.6±2.1 and 4.0±0.5 Ma that support earlier tectonically and petrologically findings of a juxtaposition and stack of Indian Plate units. As this nappe is tectonically lowermost, a later distinct exhumation and uplift driven by thrusting along the Main Boundary Thrust is inferred. Out of this geochemical, petrological, isotope-geochemical and low temperature thermochronology investigations it was concluded that the exhumation was buoyancy driven and caused an initial rapid exhumation: exhumation as fast as recent normal plate movements (ca. 10 cm/a). As the exhuming units reached the crust-mantle boundary the process slowed down due to changes in buoyancy. Most likely, this exhumation pause has initiated the reheating event that is petrologically evident (e.g. glaucophane rimmed by hornblende, ilmenite overgrowth of rutile). Late stage processes involved widespread thrusting and folding with accompanied regional greenschist facies metamorphism, whereby contemporaneous thrusting on the Batal Thrust (seen sometimes equivalent to the MCT) and back sliding of the Kohistan Arc along the inverse reactivated Main Mantle Thrust caused final exposure of these rocks. Similar circumstances have been seen at Tso Morari, Ladakh, India, 200 km further east where comparable rock assemblages occur. In conclusion, as exhumation was already done well before the initiation of the monsoonal system, climate dependent effects (erosion) appear negligible in comparison to far-field tectonic effects. Thus, the channel flow model is not applicable for this part of the Himalayas.
    Keywords: whole rock geochemistry ; microprobe ; U-Pb geochronology ; Ar/Ar geochronology ; apatite fission track ; U-Th/He thermochronology ; metamorphic rocks ; eclogite ; Himalayas ; Pakistan ; Kaghan Valley ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROCESSES ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY 〉 GEOCHEMICAL PROPERTIES 〉 ISOTOPIC AGE ; In Situ/Laboratory Instruments 〉 Spectrometers/Radiometers 〉 LA-ICP-MS ; In Situ/Laboratory Instruments 〉 Spectrometers/Radiometers 〉 XRF
    Type: Dataset , Dataset
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  • 34
    Publication Date: 2022-03-16
    Description: Abstract
    Description: A sequence of three strong (M W 7.2–6.4) and several moderate (M W 4.4–5.7) earthquakes struck the Pamir Plateau and surrounding mountain ranges of Tajikistan, China, and Kyrgyzstan in 2015–2017. With a local seismic network in operation in the Xinjiang province since August 2015, an aftershock network on the Pamir Plateau of Tajikistan since February 2016, and additional permanent regional seismic stations, we were able to record the succession of the fore-, main-, and aftershock sequences at local distances with good azimuthal coverage. We located 11,784 seismic events and determined the moment tensor for 33 earthquakes. The seismicity delineates the major tectonic structures of the Pamir, i.e., the thrusts that absorb shortening along the plateau thrust front, and the strike-slip and normal faults that dissect the Plateau into a westward extruding and a northward advancing block. Fault ruptures were activated subsequently at increasing distances from the initial M W 7.2 Sarez. All mainshock areas but the initial one exhibited foreshock seismicity which was not modulated by the occurrence of the earlier earthquakes. The tabular ASCII data of the seismic event catalog consist of origin date, time, location, depth and magnitude of the events, along with the quality measures: number of P- and S-wave arrival time picks, location root-mean-square misfit and localization method. The tabular ASCII data of the moment tensor catalog consist of origin date, time, location, the six independent components of the moment tensor, the moment magnitude, and the orientation of the preferred fault plane parameterized as fault strike, dip and rake.
    Keywords: Pamir ; Tajikistan ; China ; Xingjiang ; disaster 〉 natural disaster 〉 geological disaster ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 EARTHQUAKE MAGNITUDE/INTENSITY ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 EARTHQUAKES 〉 EARTHQUAKE OCCURRENCES ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 NEOTECTONICS ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 PLATE TECTONICS 〉 FAULT MOVEMENT 〉 FAULT MOVEMENT DIRECTION ; EARTH SCIENCE 〉 SOLID EARTH 〉 TECTONICS 〉 PLATE TECTONICS 〉 STRESS ; environment 〉 geophysical environment ; geological process 〉 seismic activity 〉 earthquake ; land 〉 world 〉 Asia 〉 Central Asia ; physical process 〉 diffusion
    Type: Dataset , Dataset
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  • 35
    Publication Date: 2022-03-18
    Description: The Bias Corrected CESMv1 data for mid-century (2041-2050) for RCP8.5 emission scenario at coarser resolution has been downscaled to 10km resolution over India using the Weather Research and Forecasting (WRF) model. The climate variables included are 2m Temperature (t2m), relative humidity (rh), wind speed (wspd), total precipitation (prec), mean surface shortwave flux (sw), top-of-atmosphere outgoing longwave radiation (lw), mean surface latent (lhf) and sensible (shf) heat fluxes along with the latitude, longitude, and time information. The dataset covers the Indian National Territory region at a 369 x 369 grid. The data is available at three temporal resolutions: Daily TS, Monthly TS, and Monthly Climatology. The dataset has been structured into a total of 30 files (10 variables x 3 temporal resolutions) packed in self-explanatory NetCDF format. The daily, monthly, and monthly climatology files contain 369x369x3650, 369x369x30, and 369x369x12 data points, respectively. The entire dataset is about 30 GB in size. The precipitation files in the older version contained hourly accumulated values for every day. This version contains the correct daily accumulated, monthly accumulated and monthly climatology precipitation data.
    Type: experiment
    Format: NetCDF
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  • 36
    Publication Date: 2022
    Description: In the study of solar-terrestrial relationships, magnetic storms and solar activity play important roles. In this paper, the intense magnetic storms in company with solar proton events occurred in October and November 2003, January 2005, December 2006, January and March 2012 have been considered. The variation of the odd nitrogen (NOy) oxides and ozone in the stratospheric layer is investigated by the effects of energetic particle precipitation. Anomaly percentage of the odd nitrogen (NOy) oxides and ozone are calculated separately for the Southern and the Northern hemispheres and geographic latitude from 60 to 80 degrees. The analyzed results of the observational data showed that the intense magnetic storms, which consist of more than 500 (particles/cm2 s sr) solar energetic proton (E〉10MeV), gave rise to the increase of the odd nitrogen (NOy) oxides in the stratosphere, from level 1 mb to 200 mb. Also, the results showed that in November 2003, January 2005, December 2006, January and March 2012 the odd nitrogen (NOy) oxides, which consist of over 500 (particles/cm2 s sr) increased in the Northern hemisphere but decreased a little in the Southern hemisphere . Among the events of the magnetic storms in the autumn and winter seasons, the only event on the October 2003, showed that the odd nitrogen (NOy) oxides increased in the Southern hemisphere. The results showed that the increase in the odd nitrogen (NOy) oxides caused a decrease of ozone in the altitude below the odd nitrogen (NOy) with a delay.
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  • 37
    Publication Date: 2022
    Description: The electrical properties of rock types or channel structures have been the object of intense studies for many years. The main aim of the present work is to show the frequency response of electrical properties of some Granite samples concerning chemical, minor and major composition. This may be used as a fingerprint for the characterization of some Granite rocks. Electrical measurements on Granite samples (surface, Aswan, Egypt) were measured (100 Hz up to 107 Hz). Differences in samples due to changes in texture lead to different changes in electrical properties. The changes at conductivity and dielectric constant are reflections from the texture within grains. Conductivity and dielectric constant values extend from ~10-8 to 10-4 (S/m) and 24 to 3.5, respectively. With frequency increase, conductivity increases, and dielectric constant decreases (10 kHz), and then it settles down. Differences in electrical properties between samples are small as a direct result of the homogeneity and texture of most samples. There is a high dispersion of dielectric constant for relatively low-frequency values (〈10 kHz) and no dispersion at relatively high frequencies. In conclusion, the dielectric constant decreases due to the shrinkage of energy levels for electrons and the increase of hopping particles between different particles.
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  • 38
    Publication Date: 2022
    Description: A strong earthquake () (34.911° N, 45.959° E, ~19 km depth) occurred on November 12, 2017, at 18:18:17 UTC (LT=UTC+03:30) in Sarpol-e Zahab, Iran. Six different Neural Network (NN) algorithms including Multi-Layer Perceptron (MLP), Recurrent Neural Network (RNN), Gated Recurrent Unit (GRU), Convolutional Neural Network (CNN), Long-Short Term Memory (LSTM) and CNN-LSTM were implemented to survey the four months of GPS Total Electron Content (TEC) measurements during the period of August 01 to November 30, 2017 around the epicenter of the mentioned earthquake. By considering the quiet solar-geomagnetic conditions, every six methods detect anomalous TEC variations nine days prior to the earthquake. Since time-series of TEC variations follow a nonlinear and complex behavior, intelligent algorithms such as NN can be considered as an appropriate tool for modelling and prediction of TEC time-series. Moreover, multi-methods analyses beside the multi precursor’s analyses decrease uncertainty and false alarms and consequently lead to confident anomalies.
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  • 39
    Publication Date: 2022
    Description: Direct current electrical resistivity imaging is provided by measuring the vertical and horizontal electrical potential variations of subsurface structures using surface and borehole records. To recover the resistivity tomograms from the observed data, a non-linear inverse problem is required to be iteratively solved. A 2.5-dimensional forward modeling based on the finite-difference method with rectangular meshes is also formulated. The two-dimensional reconstruction of earth resistivity data is implemented using a smoothness constrained inversion algorithm (i.e. Occam’s method), wherein a Gauss-Newton technique for updating the sensitivity function is proposed. After verifying the accuracy and efficiency of the forward modeling and the sensitivity function calculation, the inversion algorithm is tested on synthetic data from both geometrically simple and complicated bodies and a real data set. A stopping criterion based on the noise level, roughly estimated using the method of reciprocal resistance measurements, is also provided leading to preventing over-or under-interpreted structure during the inversion process. The numerical experiments reveal that the proposed inversion algorithm provides stable inversion results and an acceptable representation of the main features and structure of the models without producing spurious effects. Furthermore, to deal with the reliability of the recovered models, a model sensitivity analysis is implemented using the resolution density distribution. All used formulations and concepts are part of a Matlab source code developed during this study.
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  • 40
    Publication Date: 2022
    Description: یکی از نتایج مهم نظریه گرانش کوانتومی اصلاح قوانین فیزیک در فواصل کوتاه است. مثلا روابط جابجایی مکانیک کوانتومی استاندارد در مقیاس هایی از طول – به نام طول پلانک – تغییر می یابند. البته باید توجه داشت که این تغییرات در انرژی های پایین قابل صرفنظر کردن است و فقط در حد انرژی های بالا همچون جهان اولیه این تصحیحات قابل توجه می شوند. در این راستا اصل عدم قطعیت استاندارد مکانیک کوانتوم با روابط اصلاح شده عدم قطعیت که شامل یک طول کمینه قابل مشاهده از مرتبه پلانک است تغییر می یابند. از طرفی لحظات ابتدای پیدایش عالم که شامل دوره تورم بوده دوره ای است که به دلیل سطح بالای انرژی ، اثرات کوانتومی گرانش در آن قابل توجه و لذا می توان در این دوره به بررسی این اثرات پرداخت. برای این کار می توان ویژگی های دوره تورمی را از روی پارامتر های اولیه عالم همچون افت و خیزهای اولیه تشکیل ساختار عالم و نمایه طیفی مورد بررسی قرار داد. این پژوهش اثرات کوانتومی گرانش را در یک مدل برداری گرانش تعمیم یافته مورد بررسی قرار داده ایم. به این صورت که با استفاده از اصل عدم قطعیت اصلاح شده از طریق هندسه ناجابجایی (که بر اساس اصلاحات گرانش کوانتومی بدست آمده)، دینامیک تورمی جهان اولیه را مورد مطالعه قرار داده و سپس اثرات کوانتومی گرانش ناشی از تعمیم اصل عدم قطعیت را در پارامتر نمایه طیفی را بررسی می کنیم . همچنین چگالی اختلالات اسکالر متاثر از این اثرات مورد محاسبه قرار گرفته است.
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  • 41
    Publication Date: 2022
    Description: با توجّه به اهمیّت پدیده‌ی تغییرات آب‌وهوایی و گرمایش جهانی، آگاهی از رفتار گذشته، حال و آینده‌ی عناصر آب‌وهوایی از اهمیّت شایان توجهّی برخوردار است. در همین راستا، در پژوهش حاضر تلاش می‌شود داده‌های میانگین سالانه‌ی دما در ایستگاه مهرآباد تهران از سال 1330 تا 1394 بررسی شود. بدین منظور و برای شناسای تغییرات زمانی میانگین دمای سالانه، مدل سازی آماری – خانواده‌ی مدل‌های آریما (ARIMA) به کار گرفته شد. برای نیل به این هدف، معنی‌داری آماری مراتب و اجزای مختلف مدل، برای پیش‌بینی وارسی شد. در نهایت دو مدل ARIMA(0,1,1)_{con}، و ARIMA(2,1,0)_{con} به عنوان مدل‌های رقیب انتخاب شدند. معیارهای نهایی نشان دادند که مدلARIMA(0,1,1)_{con} به عنوان مناسب‌ترین مدل برازنده بر دمای سالانه‌ی ایستگاه مهرآباد تهران است. همچنین، آزمون‌های آماری خودهمبستگی، ضریب همبستگی پیرسون، همگنی نرمال استاندارد، وانیومن، انحرافات تجمعی، نقاط عطف، علامت و پورت مانتئو برای وارسی رفتار باقی‌مانده‌های مدل پیش‌بین استفاده شد. علاوه بر این، شیوه‌های ترسیمی برای نرمال بودن باقی‌مانده‌ها، استقلال ، ثابت بودن واریانس بر روی باقی‌مانده‌های مدل ARIMA(0,1,1)_{con}، در راستای بالا بردن اطمینان آماری عدم قطعیّت مدل پیش‌بین انجام شد. یافته‌های حاصل از مدل نشان می‌دهد که به‌طور میانگین هر سال نسبت به سال قبل از خود حدود میزان 038/0 درجه‌ی سلسیوس افزایش دما را تجربه می‌کند. میانگین دمای 16 سالۀ پیش‌بینی به طور میانگین برابر 742/17 درجه‌ی سلسیوس خواهد بود. نتایج آزمون‌ها نیز نشان دادند باقی‌مانده‌های مدل ARIMA(0,1,1)_{con} رفتار تصادفی دارند، که نشان می‌دهد مدل حاصل، برازنده‌ی پیش‌بینی برای سری زمانی میانگین سالانه دما در ایستگاه مهرآباد تهران است.
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  • 42
    Publication Date: 2022
    Description: شناسایی رفتارهای تناوبی و تصادفی سری‌های زمانی پارامترهای توجیه زمین (EOP)، به‌منظور کاربردهای مختلفی همچون تعیین دقیق مدار ماهواره‌ها، نجوم ژئودزی، ناوبری فضایی و همچنین مطالعه‌ی پدیده‌های ژئوفیزیکی مورد نیاز می‌باشد. روش‌های مختلف آنالیز سری‌های زمانی از دیرباز تا کنون مورد بررسی قرار گرفته است. در این تحقیق، بررسی و تعیین فرکانس‌های موجود در پارامترهای توجیه زمین، با استفاده از آنالیز هارمونیک کمترین مربعات یک متغیره و چند متغیره‌‌ی سری‌های زمانی IERS 14 C04، از تاریخ اول ژانویه 1980 تا 31 دسامبر سال 2020 صورت گرفته است. با تشکیل مدل تابعی با استفاده از فرکانس‌های تعیین شده، ضرایب مدل تابعی با استفاده از برآوردگر کمترین‌مربعات برآورد شدند. سپس مدل مناسب اتورگرسیو-میانگین متحرک (ARMA)، متناظر با بردار باقیمانده‌های کمترین‌مربعات حاصل از این مدل تابعی تعیین گردید. در نهایت با استفاده از ضرایب برآورد شده‌ی مدل تابعی و مدل ARMA، پارامترهای توجیه زمین برای 20 روز اول سال 2021 پیش‌بینی شدند و دقت روش ارائه شده مورد ارزیابی قرار گرفت. نتایج این تحقیق با دو روش یادگیری عمیق مقیاسه گردید و نتایج نشان داد دقت بهتری نسبت به آن‌ها داراست و رفتارهای تناوبی و تصادفی EOP با دقت بالایی شناسایی شده‌اند. پس از گذشت 10 روز دقت پیش‌بینی برای مولفه‌ی x حدود 9/7 برابر، برای مولفه‌ی y حدود 5/3 برابر و برای مولفه‌ی LOD حدود 5/1 برابر بهبود یافت. همچنین با گذشت 20 روز دقت روز دقت پیش‌بینی برای مولفه‌ی x حدود 15/1 برابر ،برای مولفه‌ی y حدود 89/2 برابر و برای مولفه‌ی LOD حدود 18/5 برابر بهبود یافت.
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  • 43
    Publication Date: 2022
    Description: This research is focused on the dolines of Dobrá Voda Karst, which is situated in the Brezovské Karpaty Mts. (north-eastern part of the Malé Karpaty Mts) near the villages of Chtelnica and Dobrá Voda. 263 dolines were identified here and measured in the field, which is presumably the final count. The measured parameters of the dolines were used for morphometric analyses, as well as for finding out the relationships with the geology of the area. The karst is formed in Triassic carbonates of the Považie and Dobrá Voda nappes of the Hronic Unit. Dolines were identified in Neogene basal carbonatic conglomerates (Dobrá Voda Formation) as well. The area of karst rocks is approximately 87.2 km2. Dolines often tend to be formed in lines with tectonical or lithological predisposition. The most significant lines in the Dobrá Voda Karst are Hlboký Dol, Chtelnické Uhliská, and Cínovec. The origin of dolines can be assumed to the Quaternary Period and related to neotectonics, the development of the relief, and the formation of the river network. This is also confirmed by the trends of the maximum axes of the extension of dolines in the direction N-S, NE-SW and WNW-ESE, which partially correspond to the regional faults. New faults (Hlboký Dol, Cínovec, Bzová) were also identified on the basis of dolines in the lines.
    Electronic ISSN: 1338-0044
    Topics: Geosciences
    Published by Comenius University
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  • 44
    Publication Date: 2022
    Description: In this paper, a code for 3D forward modeling of electromagnetic low induction number (EM-LIN) data is developed based on the linear integral equations (IE). At first, the code is manipulated for a resistive block immersed in a homogenous background, and the obtained results have RMS errors of 2% comparing with the previously standard published results, which demonstrates the productivity of the 3D forward modeling code. Then, a model composed of two conductive anomalies with different depth ranges and conductivities in a resistive background is considered. IE Forward reposes shows that the shallower block produce larger values in spite of having less conductivity.Since the forward modeling is linear, the productivity of the forward modeling code depends on the efficiency of the forward operator. Furthermore, linear forward operator plays the key role in the linear inversion procedure, therefore, a real data set of a thick dyke in Bloemfontein Nature Reserve region in South Africa is manipulated. Weighted damped minimum length solution is utilized for the inversion procedure and the inverted model is demonstrative of the forward operator efficiency in practical applications.
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  • 45
    Publication Date: 2022
    Description: In recent years, an increase in the frequency of dust storms in the Middle East has been experienced. Identifying the potential sources of dust is essential to manage the hazardous consequences of dust storms. In addition, the relation between dust events and meteorological factors such as wind speed and horizontal visibility in the Middle East is lacking. The relation between dust events and topographical features such as soil texture in the Middle East is also unclear. In this study, dust events in the Middle East were classified based on horizontal visibility and the present weather reports during the period 1996-2015. Frequencies of different types of dust events, including blowing dust, dust in suspension, dust storm and severe dust storm, were estimated. The average concentrations of dust particles in the Middle East were also estimated based on horizontal visibility. Wind speed makes a critical contribution to dust events in the Middle East, thus wind speeds were also analyzed over the regions with relatively high frequency of dust events. In addition, maps of soil texture, elevation of landforms and the vegetation cover percentage, which have been obtained by the Weather Research and Forecasting (WRF) preprocessing system (WPS), were evaluated. The highest frequency of dust events is observed in five domains, which include Sudan, Saudi Arabia, Iraq, the United Arab Emirates (UAE), Afghanistan, Pakistan and Iran. Dust in suspension has the highest frequency among all types of the dust events studied here, particularly in southeastern Iran and central and eastern Iraq. Seasonal variations in dust event activity are directly related to wind speed, such that the frequency of dust events is the highest in June and July when winds are strongest, and lowest in January when winds are weakest. Maximum dust concentrations are observed in Saudi Arabia, Yemen and Iraq. The maximal frequency of dust storms in the Middle East occurs in May, June and July. Due to the differences in soil texture, elevation and vegetation cover, the dust emission in the Middle East is characterized by significant spatial heterogeneity. Our numerical analysis shows that sources of dust in the Middle East are mostly topographical lows with heights below 400 m, including sources in Sudan, northeastern and eastern Saudi Arabia, Iraq and Pakistan. Nevertheless, in the southwestern Arabian Peninsula, the height of sources of dust reaches to approximately 1200-2400 m. The upper surface texture of soil in region A (northeastern Sudan) is loam and sandy loam, in region B (Yemen and the southwestern Arabian Peninsula) is loamy sand and loam, in region C (northeastern Saudi Arabia, eastern Iraq and western Iran) is clay loam and loam, in region D (the UAE) is sand, sandy loam and loam, and in region E (Afghanistan, Pakistan and southeastern Iran) is loam clay and loam. The upper surface texture of soil in areas with the highest dust frequency is sandy loam and clay loam. The spatial distributions of the vegetation cover percentage show a sharp decline (below 1%) in Sudan, Saudi Arabia, Iraq, Central and Southern Iran and Pakistan.
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  • 46
    facet.materialart.
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉The invasion of Ukraine by Russian forces has led to sharp rises in gas prices in Europe and around the world with real concerns about the possible curtailment of gas flows from Russia to Europe. Pipeline imports from Russia began falling in the last quarter of 2021 and declined even further in January and most […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/ukraine-invasion-what-this-means-for-the-european-gas-markets/"〉Ukraine Invasion: What This Means for the European Gas Market〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
    Print ISSN: 0959-7727
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 47
    Publication Date: 2022
    Description: عدم‌توازن و به دنبال آن شکل‌گیری امواج گرانی- لختی به‌عنوان یکی از عوامل شناخته‌شده در وقوع تلاطم هوای صاف (CAT)، در وردسپهر زبرین شناخته می‌شوند. در این پژوهش ابتدا امواج کژفشار با استفاده از مدل WRF به صورت آرمانی در یک کانال با ابعاد 4000، 10000 و 22 کیلومتر به‌ترتیب در راستاهای مداری، نصف‌النهاری و قائم بر روی صفحهf با تفکیک افقی (قائم) برابر با 25 (25/0) کیلومتر برای 15 روز شبیه‌سازی شد. در ادامه، با کاربست روش تجزیه موج-تاوه، بخش نامتوازن شارش تعیین و برای محاسبه دامنه و دامنه بی‌بعد امواج گرانی-لختی مورد استفاده قرار گرفت. سپس مقادیر دامنه بی‌بعد امواج گرانی-لختی، برمبنای نظریه عدم‌توازن خودبه‌خودی لایت‌هیل- فورد، روش ناکس و همکاران (2008) (KMW)‌ نیز محاسبه شد و برای بررسی تلاطم و شدت آن، اتلاف انرژی جنبشی تلاطمی و آهنگ اتلاف پیچکی (EDR) با استفاده از مقادیر هر دو دامنه محاسبه شدند. نتایج توزیع EDR با استفاده از دامنه بی‌بعد روش تجزیه موج-تاوه نشان داد که در تمام محدوده اطراف جریان‌ جتی تلاطم متوسط وجود دارد و بیشینه این مقادیر، در نواحی پایین هسته و خروجی جریان‌ جتی قرار می‌گیرد که منطبق بر محل فعالیت امواج گرانی- لختی و مطالعات پیشین CAT نیز است. همین‌طور نتایج توزیع EDR با استفاده از دامنه بی‌بعد روش KMW تلاطم‌های شدید را در مناطق کوچکی بر روی هسته جت و در ناحیه ورودی جریان جتی نشان می‌دهد و بر‌خلاف روش تجزیه موج- تاوه در بیشتر مناطق، تلاطمی پیش‌بینی‌ نمی‌شود که این امر می‌تواند به اختلاف دو روش در محاسبه دامنه امواج مربوط باشد.
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  • 48
    Publication Date: 2022
    Description: با توجه به نیاز اکتشاف منابع کم عیار نظیر پورفیری‎ها به دلیل کاهش ذخایر کانه‎ های معدنی پرعیار سطحی، امروزه پی‎جویی‎های ژئوفیزیکی مورد توجه بیشتری قرار گرفته‎اند. وجودکانی‎هایی با خودپذیری مغناطیسی و رسانایی الکتریکی بالا در محدوده زون پتاسیک کانسارهای مزبور، استفاده از روش‎های مغناطیس‌سنجی، مقاومت ویژه و پلاریزاسیون القایی را به منظور تخمین عمق و شکل کانسارهای مزبور امکان پذیر می‎سازد. در تحقیق حاضر داده‎های یاد شده در محدوده کانسار پورفیری مس و طلای دالی جنوبی مورد مطالعه مجدد قرار گرفته‎اند تا با انجام پردازش‎ها و مدل‎سازی‎های جدید، نتایج مطالعات قبلی را بهبود بخشیده و ارتباط کانی‎زایی با مدل‎های ژئوفیزیکی جدید مشخص گردد. در این بررسی برای اولین بار با انجام مدل‌سازی وارون سه بعدی داده‌های پردازش‎شده مغناطیس‌سنجی در این منطقه و تحلیل خطای آن، مقاطعی از خودپذیری مغناطیسی در جهت آزیموت گمانه‌های موجود در منطقه به همراه نتایج عیار طلا و مس به دست آمده از آنالیز ژئوشیمیایی گمانه‎ها ارائه شد. همچنین نتایج مدل‌سازی وارون دو بعدی داده‌های مقاومت ویژه و پلاریزاسیون القایی در راستای سه پروفیل با خطای مناسب نیز ضمن سازگاری با نتایج مطالعات قبلی، با خودپذیری مغناطیسی تخمین زده شده در راستای یک پروفیل IP/Res مقایسه گردید. مقایسه مقاطع و صحت سنجی آن‌ها با عیار مس و طلای موجود در طول گمانه‌ها نشان می‎دهد که مناطق مشکوک به کانی‌سازی، در ارتباط با خودپذیری مغناطیسی و شارژ پذیری بالا و مقاومت ویژه کم بوده و با توجه به مدل‌مغناطیسی، حداکثر کانی‌سازی در حاشیه توده با خودپذیری مغناطیسی بالا مشاهده می‌شوند.
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  • 49
    Publication Date: 2022
    Description: این مطالعه به مقایسه کارایی دو روش کولوکیشن کمترین مربعات و انتگرال پواسن در انتقال فروسوی داده های گرانی هوابرد با استفاده از داده های زمینی در منطقه کلرادو امریکا اختصاص دارد. روش کولوکیشن نیاز به داده های با خواص آماری مستقل از مکان و جهت دارد. لذا اثر طول موجهای بلند با استفاده از مدل ژئوپتانسیل و اثر طول موج های کوتاه توپوگرافی از روی داده ها برداشته شد. حذف اثر طول موجهای کوتاه مدل از مدل پتانسیل پوسته dV_ELL_Earth2014_5480 از درجه/مرتبه 5480/5480 انجام شد. نتایج عددی با داده های شبیه سازی شده در ارتفاع پرواز و سطح زمین نشان از برتری روش پواسن نسبت به کولوکیشن در انتقال فروسوی داده های هوایی دارد. اختلاف بین نتایج عددی روشهای کولوکیشن و انتگرال پواسن برابر 2 میلی گال است. این مقدار در سطح نویز داده ها است. همچنین انحراف معیار اختلاف بین نتایج هر دو روش با داده های زمینی حدود 8 میلی گال است. همچنین هر دو روش وجود یک بایاس به اندازه 2 میلی گال در داده های هوابرد را نشان می دهند. با توجه به وجود همین مقدار بایاس در داده های زمینی نمی توان این مقدار بایاس را برای داده های هوابرد کلرادو نسبت داد.
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  • 50
    Publication Date: 2022
    Description: Hexlant explores the current state and future of decentralized autonomous organizations.〈div class="enclosure"〉〈/div〉
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  • 51
    Publication Date: 2022
    Description: Direct legal regulation is not the most efficient primary tool for regulating DEX protocols. Code is. When DEX protocol’s architecture falls short is when the law should step in to supplement code in order to shape behavior to ensure maximum public value for minimum public cost.〈div class="enclosure"〉〈/div〉
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  • 52
    Publication Date: 2022
    Description: The use of distributed ledger technology-based tools and smart contracts for customs compliance purposes subjects the idea of a “declarant” or “declaration” to potential re-characterization.〈div class="enclosure"〉〈/div〉
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  • 53
    Publication Date: 2022
    Description: The AsicBoost patent controversy led to the creation of the Blockchain Defensive Patent License and may also have influenced the creation of the Cryptocurrency Open Patent Alliance.〈div class="enclosure"〉〈/div〉
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  • 54
    Publication Date: 2022
    Description: آنامولی سطح دریا به عنوان کمیتی که بیان‌کننده اختلاف ارتفاع سطح‌لحظه‌ای آب با مقدار متوسط سطح‌آب در یک بازه زمانی می‌باشد در مطالعه وضعیت سطح آب مناطق مختلف دارای اهمیت چشمگیری می‌باشد. منطقه آبی دریاچه خزر به عنوان یکی از دو منبع مهم آبی برای کشور ایران از اهمیتی استراتژیک برخوردار است. بدین منظور در این پژوهش با استفاده از داده‌های گذر 92 مأموریت‌های ارتفاع‌سنجی‌ماهواره‌ای؛ عبوری از منطقه آبی خزر به مشاهده تغییرات کمیت آنامولی سطح دریا در این منطقه از سال 1993 تاکنون پرداخته شده است. سپس این کمیت با استفاده از روش تجزیه به مودهای ذاتی به عنوان روشی کارا در جداسازی فرکانس های تشکیل‌دهنده یک سیگنال مورد آنالیز قرار گرفته است و سپس با استفاده از شبکه عصبی توابع پایه شعاعی یک شبکه به منظور پیش‌بینی آنامولی سطح دریا ایجاد گردیده است. 9 فرکانس غالب به همراه یک ترند نتیچه تجزیه سیگنال مدنظر در این پژوهش می باشد که در نهایت منجر به پارمترهای مجذور میانگین خطا به میزان 0/029 متر و 0/034متر به همراه ضریب همبستگی 0/99 و 0/97 به ترتیب در دو مرحله آموزش و تست شبکه عصبی می‌شود.
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  • 55
    Publication Date: 2022
    Description: حفاظت قطعات الکترونیکی در برابر پرتوهای فضایی یکی از مهم‌ترین الزامات اولیه در طراحی و ساخت ماهواره‌ها می-باشد. در این کار با محاسبه دز ناشی از پرتوهای فضایی در ماده سیلیکونی با استفاده از کد مونت کارلوی MCNPX به ارزیابی تاثیر سازه‌های مختلف در حفاظ سازی پرتوهای فضایی پرداخته شده است. حفاظ پرتویی چند لایه متشکل از آلومینیوم، کربن و پلی‌اتیلن طراحی شد و عملکرد آن با حفاظ‌هایی از جنس آلومینیوم و پلی‌اتیلن برای بازه‌های دز متفاوت بررسی شد. همچنین سه بازه دز پرتویی که برای اکثر قطعات تجاری بصورت ریسک کارکردی تعریف می‌شود در نظر گرفته شد. نتایج نشان می دهد که با جایگزینی حفاظ چند لایه به جای حفاظ مرسوم آلومینیومی در بازه های دز مشخص، در بیشترین حالت 12/22% کاهش وزن حاصل خواهد شد. علاوه برآن، در صورت عدم الزام به استفاده از جعبه-های آلومینیومی جهت قرارگیری قطعات الکترونیکی داخل ماهواره، استفاده از حفاظ پلی‌اتیلنی از لحاظ بودجه وزنی در حالت خطر بالا با 65/17%، خطر متوسط 16/13% و خطر کم با 23/19% اختلاف نسبت به حفاظ آلومینیومی مقرون به‌صرفه می‌باشد.
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  • 56
    Publication Date: 2022
    Description: Different learning methods have been used to recognize seismic facies and reservoir characterization using seismic attributes. One of the significant issues in automatic facies analysis is to relate the seismic data to facies properties using the well data. According to previous studies, the role of attributes is more significant than the learning method for automatic classification. The proposed method uses supervised selection of seismic attributes for automatic facies analysis.Extended Elastic Impedances (EEI) at different angles as seismic attributes are being increasingly utilized in both seismic facies analysis and reservoir characterization. They are representative of elastic parameters of rocks appropriately. In the presented method, proper EEI seismic attributes are selected after a feasibility study using petro-physical logs, and EEI template analysis of the well data. Adaptive Neuro-Fuzzy Inference System (ANFIS) is applied to the fuzzy coded data of the well facies to train an automatic model to predict facies from the seismic data. Subsequently, the same particular EEI attributes are prepared. The EEI attributes from the seismic data are inputs for the trained ANIFIS model to perform seismic facies analysis. In this method, the seismic facies and the well facies are compatible. Only one well data can be sufficient for the well analysis stage and well facies clustering.The proposed method is applied on 3D prestack seismic data located in Abadan plain to discriminate hydrocarbon interval of Sarvak Formation. The results reveal that the supervised selection of attributes and fuzzy concepts present remarkable ability in dealing with imprecise seismic facies analysis and reservoir characterization.
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  • 57
    Publication Date: 2022
    Description: The radon transform has a wide application in seismic processing for each project in different areas. Multiple attenuation is mostly summarized in the use of radon analysis in practice, especially in marine data processing. The definition of mute function is the major challenge in parabolic radon transform. In this paper, a method for segmentation of the radon transform by fuzzy inference system is introduced to separate energy parts in the radon domain. We applied a fuzzy inference system based on the property of energy distribution and its attribute in the radon domain. The result of clustering is the partitioning of the radon domain in three major classes: 1- random noise, 2- multiple, and 3- primary and multiple. The result of applying the new method on real data has shown the applicability of the new method for separation of multiple class from other classes that can assist the processor to define the mute function in the absence of other events in the radon domain.
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  • 58
    Publication Date: 2022
    Description: این پژوهش با هدف درستی سنجی و پیش بینی دهه‌ای دمای ماهانه ایران با استفاده از برونداد پروژه پیش بینی اقلیمی دهه ای (DCPP) که در پروژه مقایسه مدل‌های جفت شده فاز ششم (CMIP6) مشارکت داده شده است، انجام شد. به این منظور از دو گروه داده شامل دمای 42 ایستگاه همدید و برونداد دو مدل BCC-CSM2-MR و MPI-ESM1-2-HR با تفکیک افقی 100 کیلومتر برای دوره گذشته نگر(2019-1980) و دوره پیش‌بینی (2028-2021) استفاده شد. برای درستی سنجی‌ مدل‌ها از سنجه های آماری RMSE ، MBE و PCC و نمودار تیلور استفاده گردید. نتایج درستی سنجی نشان دهنده کارایی بهتر مدل MPI-ESM1-2-HR نسبت به مدل BCC-CSM2-MR در ایران می‌باشد. در مقابل مدل BCC-CSM2-MR به خصوص در سواحل شمالی و جنوبی کشور با خطای قابل توجهی همراه بوده و صرفاً در مناطق کوهستانی ایران عملکرد قابل قبولی را نشان داده است. نتایج بررسی دمای ماهانه دوره گذشته‌نگر با استفاده از مدل MPI-ESM1-2-HR نشان داد که این مدل بخوبی الگوهای دمایی کشور را به تصویر می‌کشد. پیش‌بینی دمای ایران برای دوره 2028-2021 نشان داد که بی‌هنجاری دما در دهه‌ی‌ آینده در تمامی ماه‌های سال مثبت و بطور متوسط 0.9 درجه‌سلسیوس افزایش می‌یابد. آنچه در این میان بسیار حائز اهمیت است بی‌هنجاری مثبت دمای ماه‌های مارس، آوریل، ژوئن و ژوئیه در تمامی پهنه‌های اقلیمی کشور است. بی‌هنجاری مثبت در این ماه‌ها بیش‌از یک درجه سلسیوس بوده که یک تهدید جدی برای محیط زیست و منابع آب ایران در سال‌های آینده به‌شمار می‌رود.
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  • 59
    Publication Date: 2022
    Description: در مسائل مرتبط با هواشناسی، آبشناسی و کشاورزی دسترسی به پیش‌بینی‌های دقیق دمای کمینه و بیشینه در هر مکانی ضروری است. ازاینرو استفاده از پیش‌بینی‌های با دقت مناسب مدل‌ WRF در تمام نقاط شبکه ضروری است. اما خروجی مدل با خطای سامانمند همراهست. هدف این مطالعه تصحیح خطای پیش‌بینی‌های 24، 48 و 72 ساعته دمای بیشینه و کمینه در نقاط شبکه بر روی ایران است. خطای مدل طی دوره آموزش 5 و 14 روزه، برای نقاطی از شبکه که دارای داده مشاهداتی هستند محاسبه شد. این خطاها در نواحی هم‌اقلیم، با استفاده از روش درون‌یابی کوکریجینگ، در سایر نقاط شبکه برآورد شد. بدین ترتیب پیش‌بینی خام مدل برای نقاط فاقد داده مشاهداتی حفظ، و تنها مقادیر برآورده شده خطا بر روی آنها اعمال می‌شود. دوره آماری 15 ماه، از 1/11/2019 الی 1/2/2021 برای 560 ایستگاه مشاهداتی کشور در نظر گرفته شد. نتایج نشان داد خطای برونداد خام مدل در ماه‌ها، مکان‌ها و نواحی اقلیمی مختلف، توزیع یکنواختی ندارد. RMSE برونداد خام مدل برای کل کشور در پیش‌بینی‌های دمای بیشینه و کمینه به ترتیب تقریباً 6 و 5 درجه سلسیوس است، که بعد از تصحیح، به ترتیب به کمتر از 2 و 4 درجه می‌رسند. تغییر‌پذیری نمره مهارت در تمامی نواحی اقلیمی و ماه‌های مختلف بعد از تصحیح خطا بسیار کاهش یافته و در محدوده صفر تا یک قرار می‌گیرد. روش تصحیح خطای 14 روزه نسبت به روش 5 روزه چندان سبب بهبود نمره مهارت مدل نشد و می‌توان با روش 5 روزه با هزینه محاسباتی کمتر به دقتی مشابه رسید.
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  • 60
    Publication Date: 2022
    Description: گسل دوچاه با ظاهری خمیده و با راستای تقریبی خاوری-باختری و شیب حدود 70 درجه به سمت شمال واقع در پایانه شمال باختری گسل قم- زفره، از ساختارهای جالب توجه در ایران مرکزی می‌باشد. تاکنون پژوهش‌های متعددی به‌ویژه از دیدگاه رسوب‌شناسی و دیرینه‌شناسی در منطقه دوچاه صورت گرفته‌است اما کماکان اطلاعات ساختاری از گسل دوچاه واقع در باختر استان قم (کوه‌های یزدان و دوچاه) بسیار اندک است. در این پژوهش با تمرکز بر اطلاعات هندسی وجنبشی گسل دوچاه و پهنه‌ی دگرریخت شده‌ی اطراف آن در سازندهای قم و قرمزفوقانی به تحلیل تنش دیرینه در این محدوده پرداخته شده است که موقعیت محور یبیشینه تراکمی اصلی (σ1) و محور بیشینه کششی اصلی(σ3) به ترتیب برابر با 05 / 030 و 05 / 285 بدست آمد. تحلیل هندسی و جنبشی ساختاری مرتبط با گسل دوچاه و با توجه به آرایش فضایی محورهای اصلی تنش بیانگر فرانهادگی برش چپگرد بر روی برش راستگرد بویژه در قسمتهای باختری منطقه است که دلیل این امر را میتوان به خمیدگی رو به شمال گسل دو چاه و چرخش ورقه خزر (کاسپین) نسبت داد. آرایش خط‌های گذر تنش بیشینه، نشانگر پیروی آن‌ها از رژیم تنشی کلی حاکم بر پوسته ایران است. پتانسیل حرکتی گسل‌ها (Fault Movement Potential) رابطه نزدیکی با وضعیت تنش زمین‌ساختی حاکم در محدوده آن گسل دارد. با توجه به موقعیت فضایی بین گسل دوچاه و محور تنش بیشه تراکمی (σ1)، پتانسیل حرکتی گسل دوچاه حدود 33/0 برآورد گردید که نشانگر پتانسیل پایین این گسل برای فعالیت و ایجاد زمین‌لرزه‌ است.
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  • 61
    Publication Date: 2022
    Description: This paper investigates the mechanism of the eddy’s formation and their locations in the Caspian Sea using numerical simulations. The HYCOM model is used to simulate the evolutions of eddies. The model ran for 18 years from 1992 to 2009 while river runoff and atmospheric forcing are applied in the model as input files. The model output is appropriately compared to some observation data. The results indicate that one cyclonic eddy in the middle and two cyclonic and anticyclonic eddies in the southern basin of the Caspian Sea are the main eddies in this closed sea. Herein we prepare a comprehensive map to show the exact location of eddies with their important features like scales of them in all months using model simulation outputs. Topographic steering seems to be very important in the formation of mesoscale deep basin size eddies.
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  • 62
    Publication Date: 2022
    Description: روش های پالایش رقمی برای جداسازی اطلاعات مجزا از سیگنال های پیچیده هواشناسی بسیار موثر هستند. هدف از مطالعه حاضر طراحی پالایه مناسب برای اعمال بر روی سیگنال های هواشناسی دما و بارش به منظور هموارسازی، جداسازی مولفه های بسامدی با اهمیت و حذف نوفه های بسامد بالای بی اهمیت است. طراحی این پالایه ها، هم در حوزه زمان و هم در حوزه بسامد امکان پذیر است که در این تحقیق طراحی و اعمال پالایه در حوزه زمان انجام شده است. نتایج اهمیت انتخاب پالایه ی مناسب در تحلیل محتوای طیفی موجود در سیگنال هواشناسی را نشان می دهد. با پالایش سیگنال خام دما و بارش ماهانه طی دوره آماری 1979 تا 2021 در ایستگاه های تهران و تبریز به مولفه های فصلی، سالانه و بین سالی، ارتباط خطی بین این مولفه ها به طور مجزا توسط ضریب همبستگی پیرسون مورد بررسی قرار گرفته و شباهت ها و تفاوت ها با هم مقایسه شده اند. همچنین پالایه همینگ نسبت به پالایه میانگین متحرک ساده، عملکرد بهتری را در تضعیف نوسان های گیبس در بخش های جانبی پاسخ بسامدی پالایه نشان می دهد. البته انتخاب تعداد وزن بیشتر در طراحی پالایه می تواند در بهبود عملکرد پالایه اثرگذار باشد. این مساله در زمانی که تعداد مولفه های با اهمیت بیشتری در طیف بسامدیِ سیگنال هواشناسی وجود دارند، بایستی بیشتر مورد توجه قرار گیرد.
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  • 63
    Publication Date: 2022
    Description: The Authors present a critical assessment of ODR+ mechanisms to settle Belt & Road Initiative disputes (primarily smart courts and smart contracts).〈div class="enclosure"〉〈/div〉
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  • 64
    Publication Date: 2022
    Description: 〈div〉〈p〉〈em〉A Geographic Information System (GIS) includes of a hardware and software which are used for purposes such as to capture, store, evaluate, administer and distribute spatial data. GIS has a vast array of spatial analysis tools such as GIS viewer, Geodatabase, mapping tools, modelling tools etc. At present GIS is broadly used in conjunction with multi criteria decision analysis method to perform infrastructure studies and transportation studies such as road and rail. Multi criteria decision analysis can be applied in vehicle routing, site selection, scenario evaluation, land suitability, impact assessment, and location allocation for different sectors. According to majority of the literature, main factors considered in designing railway with GIS are land use, slope, drainage and soil. When multi criteria decision analysis is combined with GIS, it considers different geographical data models, spatial dimension of the evaluating criteria and decision alternatives in those criteria. The best route out of various alternate alignments has been designed using GIS thematic maps and network analysis in ArcGIS as a base. As a conclusion, this review study proves that multi criteria decision analysis combined with GIS plays a major role in modern railroad construction. 〈strong〉 〈/strong〉〈/em〉〈/p〉〈/div〉
    Print ISSN: 2321-421X
    Electronic ISSN: 2230-7990
    Topics: Geography , Geosciences
    Published by STM Journals
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  • 65
    Publication Date: 2022
    Description: 〈p〉In late 2021, China experienced a severe electricity supply crisis that affected 20 provinces. Industrial activity was curtailed, and even households suffered prolonged outages in some areas. The country is no stranger to periodic energy supply shortages and in many outages in the past, the principal causes involved either poor policy coordination or a clash […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-forum-the-2021-energy-crisis-implications-for-chinas-energy-market-and-policies/"〉Oxford Energy Forum – The 2021 energy crisis: Implications for China’s energy market and policies – Issue 131〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
    Print ISSN: 0959-7727
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 66
    Publication Date: 2022
    Description: 〈p〉〈em〉Air pollution is mainly due to the release of pollutants into the atmosphere which are detrimental to the planet and human health in particular〈/em〉〈em〉.〈/em〉〈em〉 Monitoring for the air quality parameters is important because it may lead to the adverse effects on the environment. The quantitative analysis of the air pollution spreads over the Bangalore city is carried out using two different data sources, one from ground monitoring stations and the other from the satellite derived data. Ambient Air Quality data for Bangalore region recorded by Karnataka State Pollution Control Board (KSPCB) for 2018–2020 were analysed in the open source GIS platform. Air quality parameters like aerosol optical depth (AOD), Nitrogen di-oxide (NO〈sub〉2〈/sub〉) etc. were collected from Moderate Resolution Imaging Spectro-radiometer (MODIS) and Ozone monitoring instruments for spatial analysis. Data were analysed and compared and found that satellite based data of NO〈sub〉2〈/sub〉 from the sensors provide a reliable values in ground-level exposure for a larger urban region.〈/em〉〈/p〉
    Print ISSN: 2321-421X
    Electronic ISSN: 2230-7990
    Topics: Geography , Geosciences
    Published by STM Journals
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  • 67
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    Unknown
    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉Following Russia’s invasion of Ukraine on 24 February 2022, energy markets are in turmoil. Oil and gas prices are rising and exhibiting high volatility as the markets grapple with the impact of sanctions and the prospect of reduced flows from Russia . China is heavily exposed to Russian commodity exports and to global markets. The […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/the-russian-invasion-of-ukraine-and-chinas-energy-markets/"〉The Russian invasion of Ukraine and China’s energy markets〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
    Print ISSN: 0959-7727
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 68
    Publication Date: 2022
    Description: 〈p〉In this podcast, James Henderson talks to Anouk Honoré about her forthcoming article “Demand-side factors behind the historical gas price rally in Europe in 2021”. This article is part of a trilogy entitled “A Series of Unfortunate Events” that analyses the main supply and demand factors in the European gas market(s) that contributed to rising gas prices since summer […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-podcast-a-series-of-unfortunate-events-demand-side-factors-in-the-european-gas-price-rally-in-2021/"〉Oxford Energy Podcast – A Series of Unfortunate Events:​ Demand-Side Factors in the European Gas Price Rally ​in 2021〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉 〈div class="enclosure"〉〈p class="enclosure-content"〉〈audio preload="none" src="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/02/Podcast-132-EU-Gas-Demand.mp3" controls="controls"〉〈/audio〉 〈a download="" href="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/02/Podcast-132-EU-Gas-Demand.mp3"〉💾〈/a〉〈/p〉〈/div〉
    Print ISSN: 0959-7727
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 69
    Publication Date: 2022
    Description: 〈p〉In this latest OIES podcast James Henderson talks to Mike Fulwood and Jack Sharples about their latest research on the possible impact of an interruption of Russian gas supplies to Europe. After a quick update on current gas prices Jack Sharples reviews the current state of gas supply to Europe, looking at flows in 2021 […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-podcast-the-russian-invasion-of-ukraine-implications-for-the-european-gas-market/"〉Oxford Energy Podcast – The Russian invasion of Ukraine – implications for the European gas market〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉 〈div class="enclosure"〉〈p class="enclosure-content"〉〈audio preload="none" src="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-135-The-Russian-invasion-of-Ukraine-–-implications-for-the-European-gas-market.mp3" controls="controls"〉〈/audio〉 〈a download="" href="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-135-The-Russian-invasion-of-Ukraine-–-implications-for-the-European-gas-market.mp3"〉💾〈/a〉〈/p〉〈/div〉
    Print ISSN: 0959-7727
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 70
    facet.materialart.
    Unknown
    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉This month’s OIES Oil Monthly Special Issue assesses the implications of the Ukraine war on our short-term oil market outlook for market balances and prices to 2023. The analysis considers two scenarios. A Reference case in which self-sanctioning measures and obstacles in redirecting Russian crude flows due to financing and shipping constraints results in a […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oies-oil-monthly-issue-12/"〉OIES Oil Monthly – Special Issue 12〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
    Print ISSN: 0959-7727
    Topics: Energy, Environment Protection, Nuclear Power Engineering
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  • 71
    Publication Date: 2022
    Description: در این مقاله سری زمانی یونوسفر با استفاده از سه مدل شبکه‌های عصبی مصنوعی (ANNs)، سیستم استنتاج عصبی-فازی سازگار (ANFIS) و ماشین بردار پشتیبان (SVM) مدل‌سازی شده و سپس پیش‌بینی می‌شود. جهت انجام این تحقیق از مشاهدات ایستگاه GNSS تهران (N69/35 ، E33/51) که یکی از ایستگاه‌های شبکه جهانی IGS است، در سال‌های 2007 الی 2018 استفاده شده است. پارامترهای سال (year)، روز از سال (DOY)، ساعت (time)، شاخص فعالیت‌های خورشیدی (F10.7) و شاخص‌های فعالیت‌های ژئومغناطیسی (Kp and DST) به عنوان ورودی هر سه مدل در نظر گرفته شده و خروجی، مقدار TEC خواهد بود. برای مرحله آزمون دقت هر سه مدل، مشاهدات دو سال 2014 و 2018 از مرحله آموزش کنار گذاشته شده‌اند. دلیل انتخاب این دو سال، بررسی دقت مدل‌ها در زمان فعالیت‌های شدید خورشیدی (2014) و فعالیت‌های آرام خورشیدی (2018) است. نتایج حاصل از هر سه مدل با TEC حاصل از مدل مرجع بین‌المللی یونوسفر 2016 (IRI2016) و همچنین خروجی‌های شبکه جهانی IGS مقایسه شده است. همچنین از شاخص‌های آماری ضریب همبستگی، خطای نسبی و جذر خطای مربعی میانگین (RMSE) جهت بررسی دقت و صحت سه مدل استفاده شد. کمینه RMSE محاسبه شده برای مدل SVM، 11/3 TECU بدست آمده که در مقایسه با سایر مدل‌ها، از دقت بالاتری در مدل‌سازی و پیش‌بینی سری زمانی TEC یونوسفر در دوره فعالیت‌های آرام و شدید خورشیدی برخوردار است.
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  • 72
    Publication Date: 2022
    Description: An ensemble of elementary radiators is generated on the basement rock because of the applied stresses in the preparation zone of the earthquakes in the earth crust. Considering such an ‘ensemble’ as the source of electromagnetic signals, the strength of the electric field is estimated at different distances and frequencies laying in range (3 – 27 kHz) at three different conductivities of the crustal layers (10-8, 10-9, 10-10 S/m). The results of the computation are presented in this paper. Moreover, propagation distances for the seismogenic VLF emissions have also been calculated in the frequency band (3 – 27 kHz) at the conductivities laying in the range (10-8 - 10-10 S/m) within the limit of detectability of measuring instruments (10-7 V/m). It is observed that these distances increase with the decrease of conductivity of the middle layer of crust. Furthermore, theoretical results of computations are verified from the experimental observations of the seismic event that occurred at the distance of 698 km from the observing station at Chaumuhan Mathura (Geographic lat. 27.490N, long. 77.670E). In addition to this, the generation and propagation mechanisms of seismo-electromagnetic radiations have also been discussed briefly.
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  • 73
    Publication Date: 2022
    Description: جت حاره وابسته به نوسان شبه دوسالانه QBO (Quasi Biennial Oscillation) به عنوان یک عامل تاثیر‌گذار بر جنب‌حاره وردسپهرزبرین مطرح است. در این پژوهش اثر QBO بر شکست امواج روی شرق مدیترانه و غرب‌آسیا از دیدگاه عرضهای بحرانی بررسی می‌شود. با استفاده از داده‌های بازتحلیل ERA-Interim بین سالهای 2018-1979، کمیت‌های شار فعالیت موج و شیو تاوایی پتانسیلی شبه زمینگرد در فازهای شرقی و غربی نوسان شبه‌دوسالانه QBO محاسبه و بررسی شده‌اند. نتایج نشان داد که در شکست امواج روی غرب‌آسیا همراه با استقرار و تقویت جت‌ها در بالادست و پایین‌دست ناوه‌ها، مقادیر منفی شیو تاوایی پتانسیلی شبه زمینگرد شکل می‌گیرند. در فاز شرقی نسبت به فاز غربی QBO جت‌ها و مقادیر منفی شیو تاوایی پتانسیلی شبه زمینگرد در بالادست و پایین‌دست ناوه‌ها بیشتر تقویت می‌شوند. بنابراین در فاز شرقی نسبت به فاز غربی QBO تقویت بازتاب استواسوی ناوه از عرضهای بحرانی موجب افزایش گردش واچرخندی و نفوذ بیشتر ناوه به عرضهای پایین‌تر می‌شود. در شکست چرخندی امواج نیز جت‌حاره شرقی وابسته به QBO سبب تقویت جت‌ها در عرضهای میانی می‌شود. بنابراین افزایش بازتاب قطب‌سوی ناوه از عرضهای بحرانی در بالادست و پایین‌دست ناوه سبب تقویت گردش چرخندی ناوه در فاز شرقی می‌شود. در نتیجه در فاز شرقی مولفه نصف‌النهاری شار فعالیت موج در پایین‌دست ناوه افزایش می‌یابد و شکست امواج روی غرب‌آسیا در فاز شرقی قوی‌تر از فاز غربی صورت می-گیرد. در حالیکه در شکست واچرخندی امواج روی غرب مدیترانه جت حاره غربی وابسته QBO سبب تقویت عرضهای بحرانی نسبت به فاز شرقی می‌شود.
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  • 74
    Publication Date: 2022
    Description: با توجه به پیچیدگی و تنوع ساختار‌ تکتونیکی در منطقه خاورمیانه استفاده از روشی که بتواند عمق موهو را با بیشترین همخوانی با این ساختارها را ارائه دهد، از اهمیت ویژه‌ای برخوردار است. در این مقاله به مقایسه عمق موهو بدست‌آمده در منطقه خاور‌میانه با استفاده از دو شیوه متفاوت 1) وارون‌سازی گرانی منشور‌های کروی و 2) تخمین عمق موهو با بکار‌گیری منشور‌های کروی و استفاده از مدل پوسته لرزه‌ایCRUST1.0 ، می‌پردازیم. در حالت کلی بدست آوردن عمق از داده‌های گرانی یک مساله وارون غیرخطی است. در هر دو شیوه داده‌های گرانی با استفاده از روش یودا برگردان می‌شوند. با توجه به وسعت منطقه، استفاده از منشورهای کروی بجای منشورهای تخت در روش وارون سازی بکار رفته علاوه بر در نظر گرفتن انحنای زمین موجب کارآمدی روش نیز می‌گردد. کمینه عمق موهوی بدست آمده از روش اول ۱۲ کیلومتر مربوط به بخش‌هایی از اقیانوس هند و بیشینه عمق موهو ۵۴ کیلومتر مربوط به قسمت‌های غربی فلات تبت است که با مرز صفحات و ساختارهای تکتونیکی همبسته است. محدوده عمق موهو در روش دوم در بازه‌ ۵/۷ تا ۴۹ کیلومتر است که مقدار کمینه مربوط به بخش‌هایی از اقیانوس هند و مقدار بیشینه مربوط به قسمت‌هایی از زاگرس است. مقایسه نتایج دو روش نشان می‌دهد که نتایج حاصل از روش اول بخاطر وارون سازی داده‌های گرانی‌سنجی نسبت به روش دوم که از مدل پوسته لرزه‌ای CRUST 1.0 برای تخمین عمق موهو استفاده کرده، کاملا با مرز صفحات همخوانی داشته و کلیه ساختار‌های تکتونیکی منطقه را نشان‌ می‌دهد.
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  • 75
    Publication Date: 2022
    Description: We investigate the capability of the WRF/Chem model in the simulation of some criteria air pollutants, during a major air pollution episode between 16 and 21 December 2017. In this study, by employing the EDGAR-HTAP_v2 global emissions data in the WRF/Chem model, we evaluate the simulations of the surface mixing ratios of NO2, SO2, and CO. The RADM2 chemical mechanism with MADE-SORGAM aerosol scheme has been used as the chemical option of the WRF/Chem model, to simulate the meteorology-chemistry interactions. The variations of the time series of the pollutants and the comparisons of the results in Tehran with the measurement data showed that although the WRF/Chem simulations in Tehran presented considerable over-estimations, but the model’s performance with regard to the time variations of the concentrations of the gaseous agents over the polluted episode is acceptable, and therefore, could be considered in the operational air quality systems. Since emission data are not available for many metropolitan areas over Iran, the HTAP_v2 global dataset could be used as the emissions data with reliable accuracy for the numerical air quality models.
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  • 76
    Publication Date: 2022
    Description: تجزیه و تحلیل احتمالی وقایع خشکسالی در مدیریت و برنامه‌ریزی مناسب سیستم‌های منابع آب نقش مهمی دارد. به طور خاص، برآورد دوره‌های بازگشت این پدیده می‌تواند اطلاعات مفیدی برای استفاده مناسب از آب در شرایط خشکسالی فراهم کند. در این مطالعه، توانمندی دو مدل سری CMIP5 در شبیه‌سازی ویژگی‌های احتمالاتی توام شدت و مدت این بلیه با استفاده از مفصل مورد بررسی قرار گرفته و تحلیل فراوانی دو متغیره مفصل-مبنا بر حسب شدت و مدتSPEI3 برای دوره پایه و دوره آتی در بخش جنوبی حوضه کارون انجام شده است. رویداد خشکسالی در سری SPEI3 به صورت تعدادی متوالی از این رویداد در فواصل زمانی که مقادیر SPEI کمتر از 1- است تعیین شد. پس از شناسایی خشکسالی، چندین ویژگی مانند شدت، مدت، سختی و ... را می‌توان تعیین کرد. از توابع مفصل و توزیع‌های حاشیه‌ای برای محاسبه دوره‌های بازگشت توام شدت و مدت به دو صورت "و" و "یا" استفاده و تأثیرات تغییرات اقلیمی بر ویژگی‌های خشکسالی آینده با استفاده از دو مدل اقلیم (HadGEM2-es و IPSL-CM4-MR) تحت سناریوهای RCP8.5 و RCP4.5 طی دوره 2050-2021 ارزیابی شد. نتایج نشان داد که توابع فرانک (ایستگاهی) و گامبل (CRU و دو مدل اقلیمی) بهترین انتخاب برای برازش بر مقادیر مدت و شدت استخراج شده از سری SPEI-3 بودند. مدل HadGem توانمندی خوبی را در شبیه‌سازی رفتار احتمالاتی توام خشکسالی طی دوره پایه نشان داد. همچنین پیش‌نگری‌ها نشان داد اهواز در آینده نزدیک در مقایسه با دوره پایه تحت دو سناریو، خشکسالی‌های شدیدتری بویژه در شبیه‌سازی مدل HadGEM2-es تجربه خواهد کرد.
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  • 77
    Publication Date: 2022
    Description: در این پژوهش روش تنظیم سطح برای وارون‌‌سازی مسائل گرانی‌سنجی استفاده شده است. با توجه به اینکه در مسائل وارون گرانی سنجی همواره با عدم یکتایی روبه رو هستیم، روش تنظیم سطح کمک می نماید تا با منظم سازی مسئله به کاهش در عدم یکتایی جواب نزدیک تر شویم. این روش دارای یک الگوریتم مناسب است که حساسیت مطلوبی در تعیین دقیق مرزها در مقطع جانبی دارد. همچنین برای بهینه‌ سازی و کاهش ابعاد پارامترهای مسئله، توابع پایه شعاعی برای نشان دادن عملکرد تابع تنظیم سطح انتخاب می شود. در این پژوهش الگوریتم مذکور برای بررسی نقاط ضعف و قوت آن و به منظور اعمال برداده های ژئوفیزیکی گرانی سنجی، کد نویسی و برنامه نویسی صورت گرفته است. در نتیجه با اعمال بر مدل‌های مصنوعی مشابه گنبد نمکی و مکعب ساده و نیز اعمال نویز تصادفی مختلف، مورد آزمایش قرار گرفت و نهایتاً برای تست واقعی از داده های معدن موبرون کانادا استفاده شده است.
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  • 78
    Publication Date: 2022
    Description: بخارآب یکی از مهم‌ترین شاخص‌های جوی است که تعیین دقیق آن به افزایش دقت مدل‌های عددی هواشناسی کمک فراوانی می‌کند. امروزه با استفاده از مشاهدات GNSS و به‌کارگیری روش توموگرافی می‌توان ضرایب شکست تر در هر یک از المان‌های حجمی در نظر گرفته‌شده را برآورد کرد. استفاده از مشاهدات رخداد آکولتیشن می‌تواند باعث افزایش تعداد مشاهدات از جنس پارامترهای جوی حتی در نقاطی که مشاهدات ایستگاه‌های GNSS حضور ندارد، گردد. هدف از این تحقیق تلفیق مشاهدات آکولتیشن با مشاهدات GPS به‌منظور بالا بردن دقت ضرایب شکست برآورد شده در توموگرافی تابعی تروپوسفر است. به‌منظور برآورد نمودن مجهولات مسئله توموگرافی از مدل تابعی به کمک هارمونیک‌های کلاه کروی به همراه توابع متعامد تجربی برای تشکیل مدل سه‌بعدی استفاده‌شده است. همچنین از توابع پایه‌ی اسپیلاین برای نمایش توزیع ضرایب شکست تر در زمان و تشکیل مدل چهاربعدی بهره گرفته‌شده است. منطقه موردمطالعه، شبکه‌ ایستگاه‌های دائمی در کالیفرنیا می‌باشد بطوریکه پروفیل ضرایب شکست تر حاصل از توموگرافی در دو اپک زمانی (دو فصل مختلف) محاسبه گردیده و با داده‌های رادیوسوند مقایسه می‌شوند. نتایج نشان می‌دهد که استفاده از مشاهدات آکولتیشن در کنار مشاهدات زمینی GPS در توموگرافی انجام‌شده با استفاده از مدل‌های تابعی سه‌بعدی و چهاربعدی می‌تواند مقدار RMSE پروفیل‌های ضرایب شکست تر را تا حدود 8 درصد نسبت به توموگرافی انجام‌شده فقط با استفاده از مشاهدات GPS بهبود دهد. نهایتا نشان داده‌شده که اضافه نمودن مشاهدات آکولتیشن باعث تغییر در تأخیر تروپوسفری تر برآورد شده برای منطقه موردمطالعه در حدود 4 سانتی‌متر می‌گردد.
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  • 79
    Publication Date: 2022
    Description: دمای سطح زمین (LST) که حاصل اندرکنش جو ـ زمین است، به دلیل تأثیرپذیری از پوشش سطح زمین، رطوبت خاک، آلبیدو، زبری سطح و اندرکنش این عوامل با هواسپهر، می‌تواند تغییرات شرایط حرارتی سطح زمین را آشکار نماید. در پژوهش حاضر از داده‌های LST شب‌‌هنگام سنجنده‌ی مودیس ماهواره‌های ترا و آکوا (MOD11C3 & MYD11C3) که از وبگاه http://earthdata.nasa.gov دریافت گردید، برای برآورد LST در حوضه‌ی آبریز جازموریان طی سال‌های 2019-2003 استفاده شد. پس از فراهم‌سازی داده‌ها با گام‌های زمانی ماهانه و مکانی 5 کیلومتر، محاسبات بر روی دو ماتریس ماهانه و فصلی انجام گردید و به تهیه‌ی خروجی‌های آماری‌ـ-فضایی منطبق با هدف تحقیق، در محیط نرم‌افزارهای Excel، ENVI و GIS اقدام شد. نتایج نشان داد؛ LST شب‌هنگام در حوضه‌ی آبریز جازموریان، طی دوره‌ی آماری مورد مطالعه حدود °C 1 افزایش یافته‌است. این افزایش در دمای کمینه ‌بیش از افزایش در دمای بیشینه بوده‌است. توزیع فضایی LST شب‌هنگام نیز، بیان‌گر دامنه‌ی گسترده‌ای از دماها از°C10 - تا°C 35 + است که بیشینه‌ی آن در مناطق پست و کم‌ارتفاع مرکزی و جنوبی و کمینه‌ی آن در ارتفاعات شمالی حوضه برآورد گردید. همچنین برآورد فضایی ناهنجاری LST شب‌هنگام، ضمن تأیید روند افزایشی LST، بیشترین/کمترین ناهنجاری‌ مثبت LST را به ترتیب در بخش‌های مرکزی و غربی/بخش‌های شرقی و ارتفاعات شمالی حوضه نشان داده‌است. این شرایط می‌تواند به عنوان نمایه‌ای از تغییر اقلیم مورد توجه قرار گرفته و منجر به تغییر برخی از فراسنج‌های محیطی از قبیل رطوبت نسبی، تبخیر و تعرق، رطوبت سطح خاک، ماندگاری برف، دمای نقطه‌ی شبنم و انرژی بازتابی شبانه شود.
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  • 80
    Publication Date: 2022
    Description: Some extreme precipitations have occurred in Iran in recent years. This paper is devoted to the study of extreme precipitations in the west of Iran, affected by combination of atmospheric pressure patterns in the period of 1987–2016. At first, monthly precipitations for seven synoptic stations of the west of Iran in autumn and winter with positive anomalies greater than 100% were identified. Then, for statistical-dynamical analysis, the El-Nino Southern Oscillation (ENSO), North Atlantic Oscillation (NAO), Madden–Julian Oscillation (MJO) indices were used. Results showed that the extreme precipitations had occurred during moderate to strong El-Nino, while MJO was critical and strong, in phases 2 and 8, and NAO was in positive phase. The anomalies of the MJO index in case studies had positive values. The NAO for case studies has entered a positive phase from a strong negative phase a few days before extreme precipitation. Analyzing the relationship between the NAO and the MJO with lagged composites showed when the MJO leads the NAO, significant positive NAOs are found for phases 2, and negative NAOs for phases 8, indicating a significant influence of the MJO on NAO. The synoptic-dynamic analysis showed that three low pressure and one high pressure were the dominant systems that have been effective in producing extreme precipitation. Examination of the moisture fluxes revealed that the main humidity sources of the heavy precipitation were the Arabian Sea due to easterly winds that travel a long distance over the north west of Indian Ocean to the Arabian Sea.
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  • 81
    Publication Date: 2022
    Description: An integrated GIS, Remote sensing, and Geophysical techniques have been successfully applied to generate the previously non-available groundwater prospectivity map for the present study area. Selected thematic maps were integrated using the weighted sum tool of the spatial analyst tool of the ArcGIS software. The five thematic maps used are: lithology map, drainage density map, slope map, lineaments density map, and the topographic map of the area. The groundwater prospectivity map generated was reclassified into low, moderate, high, and very high potential zones on the basis of their assigned layer rank, which also depends on their degree of influence on groundwater occurrence. Areas around Gombe, Wuyo, Deba, Alkaleri, Kaltungo, Misau, Nafada, Bajoga towns are the regions that showed very high prospects for groundwater occurrence. Data processing filters such as: horizontal derivatives, Analytic signal processing, 3D-Euler depth estimation was applied on the magnetic data in order to map structures and lithologic contacts before its subsequent integration with other structural lineaments as a thematic layer. Vertical Electrical Sounding (VES) data were used to compute hydraulic conductivity, and Transmisivity etc. for the acquiferous layers identified. The results of the present study showed some regions that are classified as highly prospective to be consistent with high transmisivity and high yield values. The final outcome (groundwater potential map) of this research demonstrated that GIS/remote sensing, and the geophysical technique employed is a very powerful tool for generating groundwater prospectivity map, which is very vital in terms of planning for groundwater exploration and exploitation.
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  • 82
    Publication Date: 2022
    Description: امروزه انواع شبکه‌های عصبی مصنوعی در حوزه های مختلف علوم جو و اقلیم‌شناسی برای اهدافی نظیر طبقه‌بندی، رگرسیون و پیش-بینی استفاده می‏شوند. اما سوال اساسی در استفاده از شبکه‌های عصبی مصنوعی، نحوه طراحی و معماری آنهاست. یکی از نکات مهم در استفاده از شبکه‌های عصبی مصنوعی که باید مد نظر طراحان قرار بگیرد، انتخاب الگوریتم مناسب برای آموزش شبکه است. در این مقاله، شش روش مختلف آموزش شبکه عصبی پرسپترون چند لایه شامل روشهای منظم سازی بیزی، لِوِنبرگ-مارکوات و گرادیان مزدوج پاول-بل، الگوریتم شبه نیوتنی BFGS، گرادیان مزدوج فلچر-پاول و گرادیان مزدوج مقیاس شده برای پیش‌بینی ماهانه بارش کشور مورد بررسی و مقایسه قرار میگیرند. برای این منظور، یک شبکه عصبی پرسپترون برای پس پردازش خروجی بارش ماهانه مدل ECMWF طراحی می‏شود که برای آموزش آن از داده‏های ERA5 و روشهای آموزش مختلف استفاده می‏شود. برای بررسی عملکرد شش روش آموزش مختلف، مقدار سه شاخص ضریب همبستگی، میانگین مربعات خطا و نیز شاخص نش-ساتکلیف برای هر مدل محاسبه گردید. همچنین، عملکرد روشهای مذکور در مناطق جغرافیایی مختلف کشور برای ماه ژانویه، به عنوان نمونه، مورد ارزیابی قرار گرفت. نتایج حاصل از مقایسه شاخصها نشان داد که عملکرد دو روش منظم سازی بیزی و لِوِنبرگ-مارکوات، در مقایسه با چهار روش دیگر برای آموزش شبکه عصبی بهتر است. همچنین این دو روش توانستند، در مقایسه با داده‏های مدل ECMWF، قبل از پس پردازش، نتایج با دقت بیشتری را بدست آورند.
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  • 83
    Publication Date: 2022
    Description: بررسی رخداد توأم چرخندها و تغییر تراز فشار وردایست اطلاعات مفیدی دربارۀ ویژگی‌های جو به‌ویژه در ارتباط با رخداد بارش‌های فراگیر ایران به‌دست می‌دهد؛ زیرا از عواملی که منجر به بروز بارش‌های فراگیر در ایران می‌شود چرخندهای ورودی به کشور است. شناخت ساز وکارهای مرتبط با چرخند‌ها می‌تواند در شناخت بهتر و پیش‌بینی آنها موثر باشد. به‌همین دلیل در پژوهش حاضر ارتباط وردایست با چرخندهای تاثیرگذار بر بارش‌های فراگیر ایران مورد بررسی قرار گرفت. جهت انجام پژوهش از داده‌های دما و ارتفاع ژئوپتانسیل پایگاه داده ECMWF و جهت انتخاب روزهای توأم با بارش فراگیر ایران نیز از داده‌های پایگاه اسفزاری (نسخۀ سوم) استفاده شده‌است. با توجه به این‌که مطالعه‌ی تمام روزهای توأم با بارش فراگیر در این پژوهش امکان‌پذیر نبود، از میان تمام روزهای توأم با بارش فراگیر، روزهایی که درصد مساحت تحت پوشش بارش در آنها بیشتر بود، برای ماه‌های مختلف انتخاب شد. در نهایت درطول دوره‌ی مورد مطالعه 8 روز در 8 ماه مختلف انتخاب شد. برای هر روز منتخب، چرخند فعال شناسایی و ویژگی‌‌های وردایست در زمان شروع چرخند و روز رخداد بارش فراگیر بررسی شد. براساس نتایج به دست آمده از این پژوهش مشخص شد که در تمام 8 روز مورد واکاوی، در روز شروع فعالیت چرخند و در روز توأم با بارش فراگیر برروی ایران، تراز فشار وردایست تفاوت‌های قابل توجهی با مناطق هم عرض (و اطراف) خود دارد. در این هنگام تراز فشار وردایست مقادیر عددی بزرگ‌تری را نشان می‌دهد.
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  • 84
    Publication Date: 2022
    Description: 〈p〉This paper aims to examine consumer behaviour towards, and the willingness to adopt, ‘green steel’ in the automotive sector. Semi-structured interviews were held with experts from global, regional and country-specific industry associations and automakers. This paper appraises potential demand for green steel within different vehicle types (based both on size and powertrain) and shows that manufacturers […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/steeling-the-race-green-steel-as-the-new-clean-material-in-the-automotive-sector/"〉Steeling the race: ‘Green steel’ as the new clean material in the automotive sector〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 85
    Publication Date: 2022
    Description: 〈p〉In this podcast David Ledesma discusses the implications of Russia’s invasion of Ukraine for global oil markets with Bassam Fattouh, Director of OIES based on his latest paper: Russia-Ukraine crisis: Implications for global oil markets with Andreas Economou and Ahmed Mehdi. In this wide-ranging discussion, Bassam Fattouh discusses what the potential loss of Russian oil […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-podcast-russia-ukraine-crisis-implications-for-global-oil-markets/"〉Oxford Energy Podcast – Russia-Ukraine crisis – Implications for global oil markets〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉 〈div class="enclosure"〉〈p class="enclosure-content"〉〈audio preload="none" src="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-134-Russia-Ukraine-crisis-Implications-for-global-oil-markets.mp3" controls="controls"〉〈/audio〉 〈a download="" href="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-134-Russia-Ukraine-crisis-Implications-for-global-oil-markets.mp3"〉💾〈/a〉〈/p〉〈/div〉
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  • 86
    Publication Date: 2022
    Description: 〈p〉In September-October 2021, China experienced a severe electricity supply crisis that impacted over twenty provinces, leading to industrial curtailment and residential supply cuts in some areas. In this podcast David Ledesma discusses the causes and implications of this supply crisis with Michal Meidan Director of the Gas Research Programme & the China Energy Research Programme […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-podcast-the-2021-energy-crisis-implications-for-chinas-energy-market-and-policies/"〉Oxford Energy Podcast – The 2021 energy crisis: Implications for China’s energy market and policies〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉 〈div class="enclosure"〉〈p class="enclosure-content"〉〈audio preload="none" src="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-133-The-2021-energy-crisis-Implications-for-Chinas-energy-market-and-policies.mp3" controls="controls"〉〈/audio〉 〈a download="" href="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-133-The-2021-energy-crisis-Implications-for-Chinas-energy-market-and-policies.mp3"〉💾〈/a〉〈/p〉〈/div〉
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  • 87
    Publication Date: 2022
    Description: Through empirical and policy analysis, this Article explores a fundamental disconnect between the statutory objectives of the Securities and Exchange Commission and the actual outcome of its policies in digital-asset markets.〈div class="enclosure"〉〈/div〉
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  • 88
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉This paper considers potential import routes for low-carbon and renewable hydrogen (H2) to main European markets like Germany. In particular, it analyses claims made by Hydrogen Europe and subsequently picked up by the European Commission in its Hydrogen Strategy that there will be 40GW of electrolyser capacity in nearby countries providing hydrogen imports to Europe […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/potential-development-of-renewable-hydrogen-imports-to-european-markets-until-2030/"〉Potential development of renewable hydrogen imports to European markets until 2030〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 89
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉After weeks of tensions, Russian President Vladimir Putin ordered Russian troops to invade Ukraine, prompting an international sanctions response targeting Russia’s economy but not directly its oil supplies or energy payments. But as sanctions on Russia intensified and as financial institutions started to refuse financing Russia-related transactions, including opening letters of credit or clearing payments […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/russia-ukraine-crisis-implications-for-global-oil-markets/"〉Russia-Ukraine crisis: Implications for global oil markets〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 90
    Publication Date: 2022
    Description: 〈p〉The specter of climate change has impacted shareholder sentiment making many market participants evaluate their business models in accordance with Cop-26 pledges – looking for ways of winning the mandate for capital in a sustainable way. The most familiar approach to reducing carbon footprint is by creating ‘GHG-verified’ claims. Typically, these involve a verified account […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/ghg-verified-mechanisms-for-internationally-traded-crude-oil-and-possible-impact-on-oil-benchmarks/"〉GHG-verified mechanisms for internationally traded crude oil and possible impact on oil benchmarks〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 91
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉Central banks worldwide are stepping up actions in relation to climate change and taking on an increasingly important role in supporting the energy transition. Given the prominent role that central banks play in the financial markets and in influencing financing conditions, they can act as a powerful catalyst in addressing climate change. But their involvement […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/central-banks-green-shift-and-the-energy-transition/"〉Central Banks’ ‘Green Shift’ and the Energy Transition〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 92
    Publication Date: 2022
    Description: 〈p〉On 8 March 2022, the European Commission published the outline of a plan to make Europe independent from Russian fossil fuels well before 2030, starting with gas, in light of Russia’s invasion of Ukraine. The Commission noted that EU gas imports from Russia in 2021 (pipeline and LNG combined) totalled 155 billion cubic metres (bcm), […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/the-eu-plan-to-reduce-russian-gas-imports-by-two-thirds-by-the-end-of-2022-practical-realities-and-implications/"〉The EU plan to reduce Russian gas imports by two-thirds by the end of 2022: Practical realities and implications〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 93
    Publication Date: 2022
    Description: 〈p〉On 17 March, Michal Meidan testified before the U.S.-China Economic & Security Review Commission on China’s Energy Plans and Practices. In her testimony, Michal discussed the outlook for China’s fossil fuel demand in China, the successes and challenges associated with fossil fuel supply and how this fits into the country’s low carbon energy transition. Michal […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/statement-before-the-u-s-china-economic-and-security-review-commission-policymaking-and-energy-supply-and-demand-in-chinas-domestic-economy/"〉Statement before the U.S.-China Economic and Security Review Commission: Policymaking and Energy Supply and Demand in China’s Domestic Economy〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 94
    Publication Date: 2022-03-22
    Description: Abstract
    Description: We present a dataset of in-situ measurements in the marginal area of a CO2- and brine-rich cavernous structure in an underground salt mine. The data were collected within the framework of the BMBF-project ProSalz. One aim was to reveal the sources and dynamics of fluid movement as well as temporal and spatial distribution of fluids in a potentially weakened cavern rim. Over a period of three years pressure and gas monitoring was carried out along a transect from a cavernous structure to undisturbed rock salt. In addition, temperature and relative humidity data from the underground gallery were recorded. The gas inflow into isolated borehole sections provided an insight into short- and long-term changes of gas migration patterns in rock salt. Pressure increases of up to 4kPa/day and CO2 concentrations of up to 1.2%, especially at the start of the campaign were measured. The gas migration is coupled to discrete fractures and was limited spatially and temporary. Overall, gas occurrences were not correlated to their distance to the cavern, suggesting no wide-ranging fluid-rock interaction within the rim of the investigated natural cavernous structure in rock salt.
    Description: Methods
    Description: The gas pressures in C1, B3, B6, B10A and B10B were measured with pressure sensors (Greisinger) connected to the packer system. The data were recorded with a data logger (ADL-MX Advanced Datalogger, Meier-NT). The humidity and temperature data were recorded using a humidity sensor (Galltec + Mela). The gases were collected underground in sampling bags (calibrated instruments), and analysed in the lab using an OmniStar mass spectrometer (Pfeiffer).
    Keywords: rock salt ; potassium bearing salt deposits ; salt cavern ; gas migration ; long time monitoring ; in situ underground study ; compound material 〉 sedimentary material 〉 chemical sedimentary material 〉 evaporite 〉 rock salt ; EARTH SCIENCE 〉 PALEOCLIMATE 〉 LAND RECORDS 〉 BOREHOLES ; EARTH SCIENCE 〉 SOLID EARTH 〉 GEOCHEMISTRY
    Type: Dataset , Dataset
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  • 95
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉In 2021, China experienced several episodes of power shortages and outages, heightening already existing concerns about energy security. In response, the government instituted a rapid succession of market reforms and other regulatory changes, which have pushed the majority of power users into the power market and also allowed for a wider range of electricity prices. […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-podcast-chinas-power-market-reforms-in-an-age-of-insecurity/"〉Oxford Energy Podcast – China’s power market reforms in an age of insecurity〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉 〈div class="enclosure"〉〈p class="enclosure-content"〉〈audio preload="none" src="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-136-–-Chinas-power-market-reforms-in-an-age-of-insecurity.mp3" controls="controls"〉〈/audio〉 〈a download="" href="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-136-–-Chinas-power-market-reforms-in-an-age-of-insecurity.mp3"〉💾〈/a〉〈/p〉〈/div〉
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  • 96
    Publication Date: 2022
    Description: 〈p〉The dramatic rise in European, and indeed in global, gas prices over the summer of 2021, leading to unprecedented prices in Q4, has been the subject of much debate. Is it simply a market reflection of stronger than expected demand and weaker than expected supplies? Or is it a step change in the context of […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/a-series-of-unfortunate-events-explaining-european-gas-prices-in-2021-the-role-of-the-traded-gas-hubs/"〉A Series of Unfortunate Events – Explaining European Gas Prices in 2021: The role of the traded gas hubs〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 97
    Publication Date: 2022-03-26
    Description: The global climate model system MPI-ESM-LR was applied to create an ensemble of 30 members for the historical period 1950-2005 and a continuation of the simulations for the RCP8.5 period 2006-2099. Additionally, a pre-industrial control run was performed for 1950-2099 with atmospheric pCO2 of 1850. All members were subsequently directly regionalized using the regionally coupled MPIOM-REMO climate model system consisting of the global ocean model MPIOM focused with its horizontal resolution on the North Sea and the regional atmospheric model REMO over the EURO CORDEX22 region (euro-cordex.net), which was fully coupled with MPIOM in this region. For extreme value analyses, certain variables were stored with hourly time step. Here, global sea surface height and regional (EURO CORDEX22) u and v wind components at 10 m above ground are available. Further data can be requested from the authors.
    Type: experiment
    Format: NetCDF
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  • 98
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉In this OIES podcast James Henderson talks to Anouk Honoré and Jack Sharples about the EU plan to diversify gas imports away from Russia in 2022. They discuss the latest strategy published by the European Commission on March 8, which addresses both the supply and demand-side options. The podcast considers the potential to import an […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/oxford-energy-podcast-eu-plans-to-reduce-russian-gas-imports/"〉Oxford Energy Podcast – EU plans to reduce Russian gas imports〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉 〈div class="enclosure"〉〈p class="enclosure-content"〉〈audio preload="none" src="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-137-EU-plans-to-reduce-Russian-gas-imports-.mp3" controls="controls"〉〈/audio〉 〈a download="" href="https://a9w7k6q9.stackpathcdn.com/wpcms/wp-content/uploads/2022/03/Podcast-137-EU-plans-to-reduce-Russian-gas-imports-.mp3"〉💾〈/a〉〈/p〉〈/div〉
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  • 99
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉India has been implementing climate actions since 2001, when it was one of very few countries to pass an Energy Conservation Act, followed by an industrial emissions trading scheme to force large manufacturing companies to become more energy efficient. A National Action Plan for Climate Change (NAPCC) was passed in 2008, and included relatively modest […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/indias-progress-on-its-climate-action-plan-an-update-in-early-2022/"〉India’s Progress on its Climate Action Plan – An Update in Early 2022〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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  • 100
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    The Oxford Institute for Energy Studies
    Publication Date: 2022
    Description: 〈p〉Russia’s invasion of Ukraine has catalysed a chorus of dismay and outrage from western companies with investments in Russia and has led some to announce their withdrawal from the country. Furthermore, it has also caused the US and the EU to impose sanctions on individuals and companies involved in the energy sector and to announce […]〈/p〉 〈p〉The post 〈a rel="nofollow" href="https://www.oxfordenergy.org/publications/thoughts-on-the-impact-of-foreign-companies-exiting-the-russian-oil-and-gas-industry/"〉Thoughts on the impact of foreign companies exiting the Russian oil and gas industry〈/a〉 appeared first on 〈a rel="nofollow" href="https://www.oxfordenergy.org/"〉Oxford Institute for Energy Studies〈/a〉.〈/p〉
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