ALBERT

Description: The accurate knowledge of the Earth’s orientation and rotation in space is essential for a broad variety of scientific and societal applications. Among others, these include global positioning, near-Earth and deep-space navigation, the realisation of precise reference and time systems as well as studies of geodynamics and global change phenomena. In this paper, we present a refined strategy for processing and combining Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), Global Navigation Satellite Systems (GNSS), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) observations at the normal equation level and formulate recommendations for a consistent processing of the space-geodetic input data. Based on the developed strategy, we determine final and rapid Earth rotation parameter (ERP) solutions with low latency that also serve as the basis for a subsequent prediction of ERPs involving effective angular momentum data. Realising final ERPs on an accuracy level comparable to the final ERP benchmark solutions IERS 14C04 and JPL COMB2018, our strategy allows to enhance the consistency between final, rapid and predicted ERPs in terms of RMS differences by up to 50% compared to existing solutions. The findings of the study thus support the ambitious goals of the Global Geodetic Observing System (GGOS) in providing highly accurate and consistent time series of geodetic parameters for science and applications.

Description: BACKGROUND AND OBJECTIVES: Soil or rock types in a region are often interpreted qualitatively by visually comparing various geophysical properties such as seismic wave velocity and vulnerability, as well as gravity data. Better insight and less human-dependent interpretation of soil types can be obtained from a joint analysis of separated and independent geophysical parameters. This paper discusses the application of a neural network approach to derive rock properties and seismic vulnerability from horizontal-to-vertical seismic ratio and seismic wave velocity data recorded in Majalengka-West Java, Indonesia.METHODS: Seismic microtremors were recorded at 54 locations and additionally multichannel analyses of surface wave experiments were performed at 18 locations because the multichannel analyses of surface wave experiment needs more effort and space. From the two methods, the values of the average shear wave velocity for the upper 30 meters, peak amplitudes and the dominant frequency between the measurement points were obtained from the interpolation of those geophysical data. Neural network was then applied to adaptively cluster and map the geophysical parameters. Four learning model clusters were developed from the three input seismic parameters: shear wave velocity, peak amplitude, and dominant frequency. FINDINGS: Generally, the values of the horizontal to vertical spectral ratios in the west of the study area were low (less than 5) compared with those in the southeastern part. The dominant frequency values in the west were mostly low at around 0.1–3 Hertz, associated with thick sedimentary layer. The pattern of the shear wave velocity map correlates with that of the horizontal to vertical spectral ratio map as the amplification is related to the soil or rock rigidity represented by the shear wave velocity. The combination of the geophysical data showed new features which is not found on the geological map such as in the eastern part of the study area. CONCLUSION: The application of the neural network based clustering analysis to the geophysical data revealed four rock types which are difficult to observe visually. The four clusters classified based on the variation of the geophysical parameters show a good correlation to rock types obtained from previous geological surveys. The clustering classified safe and vulnerable regions although detailed investigation is still required for confirmation before further development. This study demonstrates that low-cost geophysical experiments combined with neural network-based clustering can provide additional information which is important for seismic hazard mitigation in densely populated areas.

Description: Tropical Lake Sentani in the Indonesian Province Papua consists of four separate basins and is surrounded by a catchment with a very diverse geology. We characterized the surface sediment (upper 5 cm) of the lake’s four sub-basins based on multivariate statistical analyses (principal component analysis, hierarchical clustering) of major element compositions obtained by X-ray fluorescence scanning. Three types of sediment are identified based on distinct compositional differences between rivers, shallow/proximal and deep/distal lake sediments. The different sediment types are mainly characterized by the correlation of elements associated with redox processes (S, Mn, Fe), carbonates (Ca), and detrital input (Ti, Al, Si, K) derived by river discharge. The relatively coarse-grained river sediments mainly derive form the mafic catchment geology and contribution of the limestone catchment geology is only limited. Correlation of redox sensitive and detrital elements are used to reveal oxidation conditions, and indicate oxic conditions in river samples and reducing conditions for lake sediments. Organic carbon (TOC) generally correlates with redox sensitive elements, although a correlation between TOC and individual elements change strongly between the three sediment types. Pyrite is the quantitatively dominant reduced sulfur mineral, monosulfides only reach appreciable concentrations in samples from rivers draining mafic and ultramafic catchments. Our study shows large spatial heterogeneity within the lake’s sub-basins that is mainly caused by catchment geology and topography, river runoff as well as the bathymetry and the depth of the oxycline. We show that knowledge about lateral heterogeneity is crucial for understanding the geochemical and sedimentological variations recorded by these sediments. The highly variable conditions make Lake Sentani a natural laboratory, with its different sub-basins representing different depositional environments under identical tropical climate conditions.

Description: Along the Northern Chilean active continental margin, the subducting Nazca plate is characterized by a rough sea floor topography that has been suggested to control the rupture behaviour of megathrust earthquakes. However, there is still debate of what structures exactly controlled the extent of the rupture of the Mw 8.12014 April 1st Iquique earthquake and why it only broke 1/3 of a large seismic gap that last ruptured completely in 1877. To better understand the seismotectonic segmentation of the northern Chilean convergent margin, we use datasets from different geophysical and geodetic studies in this area to produce a 3D model. We combine depth migrated images of the two northernmost multi-channel seismic reflection CINCA’95 (Crustal Investigations off- and onshore Nazca Plate/Central Andes) lines, bathymetry data, coseismic slip models, geodetic coupling, seismic b values, relocated seismic events and the morphology of the subduction interface from gravity modelling. The interface morphology shows a prominent surface relief that spacially correlates with the rupture process of the mainshock on April 1st and also for the largest aftershock on April 3rd. The main slip area exhibits a strong correlation with a large elongated topographic depression of the subducting slab. An elongated topographic high on the subducting plate to the south of that depression correlates with low pre-seismic locking and very likely acted as a barrier for rupture propagation for the main shock, as well as for the largest after shock. A subducted circular topographic high of 25 km in diameter located updip of the rupture area, possibly prevented coseismic slip to rupture all the way up to the trench axis. Thus, our observations support that subducting sea floor morphology plays an important role controlling rupture processes.

Description: Modern continental crust has evolved to a more potassic, granitic composition than early continental crust, which comprises largely sodic TTG-suite magmas. The present paradigm holds that the latter are largely “juvenile” (in the sense that the time from mantle extraction to felsic crust production is comparatively short, of the order 10–100 Ma) while the former represent recycled older crust of igneous or sedimentary composition. The data from high-Mg diorites, tonalites, granodiorites and potassic granites of the 125–115 Ma Menglian Batholith (SE Tibet) exemplify the modern situation and can therefore be used to constrain current crust formation processes. These rocks have higher concentrations of incompatible elements than magmatic rocks from typical continental arc settings, with a continuum of increasing K2O/Na2O ratios, SiO2, K2O, Rb, and Th concentrations juxtaposed with decreasing MgO, CaO, and Sr. They consistently record both higher zircon δ18O values than mantle values and decoupled Ndsingle bondHf isotope systems caused by the interaction of subducted sediments with the mantle wedge. Petrogenetic mechanisms that connect the suite include crystal fractionation within the diorites, melting of the lower crust induced by advection of heat and water by the diorites, and high-level fractionation of the tonalite-granodiorite suite to produce the high-silica granites. Therefore, this example of modern fertile continental crust had a five-stage evolution: (1) subduction-enrichment of the mantle source, (2) mantle melting to produce mafic magmas that pooled in or below the lower crust, (3) mafic magma differentiation to produce the tonalite-granodioritic magmas controlled by crystal-liquid equilibria, (4) crustal melting and admixture to the evolving felsic magmas and (5) final high-level fractionation and melt extraction to produce the silicic extreme, enriched in incompatible elements such as Rb, Th and K. This model could be a general mechanism for how modern mature continental crust evolves. Importantly, it indicates a significant role for mafic magmas and thence a more important role for juvenile additions than is generally accepted.

Description: Most tectonic models consider that the “Samail subduction zone” was the only subduction zone at the mid-Cretaceous convergent Arabian margin. We report four new Rb-Sr multimineral isochron ages from high-pressure (HP) rocks and a major shear zone of the uppermost Ruwi-Yiti Unit of the Saih Hatat window in the Oman Mountains of NE Arabia. These ages demand a reassessment of the intraoceanic suprasubduction-zone evolution that formed the Samail Ophiolite and its metamorphic sole in the Samail subduction zone. Our new ages constrain waning HP metamorphism of the Ruwi subunit at ∼99-96 Ma and associated deformation in the Yenkit shear zone between ∼104 and 93 Ma. Our ages for late stages of deformation and HP metamorphism (thermal gradients of ∼8–10°C km−1) overlap with published ages of ∼105-102 Ma for Samail-subduction-zone prograde-to-peak metamorphism (thermal gradients of ∼20–25°C km−1), subsequent decompressional partial melting of the metamorphic sole and suprasubduction-zone crystallization of the Samail Ophiolite (thermal gradients of ∼30°C km−1) between ∼100 and 93 Ma. Thermal considerations demand that two subduction zones existed at the mid-Cretaceous Arabian margin. High-pressure metamorphism of the Ruwi-Yiti rocks occurred in a mature, thermally equilibrated “Ruwi subduction zone” that formed at ∼110 Ma. Initiation of the infant, thermally unequilibrated and, thus, immature, outboard intraoceanic Samail subduction zone occurred at ∼105 Ma. The Samail Ophiolite and its metamorphic sole were then thrust over the exhuming Ruwi-Yiti HP rocks and onto the Arabian margin after ∼92 Ma, while the bulk of the Saih Hatat HP rocks below the Ruwi-Yiti Unit started to be underthrust in the Ruwi subduction zone.

Description: A massive landslide often causes long-lasting instability dynamics that need to be analyzed in detail for risk management and mitigation. Multiple satellite remote sensing observations, in-situ measurements, and geophysical approaches have been jointly implemented to monitor and interpret the life cycle of landslides and their failure mechanisms from various perspectives. In this work, we propose a framework where satellite optical and synthetic aperture radar (SAR) remote sensing techniques are combined with feature extractions using independent component analysis (ICA) and a mathematical relaxation model to assess the complete four-dimensional (4D) spatiotemporal patterns of post-failure slope evolution. The large, deep-seated Aniangzhai landslide in Southwest China that occurred on 17 June 2020 is comprehensively analyzed and characterized for its post-failure mechanism. Time series of Planet high-resolution optical images are first explored to derive the large horizontal motions for the first six months after the failure. Spatiotemporal dynamics of line-of-sight (LOS) displacement in the landslide body are then derived between November 2020 and February 2022 by combining 40 TerraSAR-X (TSX) High-resolution Spotlight (HS) images and 76 medium-resolution Sentinel-1 (S1) SAR datasets using Multi-temporal InSAR (MTI) method. The InSAR-derived results are subsequently analyzed with ICA to find common deformation components of points between optical and MTI results, indicating the same temporal evolution in the deformation pattern. Finally, the complete 4D deformation field for the whole post-failure period is modeled using a decaying exponential model representing stress relaxation after the failure by integrating multiple remote sensing datasets. Cross-correlation analysis of Planet imagery shows a decaying exponential pattern of post-failure displacements with an approximately 94% reduction in the deformation rate after six months with respect to the co-failure event. MTI analysis suggests a maximum LOS displacement rate of approximately 30 cm/year over the main failure body from November 2020 to February 2022; while the high-resolution TSX datasets show irreplaceable advantages in choosing the number of measurement points in MTI analysis with the number of measurement points being five times larger than those obtained by S1 datasets. The ICA analysis reveals three main types of kinematic patterns in the temporal evolution of post-failure deformation in MTI results, the dominant one being an exponential declining pattern similar to the results from Planet observations. Integrated 4D deformation modeling suggests that the most significant post-failure displacement mainly occurred toward the west, amounting to 28 m during the entire post-failure acquisitions from June 2020 until February 2022. Additionally, maximum displacements of 17 m and 19 m occurred in this period toward the north and downward, respectively.

Description: Planned decommissioning of coal-fired plants in Europe requires innovative technical and economic strategies to support coal regions on their path towards a climate-resilient future. The repurposing of open pit mines into hybrid pumped hydro power storage (HPHS) of excess energy from the electric grid, and renewable sources will contribute to the EU Green Deal, increase the economic value, stabilize the regional job market and contribute to the EU energy supply security. This study aims to present a preliminary phase of a geospatial workflow used to evaluate land suitability by implementing a multi-criteria decision making (MCDM) technique with an advanced geographic information system (GIS) in the context of an interdisciplinary feasibility study on HPHS in the Kardia lignite open pit mine (Western Macedonia, Greece). The introduced geospatial analysis is based on the utilization of the constraints and ranking criteria within the boundaries of the abandoned mine regarding specific topographic and proximity criteria. The applied criteria were selected from the literature, while for their weights, the experts’ judgement was introduced by implementing the analytic hierarchy process (AHP), in the framework of the ATLANTIS research program. According to the results, seven regions were recognized as suitable, with a potential energy storage capacity from 1.09 to 5.16 GWh. Particularly, the present study’s results reveal that 9.27% (212,884 m2) of the area had a very low suitability, 15.83% (363,599 m2) had a low suitability, 23.99% (550,998 m2) had a moderate suitability, 24.99% (573,813 m2) had a high suitability, and 25.92% (595,125 m2) had a very high suitability for the construction of the upper reservoir. The proposed semi-automatic geospatial workflow introduces an innovative tool that can be applied to open pit mines globally to identify the optimum design for an HPHS system depending on the existing lower reservoir.

Description: The minor and trace element composition of minerals provides critical insights into a variety of geological processes. Multi-element mapping by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is an important technique applied for this purpose and although the method is rapidly advancing, there remains a fundamental compromise between spatial resolution, detection limit, and experiment duration when using sequential mass analyzers. To address the limitation of limited analyte selection for high spatial resolution maps imposed by the sequential nature of typical quadrupole (Q)-ICP-MS, we tested the Aerosol Rapid Introduction System (ARIS) for repeat mapping of the same area. The ARIS is a high-speed transfer tubing system that reduces aerosol washout times, permitting resolution of individual pulses at 40–60 Hz. Here, the ARIS was tested not for pulse resolution but with novel operating conditions optimized to perform fast, high spatial resolution mapping of minor and trace element distribution in pyrite and marcasite. For this purpose, ablation was conducted with a 5 µm beam aperture, a repetition rate of 50 Hz, and a continuous stage scan speed of 40 µm s−1. For each LA-Q-ICP-MS map, data were acquired for six elements with an acquisition time of 20 ms per element. This deliberately reduced the individual pulse resolution of the ARIS but instead exploited the spatial resolution and sensitivity gains afforded by the high-laser repetition rate combined with efficient aerosol transfer. The new method successfully mapped trace elements at single to double-digit parts per million levels, and the maps reveal fine-scale zoning of trace elements with an effective x and y resolution of 5 µm, while white light interferometry showed that for each experiment, only ca. 1 µm of the sample was removed. Repeated mapping of the same area showed excellent correspondence not only between element concentrations in successive experiments but also in the shape, dimension, and location of regions of interest defined by concentration criteria. The very good repeatability of the elemental maps indicates that for studies requiring more analytes, successive mapping of additional elements is possible. By contrast with conventional very small spot (i.e., 5 µm) analysis, fast repetition rate and stage scan speed mapping avoids down-hole fractionation effects and minimizes accidental analysis of buried invisible inclusions. Compared to conventional LA-ICP-MS mapping, the method reduces the experiment time by 4–8 times.

Description: This paper presents a series of surface experimental simulations of methane-oriented underground coal gasification using hydrogen as gasification medium. The main aim of the experiments conducted was to evaluate the feasibility of methane-rich gas production through the in situ coal hydrogasification process. Two multi-day trials were carried out using large scale gasification facilities designed for ex situ experimental simulations of the underground coal gasification (UCG) process. Two different coals were investigated: the “Six Feet” semi-anthracite (Wales) and the “Wesoła" hard coal (Poland). The coal samples were extracted directly from the respective coal seams in the form of large blocks. The gasification tests were conducted in the artificial coal seams (0.41 × 0.41 × 3.05 m) under two distinct pressure regimes - 20 and 40 bar. The series of experiments conducted demonstrated that the physicochemical properties of coal (coal rank) considerably affect the hydrogasification process. For both gasification pressures applied, gas from “Six Feet” semi-anthracite was characterized by a higher content of methane. The average CH4 concentration for “Six Feet” experiment during the H2 stage was 24.12% at 20 bar and 27.03% at 40 bar. During the hydrogasification of “Wesoła" coal, CH4 concentration was 19.28% and 21.71% at 20 and 40 bar, respectively. The process was characterized by high stability and reproducibility of conditions favorable for methane formation in the whole sequence of gasification cycles. Although the feasibility of methane-rich gas production by underground hydrogasification was initially demonstrated, further techno-economic studies are necessary to assess the economic feasibility of methane production using this process.

Description: Forest soils have large contents of carbon (C) and total nitrogen (TN), which have significant spatial variability laterally across landscapes and vertically with depth due to decomposition, erosion and leaching. Therefore, the ratio of C to TN contents (C:N), a crucial indicator of soil quality and health, is also different depending on soil horizon. These attributes can cost-effectively and rapidly be estimated using visible–near infrared–shortwave infrared (VNIR–SWIR) spectroscopy. Nevertheless, the effect of different soil layers, particularly over large scales of highly heterogeneous forest soils, on the performance of the technique has rarely been attempted. This study evaluated the potential of VNIR–SWIR spectroscopy in quantification and variability analysis of C:N in soils from different organic and mineral layers of forested sites of the Czech Republic. At each site, we collected samples from the litter (L), fragmented (F) and humus (H) organic layers, and from the A1 (depth of 2–10 cm) and A2 (depth of 10–40 cm) mineral layers providing a total of 2505 samples. Support vector machine regression (SVMR) was used to train the prediction models of the selected attributes at each individual soil layer and the merged layer (profile). We further produced the spatial distribution maps of C:N as the target attribute at each soil layer. Results showed that the prediction accuracy based on the profile spectral data was adequate for all attributes. Moreover, F was the most accurately predicted layer, regardless of the soil attribute. C:N models and maps in the organic layers performed well although in mineral layers, models were poor and maps were reliable only in areas with low and moderate C:N. On the other hand, the study indicated that reflectance spectra could efficiently predict and map organic layers of the forested sites. Although, in mineral layers, high values of C:N (≥ 50) were not detectable in the map created based on the reflectance spectra. In general, the study suggests that VNIR–SWIR spectroscopy has the feasibility of modelling and mapping C:N in soil organic horizons based on national spectral data in the forests of the Czech Republic

Description: We present a study to estimate the large-scale landscape history of a continental margin, by establishing a source-to-sink volume balance between the eroding onshore areas and the offshore basins. Assuming erosion as the primary process for sediment production, we strive to constrain a numerical model of landscape evolution that balances the volumes of eroded materials from the continent and that deposited in the corresponding basins, with a ratio imposed for loss of erosion products. We use this approach to investigate the landscape history of Madagascar since the Late Cretaceous. The uplift history prescribed in the model is inferred from elevations of planation surfaces formed at various ages. By fitting the volumes of terrigenous sediments in the Morondava Basin along the west coast and the current elevation of the island, the landscape evolution model is optimized by constraining the erosion law parameters and ratios of sediment loss. The results include a best-fit landscape evolution model, which features two major periods of uplift and erosion during the Late Cretaceous and the middle to late Cenozoic. The model supports suggestions from previous studies that most of the high topography of the island was constructed since the middle to late Miocene, and on the central plateau the erosion has not reached an equilibrium with the high uplift rates in the late Cenozoic. Our models also indicate that over the geological time scale, a significant portion of materials eroded from Madagascar was not archived in the offshore basin, possibly consumed by chemical weathering, the intensity of which might have varied with climate.

Description: The interpretation of low-temperature thermochronology (LTT) data in magmatic and metallogenic provinces requires a knowledge of the geothermal field through time. There, the challenge is differentiating rapid cooling following transient perturbations of the geotherms (reheating) from exhumational cooling induced by erosion during tectonic uplift or normal faulting. The Takab Range Complex (NW Iran) is a basement-cored range of the Arabia-Eurasia collision zone that experienced voluminous Eocene to Miocene magmatism and mineralization. Our new apatite and zircon (U-Th-Sm)/He and apatite fission track data, together with field observations, a dedicated numerical thermal model, and a re-evaluation of available geochronology data document the occurrence of a complex geological and thermal history including: (a) late Cretaceous-Paleocene exhumation possibly controlled by regional contractional deformation followed by Eocene deposition; (b) Oligocene to possibly early Miocene (29 to 22–20 Ma) exhumation of basement rocks from 13 to 8 km of depth, most likely through normal faulting during a thermal anomaly that led to migmatization and partial melting; (c) early to late Miocene (∼22–20 or earlier to 11–10 Ma) regional subsidence with deposition of an up to ∼2- to 3-km-thick Oligo-Miocene sedimentary sequence in association with the emplacement of shallow intrusions, which led to a partial to total reset of our LTT systems sometime between 18 and 13 Ma; and (e) erosional exhumation after 11–10 Ma with the development of a transpressional system and a master, right-lateral, strike slip fault (Chahartagh Fault). Our data highlights the impact of magmatic reheating on LTT ages in areas affected by intense magmatism.

Description: To share best practices and to foster the research data management (RDM) community within Helmholtz, the Helmholtz Open Science Office hosted its first "Helmholtz Open Science Practice Forum Research Data Management" virtually in February 2022. A follow-up event on October 20, 2022 has taken up and continued this theme. The following aspects were highlighted through presentations with ample time for discussion in the forum: - Thinking and linking data, text, and research software together - Data Stewards, Data Librarians, Research Data Managers, Data Curators... – Their profiles and roles in Helmholtz - Data Management Plans – DMPs as Living Documents - Monitoring data publications

Description: Improving and homogenizing time and space reference systems on Earth and, more specifically, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1 mm and a long-term stability of 0.1 mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, such as those located at tide gauges, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation, contributing to a better understanding of natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities, including the International Association of Geodesy (IAG), which has enunciated geodesy requirements for Earth sciences. Moreover, the United Nations Resolution 69/266 states that the full societal benefits in developing satellite missions for positioning and Remote Sensing of the Earth are realized only if they are referenced to a common global geodetic reference frame at the national, regional and global levels. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology. This paper has been written and supported by a large community of scientists from many countries and working in several different fields of science, ranging from geophysics and geodesy to time and frequency metrology, navigation and positioning. As it is explained throughout this paper, there is a very high scientific consensus that the GENESIS mission would deliver exemplary science and societal benefits across a multidisciplinary range of Navigation and Earth sciences applications, constituting a global infrastructure that is internationally agreed to be strongly desirable.

Description: The study of Electro Magnetic Ion Cyclotron (EMIC) wave-induced electron precipitation has a legacy in early work suggesting EMIC waves could precipitate relativistic electrons. As such, EMIC waves represent a significant loss process for the Outer Radiation Belt, and deposit high energy electron precipitation flux deep into the atmosphere. Here we present an analysis of an example of EMIC-induced electron precipitation observed by two satellites in Low Earth Orbit, combined with EMIC wave signatures in ground-based magnetometers in Finland, and Antarctica. Electron precipitation spectral information is provided by satellite data which considers the energy range of scattered electrons during the potential EMIC wave event. We investigate the high energy resolution DEMETER IDP electron measurements in the 80 keV - 2 MeV range, when the detector was looking into the bounce-loss-cone, i.e., flying over the North Atlantic region. In order to assess the effect of potential proton precipitation contamination of the IDP detector we use nearby POES proton flux measurements, compensating for the IDP protective aluminium foil through a calculation of the attenuation of the proton spectrum using the integrated MULASSIS transport code. Our results are considered in the context of recent work indicating a wide energy range of non-relativistic electron precipitation is present in EMIC-induced precipitation in addition to the relativistic energy electrons suggested from the original theoretical suggestions. Our confirmation of non-relativistic energy ranges in EMIC-induced precipitation events supports the atmospheric chemical modelling analysis undertaken recently which showed that EMIC-induced precipitation is capable of causing notable composition changes.

Description: In Germany, climate resilient tree species are increasingly used in the process of forest conversion towards climate-change adapted stands. However, information on the impact of this conversion on groundwater resources is scarce. To fill this gap, the joint project “Effects of climate-adapted tree species selection on groundwater recharge” of the Federal Institute for Geosciences and Natural Resources (BGR) and the Northwest German Forest Research Institute (NW-FVA), funded by the Forest Climate Fund (WKF), aims at better understanding processes of groundwater recharge at six forest sites. The study sites comprise monoculture forest stands of European beech, Norway spruce, Douglas fir, Scots pine, red oak and pedunculate oak. To assess groundwater recharge rates, we performed D2O-tracer experiments on four sites since December 2022. At each site one plot of 4 m² was irrigated with 5 mm of D2O-labelled water (δ2H: 110 000 – 140 000 ‰). We will present the results of the tracer peak displacement until spring 2023 for each plot together with groundwater recharge estimates based on soil gravimetric water content and bulk dry density data. In addition, at two sites (red oak and Scots pine), these results will be compared to natural seasonal signals of stable isotopes in the soil water. Preliminary results of the red oak lowland forest site show that during summer 2022 seasonal signals reached down to 4 m depth and that gravimetric water contents dropped below 4 % for the entire mineral soil profile reaching down to the capillary fringe at 6.50 m.

Description: The flow dependent impact of multiple sources of uncertainty on convective precipitation is investigated in a consolidated way using the operational convection permitting ICON-D2 model in ensemble mode. Two model uncertainties -- microphysics (MP) and planetary boundary layer (PBL) turbulence --are considered in the presence of initial and lateral boundary condition uncertainties. The case studies are stratified based on the strength of synoptic control on convection. We found that model uncertainties act on different processes and spatiotemporal scales. MP uncertainty hardly has an impact on precipitation amounts at small spatiotemporal scales but influences daily accumulations. In contrast, the physically-based stochastic perturbations (PSP) in the PBL directly impact the diurnal cycle of precipitation. MP uncertainty only weakly impacts scales of O(100km), whereas the uncertainty in PBL significantly changes the spatial distribution at smaller scales at certain times. Those impacts on amounts and spatial distributions are more sensitive during weak synoptic control. The combination of various uncertainties adds further variability to forecast distributions and is potentially beneficial for improving the underdispersion of forecast spread of precipitation, especially during weak synoptic control.

Description: Recent years have seen an increase in the use of non-contact methods of river discharge estimation, which calls for the measurement of surface velocity in the top portion of the cross-section utilizing non-contact doppler radar sensors like Handheld or Mounted radars. Given the constrained and probabilistic character of the flow, these radars can be utilized to predict discharge based on the entropy theory. Additionally, a river section can be utilized to measure surface velocity at several predetermined verticals using the traditional area-velocity approach. One of the major prerequisites for the estimation of discharge through non-contact techniques is the characterization of the nature of the surface velocity profile at the section. The problem arises when the flow experiences large turbulence due to sidewall effects and other characteristics of the channel, especially in narrow mountainous channels. This study compares different velocity profiles for the measured surface velocity at several predefined verticals at two cross-sections of Bhagirathi and Ganga, two significant Himalayan rivers having widths of 30m and 60m respectively. . Three velocity profiles i.e. Elliptic, Parabolic, and Polynomial profiles obtained through the curve-fitting technique were compared based on error distribution and uncertainty analysis using Forecast Range Error Estimate method. Further, to determine which profile would be optimal for the selected segments, the measured mean velocity of current-meter was compared to the estimated mean velocity for each profile. The study offers a straightforward method for choosing the ideal surface velocity profile for a river by just measuring the surface velocity at predetermined verticals.

Description: The present study investigates the interannual variability of the tropical Indian Ocean (IO) based on the transfer routes of wave energy in a set of 61-yr hindcast experiments using a linear ocean model. To understand the basic feature of the IO dipole mode, this paper focuses on the 1994 pure positive event. Two sets of westward transfer episodes in the energy flux associated with Rossby waves (RWs) are identified along the equator during 1994. One set represents the same phase speed as the linear theory of equatorial RWs, while the other set is slightly slower than the theoretical phase speed. The first set originates from the reflection of equatorial Kelvin waves at the eastern boundary of the IO. On the other hand, the second set is found to be associated with off-equatorial RWs generated by southeasterly winds in the southeastern IO, which may account for the appearance of the slower group velocity. A combined empirical orthogonal function (EOF) analysis of energy-flux streamfunction and potential reveals the intense westward signals of energy flux are attributed to off-equatorial RWs associated with predominant wind input in the southeastern IO corresponding to the positive IO dipole event.

Description: Over the past years, with the rapid progress of Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) technique, near-shore geodetic GNSS receivers have been attempted to retrieve dynamic sea-level variation induced by storm surges and tsunamis. As the largest event since 1939, the 2023 M7.8 Turkiye earthquake not only caused terrifying building collapses on land but also generated observable tsunamis in the sea as recorded by coastal tide gauges. In this study, we thus try to verify the performance of GNSS-IR sea-level retrieval for tsunami monitoring based on GNSS data from IGS and TPGN(Turkish Permanent GNSS Network). Our preliminary findings show that, in spite of a continental strike-slip rupture, a tsunami with 30 cm wave height, following days of ocean resonance, is clearly seen by GNSS-IR, consistent with nearby tide gauge records. Furthermore, we also perform a finite source inversion to explore whether a submarine landslide contributes to the tsunami. Our work demonstrates the capability of GNSS-IR for detecting medium and small tsunamis accurately. In fact, such geodetic GNSS receivers have been now well-deployed for co-seismic displacement monitoring and fast earthquake source characterizing for tsunami early warning in many places in the world. If more receivers can be installed near-shore, without extra operational costs, such a network will extend our tsunami observation power and improve the robustness of the tsunami early warning system.

Description: On 30 October 2020 at 11:51 UT, a magnitude 7.0 earthquake occurred in the Dodecanese sea (37.84°N, 26.81°E, 10 km depth), that generated a tsunami with an observed run-up of more than 1 meter on the Turkish coasts. Both the earthquake and the tsunami produced acoustic and gravity waves that propagated upward, triggering co-seismic and co-tsunamic ionospheric disturbances. This paper presents a multi-instrumental study of the ionospheric impact of the earthquake and related tsunami based on ionosonde data, ground-based and Swarm-based GNSS receivers, and Jason3/DORIS [L1] receivers in the Mediterranean region. Our study focuses on the Total Electron Content derived from the European GNSS network, Swarm, and Jason3, to describe the propagation of Medium Scale Travelling Ionospheric Disturbances (MSTIDs), possibly related to gravity waves triggered by the earthquake and tsunami. We use simultaneous vertical ionosonde soundings to study the interactions between the upper and lower atmosphere. The results of this study provide a detailed picture of the Litosphere-Atmosphere-Ionosphere coupling in the scarcely investigated area that is the Mediterranean region.

Description: The tropical Angolan upwelling system (tAUS) is a highly productive ecosystem with a distinct seasonal variability with productivity peaking in austral winter. The tAUS is connected to equatorial dynamics via the propagation of equatorial and coastal trapped waves (CTWs). We use hydrographic, ocean turbulence and satellite data to investigate the role of CTWs in controlling the seasonal cycle of productivity in the tAUS. During austral winter associated with the passage of an upwelling CTW, the nitracline is displaced upward by about 50 m. Through this vertical advection nitrate-rich waters passes onto the shelf. Due to the elevated mixing rates on the shelf, this movement of the nitracline results an increased vertical nitrate flux into the ocean mixed layer. Our analysis further shows that interannual variability in the strength of the austral winter net primary production correlates with the amplitude of the seal level anomaly signal of the corresponding upwelling CTW. The signal of sea level depression leads the maximum productivity signal by about 40 days. It is suggested that this time lag arises, among other factors, from the vertical structure of the CTWs arriving in the tAUS. While the sea level anomaly is dominated by the faster low-baroclinic mode CTWs, the displacement of the nitracline is mainly influenced by the slower high-baroclinic mode CTWs that arrive later in the tAUS. Our results highlight the crucial role CTWs play for the productivity in the tAUS. The strong connection between equatorial dynamics and productivity further introduces a possibility for predicting interannual variability.

Description: The recent global MHD simulation code (REPPU code by Tanaka [2015]) successfully reproduces even observed phenomena such as the auroral breakup of the substorm. We judge that the simulation code correctly reproduces the physical processes of the magnetosphere and ionosphere from the fact that the phenomenon is reproduced realistically. REPPU code employs several empirical parameters expressing the non-MHD mechanisms. We tried to determine the optimal values of the parameters by using the data assimilation technique. For this purpose, we improve the REPPU code to include both the effect of the inclined rotation axis of the Earth and the effect of the discrepancy between the rotational axis and the magnetic axis. Next, we apply the data assimilation technique to determine the ionospheric conductivity distribution which is given as empirical parameters in the original REPPU code. For this purpose, we use the ionospheric electric potential determined by SuperDARN and AE indices. We employed the ensemble variational method as the assimilation technique to obtain the optimal values of the parameters. As a result, we obtained that the ionospheric conductivities are enhanced compared with the empirical results. At the same time, modification of the ionospheric conductivity does not change significantly the magnetosphere. The simulation data become the “reanalysis data” of the space weather which is useful for space weather research. Our future goal is to provide a database of the reanalysis data for space weather.

Description: Climatology, also named the "Climate Normal" by World Meteorological Organization (WMO), is critical for characterizing historical or near-future weather and climate states, and is usually calculated for a uniform 30-year period according to the WMO definitions. However, in addition to external forcing changes, climatology can be impacted by internal climate variabilities on multi-decadal and longer time scales. Here we introduce a simple sampling model and conduct three equilibrium climate sensitivity experiments using a Global Climate Model EC-Earth to quantify the potential uncertainties in estimating equilibrium climate change. We take into account the effect of multi-centennial variability in the climate system, which has been identified in paleo-climate proxy records and long climate model simulations. For the time series that contain multi-centennial oscillation, the estimate of climate change refers to the difference between two equilibrium climate states that may have significant uncertainty due to random selection of the phase location of the sampling. Our exercises with EC-Earth experiments show that such uncertainties are significant at high latitudes where low-frequency oscillations dominate. The accuracy of the estimated climate state at mid-to-high latitudes in the Northern Hemisphere is mainly impacted by the multi-centennial oscillation, while the uncertainty in mid-to-high Southern Hemisphere is affected by the oscillation on multi-centennial to millennial time scales. We show that applying quasi-periodic sampling in calculating the equilibrium climate state can significantly reduce such uncertainties. This work reminds us that the potential uncertainties induced by multi-centennial climate variability cannot be ignored when the length of sampling data is limited.

Description: The study examines the interannual relationship between the variability of sea ice extent in the Indian Ocean sector (20–90oE) and Indian summer monsoon rainfall under the influence of Mascarene High. Sea ice extent during April-May-June (AMJ) appears to have a significant correlation with the summer monsoon rainfall over the Peninsular India region during June-July-August-September from 1979 to 2013. We utilized reanalysis, satellite, and in-situ observation data from 1979 to 2013. The empirical orthogonal function (EOF) and correlation analysis show that the first and third modes of principal component (PC1 and PC3) of SIE in the Indian Ocean sector during April-May-June (AMJ) are significantly correlated with the second mode of principal component (PC2) of Indian summer monsoon rainfall. The reanalysis data revealed that the changes in the SIE in the Indian Ocean sector excite meridional wave train responses along the Indian Ocean for both principal component modes. Positive (negative) SIE anomalies based on first and third EOFs (EOF1 and EOF3) contribute to the strengthening (weakening) of the Polar, Ferrel, and Hadley cells, inducing stronger (weaker) convective activity over the Indian latitudes. The weak (strong) convective activity over the Indian region leads to less (more) rainfall over the region during low (high) sea ice phase years. Furthermore, a weaker (stronger) polar jet during the low (high) sea ice phase is also noted.

Description: Frequency of extreme rainfalls and snowfalls has been increasing these years, and those events severely affect human lives and properties. It has been considered that tropical ocean and atmosphere variability as well as the warming climate, remotely influences mid-latitude extreme weather/climate, while the mid-latitude ocean is passive to atmospheric variability. Recent high-resolution ocean/atmospheric data analyses, however, have revealed that mid-latitude ocean also influences atmospheric circulations and their variability. Rediscovering strong warm current and associated strong ocean frontal zones as “climate hotspot”, we have elucidated mechanisms of ocean-atmosphere interactions. The research progress has prompted a new crucial task: application of such new knowledge to predictions of extreme rainfalls/snowfalls and climate variability. For the new task, in the five-year research project called “Climatic Hotspot2” from 2019, we have conducted studies to further our understandings of mid-latitude ocean-atmosphere interaction processes. In the project, several observation campaigns and also oceanic and atmospheric high-resolution numerical modeling studies have been conducted. Those studies have revealed crucial influence of ocean currents and oceanic structures on climate extreme events. In this presentation, we introduce results of the projects, including predictability of the Kuroshio Extension and Gulf Stream jet speeds and eddy activities around them. This presentation is co-authored with the Climatic Hotspot2 group.

Description: Direct observations of sunspots exist for the past four centuries while proxy based reconstructions exist for thousands of years. Over a significant fraction of the past century, records of sunspot tilt angles and areas have also been collected. These observations provide a means to understand the physics of long-term solar variability by discriminating between various models of the solar cycle. In this talk, I shall discuss how the synergy of solar surface flux transport modelling, dynamo modelling and solar activity observations have led us to the conclusion that the primary driver for decadal-scale variability in the solar cycle is imbibed in the Babcock-Leighton mechanism for poloidal field generation which is governed by the emergence of tilted bipolar sunspot pairs and their subsequent evolution driven by flux transport processes. I shall also highlight what this emergent understanding implies for solar cycle 25 forecasts.

Description: Upper-ocean fronts are dynamically active features of the global ocean that have significant implications for air-sea interactions, vertical mass and heat transfers, stratification and phytoplankton production and export. Their small dimensions and short duration have limited our capacity of observing, modelling and understanding fully these processes and their impact. To address this challenge, five Saildrones - which are uncrewed platforms instrumented to measure the air-sea interface – were deployed during the EUREC4A-OA/ATOMIC field experiment in the Northwest Tropical Atlantic in winter 2020. This region is strongly affected by the outflow of the Amazon River, leading to the generation of fine-scale horizontal thermohaline gradients with the stirring of this freshwater input by large anticyclonic eddies. Very intense gradients, including at the smaller spatial scales, were measured. The coherence of temperature and salinity fronts was estimated by a wavelet transform analysis which revealed large-scale density fronts are primarily controlled by salinity but with increasing temperature-salinity coherence at the small scales range of the spectrum (O (0.1 km)) for strong gradients whereas they are poorly correlated for weaker fronts. Our study shows that processes such as the mixed layer depth, the diurnal cycle, and air-sea exchanges are strongly affected by these small-scale frontal regimes. The parallel and quasi synchronous tracks of a 4-Saildrone formation provide a detailed picture of the upper ocean vorticity, divergence, and strain from their ADCP current measurements. Overall the methodology developed could be extended on other datasets to assess the phenomenology of fine-scale structures in other dynamical regions.

Description: Localized disturbances within the altitude range of lower ionospheric D-region, related to precipitation of energetic electrons from radiation belts, causes perturbations of VLF signal propagation parameters during nocturnal conditions within Earth-ionosphere waveguide. Based upon Very Low Frequency (VLF) signal perturbations through the remote sensing technique, indirect conclusions regarding some of the features of such Localized Ionospheric Enhancements (LIEs) can be obtained. In this work, several dozens of Lightning-induced Electron Precipitation (LEP) type VLF signal perturbations were analyzed as case studies, with the goal to get insight into similarities and differences between related LIEs formed in mid-latitude lower ionosphere over the west and central European region, using VLF recordings from two ground-based receiving systems, stationed at the Institute of Physics Belgrade (Serbia). Inspected cases included LEP events from period 2003 – 2011, with notable amplitude and phase changes compared to unperturbed ionospheric conditions. As input data for numerical simulations, amplitude and phase perturbations monitored on signals emitted from major European and American transmitters, were used. Subionospheric VLF signal propagation was modeled using the LWPCv21 program routine, relying on Wait's theory and by employing parameters sharpness and reflection edge height, for nighttime Great Circle Path (GCP) sections. Obtained electron density height profile changes along observed GCPs according to Belgrade VLF data, place the size as main common feature of considered LIEs, as less than: 1000 km in length and 500 km in width, with significant differences regarding their internal structure and position.

Description: The dynamic behavior of saline water intrusion along coastal areas affects groundwater resources adversely. For the assessment of such problems, the present study deals with time-lapse electrical resistivity monitoring. The study observed changes in subsurface resistivity with time constraints to locate the saline zones in aquifers. Resistivity data was collected using Dipole-Dipole and Wenner-Schlumberger arrays for getting optimum resolution. The damping factor was chosen for the time-lapse inversion algorithm according to the noise present in field data. 2D images of subsurface conditions were interpreted according to the percentage variation in resistivity values. It was observed that saline clay layers were present in multiple depths ~12m and 39m below ground level. Further, different attributes can be retrieved from the time-lapse inversion results as desaturation percentage and resistivity ratio, which can give a brief idea about the movement of contaminants inside the subsurface.

Description: In this study, we re-examine the use of an existing theoretical model for predicting the time-variable large-scale circulation along contours of constant ambient potential vorticity, given by f/H, in the Nordic Seas and Arctic Ocean. The theoretical model is an integral relation derived from the linear depth-averaged shallow water equations, and assumes that the circulation is driven by surface stresses and regulated by bottom drag. By applying this simplified model to a high-resolution numerical simulation, we assess its ability to accurately predict the circulation. Improvements from earlier examinations include better parametrization of stresses in ice-covered regions and higher resolution in the numerical simulation. Our results show that the linear model agrees well with the complex model. This indicates that much of the variability in the large-scale circulation can be explained by linear processes. However, we find that the performance of the linear model depends on the direction of the circulation, with the linear model overestimating anti-cyclonic circulation. This suggests that additional processes, not captured in the linear model, play a crucial role in anti-cyclonic circulation.

Description: In this study, we demonstrate that the enhanced storm track activity in the North Pacific midlatitudes during boreal winter over the past four decades was correlated with subtropical warming which strengthened midlatitude meridional temperature gradient. On the contrary, Arctic warming reduced the near-surface temperature gradient and had negative correlation with midlatitude storm track activity. The close relationship between temperature gradient and synoptic eddy activity is dynamically fundamental and can be seen in both long-term trends and the interannual variation. The observed trends in warming sea surface temperature (SST) in the subtropical North Pacific, ascending motion over the subtropical western North Pacific and anticyclonic circulation over the central and western North Pacific suggests a positive feedback between warming SST and atmospheric circulation. Numerical experiments further revealed that SST warming in the subtropical North Pacific and in the Indian Ocean could drive subtropical tropospheric warming and anticyclonic circulation in the North Pacific, as well as the strengthening of the North Pacific midlatitude storm track activity. The results suggest tropical and subtropical influence on North Pacific midlatitude winter weather.

Description: The system of oceanic flows constituting the Atlantic Meridional Overturning Circulation (AMOC) moves heat and other properties to the subpolar North Atlantic, controlling regional climate, weather, sea levels, and ecosystems. Climate models suggest a potential AMOC slowdown towards the end of the 21〈sup〉st〈/sup〉 century due to anthropogenic forcing, which would accelerate coastal sea level rise along the western boundary and dramatically increase coastal flood risk. While the slowdown has not been observed to date, we show here that the AMOC-induced intrinsic changes in gyre-scale heat content, superimposed on the global mean sea level rise, are already influencing the frequency of floods along the United States southeastern seaboard. For the South Atlantic Bight and Gulf of Mexico coasts, using observations and an ocean state estimate, we have established a strong link between coastal sea level, the associated flood frequency, and gyre-scale dynamic sea level and oceanic heat content variability, which are largely controlled by AMOC-driven ocean heat convergence. We find that ocean heat convergence, being the primary driver for interannual sea level changes in the subtropical North Atlantic, has led to an exceptional gyre-scale warming and associated dynamic sea level rise since 2010, accounting for 30-50% of flood days in 2015-2020. The results of this study highlight the importance of accounting for natural, large-scale sea level variability in order to improve coastal sea level projections and to better assess coastal flood risk.

Description: The depletion of plasma in the nighttime F region ionosphere is called the mid-latitude ionospheric trough (MIT). The objective of this study is to identify and describe the mid-latitude ionospheric trough by using new satellite data and expanding our understanding of the MIT phenomenon. To evaluate the MIT, we used electron density in-situ data derived from GRACE satellite K-Band Ranging system (KBR) measurements. The trough was examined using data collected between 2002 and 2015, including high and low solar activity periods. We analyze the characteristics of the mid-latitude ionospheric trough (MIT) in both the Northern and Southern Hemispheres. The MIT is characterized by its trough’s minimum position, width, depth, and probability. We investigated how MIT parameters were affected by the magnetic local time, geographic distribution, seasons, and solar and geomagnetic activity conditions, including solar wind plasma speed, interplanetary magnetic field components, and high-resolution geomagnetic indices SYM-H and Hp30. In this study, we demonstrate the elliptical distribution of the mean location of the trough minimum over three seasons for the Northern and Southern hemispheres and the MIT parameter dependency on high-resolution geomagnetic indices. Our findings confirm and extend earlier research on MIT. The obtained dependencies related to MIT climatology and occurrence probability can be used to validate existing MIT models and create new MIT models since it has not yet been represented in commonly used 3D electron density models, such as IRI, NeQuick, NEDM2020, etc. The integration of an MIT model may improve the performance of the 3D electron density models.

Description: The second national pollution source survey showed that agricultural non-point source pollution (ANP) has become one of the main causes of water environment deterioration in Guangdong Province. It is important to clarify the ANP status in the province for the prevention and control of water pollution and the construction of rural revitalization. The improved export coefficient method was used to analyze the annual ANP loads and their spatial and temporal variation characteristics in Guangdong Province from 2009 to 2019. The seasonal and monthly pollution loads of ANP were also evaluated with consideration of monthly differences in fertilizer application, precipitation, livestock, and aquaculture. The impact of ANP on the water environment was evaluated by the unit area load coefficient method, and the main sources of ANP were explored. The results indicate that (i) from 2009 to 2019, the total nitrogen load in Guangdong province showed a decreasing trend and the total phosphorus load showed a rising trend with spring and summer being the peak seasons of pollution emissions in a year; (ii) The total nitrogen load trended decreasing in 76.2% of the cities and the total phosphorus load trended increasing in 61.9% of the cities; (iii) in general, the environmental damage caused by agricultural nitrogen and phosphorus loads in western Guangdong was more serious than that in Pearl River Delta, northern and eastern Guangdong; and (iv)the contribution rate of pollution source to nitrogen and phosphorus pollution loads from high to low is livestock and poultry breeding, planting and aquaculture.

Description: De Santis et al. (EPSL 2017) detected that for the first time in Swarm satellite data some magnetic field anomalies associated with the 2015 Nepal M7.8 earthquake, with similar S-shapes for the cumulative number of satellite anomalies and earthquakes, providing an empirical proof on the lithospheric origin of the anomalies. Following the same approach, De Santis et al. (Atmosph. 2019) obtained other promising results for 12 earthquakes in the range M6.1-8.3, in the framework of the ESA funded SAFE (SwArm For Earthquake study) Project. Then, almost five years of Swarm magnetic field and electron density data were analysed with a Superposed Epoch and Space approach finding a robust correlation with major worldwide M5.5+ earthquakes (De Santis et al. Sc.Rep. 2019). The work also confirmed the Rikitake (1987) law, initially proposed for ground data: the larger the magnitude of the impending earthquake, the longer the precursory time of anomaly occurrences. An analogous analysis was also applied in the framework of the ASI funded Limadou-Science Project to the Chinese Seismo-Electromagnetic satellite (CSES) electron density providing similar results (De Santis et al. N.Cim. 2021). Marchetti et al. (Rem.Sens. 2022) confirmed the same result over a longer time series , i.e. 8 years, of Swarm satellite data. Furthermore, we demonstrated in several case studies (e.g. Marchetti et al. JAES 2019, Akhoondzadeh et al. Adv.S.R. 2019; De Santis et al. Fr.E.Sc. 2020) that the integration of CSES and Swarm data with other measurements from ground an atmosphere reveals a chain of processes before many mainshocks.

Description: We present 10-day water mass solutions estimated from both GRACE and GRACE-FO KBR Range (KBRR) residuals for continental hydrology using GINS software developed by the CNES/GRGS group. The inter-satellite velocity residuals have been converted into along-track differences of potential using the energy balance approach. Maps of equivalent water height are obtained by inversion of these potential differences onto juxtaposed surface elements over the region of interest, or better, time coefficients of designed orthogonal Slepian functions. This latter band-limited representation offers the advantage of reducing drastically the number of parameters to be fitted. Shannon number of 60 for the regional Slepian representation is usually considered for GRACE-type data for basins of arbitrary shapes. The regional solutions are validated by comparison with series of existing Level-2 solutions produced by (official) centers once the contribution of the missing long-wavelength part of the time-varying field, i.e. low degree harmonic coefficients such as C〈sub〉20〈/sub〉, is simply added for completion. The patterns shown in the regional solutions reveal strong seasonal variations of water mass in the large tropical basins, e.g. Amazon and Congo, as well as important trends corresponding to regional droughts and continuous melting of the ice sheets that contributes to sea level rise.

Description: Stratospheric ozone levels, temperature trends and their evolution in time have been the subject of global concern and scientific research already since the mid 1970’s. The evolution of changes and trends in the vertical distribution of ozone and temperature as depicted in Chemistry-Climate Models simulations (CCMI) is examined. The solar signature in stratospheric variability is assessed, as well as the contribution of other natural variability forcings (such as ENSO, QBO and volcanic activity). Ozone and temperature trends are calculated for the periods before and after the year 2000 (pre-2000 and post-2000). Results are compared to trends derived from earlier model studies as well as to ozone trends from satellite records updated in the LOTUS SPARC project, over the same periods and latitude belts characteristic to the ozone variability, by applying the same statistical methods in accordance with the regression analysis and tools presented in the LOTUS Project.

Description: Coastal submarine canyons are potential sites of enhanced turbulent mixing that could make them productive fishing grounds. Recent studies suggest the crucial role of diurnal coastal trapped waves (CTWs) in inducing significant turbulent mixing in coastal submarine canyons poleward of 30º, where the diurnal tide is subinertial. However, the detailed physical processes responsible for the generation and dissipation of CTWs in such submarine canyons remain to be investigated. In this study, to investigate the turbulent mixing processes associated with diurnal CTWs in submarine canyons, we conduct high-resolution three-dimensional numerical experiments focusing on the northern end of the Suruga Trough, Japan. It is found that CTWs generated by diurnal (subinertial) tidal currents over the nearby Izu-Ogasawara Ridge propagate anticlockwise with the slope of the Suruga Trough on the right. Furthermore, the bottom-intensified flow associated with the diurnal CTWs interacts with the rough seafloor topography to excite internal lee waves that propagate upward while creating mixing hotspots that extend high above the seafloor. We also find that the baroclinic energy flux based on a simple barotropic-baroclinic decomposition severely underestimates the wave energy flux in areas of high CTW activity. These results indicate that the presence of CTWs is a key factor in elucidating the dissipation/mixing processes in submarine canyons. In the presentation, we will also compare the results of the above numerical experiments with those of direct microstructure measurements conducted in the Suruga Trough in November 2021.

Description: Local evaporation in the Arctic is likely to increase with sea-ice retreat in the context of climate change. In parallel, the transport of moisture from the North Atlantic may also increase, especially in cases of weak polar vortex, associated to blocking over the Norwegian Sea and fast vapor transport into the Arctic. In order to evaluate the contribution of different sources to the moisture budget in the Arctic, a tool is needed to track the transport of vapor in the region. Here, we combine in-situ measurements of vapor isotope composition to analysis of back- trajectories, to reconstruct the pathway of vapor transport in different synoptic situations during two cruises North of Svalbard in 2018 and 2019. During the hot summer of 2018 in Europe, high dD values are observed in the Arctic. These high values could result from intense evaporation during the heat wave followed by quick transport into the Arctic. Indeed, back-trajectories indicate northern Europe as a dominant contributor to the moisture sampled during this period. During summer 2019, we observe wide oscillations of dD values depending on the moisture origin. An atmospheric river is sampled on the 29th of August 2019, that shows that Atlantic (southerly) air is characterized by high humidity and high dD values, opposite to Arctic (northerly) air. The secondary parameter d-excess varies in opposition to dD. This study highlights the potential of isotopes for identifying moisture sources around the Arctic.

Description: Modeling tropospheric delay is critical to achieving high-precision data analysis of space geodetic techniques, such as Global Navigation Satellite System (GNSS), Very Long Baseline Interferometry (VLBI), and satellite altimetry. Numerical Weather Models (NWMs) are an important source to provide both empirical tropospheric delay models and real-time corrections, and are widely used as a priori values, external constraints, and precise correction values. The uncertainty of NWM-derived empirical models is around 3 to 4 cm, and that of reprocessed and real-time products is around 1 to 2 cm. However, this uncertainty is mostly derived using long-term data on a global scale, and the geography- and season-related uncertainty variations have not been revealed thoroughly. In this study, we investigate the uncertainty of NWM-derived tropospheric delay products using a huge amount of globally distributed GNSS stations (more than 10,000) over ten years, and focus on the geographical and seasonal distributions. We demonstrate that the uncertainty of NWM-derived tropospheric delays (1) have clear seasonal variations, that is, larger in the Summer season when the water vapor is more abundant and with rapid fluctuations, and (2) shows a strong dependence on the geography, which is also attributed to the water vapor distribution and variation differences. Our work could provide a reference for future research of exploiting NWM-derived tropospheric delays, especially in real-time GNSS positioning and navigation.

Description: With the advent of plate tectonics in the last century, our understanding of the geological evolution of the Earth system improved essentially. The internal deformation and evolution of tectonic plates remain however poorly understood. This holds in particular for the Central Mediterranean: The formerly much larger Adriatic plate is recently consumed in tectonically active belts spanning at its western margin from Sicily, over the Apennines to the Alps and at its eastern margin from the Hellenides, Dinarides towards the Alps. It has been shown that data acquired by dense, regional seismic networks like AlpArray provide crucial information on seismically active faults as well as on the structure and deformation of the lithosphere. The Adriatic Plate and in particular its eastern margin have however not been covered by a homogeneous seismic network yet. Here we report on the status of AdriaArray – a seismic experiment to cover the Adriatic Plate and its actively deforming margins by a dense broad-band seismic network. Within the AdriaArray region, currently about 990 permanent broad-band stations are operated by more than 40 institutions. In addition, 414 temporary stations from 24 mobile pools are deployed in the region achieving a coverage with an average station distance of 50 – 55 km. The experiment is based on intense cooperation between local network operators, mobile pool operators, field teams, and ORFEUS. Altogether, more than 50 institutions are participating in the AdriaArray experiment. We will report on the time schedule, participating institutions, mobile station pools, and maps of temporary station distribution.

Description: The term "space weather" summarizes phenomena in the solar system that originate from the sun and can affect modern technological infrastucture - including disturbances of navigation systems (e.g. GNSS), problems in power supply operation, as well as the loss of radio communication. The SWAP (Space Weather: The Austrian Platform) project deals with the diffusion of space weather information and expertise to potential users and the public. Funded as part of the Austrian Space Applications Programme (FFG), the project is carried out by a consortium of eight partners in space weather research and application. Our aims are to (1) create a network of national experts in the field, (2) establish a national space weather platform, and (3) plot a road map for future development in Austria. In this presentation, we will provide an overview on our progress in developing a national platform. A newly established website serves as a single point of entry into the topic of space weather in Austria. We use this platform as a launchpad to contact potential stakeholders and provide a resource of combined space weather expertise, with the intent to extend awareness of space weather events and their potential consequences. Using a space weather “atlas”, the website ties together the existing expertise with space weather topics. A direct line of contact to the relevant experts is provided in case of extreme events. We have identified various stakeholders including regional warning centres, power grid operators, groups relying on GPS and radio signals, and the press, among others.

Description: Extreme weather events caused by tropical and extratropical cyclones have destructive impacts on infrastructure, society, and environment. Forecasting extreme weather continues to present challenges. We consider solar wind coupling to the magnetosphere-ionosphere-atmosphere system, mediated by globally propagating aurorally excited atmospheric gravity waves, influencing the occurrence of severe weather. While these gravity waves reach the troposphere with attenuated amplitudes, they are subject to amplification when encountering opposing winds and vertical wind shears. They can release conditional symmetric instability [1] leading to slantwise convection, latent heat release, and contributing to intensification of storms. It has been shown that significant weather events, including explosive extratropical cyclones [2,3], rapid intensification of tropical cyclones [4], and heavy rainfall causing floods and flash floods [5,6] tend to follow arrivals of solar wind high-speed streams from coronal holes. To further support these results, we use various data sets in the superposed epoch analysis of the occurrence of severe weather, including heavy rainfall events and tornado outbreaks, in the context of solar wind coupling to the magnetosphere-ionosphere-atmosphere system. [1] Chen T.-C., et al., J. Atmos. Sci. 75, 2425–2443. doi:10.1175/JAS-D-17-0221.1 [2] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 149, 219–231. doi:10.1016/j.jastp.2016.04.002 [3] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 171, 94–10, 2018. doi:10.1016/j.jastp.2017.07.023 [4] Prikryl P., et al., J. Atmos. Sol.-Terr. Phys. 183, 36-60, 2019. doi:10.1016/j.jastp.2018.12.009 [5] Prikryl P., et al., Ann. Geophys. 39 (4), 769–93, 2021. doi:10.5194/angeo-39-769-2021 [6] Prikryl P., et al., Atmosphere 12 (9), 2021. doi:10.3390/atmos12091186.

Description: In GNSS, tropospheric Mapping Functions (MFs) are used to provide the relationship between slant and zenith delays. In order to regard asymmetry of the atmosphere, tropospheric gradients are taken into account. In this study, we present a new approach to parameterize the tropospheric delay and modify the wet MF with an additional parameter to decrease the errors in the analysis. Hence, we have calculated tropospheric delays on global scale using ray-tracing algorithm. ECMWF’s reanalysis ERA5 hourly datasets have been used with 0.25° horizontal resolution. According to the results, it can be concluded that the additional parameter is related to the humidity field. Since the humidity field is highly variable in space and time Numerical Weather Models will have difficulties to predict the additional parameter accurately.

Description: High-speed jets formed downstream of the Earth’s bow shock are localized and transient dynamic pressure enhancements. Due to their properties, they can have an effect on Earth’s magnetosphere, and they interact with background magnetosheath plasma. Jets have been connected to a variety of different effects, for example, magnetopause reconnection, excitation of ULF waves, and direct plasma penetration in the magnetosphere. While jets have been studied for several decades, their formation mechanism is still under debate. Several generation models have been proposed that include solar wind discontinuities, foreshock transients, non-stationarity of the shock (i.e., ripples/reformation) and many others. In this work, we focus on the connection between magnetosheath jets and the Earth’s bow shock. Specifically, we focus on observations of magnetosheath jets made by NASA’s Magnetosphere Multiscale (MMS) mission. Due to the high-resolution measurements, we found evidence of shock reformation allowing solar wind plasma to be less compressed than the typical magnetosheath, allowing the formation of magnetosheath jets as a direct consequence of the shock’s cyclic behaviour. Moving on, we exhibit how jets evolve at the Earth’s magnetosheath environment and how their velocity distribution functions (VDFs) can provide insight into their origin. Analyzing jets' VDFs highlights their kinetic nature and indicates the limitations of studying them from a full particle moment fluid picture. Finally, we investigate aspects of non-Maxwelianity that jets exhibit, and discuss how future research could include multiscale investigation made by conjunctions of several missions that reside in the outer magnetospheric region such as Cluster, MMS and THEMIS.

Description: During eruptive crises, questions on the potential climate response to an eruption rapidly emerge within scientific communities, stakeholders, and the public. However, rapid prediction of the climatic response is challenging because of: i) the uncertainties associated with near-real time satellite estimates of volcanic emissions; ii) the fact that most climate model simulations require detailed aerosol optical properties to be run; and iii) the significant computational costs of and uncertainties associated with climate models with interactive stratospheric aerosol capabilities, which only require estimates of the initial volcanic sulfur emissions. To address this challenge, we developed Volc2Clim (https://volc2clim.bgs.ac.uk/), a webtool predicting volcanic radiative forcing and climate response from volcanic sulfur emissions. Volc2Clim combines three simple published models: EVA_H, which predicts perturbations in aerosol optical properties, such as the stratospheric aerosol optical depth (SAOD) for a given mass of sulfur dioxide (SO₂), injection altitude and injection latitude. A scaling factor that links the global-mean SAOD perturbation (at 550 nm) and the global-mean effective volcanic radiative forcing at the top of the atmosphere. FaIR, a simple climate response model that calculates the global-mean surface temperature response based on the global-mean effective volcanic radiative forcing. Volc2Clim is computationally inexpensive and outputs both simple metrics and figures characterizing the radiative forcing and climate response, as well as full 4-dimensionnal fields of aerosol optical properties required to run climate models. We will showcase Volc2Clim’s main functionalities and discuss how well it performs for recent eruptions such as that of Raikoke in 2019.

Description: Human-induced climate change is increasing the frequency of heat waves and heavy rainfall, and their impacts have begun to manifest themselves in the form of various health hazards, wildfires, floods, and other types of damaging events. Significant risks can arise when the magnitudes of climate change exceed the adaptive capacity of a region. An unprecedented climatic risk could potentially have serious impacts on socioeconomic systems. Considering the adaptability to extreme climatic risks in the future, this study focused on determining whether humans have been exposed to the risks before, and defined the rim of two-dimensional histograms of population under 20-year extreme temperature and precipitation as a climatic risk boundary. It was revealed that more than 30% (16.3%) of world population in South Asia, sub-Saharan Africa, and other regions will transgress the climatic risk boundary by the end of this century under RCP8.5 (RCP2.6) scenario. Furthermore, under the assumption that the acceptability of adaptation measures currently adopted by people in other regions cannot avoid the influence of cultural and social aspects, regional climate risk boundary for people in each region is also developed. While many areas with large cities will remain within the global climatic risk boundary, they will transgress their regional climatic risk boundaries. This study shows that it is also necessary to consider the limits to adaptation for each appropriate area, considering the cultural, technological, and social transferability of adaptation, and will help refine public perceptions of extreme climatic risks and lead to more efficient policy making.

Description: The lower limb of the Meridional Overturning Circulation fills the abyssal ocean across much of the globe with Antarctic Bottom Water (AABW). However, this abyssal overturning cell only outcrops in the Southern Ocean; it depends upon rapid water mass transformation that occurs in a small number of distinct sites near the Antarctic continent, coupled with export of dense water from the Antarctic continental shelf. This strong dependence on local processes has compromised the fidelity of global models in representing the abyssal overturning - particularly for low-resolution climate models. Recent advances in high-resolution global ocean-sea ice models has led to significant improvements in model representation of AABW processes and has allowed deeper investigation into the dynamics of the lower cell of the MOC. In this presentation I will review recent progress in using high-resolution models to understand the dynamics of dense water export from the Antarctic, the sensitivity of dense water formation and the abyssal MOC to surface forcing, the variation of the AABW export and the pathways of AABW throughout the deep ocean. These advances help to constrain future potential changes in the lower overturning cell, and suggest methods to diagnose change from observations.

Description: The benefit of continuous modelling in hydrological studies is widely recognized, indeed it is particularly promising for estimating the design hydrological input for a variety of practical applications and there is a clear tendency to overcome the concept of design hydrograph in favor of the design runoff simulation. Recently, it was underlined the possibility and the opportunity to apply the continuous framework also in the challenging case of ungauged basins. However, while promising, this approach is still not commonly adopted in practice mainly because it needs as input a simulated rainfall time series, that still is not user-friendly task. In this contribution we summarize the recent steps forward of the continuous modelling in ungauged basins and the residual procedural bottlenecks, moreover we explore its use for designing flood early warning systems. We illustrate a framework based on hydrological-hydraulic synthetic scenarios for selecting the best-performing machine learning model for forecasting discharges. Finally, feature importance measures are introduced for discerning the most influential sub-basins where the measurement instrumentations should be installed enabling the implementation of a cost-effective flood early warning system.

Description: The gravity field plays a crucial role in Earth System Sciences. Currently available static global gravity field models are limited in resolution due to the band-limited spectral content of the input data from satellite observations and gravity measurements on the Earth’s surface. Such models are complemented beyond their current limits using high-resolution digital elevation models (DEMs) and density estimates. At GFZ, we are interested in developing such high-resolution topographic models to enhance the representation of static global gravity field models such as EIGEN-6C4. Our preliminary study expanded the model representation of EIGEN-6C4 up to d/o 5400 using Earth2014 and four density values estimated for rock, ocean, lake and ice. Moreover, we tested the impact of different shell thicknesses to the numerical stability and computation time. Current study is a continuation of our previous activities and summarises the first results of a DFG project GRAV4GEO (GRAVitational field modelling of Earth’s topography For GEOdetic and GEOphysical applications). We aim to improve the performance of our preliminary model ROLI_EllApprox_SphN_3660 further via introducing improved DEM and laterally varying density estimations and optimized methodology. Our preferred DEM model will be a product of combined solutions from TanDEM-X 90 m and other state-of-the-art DEM models developed/improved recently. Moreover, we aim to introduce a 3D density estimation globally. The new model is expected to enhance our preliminary model and contribute to the accurate representation of very high-resolution static global gravity field modelling.

Description: The PAGER project provides space weather predictions that are initiated from observations on the Sun and predicts radiation in space and its effects on satellite infrastructure. Real-time predictions and a historical record of the dynamics of the cold plasma density and ring current allow for evaluation of surface charging, and predictions of the relativistic electron fluxes allow for the evaluation of deep dielectric charging. The project provides a 1-2 day probabilistic forecast of ring current and radiation belt environments, which will allow satellite operators to respond to predictions that present a significant threat. As a backbone of the project, we use the most advanced codes that currently exist and adapt existing codes to perform ensemble simulations and uncertainty quantifications. This project includes a number of innovative tools including data assimilation and uncertainty quantification, new models of near-Earth electromagnetic wave environment, ensemble predictions of solar wind parameters at L 1, and data-driven forecast of the geomangetic Kp index and plasma density. Our developed codes may be used in the future for realistic modelling of extreme space weather events. The PAGER consortium is made up of leading academic and industry experts in space weather research, space physics, empirical data modelling, and space environment effects on spacecraft from Europe and the US.

Description: In November 2022 the new United Nations Global Geodetic Centre of Exellence has been established at the UN Campus in Bonn. The main task of the UN-GGCE is to assist the UN Member States to implement the goals of the UN-Resolution 69/266 from 26 February 2015: ‘Global Geodetic Reference Frame for Sustainable Development (GGRF)’. The GGRF is an authoritative, reliable, highly accurate and global spatial referencing infrastructure. With its high accuracy and long-term stability, it provides a reliable reference for precise positioning on the Earth and is the basis for monitoring changes of the Earth system. Quantification of numerous and diverse societal and scientific applications, like monitoring of sea level change, glacial melt or movement of tectonic plates are not possible without a reliable GGRF. The objective of UN-GGCE is therefore to support the implementation of the UN General Assembly resolution through strengthening and advancing: global geodetic cooperation and coordination; worldwide geodetic infrastructure; standards, policies and conventions; education, training and capacity building; and communication and awareness, while also coordinating measures and overseeing their implementation. The UN-GGCE will improve global cooperation and coordination between Member States and other geodetic stakeholders and focus on the establishment of a globaly coordinated geodetic infrastructure enabling all Member States and geodetic stakeholders to work more efficiently and effectively together.

Description: Major economic losses are caused by the presence of low visibility weather conditions such as fog, which happens frequently all year around in the United Arab Emirates (UAE). An accurate forecast of fog initiation and dissipation are vitally important to mitigate these losses, which includes air traffic delays, car damage and loss of life. The study reported here aims to investigate whether releasing electrically charged corona ions into fog can modify fog droplet properties and help to dissipate fog. Measurements of Potential Gradient (PG), visibility and droplet size distribution were made from an internal desert region of the UAE where radiation fog formation is common. Experiments were devised in which an array of four corona ionisers were pulsed on and off at regular time intervals. Preliminary tests were conducted in clear air conditions, to investigate the magnitude of changes in PG, which were found to be from 50 to 80 V/m when ions were released. Further analysis conducted in fog cases will also be reported here to investigate the effects of corona emitted ions on droplet size distribution and thus, examine if charging can modify fog droplet size and number concentration.

Description: Impact of solitary breaking waves on partly submerged boulders is studied experimentally in a small wave tank. Focus is on the forces and motion of boulder with different size. Furthermore, sand is added which change the friction coefficient. Experiments are conducted at the Hydrodynamics lab at the University of Oslo in a small 3m long and 10 cm wide wave tank, filled with 5 cm water.A block releasing mechanism generates solitary waves with an amplitude normalized by the water depth a/h = 0.47. The dimensions of the block are 15.03 cm, 10 cm and 5.00 cm (length, width, height). Generated solitary waves propagate to a 1:10 beach. Boulders of different size, volume and orientation are placed alternately (one at a time) at different locations on the beach slope (smooth or sandy) with respect to the wave breaking point. The transport of boulders and their motion is studied with respect to the boulder characteristics (volume, size, orientation), inclusion of sand and the initial position of the boulders. The sand on the slope changes bottom friction, and therefore, increases the boulder transport. Overall, the effects of boulders’ length (parallel to wave direction) on the displacement of boulders are more evident in this study.

Description: Statistical earthquake forecast models are a critical component of several products released by the U.S. Geological Survey as part of its mission to deliver actionable information to decision makers in the US. These include the National Seismic Hazard Model (NSHM) and Operational Aftershock Forecasts (OAF), the latter of which can include swarm forecasts. Both products require earthquake forecast models that are applicable on different timescales, ranging from days to years (OAF) to decades (NSHM). OAF uses short-term forecast models that are based primarily on catalog statistics and include clustering behavior, such as encompassed in Reasenberg and Jones (1989), the ETAS model (Ogata, 1988), and swarm models (Llenos and van der Elst, 2019). The NSHM uses a long-term (50-year) earthquake forecast, one component of which is a smoothed seismicity model based on an earthquake catalog. Clusters are removed when forecasting the location of future seismicity but retained when estimating the future earthquake rate. Both OAF and the NSHM face challenges in catalog incompleteness, in both the short term and the long term. And both may be affected by anomalous earthquake rate changes, such as natural earthquake swarms, human-induced seismicity, or volcanic events. In this presentation, I will give an overview of the statistical models that are used for these two products, updates that have been made to address some of these challenges, future updates that could be considered such as the use of machine learning methods, and how the forecasts are used and presented to the public.

Description: In the United Arab Emirates (UAE), fog forms frequently throughout the year leading to significant economic cost due to transport disruptions such as air traffic delays, car damages and loss of life. By understanding the electrical characteristics of fog, it may be possible to provide early warning of fog. Previous research showed distinct differences in electrical characteristics of the atmosphere between clear and foggy-laden air. This is due to the presence of droplets, which causes the removal of natural cluster ions and hence, alters the conductivity and Potential Gradient (PG). Some of the first surface electrical measurements conducted during fog in the UAE will be reported here. Measurements of PG and meteorological variables were made from an internal desert region of the UAE where radiation fog is common. The analysis indicates that the magnitude of the PG observed during fog in the UAE is very large (up to thousands of V/m), with high variability. However, the PG is often negative during fog, in contrast to previous observations in the literature. The UAE PG measurements in fog will be compared to measurements conducted at Reading, UK, to demonstrate differences between the UAE fog and fog at a typical mid-latitude urban location. The research reported here will also use fog droplet measurements to investigate potential causes of the anomalous changes in PG during fog in the UAE, particularly whether this is related to larger droplet sizes in the UAE fog, causing it to act as a “precipitating” fog.

Description: Tsunamis are one of the most devastating natural disasters, causing widespread destruction and loss of life. In recent years, advances in science and technology have led to the development of sophisticated tsunami early warning systems, with promising operational applications. However, much work remains to be done in order to further improve the accuracy and timeliness of warning systems, and for enhancing the preparedness of at-risk communities. In December 2017, the U.N. proclaimed the Decade of Ocean Science for Sustainable Development (2021–2030), also referred to as the Ocean Decade. The Ocean Decade Tsunami Programme (ODTP) approved by the UNESCO IOC in 2021 in response to the call to Ocean Decade action provides an excellent framework for international cooperation to enhance the end-to-end tsunami early warning and mitigation systems. The main objectives of the ODTP are (i) to develop the warning systems’ capability to issue actionable and timely tsunami warnings for tsunamis from all identified sources to 100% of coasts at risk and (ii) 100% of communities at risk to be prepared and resilient to tsunamis by 2030 through programmes like the UNESCO IOC Tsunami Ready Recognition Programme. A Research, Development and Implementation Plan is being prepared by the ODTP Science Committee highlighting the goals, status, challenges, potential solutions and implementation pathways for enhancing (i) risk knowledge, (ii) detection, analysis and forecasting, (iii) warning dissemination and communication, and (iv) preparedness and response capabilities. The plan also highlights capacity development needs, governance aspects and international cooperation in achieving the objectives of the ODTP.

Description: We will present results of ABRUPT, a project in which we simulate and reconstruct the sea ice conditions, ocean hydrography and climate of the Nordic Seas, over two targeted Dansgaard-Oechger events. Multi-model output from three transient glacial GCM simulations (NorESM, CESM, MPI-ESM) and high-resolution reconstructions from an eastern Nordic Seas transect (from the Faeroe-Shetland Channel to the Fram Strait) show that ocean-atmosphere-sea ice processes and dynamics during the transition from H4 to GI8 are strongly coupled. Both model results and reconstructions suggest subsurface ocean warming and polynya events in the southern- and northernmost Nordic Seas during the cold stadial. For a short time during the stadial to interstadial transition, a corridor of open water and hence sea ice-free conditions existed from the southern Nordic Seas all the way to the Fram Strait. The breakup of the sea ice cover is likely caused by the overshoot of AMOC during the transition and the associated enhanced ocean heat transport into the Nordic Seas. After the transition, winter sea ice grows back in the Fram Strait during the interstadial state, but the Southern Nordic Seas remain ice-free.

Description: Updraft characteristics constrain convective mass flux, hydrometeor growth and precipitation efficiency and contribute to the spatial redistribution of energy, momentum, moisture, and aerosols in the troposphere. The impact of environmental parameters like instability, relative humidity, and vertical wind shear on convective updrafts characteristics, though important, remains poorly understood. Moreover, the relationships between updraft characteristics and cloud microphysical properties are a cause of uncertainty in cloud parameterizations for weather and climate models. The Experiment of Sea Breeze Convection, Aerosols, Precipitation and Environment (ESCAPE) campaign (2022) sampled isolated convective systems developing in different meteorological regimes in the vicinity of Houston. In this presentation the in-situ observations of cloud microphysics, vertical motion and airborne radars from the National Research Council of Canada (NRC) Convair-580 aircraft are used with ground-based radars to quantify the macrophysical and microphysical properties. During 13 research flights, the NRC Convair-580 sampled over 1100 individual updrafts, with at least 75 having strength 〉10 m s〈sup〉-1〈/sup〉 and a maximum strength of 29 m s〈sup〉-1〈/sup〉. The highest liquid water contents of 2 to 4 g m〈sup〉-3〈/sup〉 measured by bulk and scattering probes were frequently found to be coincident with the strongest updrafts. Further analysis of observed in-situ cloud microphysical properties as a function of updraft strength and environmental conditions, based on synoptic forcing, aerosol concentrations, soundings, surface observations and reanalysis data, will be presented.

Description: There is increasing awareness of the need for comprehensive information on potential future sea level rise to inform adaptation planning and coastal decision making. The IPCC Sixth Assessment Report (AR6) states that global mean sea level (GMSL) rise approaching 5 m by 2150, and more than 15 m by 2300, cannot be ruled out under high greenhouse gas emissions due to uncertainty in ice sheet processes. However, current guidance on high-end sea level rise for the United Kingdom (UK) advises users to plan for up to 1.9 m of sea-level rise by 2100 with no explicit consideration of long-term commitment. This work aims to provide a framework to accommodate updated high-end sea level rise guidance that extends to 2300. We combine the Monte Carlo methods used in the latest national sea level projections (UKCP18) with recently published projections of Antarctic ice mass loss to develop a small set of physically consistent storylines of local sea level rise. The storylines span the range of GMSL rise uncertainty at 2300 assessed by AR6 and provide continuous sea level rise information around the UK coast. For a given storyline, the relative contribution from Antarctica and Greenland is an important determinant of the UK rise. While we focus on the UK, the methods are generic and can be readily applied to other geographic locations.

Description: At high frequency (f〉0.5Hz), spatial variations of seismic attenuation parameters -scattering and absorption- control to a large extent the variability of observed ground motions at the regional scale. Hence, our ability to predict seismic hazard depends critically on mapping frequency-dependent attenuation. To address this issue, we developed a hybrid inversion method to separate attenuation parameters (scattering and intrinsic absorption) in 6 frequency bands covering the 0.75 – 24 Hz range from the modeling of the S-wave energy envelopes. Synthetic envelopes and their partial derivatives with respect to attenuation parameters are calculated using the Monte-Carlo method for elastic waves in a simple but realistic model of the Earth's lithosphere. The hybrid inversion method combines a grid-search with an iterative optimization using the Levenberg-Marquardt algorithm, which respectively test different models of random heterogeneities and constrain the level of scattering and absorption. The inversion procedure has been applied to more than 10000 waveforms retrieved from the database of the French seismological and geodetic network RESIF. The obtained attenuation maps show the extreme variability of frequency-dependent attenuation parameters (scattering and intrinsic absorption) at the regional scale. In particular, we find zones of strong scattering in the Western Pyrenees at all frequencies and in young sedimentary basins below 3 Hz. Absorption is stronger in the Paris Basin at low frequency and in the French Alps above 3-6 Hz. Western France is characterized by weak scattering and absorption. We also find that scattering generally dominates absorption below 1-2 Hz while the opposite is true at higher frequency.

Description: Atmospheric aerosols affect the absorption and dispersion of light through the atmosphere. The role of aerosols on accurate satellite images is generally expressed by the trajectory of the modulation transfer function (MTF) of aerosols. In this research, the MTF of aerosols has been estimated under different weather conditions in the atmosphere of Tehran, in Iran, for some case studies during 2021. The main aim of this research is to provide a model to be used for different times and weather conditions in the ​​Tehran urban area. This will need for the accurate design of the cargo and the selection of the sensor and channel. The required meteorological data were derived from the European Center for Weather Forecasting (ECMWF) and radiosonde data. The small angle approximation (SAA) method has been used to estimate the MTF of aerosols. The results for three different modes of the dominant aerosols including dust, urban aerosols, and the combination of both types, show that in a hypothetical imaging system, at the Nyquist frequency, the MTF value varies from the minimum of 0.5 ​​in autumn to 0.65 in summer. This drastic change is probably caused by the increase in air pollution in Tehran during mid-autumn and the dominance of urban aerosols.

Description: Volcanic impacts on the environment and climate depend on the volcanic forcing. This is controlled by the eruption source parameters like eruption magnitude, composition, season, latitude and injection altitude. But how the volcanic forcing is affected by initial conditions, and what differences tropical and extratropical volcanic eruptions have is not well understood. Here, using the coupled Earth System model CESM2-WACCM6 with prognostic stratospheric aerosols and chemistry, we performed ensemble simulations for volcanic eruptions at 15°N and 64°N in January injecting 17 Mt of SO2 together with halogens (Cl, Br) at 24 km altitude, considering different initial conditions of the quasi-biennial oscillation, El Niño–Southern Oscillation and polar vortex. We show how initial conditions control the transport of volcanic volatiles from the first month and determine the subsequent latitudinal distribution of sulfate aerosols, halogens and thus the volcanic forcing. We show how this affects the environmental and climatic impacts differentiating between tropical and extratropical eruptions. Finally, uncertainties on the volcanic forcing and responses to eruptions with varied source parameters and in two different climate aerosol models are discussed.

Description: Based on the analysis of the average characteristics of the radio emission of a thundercloud, namely, the rms value (intensity) and the kurtosis coefficient, calculated over short time intervals (100 microseconds), specific events were detected, probably corresponding to cloud-to-ground lightning discharges. These events begin suddenly with a series of fairly rare submicrosecond bipolar pulses of large amplitude, which manifests itself in a moderate intensity level and high values of the kurtosis coefficient. This stage of the event can last from a few to several hundred milliseconds and can be called the preparatory stage of a lightning discharge. The next stage is characterized by a successive decrease in the kurtosis coefficient with a slight change in both the amplitude and intensity of the radiation, and a decrease in the level of intensity fluctuations and the kurtosis coefficient, which indicates an increase in the frequency and a decrease in the amplitude of the pulses, as well as the possible appearance of a noticeable quasi-continuous (noise) component in the lightning radiation clouds. This stage may be associated with the development of a stepped lightning leader. Finally, the event ends with a sharp peak in intensity and a drop in the kurtosis coefficient to the background level, which corresponds to a return lightning strike. Observation of the short-wavelength radio emission of a thundercloud can make it possible to predict the time of a lightning strike (in a few tens of milliseconds), and, in combination with interferometry, its location.

Description: In view of the historically devastating earthquakes in Ghana, this study employed regional satellite gravity data to reveal the extension of the crustal network of fractures emanating from the seismically active zone in the Gulf of Guinea and its implications on Coulomb stress transfer of the June 22nd, 1939 Accra earthquake. The Accra earthquake (M=6.5), Ghana is one of the most devastating intra-plate earthquakes in sub-Sahara west African region. In order to carry out the Coulomb stress transfer study, we utilized the Fault Plane Solutions (FPS) obtained from the waveform inversion of Yarwood and Doser (1979), which revealed that the earthquake composed of two events (6.1 Mw and 6.4 Mw). This study resolved the static Coulomb Failure Stress (CFS) change onto the finite fault models of the 6.4 Mw and 6.1 Mw earthquakes and its effect on associated receiver faults. The gravity study revealed swarms of fractures emanating from the gulf of Guinea and connected with the Akwapim and Coastal boundary faults favored the enhanced CFS to generate the 6.1 Mw due to transmission of stress from the seismically active zones in the Gulf of Guinea (boundary between the African plate and the South-American plate). The 6.4 Mw main shock was explained to correlate with release of seismic energy from the associated secondarily stressed prominent strike-slip (Akwapim) fault and strike-slip (coastal boundary fault). The direction of Coulomb stress transfer and the receiver faults of the 6.4 Mw main event have been mapped for the next big magnitude earthquake preparedness.

Description: An accurate magnitude estimation is necessary to properly evaluate seismic hazard. Unfortunately, magnitudes of small earthquakes are subject to large uncertainties due to high-frequency propagation effects which are generally not properly considered. To address this issue, we developed a method to separate source, attenuation and site parameters from the elastic radiative transfer modeling of the full energy envelopes of seismograms. The key feature of our approach is the treatment of attenuation -both scattering and absorption- in a simple but realistic velocity model of the Earth's lithosphere, including a velocity discontinuity at the Moho. Our separation method is based on a 2-steps inversion procedure. First, for each source-station pair, we retrieve optimal frequency-dependent attenuation parameters from the fitting of observed energy envelopes in the 0.375-24Hz band. In a second step, we correct for regional propagation effects to determine site amplification and source displacement spectra. From the latter, we estimate the moment magnitude Mw. The inversion procedure is applied to the 2019 ML 5.2 Le Teil and 2014 ML 4.5 Lourdes earthquakes, which both occurred in Southern France. The inversion results confirm a significant variability in the attenuation parameters (scattering and intrinsic absorption) at regional scale and a strong frequency dependence. We determine moment magnitudes Mw 5.07±0.17 for the Le Teil earthquake and 4.13±0.13 for the Lourdes earthquake, in good agreement with previous estimates. In the future, we intend to automate our method and apply it routinely to smaller earthquakes for which traditional methods are not readily applicable due to the complexity of waveforms.

Description: The ionospheric state is constantly changing and can be described by the integrated electron density estimation commonly known as the total electron content (TEC). The estimate of ionospheric TEC during geomagnetic storms can vary significantly compared to the TEC during quiet conditions. Therefore, it is important that ionospheric models also perform well during perturbed or storm conditions. We developed a neural network (NN)-based model that predicts the storm-time TEC relative to the 27-day median prior to the storm events. The network uses the 27-day median TEC, latitude, longitude, universal time, storm time, solar radio flux index F10.7, global storm index SYM-H and geomagnetic activity index Hp30 as input parameters and the output is the relative TEC with respect to the 27-day median. A storm dataset has been used containing the TEC maps from UQRG global ionosphere maps (GIMs) from the years 1998 until 2020 and comprises in total of 398 storm events. The model was tested with unseen data from 33 storm events that occurred during 2015 and 2020 representing a high- and low solar activity year, respectively. The performance of the storm-time model during the storms in the test dataset was compared with the Neustrelitz TEC model (NTCM) and the NN-based quiet time TEC model, both developed at German Aerospace Center (DLR) and the storm-time model outperforms both.

Description: A general assumption in geodesy is that solid Earth deformation in the presence of recent hydrological and ice loading is well approximated by a purely elastic response. If thermal or petrological conditions exist that favor vigorous high-the temperature creep behavior, such as in the mantle beneath Iceland, Patagonia, Alaska, Japan and Svalbard, many response models have been approximated by using a Maxwell viscoelasticity. However, non-Maxwellian transient viscoelastic rheology is required for models of post-seismic relaxation. Here we reconsider the solid Earth response in light of a temperature-dependent transient viscoelasticity currently favored in the mineral physics and seismological communities. We develop a mantle response Green's function that accounts for the vertical isostatic motion of the mantle caused by acceleration of ice mass loss for Greenland and Patagonia measured by remote sensing since 1992 and 1945, respectively. The Green's function may be used to examine how anelasticity may express itself in the uplift associated with accelerated surface ice and water loss. We perform an extensive parameter exploration of the constants that define the Extended Burgers Material (EBM) model, a rheology having firm experimental and theoretical underpinnings, in order to isolate those material model parameters that have the greatest impact on anelastic-isostatic uplift over interannual and interdecadal time scales. Especially important are the contrasts among elastic, Maxwell and EBM predictions. Implications for the corrections for solid Earth vertical uplift in space gravimetric solutions for long-term hydrology and cryospheric change are also discussed. © 2023 California Institute of Technology. Government sponsorship acknowledged.

Description: In this study, using 7 years of Van Allen Probes electron flux and chorus wave measurements, we show a new and distinct population of very intense chorus waves that are generated in the heart of the outer radiation belt (L* = 4 - 6) during the main phase of geomagnetic storms. During 70 isolated geomagnetic storms in the entire Van Allen Probe era (2012 - 2019), we found that during the storm main phase, the power of chorus waves increases by ~2 - 3 orders of magnitude above the pre-storm levels when the fluxes of ~10 - 100 keV electrons approach or exceed a certain energy-dependent flux value theoretically predicted by Kennel and Petschek (KP) more than 50 years ago. In the original KP theory, it was predicted that at the limit, it is the intense chorus waves that scatter electrons into the loss cone preventing any further increase of flux, thereby maintaining the flux at the limit. In this study, we further used POES electron flux data to show that the precipitating flux indeed increases during the storm main phase in a similar manner as predicted in the original KP theory. We also investigated the properties of these intense chorus waves. Our results thus have a very crucial impact on the understanding of the dynamics of the Van Allen radiation belts and in future, these results can be implemented in radiation belt models to study the impact of the high-intensity chorus waves on the radiation belt electron population.

Description: Clouds play a key role for the Earth’s energy balance; however, their response to climatic and anthropogenic aerosol emission changes is not clear, yet. Here, 20 years of satellite observations of cloud radiative effects (CRE) are analysed together with reanalysis data sets in a (regularised) ridge regression framework to quantitatively link the variability of observed CREs to changes in environmental factors, or cloud-controlling factors (CCFs). In the literature the meteorological kernels of such CCF analyses are typically established in regime-specific regression frameworks based on a low (2-8) number of CCFs. In our data-driven approach, the capabilities of the regularised regression to deal with collinearities in a large number of predictors are exploited to establish a regime-independent CCF framework based on a large number of CCFs. Using a reference 7-CCF framework, we show that ridge regression produces nearly identical patterns of CCF sensitivities when compared to the traditional regression. In the data-driven framework, however, the traditional regression fails at producing consistent results due to overfitting. The data-driven analysis reveals distinct regional patterns of CCF importance for shortwave and longwave CRE: Sea surface temperatures and inversion strength are important for shortwave CRE in stratocumulus regions, in agreement with existing studies. Free tropospheric meridional winds are important drivers of CRE in the subtropical belts in both hemispheres. Aerosols are shown to be most important for shortwave CRE in the regions of stratocumulus to cumulus transition.

Description: On November 23〈sup〉rd〈/sup〉 2022, a M〈sub〉W〈/sub〉 6.0 earthquake occurred in direct vicinity of the M〈sub〉W〈/sub〉 7.1 Düzce earthquake that ruptured a portion of the North Anatolian Fault in 1999. The M〈sub〉w〈/sub〉 6.0 event was attributed to a small fault portion of the Karadere segment that did not rupture during the 1999 sequence. We analyze the spatio-temporal evolution of the M〈sub〉W〈/sub〉 6.0 Gölyaka-Düzce seismic sequence at various scales and resolve the source properties of the mainshock. Modelling the decade-long evolution of background seismicity of the Karadere Fault employing an Epistemic Type Aftershock Sequence model shows that this fault was almost seismically inactive before 1999, while a progressive increase in seismic activity is observed from 2000 onwards. A newly generated high-resolution seismicity catalog from 1 month before the mainshock until six days after created using Artificial Intelligence-aided techniques shows only few events occurring within the rupture area within the previous month, no spatio-temporal localization process and a lack of immediate foreshocks preceding the rupture. The aftershock hypocenter distribution suggests the activation of both the Karadere fault which ruptured in this earthquake as well as the Düzce fault that ruptured in 1999. First results on source parameters and the duration of the first P-wave pulse from the mainshock suggest that the mainshock propagated eastwards in agreement with predictions from a bimaterial interface model. The M〈sub〉W〈/sub〉 6.0 Gölyaka-Düzce represents a good example of an earthquake rupture with damaging potential within a fault zone that is in a relatively early stage of the seismic cycle.

Description: The shock acceleration is an important particle acceleration mechanism in the interplanetary space, but the electron shock acceleration process is not fully understood yet. Here we summarize the observational properties of in situ shock acceleration of solar wind suprathermal electrons at 1 AU, using the Wind measurements and MMS measurements. For both the Earth’ s bow shock and ICME-driven shocks, the observed power-law spectral index of shocked suprathermal electrons is significantly larger than the theoretical prediction of first-order Fermi acceleration, while the flux enhancement ratio between the downstream shocked and upstream unshocked suprathermal electrons peaks near 90° pitch angle. These observations favor the shock drift acceleration process. However, the shocked electron spectra exhibit different behaviors for ICME-driven shocks and terrestrial bow shock. At ICME-driven shocks, the significantly shocked suprathermal electrons generally have a double-power-law spectrum bending upwards at a break near 2keV with a low-energy spectral index of ∼3.7 and high-energy spectral index of ∼2.5, similar to the upstream unshocked suprathermal electrons. At the terrestrial bow shock, the strongly shocked suprathermal electrons show a double-power-law spectrum bending downwards at a break near ∼ 65 keV with a low-energy spectral index of ∼3.1 and high-energy index of ∼7.6, different from the upstream unshocked suprathermal electrons. Furthermore, the observed break energy is comparable to a critical electron energy with its cross-shock gyrodiameter equal to the bow shock’s ramp thickness. These results suggest that the shock drift acceleration process of suprathermal electrons could strongly depend on the electron trapping efficiency at shock.

Description: The advent of machine and more specifically deep learning techniques significantly boosts the capabilities of data assimilation and inverse problem techniques used in the geosciences. It also spurs new, more ambitious goals for data assimilation in high dimensions. One of the key, currently very popular, area of research consists in learning data-driven models of dynamical systems. With the natural constraints of geoscience, i.e., sparse and noisy observations, this typically requires the joint use of data assimilation and neural networks. However, the vast majority of algorithms are offline; they rely on a set of observations from the physical system, which must be available before the start of the training. We propose new algorithms that update the knowledge of the surrogate (i.e., data-driven) model when new observations become available. We carry out this objective with both variational (weak-constraint 4D-Var like) and ensemble (EnKF and IEnKS like) techniques. We test these algorithms on low-order Lorenz models, on quasi-geostrophic models, the ERA5 dataset, and sea-ice dynamics. Remarkably, in several cases, the online algorithms significantly outperform the offline ones. This opens the way to adaptive surrogate models that progressively learn trends and conform to real-time constraints of operational weather forecasting.

Description: Clouds and seasonal variations are key parameters that play a crucial role in the albedo dynamics of forest canopies that ultimately impact the surface radiation budget and long-term climate trends. Additionally, the occurrence of natural extreme events such as prolonged dry spells or floods may further alter the feedback loop between the forest canopy and the Earth’s energy radiation budget. Limitations such as low spatio-temporal resolution in case of satellite-based analyses and lack of continuous in-situ observations hinder efforts to quantify the local effects of forest-cloud dynamics on climatic trends. To this effect, we have established a long-term autonomous measurement system on a crane within the Leipzig floodplain area, Leipzig, Germany, operational since June 2, 2021. We present a comparative analysis of the spectral forest canopy albedo as a function of cloud fraction for two consecutive years with different climatic conditions: year 2021 with conditions close to the climatological mean and year 2022 with a close to eight weeks long dry spell during summer months. The spectral irradiance is recorded daily between 12 Noon and 1 P.M. local time and the cloud fraction is obtained from the Tropomi sensor onboard the Sentinel-5P satellite. The results indicate a substantial dependence of the spectral canopy albedo on the cloud fraction and an overall increased canopy albedo for the year 2022 compared to the year 2021, which shows the biophysical impact of clouds on forests and the feedback mechanism of forest-cloud dynamics following an extreme event.

Description: The core-mantle boundary (CMB) is one of the most stable interfaces inside the Earth due to the large density and viscosity contrasts. Despite significant differences in physical, chemical, and transport properties, the possible mechanisms where the core and mantle can interact has become an active area of research. Detection of chemical signatures from the CMB can provide an unprecedented glimpse into the Earth’s deep interior and ancient past, with some studies suggesting certain isotopic and elemental anomalies in ocean island basalts to be core tracers. However, there is still uncertainty regarding processes that can convey chemical signatures from the core to the mantle. A recent study proposed a new hybrid mechanism that results from collaborative feedback between dynamic topography, percolation of liquid metal into submerged rock, the gravitational collapse of a metal-silicate mush, and induced small-scale mantle circulation above this mushy layer. The grain-scale intrusion of liquid iron into mantle rocks offers an opportunity for chemical and isotopic exchange to take place, while the gravitational collapse of the mushy layer can “soften” the CMB and enhance downwellings, thereby encouraging further chemical exchange. Using a mantle convection model coupled to the gravitational spreading of a thin layer at the CMB, we will show how the enhancement of downwellings change with the rheology of the mantle, and if the reacted mantle materials emerge from the mushy layer with a certain buoyancy ratio, how much of it will be entrained in upwelling plumes.

Description: Despite its role in Arabia-Eurasia convergence between the Black and Caspian Seas, the Caucasus region lacks a comprehensive catalog. To address the issue, the Lawrence Livermore National Laboratory and the Institute of Earth Sciences (IES) at Ilia State University generated a new, comprehensive seismic catalog for the Caucasus region by combining data in the IES bulletin with bulletins of the Republic Seismic Survey Center of Azerbaijan, monitoring centers in Turkey and Armenia, and the ISC covering the period 1951 to 2019. We present the bulletin that contains some 20,000 relocated events. We first relocated each event using the single-event location algorithm iLoc and RSTT predictions and identified GT events. Then we relocated the entire seismicity of the Caucasus region with the multiple-event location algorithm Bayesloc, using the iLoc results as initial locations and the GT events as constraints. We show that each relocation step leads to significant improvements, as indicated by tightening of event clusters. The improved view of the seismicity reveals a narrow band of crustal events along the southern flank of the Greater Caucasus we interpret as a megathrust, and confirms both a region of deep seismicity beneath the northeastern Caucasus and a possible area of slab detachment in the central part of the range.

Description: Investigating the dynamics of liquid iron at the top of the core requires an inversion process from magnetic field measurements. Due to possible leakage, traditional spectral techniques are not optimal for regional investigations or studies of Secular Variation (first time derivative of magnetic field, SV) on short-time periods. Improved data coverage and quality from satellite missions have provided insight into short-period dynamics (such as jerks and waves), and improved understanding of localised features. However, there continues to be a need for new techniques for better spatio-temporal models of flow motions at the top of the core, especially for regional investigations. The aim of this work is to investigate regional dynamics at the Core-Mantle Boundary (CMB) using the SOLA (Subtractive Optimally Localised Averages) methodology. This method allows us to create point estimates of radial field SV at the CMB by considering global satellite measurements. The SOLA methodology allows for a local estimate of radial field SV at any desired location directly at the CMB, which opens the way to investigations of regional dynamics. Producing localised-average estimates at the CMB bypasses many problems encountered when using only a subset of magnetic satellite data, downward continuing data, and models based on spherical harmonics. Finally, we discuss how the SOLA methodology can be incorporated into the PyGeodyn code to produce core flow models. This approach can provide additional information on wave-like flow motions at the top of the Earth’s core where these are most prominent, and permits new investigations of shorter period phenomenon.

Description: The moment magnitude is closely related to the seismic moment, which quantifies the energy released by earthquakes, and is therefore important for understanding volcanic dynamics and assessing seismic hazard. In this study, we calculate the moment-based magnitude (MW) for selected seismic data sets, using different approaches in distinct magnitude ranges to cover the widest possible range of magnitude that characterizes Etna's seismicity. Specifically, we computed the MW from a dataset of full moment tensor solutions of earthquakes that occurred in the magnitude range 3.4≤ ML ≤ 4.8 during 2005-2020; we created a dataset of seismic moment and associated MW for earthquakes 2.0 ≤ ML 〈 3.4 obtained by analyzing source spectra; we fine-tuned two relationships, for shallow and deep earthquakes, to obtain MW from response spectra. Finally, we calibrated a specific relationship between MW and ML for the Etna area earthquakes in the range 2.0 ≤ ML ≤ 4.8 and for microseismicity (ML 〈 2.0) using synthetic data. Our results show that the scaling between ML and MW is 1 for magnitude 2.0 ≤ ML ≤ 4.8, while it becomes 2/3 when we extend the relationships to ML 〈 2.0. All the empirical relationships obtained in this study can be applied in real-time analysis of the seismicity to provide fast and robust information on the released seismic energy.

Description: The core surface flow and its radial derivative are related to geomagnetic field and its first time derivative (Secular Variation, SV) through the three components of the induction equation. Because the total geomagnetic field in the insulating mantle can be reconstructed from its radial component alone, most studies, until now, have considered only the radial component of the induction equation. Then, core surface flows can be inverted from this non-linear relationship between the flow and the SV. Here, we show that the horizontal components of the diffusion-less induction equation provide a relationship between the flow and the shear. To obtain this relationship we need to consider both the poloidal and the toroidal part of the induction equation. The use of dynamo simulations, where the velocity obeys a stress-free boundary condition, allowed us to test our derivation of the shear. We successfully recover the shear from the synthetic data. Finally, we used a geomagnetic field model based on satellite data to calculate the radial shear of the flow at the top of the core.

Description: The landfall of tropical cyclones (TCs) will bring about a series of natural disasters, causing great amount of damage and loss of life and property along coastal areas. The destructiveness and socio-economic impact of TCs are not only related to the scale of maximum wind speed, but also to the outward extension of the tangential wind field, which is generally characterized by the TC outer size (often measured by the radius of gale-force winds). This study examines the changes in the outer size distribution of landfalling tropical cyclones over Chinese mainland during the period of 1977-2020. The period was divided into two epochs: 1977-1998 and 1999-2020.The results show that the size distribution of landfalling TCs over South China has no apparent change, while that of landfalling TCs over East China (LTC〈sub〉EC〈/sub〉) is more concentrated in the second epoch. Also, the difference in the median sizes of landfalling TCs between East China and South China become more significant. It is found that LTC〈sub〉EC〈/sub〉 formed over the western part of western North Pacific shifted to larger size range (300-500 km) at landfall during the second epoch, while those formed over the eastern part of western North Pacific rarely grew to extremely large size (500 km). Dynamical reasons for the changes in size between the two epochs and links to the recent climate regime shift near the end of the twentieth century have been investigated. More details will be presented at the conference.

Description: Geodetic observations can be often powerful tools for natural disaster monitoring. To proactively monitor the potential of disaster risk, spatiotemporally comprehensive observations are required. Synthetic aperture radar (SAR) is one of promising techniques for the purpose. An interferometric SAR (InSAR) method has been utilized to broadly and locally map ground surface changes. However, the standard InSAR is not always effective because it does not have sufficient measurement accuracy due to various errors. Against the background, InSAR time series analysis is an effective technique to improve the detectability by statistically processing a large number of InSAR images. We processed ALOS-2 satellite data observed over 7 years from 2014 to 2021 for InSAR time series analysis. In general, it is difficult for InSAR to distinguish spatially long-wavelength tectonic signals from long-wavelength noises which are comparable. To overcome the shortcoming, we derived a complete nationwide surface change map that has both tectonic wide-ranging deformation and locally distributed deformation, by incorporating displacements which are measured at nationwide deployed GNSS sites. Our deformation map successfully detects various types of land deformations such as inflation/deflation of volcanoes, ground subsidence, landslides, post-seismic deformation which have slowly proceeded with a few cm/mm per year. In this presentation, we will show the analysis results and the effectivity of InSAR-based nationwide land monitoring. Acknowledgments: ALOS-2 data were provided based on the joint research agreement with JAXA and under a cooperative research contract between GSI and JAXA. The ownership of ALOS-2 data belongs to JAXA.

Description: Body forces such as gravity can drive convective motion in fluids. Convection due to thermal gradients and the resulting buoyancy force is called thermal convection and occurs ubiquitously in nature, e.g. as one of the driving mechanisms of convection in the interior of stars and planets such as the Earth’s outer core and mantle, as well as in the Earth’s oceans and its atmosphere. We present results on DNS of thermal convection in an internally heated, non-rotating full sphere with different boundary conditions. The non-dimensional control parameters of this problem are the Rayleigh and Prandtl numbers, representing the strength of the thermal forcing and the ratio of the viscous and thermal diffusivities respectively. We aim to characterise fluid flow and heat transfer in a wide range of parameters, using a global Reynolds number as a measure for the vigour of the flow and the Nusselt number quantifying the strength of heat advection as primary diagnostics. DNS are run up to a Rayleigh number appr. 10^8 times the critical Rayleigh at a Prandtl number of unity, yielding scaling relations between the diagnostics and Ra up to this regime of strong turbulence. The simulations were performed using the fully spectral, efficiently parallelised MHD/fluid dynamics code QuICC.

Description: The El Niño-Southern Oscillation (ENSO) influences climate on a global scale and is a source of long-range predictability. In order to harness this predictability, accurate model representation of relevant teleconnections and the processes that generate them is required. We use a set of CMIP6 models to assess the effect of increasing model resolution on ENSO and its boreal winter teleconnections. The spatial structure, strength and asymmetry of both ENSO and its extratropical teleconnections are considered. We find evidence of an improved El Niño teleconnection to the North Pacific in high resolution models, but this improvement is dampened for La Niña. We aim to establish whether ocean or atmospheric resolution is the primary driver of resolution-based trends, and we evaluate the relevance of mean state biases on these trends.

Description: The southern hemisphere westerly winds are projected to increase in the future, altering local ocean hydrography and dynamics. While anomalies of southern hemisphere origin were shown to affect the Atlantic Meridional Overturning Circulation, many details of this connection remain unexplained. Most existing studies are limited by the application of forced ocean models that prevent an atmospheric response to the anomalies, coarse resolution ocean models not able to explicitly simulate mesoscale variability, or a short runtime of experiments. Here we apply a coupled, nested model configuration covering the entire Atlantic at an eddying resolution of 1/10°, to study the inter-hemispheric propagation of anomalies generated by a 30% increase in southern hemisphere wind stress. To obtain statistically more robust results, a 5-member ensemble experiment is conducted with a runtime of 120 years of each member. The South Atlantic response is dominated by a sustained increase of Agulhas Leakage by 3 Sv. Based on a combination of Lagrangian and Eulerian analysis, we show that the propagation of anomalies generated by an increased inflow of Indian Ocean water into the South Atlantic, is a complicated interplay of advection, mixing and local atmospheric responses and thus not simply follows the advective pathways of the leakage water. The North Atlantic overturning responds with a strengthening of 1.5 Sv after approximately 80 years. Anomalous water mass transformation associated with the increased AMOC mainly occurs at the entry into the Nordic Seas, while enhanced sinking is seen along the boundary of the subpolar gyre.

Description: Ice clouds are challenging to investigate due to the complexity and diversity of their composition (microphysics), as well as their formation and growth processes. As a result, until recently, observations provided little constraint, resulting in significant limitations in our understanding and representation of ice clouds. The lack of information on the environmental context, which is required to identify and understand the formation mechanism and evolution of clouds, is a major issue with satellite measurements; these renditions, after all, only represent a snapshot of the state of a cloud and its microphysical properties at a given time. This work tackles this issue by providing additional metrics on ice cloud history and origin along with operational satellite products. Here, we present a novel framework that combines geostationary satellite observations with Lagrangian transport and ice microphysics models, in order to obtain information on the history and origin of air parcels that contributed to their formation. The trajectory of air parcels encountered along the DARDAR-Nice track has been traced using the air mass transport models CLaMS (Chemical LAgrangian Model of the Stratosphere). CLaMS - Ice model is jointly used to simulate cirrus clouds along trajectories derived by CLaMS. This method provides information on the cloud regime as well as the ice formation pathway (in-situ vs liquid origin). For tropical cirrus of convective origin, a Time Since Convection dataset from geostationary observations can also be incorporated into this approach. Preliminary results of this approach obtained on case studies representing various cloud types will be presented here.

Description: The Central and Eastern European Infrasound Network (CEEIN) established in 2018 as the collaboration between the Zentralanstalt für Meteorologie and Geodynamik, Vienna, Austria; the Institute of Atmospheric Physics of the Czech Academy of Sciences, Prague, Czech Republic; the Research Centre for Astronomy and Earth Sciences of the Eötvös Loránd Research Network, Budapest, Hungary; the National Institute for Earth Physics, Magurele, Romania and the Main Centre of Special Monitoring National Center for Control and Testing of Space Facilities, State Agency of Ukraine. Waveform data of the CEEIN stations are archived at the NIEP EIDA node, and can be downloaded from www.ceein.eu. We show that CEEIN improves infrasound event detection capabilities in Southern and Eastern Europe, and demonstrate that adding infrasound observations to seismic data in the location algorithm improves location accuracy. We identify coherent noise sources observed at CEEIN stations. We present the bi-annual CEEIN bulletin of infrasound and seismo-acoustic events, our contribution to the European infrasound catalogue. Many of the events in the CEEIN bulletin are ground truth events that can be used in the validation of atmospheric models and infrasound raytracing algorithms.

Description: The GRACE Follow-On mission, a partnership between NASA (US) and GFZ (Germany), reached its nominal five-year mission lifetime in May 2023, and is entering its extended mission phase through the end of 2026. GRACE-FO continues the unique essential climate data record of mass change in the Earth system initiated in 2002 by the GRACE mission (2002-2017). The combined GRACE & GRACE-FO data records now span over 22 years and provide unique observations of monthly to decadal global mass changes and transport in the Earth system derived from temporal variations in the Earth’s gravity field. These observations have become indispensable for climate-related studies that enable process understanding of the evolving global water cycle, including ocean dynamics, polar ice mass changes, and near-surface and global ground water changes.In this presentation, we will review (1) some recent GRACE/GRACE-FO science and applications highlights, (2) key data processing and calibration approaches on GRACE-FO and lessons learned during the 5-year prime mission, and (3) the GRACE-FO mission plan to operate and collect high-quality science data through the intensifying solar cycle 25, aiming for continuity with a future Mass Change mission that is currently planned by NASA and DLR.

Description: Socioeconomic livelihoods in the Horn of Africa (HA) are highly dependent on seasonal rainfall, which occurs during two main seasons: October-November-December (OND) and March-April-May (MAM). During the two last decades the HA region has been affected by severe and prolonged droughts, leading to acute food insecurity, shortage of drinking water, and increasing risk of disease. Sub-seasonal drought prediction over the HA, from two weeks to two months, is therefore crucial for decision making and early warnings across several sectors. The sub-seasonal prediction of high and low precipitation extremes (PEs) by dynamical forecast systems is challenging for both rainy seasons, but there may be potential for extending the current prediction timescale based on remote drivers. To investigate the sub-seasonal predictability of PEs during the OND season we build a Long Short-Term Memory (LSTM) Neural Network predicting biweekly precipitation tercile categories over the HA region. The LSTM is trained on observational and reanalysis data during the period 1981—2020 and provides predictions with lead times of one week to one month. The results show that floods can be more skillfully predicted than droughts for all lead times. Moreover, we use explainable AI methods to explore the contribution of remote drivers to the predictions and potential sub-seasonal forecast opportunities for PEs. Preliminary results show that the sea surface temperature over the tropical Pacific is important for the LSTM prediction, but further investigation is needed to determine more factors affecting the prediction skill for PEs over the HA region.

Description: Space geodetic techniques, particularly Global Navigation Satellite Systems (GNSS), have contributed significantly to neotectonic research on continental plates over the last decades, allowing us to observe crustal motions in all three spatial directions. Meanwhile, the previous studies of German neotectonics have mainly focused on several areas associated with the European Cenozoic rift system. Thus, this study investigates the entire German territory to identify the neotectonic motion characteristics based on GNSS-integrated data and Machine Learning (ML). Parallelly, high-precise GNSS time series processing techniques are applied to reflect actual motions. Our results show that the German Earth’s crust tends to uplift, especially in the active graben regions moving with a speed of almost +1.0 mm/yr. In contrast, the local subsidence of around -0.8 mm/yr is concentrated in the large groundwater extraction regions and the river basins such as the Rhine, Ems, Elbe, Northern Oder, and Danube. In the horizontal movements, the German Earth’s crust moves with an average intra-plate velocity of ~0.8 mm/yr, while some places reach up to ~2.5 mm/yr. Furthermore, ML detects the noticeable surface deformation regions, namely Lower Rhine Bay, Upper Rhine Graben, Eifel volcano, and Thuringian-Vogtland slate mountains. Our findings have filled the overall picture of German neotectonics and provide a valuable material source for infrastructure management toward sustainable development in Germany.