bluuebunny/crossref_metadata_2025 huggingface dataset:
Earthquake nowcasting: Retrospective testing in Greece 2019 - 2021
Authors: Chouliaras Gerasimos , Skordas Efthimios S. , Sarlis Nikolaos
Published: March 2022

Earthquake nowcasting [1] (EN) is a modern method to estimate seismic risk by evaluating the progress of the earthquake cycle in fault systems [2]. EN employs natural time [3], which uniquely estimates seismic risk by means of the earthquake potential score (EPS) [1,4] and has found many useful applications both regionally and globally [1, 2, 4-10]. Among these applications, here we focus on those in Greece since 2019 [2], by using the earthquake catalogue of the Institute of Geodynamics of the National Observatory of Athens[11–13] (NOA) for the estimation of the EPS in various locations: For example, the ML(NOA)=6.0 off-shore Southern Crete earthquake on 2 May 2020, the ML(NOA)=6.7 Samos earthquake on 30 October 2020, the ML(NOA)=6.0 Tyrnavos earthquake on 3 March 2021, the ML(NOA)=5.8 Arkalohorion Crete earthquake on 27 September 2021, the ML(NOA)=6.3 Sitia Crete earthquake on 12 October 2021. The results are promising and reveal that earthquake nowcast scores provide useful information on impending seismicity.

[1] J.B. Rundle, D.L. Turcotte, A. Donnellan, L. Grant Ludwig, M. Luginbuhl, G. Gong, Earth and Space Science 3 (2016) 480–486. dx.doi.org/10.1002/2016EA000185

[2] J.B. Rundle, A. Donnellan, G. Fox, J.P. Crutchfield, Surveys in Geophysics (2021). dx.doi.org/10.1007/s10712-021-09655-3

[3] P.A. Varotsos, N.V. Sarlis, E.S. Skordas, Phys. Rev. E 66 (2002) 011902. dx.doi.org/10.1103/physreve.66.011902

[4] S. Pasari, Pure Appl. Geophys. 176 (2019) 1417–1432. dx.doi.org/10.1007/s00024-018-2037-0

[5] M. Luginbuhl, J.B. Rundle, D.L. Turcotte, Pure and Applied Geophysics 175 (2018) 661–670. dx.doi.org/10.1007/s00024-018-1778-0

[6] M. Luginbuhl, J.B. Rundle, D.L. Turcotte, Geophys. J. Int. 215 (2018) 753–759. dx.doi.org/10.1093/gji/ggy315

[7] N.V. Sarlis, E.S. Skordas, Entropy 20 (2018) 882. dx.doi.org/10.3390/e20110882

[8] S. Pasari, Y. Sharma, Seismological Research Letters 91 (6) (2020) 3358–3369. dx.doi.org/10.1785/0220200104

[9] J. Perez-Oregon, F. Angulo-Brown, N.V. Sarlis, Entropy 22 (11) (2020) 1228. dx.doi.org/10.3390/e22111228

[10] P.K. Varotsos, J. Perez-Oregon, E.S. Skordas, N.V. Sarlis, Applied Sciences 11 (21) (2021) 10093. dx.doi.org/10.3390/app112110093

[11] G. Chouliaras, Natural Hazards and Earth System Sciences 9 (3) (2009) 905–912. dx.doi.org/10.5194/ nhess-9-905-2009

[12] G. Chouliaras, N.S. Melis, G. Drakatos, K. Makropoulos, Advances in Geosciences 36 (2013) 7–9. dx.doi.org/10.5194/adgeo-36-7-2013

[13] A. Mignan, G. Chouliaras, Seismological Research Letters 85 (3) (2014) 657–667. dx.doi.org/10.1785/0220130209
Layer Tracing of the Greenland Ice Sheet Interior: A Coupled Model Approach
Authors: Rieckh Therese , Born Andreas , Robinson Alexander
Published: March 2022

We are using an ice sheet model that explicitly represents individual layers of accumulation that are fixed in time (isochronal). With progressing time, new layers are added on the top, while older layers subside and become thinner as ice flows towards the margins. This approach eliminates unwanted diffusion and faithfully represents the englacial stratification.

The isochronal model is coupled uni-directionally to a full ice sheet model (“host model”), which provides the ice physics and dynamics. Via the isochronal model’s layer tracking, the host model’s output can be evaluated throughout the interior using the radiostratigraphy data set of the Greenland ice sheet.

We investigate the stability and resolution-dependence of this coupled modeling system in simulations of the last glacial cycle with yelmo as the host model. One key question concerns how frequent updates from the host model must be to ensure a reliable simulation. This could enable offline forcing of the isochronal model with output from a range of existing ice sheet models.

The long-term goal is to make the isochronal model flexible and easily adaptable enough to effectively force it with existing full ice sheet models and to provide it to the community as a new way to assess the models’ performance. 
Modelling of the spatial and temporal patterns of dust storms emitted from the Aralkum (the former Aral Sea) in Central Asia
Authors: Banks Jamie , Heinold Bernd , Schepanski Kerstin
Published: March 2022

The formation of the ‘Aralkum’ desert in Central Asia, as a consequence of the severe desiccation of the Aral Sea since the 1960s, has created a major new source of dust aerosol in the region. Recently dried lakebeds can be efficient dust sources, due to the availability of readily erodible sediments, and as a dry lakebed with an area of over 60,000 km2 exposed to wind erosion the Aralkum has become a significant driver of dust storms in the region. However due to a paucity of ground-based remote sensing sites in Central Asia it is difficult to quantify the behaviour and consequences of dust activity in the region.

 

Using the dust transport model COSMO-MUSCAT we perform a one-year simulation of dust emission from the Aralkum and other desiccating lakes in Central Asia, exploring the resultant dust emission and transport patterns and assessing the viability of measuring such dust using remote sensing techniques. Making use of the Global Surface Water dataset (produced by the Copernicus Programme) in order to define the surface water coverage in various epochs, we make estimates of dust emissions for the Central Asian and Middle Eastern region under three scenarios: 1) the ‘Past’, representative of water coverage in the 1980s; 2) the ‘Present’, representative of water coverage in the 2010s; and 3) the ‘Aralkum’ scenario, representing only dust emissions from the present-era Aralkum.

 

In the Present scenario we estimate that the Aralkum area (here considered as 43-47°N, 58-62°E) emitted 27.1 Tg of dust over the course of a year from March 2015 to March 2016, while in the Past scenario it emitted 14.3 Tg. However ~68% of these Aralkum emissions occurred when the cloud cover was > 95%, raising questions as to the extent to which dust storm activity from the Aralkum is measurable by standard remote sensing techniques. Exploring the patterns of wind direction and dust emission, we find that of the 27.1 Tg of dust emitted by the Aralkum during the Present scenario, 14.5 Tg were driven by westerly winds, and as a result of this the longest transport pathways are simulated to be to the east. This is in contrast to several previous studies (during previous years) of Aralkum dust which have shown more typical easterly and north-easterly dust emission patterns. Analysis of ERA5 wind data over a 15-year period reveals that there is a high degree of interannual variability as to the direction of the strongest surface winds over the Aralkum, and hence the directions of emitted dust will also vary substantially from year to year.
Impact of ice shelf crevasses on Grounding line flux 
Authors: Gerli Cristina , Rosier Sebastian , Gudmundsson Hilmar
Published: March 2022

Antarctic Ice shelves are fundamentally important components of the cryosphere and key to predictions of global sea level rise. Thinning and fracturing of ice shelf systems can reduce back-stress forces exerted on grounded glaciers upstream, increasing mass flux across their grounding lines (GL). In recent years it has been suggested that a number of ice shelves around Antarctica have rapidly broken apart as a result of hydrofracturing.  Hydrofracture is the process whereby surface crevasses are filled up with meltwater and the resulting hydrostatic pressure cause outward propagation of the crevasse fracture.

Recent work assessed the impact of ice shelf thickness change and crevasse hydrofracturing on the vulnerability of ice shelves and on ice drainage. Using a deep convolutional neural network, high-resolution crevasses and fractures were mapped throughout Antarctica, revealing that 60 ± 10 % of ice shelves are vulnerable to fracturing, if inundated with water.

Here we use these crevasse maps to evaluate their impact on the flow of upstream glaciers, quantifying the change in flux at the GL. We employ a finite element ice flow model, Ua, which solves the vertically integrated shallow shelf approximation with an unstructured mesh, that allows refined resolution in complex areas, such as at the GL. In the absence of information on crevasse depth, we make the assumption that crevasses propagate through the entire thickness, meaning our results represent the maximum possible effect that these crevasses may have on ice flow. We present results for many of the most important ice shelves in East and West Antarctica.

We find that incorporating crevasses in the ice shelf always increases the mass flux of upstream glaciers across their GLs, however, there is substantial variability in flux change among ice shelves. Small increases in flux due to crevassing (7-15%) were detected for Fimbul, Shackleton, Pine Island, Larsen C, and Brunt Ice Shelves, with a more considerable increase for the Dotson & Crosson Ice shelves (38%). The increase in flux due to crevassing was extremely large for the Totten Ice Shelf (248%). The large differences in sensitivity between ice shelves may be a result of various factors, most notably the proximity of the features identified as crevasses to important pinning points. More work investigating these factors is needed in order to have a more complete understanding of the effects of crevasse hydrofracturing on inland glaciers.
Advancing the science and practice of community hydrologic modeling: Development of open-source models, methods, and datasets to enable process-based hydrologic prediction across North America (and beyond)
Authors: Clark Martyn , Arnal Louise , Bennett Andrew , Casson Dave , Gharari Shervan , Hay Janine , Freer Jim , Knoben Wouter , Liu Hongli , Mizukami Naoki , Nijssen Bart , Papalexiou Simon , Spiteri Raymond , Tang Guoqiang , Van Beusekom Ashley , Wood Andy
Published: March 2022

Many hydrologic modelling groups face similar challenges, with untapped opportunities to share code and concepts across different model development groups. An active community of practice is emerging, where the focus is not so much on developing a community hydrologic model, but more on advancing the science and practice of community hydrologic modeling. This presentation will summarize our recent efforts to develop open-source models, methods, and datasets to enable process-based hydrologic prediction across North America (and beyond). The contributions include (1) developing ensemble meteorological datasets for North America and the globe; (2) developing modular approaches to hydrologic modeling through a hierarchal approach that separates different model sub-domains (vegetation, snow, soil, groundwater) and separates the physical representations from the numerical solution; (3) implementing third-party numerical solvers (sundials) to improve the robustness and efficiency of the numerical solutions; (4) developing agile parallelization methods capable of handling heterogeneous computing loads and bottlenecks in the downstream reaches of large river networks; (5) implementing flexible model configuration toolbox to accelerate the implementation of large-domain hydrologic models; (6) advancing methods for river lake routing, including development of integrated river-lake hydrography datasets and development of large-domain reservoir management models; (7) advancing methods for large-domain parameter estimation; (8) advancing methods for ensemble data assimilation; and (9) advancing methods for probabilistic hydrologic prediction on time scales from seconds to seasons. We will discuss some of the major challenges encountered and the high-priority research that is necessary to advance capabilities in large-domain hydrologic prediction.
On the value of benchmarking a fully coupled surface-subsurface model with spatially distributed sap flow measurements
Authors: Moussa Adnan , Sulis Mauro , Klaus Julian
Published: March 2022

Integrated hydrological models (IHM) are often used for a better understanding of the hydrological fluxes at the surface and in the subsurface. IHMs can also be coupled to land surface models to study the interactions between vegetation and hydrological processes. At our study site, the Weierbach catchment (43 ha), Luxembourg, sap flux observations showed high spatial variability in observed transpiration due to many factors such as DBH, landscape characteristics and position, and tree species. However, this spatial variability is often not captured by land surface models at small scale and transpiration fluxes are usually treated as an integrated flux. In our study, we employ the coupled integrated surface-subsurface hydrological model Parflow coupled with the land surface model (CLM) to simulate water and energy fluxes in the forested Weierbach catchment in Luxembourg. Our objectives are twofold. First, we evaluate the coupled physically-based model and land surface model with discharge, groundwater level and soil moisture, and spatiotemporal sap flow data. In addition to that, we are exploring whether simulated and observed transpiration for three different hillslope positions (plateau, midslope, hillfoot) are driven by atmospheric demand or water availability in the subsurface. Our main result was that model has captured discharge, groundwater fluxes and the average transpiration well. However, the modelled transpiration showed a much smaller spatial variability compared to the spatial variability derived from sapflow observation. For the three different hillslope positions, we found that the fluxes were mainly driven by atmospheric demand and the model captured this dominance well. Our results demonstrate that there is a limitation of the model in reproducing the spatial variability of transpiration in the heterogeneous forest and future modelling work at small scale needs to better parameterize the spatial characteristics of vegetation.
Stuck in vegetation: the role of hyacinths in macroplastic debris accumulation in tropical rivers 
Authors: Schreyers Louise , Bui Thanh-Khiet , van Emmerik Tim , Biermann Lauren , van der Ploeg Martine
Published: March 2022

Water hyacinths are considered one the world’s most invasive aquatic species and are found in most tropical rivers. Hyacinths can form dense patches of several meters of length and width at the water surface and drift due to the combined action of wind and flow velocity. In rivers, hyacinth patches can function as carriers for floating macroplastic debris from rivers into the ocean. In the Saigon river, Vietnam, water hyacinths were found to accumulate a majority of the total floating macroplastic items (Schreyers et al., 2021). Despite their crucial role in macroplastic accumulation and dispersion, precise quantification of both hyacinth coverage and macroplastic concentrations in rivers are currently lacking. We present insights on the accumulation of macroplastics within hyacinth patches based on the analysis of more than 3,000 Unmanned Aerial Vehicle images collected at the Saigon river in 2021. In particular, we explore the relation between hyacinth coverage, patch abundance and floating macroplastic concentrations, and how these vary through time and space. These findings clearly illustrate the complexity of plastic transport in rivers by highlighting its spatiotemporal variability. Our insights can be used for combined clean-up efforts and reduction strategies of both hyacinths and plastic debris in the Saigon river, and support the development of future plastic monitoring strategies in other tropical river systems.   

References

Schreyers, L., van Emmerik, T., Luan Nguyen, T., Castrop, E., Phung, N.-A., Kieu-Le, T.-C., Strady, E., Biermann, L., van der Ploeg, M. (2021). Plastic plants: Water hyacinths as driver of plastic transport in tropical rivers. Frontiers in Environmental Science 10.3389/fenvs.2021.686334  

 
Landslide Susceptibility & Risk Mapping for the Northwest Himalayan State of Uttarakhand
Authors: Sengupta Arnab , Nath Sankar Kumar
Published: March 2022

Landslide is the most significant natural hazard that causes socio-economic devastation in mountainous terrains around the world. In India, lands of mountains especially the Himalayas are vulnerable to landslide due to the high intensity of seismic shaking, prolonged rainfall and complex lithological setting. In the present study, Landslide Susceptibility Zonation (LSZ) has been carried out using Random Forest technique on Geographical Information System by combining different landslide causative factors i.e. slope angle, slope aspect, drainage density, distance to drainage, elevation, shape of slope, distance to lineament, lineament density, surface geology, soil, geomorphology, landform, rainfall, epicenter proximity, Normalize Differences Vegetation Index, Landuse/Landcover, road density and distance to road are integrated to model Landslide Susceptibility Index, thus classifying the terrain in terms of  ‘None’, ‘Low’, ‘Moderate’, ‘High’, ‘Very High’ and ‘Severe’. It is observed that around 45% of the terrain falls under the ‘High’ to ‘Severe’ landslide susceptibility zones. Receiver Operating Characteristics (ROC) places an 85% confidence level that predicts a strong correlation between LSZ and landslide inventory dataset of the region. Thus, this study suggests that a comprehensive approach for slope failure mapping can be used to develop appropriate mitigational strategies for landslide disaster management in the socio-economic context.

Keywords: Landslide Susceptibility Zonation; Northwest Himalaya.
Sensitivity of SSP585 sea-level projections to ocean model resolution in the MPI-ESM climate model
Authors: Wickramage Chathurika , Köhl Armin , Stammer Detlef , Jungclauss Johann
Published: March 2022

The existence of reliable coastal sea-level projections is essential for identifying necessary adaptation and mitigation strategies of policymakers and coastal communities over the following decades. However, today only a few ocean components of climate projections can resolve the small-scale processes that affect the Dynamic Sea Level (DSL) change in the open ocean and in coastal areas, predominantly in the eddy rich regions such as Antarctic Circumpolar Current (ACC) and the western boundary currents. Therefore, we investigate the dependence of regional sea-level projections on ocean model resolution using the recent Max Planck Institute Earth System Model (MPI-ESM) for the shared socioeconomic pathway 585 (SSP585, fossil-fuel development). By comparing the climate change scenario from 2080 to 2099 to a historical simulation from 1995 to 2014, our results indicate that the models, from eddy-rich (ER), eddy-permitting (HR) to coarser resolution (LR), successfully produce the previously identified global DSL patterns. However, the magnitude of the DSL increase in the North Atlantic subpolar gyre and the decrease in the subtropical gyre is significantly larger in the ER ocean in contrast to HR and LR; the same holds for the magnitude of the opposite dipole pattern in the North Pacific. In the southern ocean, the DSL increases north of ACC but decreases further to the south, projecting much smaller changes in the ER. We note that the meridional shift of ACC, associated with sea-level change, is smaller in ER than in HR and LR, indicating an accelerated ACC compared to HR simulation, which shows no acceleration at the end of the 21st century.
Are hydrometeorological thresholds useful for regional-scale rockfall early warning systems? A preliminary analysis of the hydrometeorological conditions leading to rockfalls in Norway
Authors: Palau Rosa M , Gilbert Graham L , Solheim Anders , Capobianco Vittoria , Gisnås Kjersti
Published: March 2022

Norway's high-relief landscape is susceptible to gravity-driven natural hazards including snow avalanches, landslides, debris flows, and rockfalls. Rockfalls are the most numerous geohazard in Norway. There are currently over 35 000 rockfall events registered in Norway's national hazard database, accounting for nearly 50% of the total number of events for all hazard types. Rockfalls commonly impact the functioning of infrastructure assets such as roads and railways, and occasionally damage buildings and result in death.

The relationship between rockfall events and weather conditions is recognised but not straightforward. Several hydrometeorological variables are significant for rockfall triggering including precipitation, snow melt, freezing and thawing, temperature, insolation, and soil or rock moisture. The highest frequency of rockfall activity in Norway is observed in spring, a period of snowmelt and freeze-thaw cycling. Given the links to meteorological variables, rockfall frequency is expected to change with climate, altering the exposure of population and infrastructures to rockfalls.

Rockfall risk mitigation at regional scale is challenging. Early warning systems are a helpful tool to depict the time and location of future rockfall events so that emergency managers can act in advance. At present, most existing rockfall early warning systems (REWS) are based on the monitoring and analysis of seismic signals to determine the movement of boulders or the cracking of joints. Little previous research has been conducted to analyse the meteorological conditions that could trigger rockfalls. There is currently no REWS in Norway.

The main objective of this work is to investigate the feasibility of using hydrometeorological thresholds for regional scale rockfall warning. To do so rainfall, temperature, and soil moisture data from SeNorge.no, and the rockfall inventory contained in the Norwegian national hazard database have been analysed to find relations between the hydrometeorological conditions and the triggering of rockfalls in Norway.
Efficiency of BMPs for the reduction of sediment loads in the control of nutrients.
Authors: Ricci Giovanni Francesco , D'Ambrosio Ersilia , De Girolamo Anna Maria , Gentile Francesco
Published: March 2022

Inappropriate tillages and the intensive use of mineral fertilizers are fundamental driver of soil erosion and land diffuse pollution. The new European environmental policies, such as the European Green Deal (EUGD) and the Farm to fork strategy aims to restore the natural functions of ground and surface soil by 2030. Best Management Practices (BMPs) are mitigation measures which will be included in EU Member States management programs to achieve the policies goals. Most of BMPs have as their first function to reduce soil erosion, however these can have effect also on the nutrient loads. This work assessed the power of soil erosion oriented BMPs in achieving nutrient load reduction by means of the Soil and Water Assessment Tool (SWAT) in the Carapelle basin (Apulia, Italy). Moreover, their economic convenience was evaluated for both the public and the private sector. Five alternative scenarios were implemented: Contour farming (CF), no tillage (NT), reforestation (RF), and two additional scenarios, including the 20% reduction of fertilizers in CF and NT, (CFR) and (NTR), following the EUGD strategy. With the current management of the areas total nitrogen (TN) was ~49 kg ha-1y-1, while total phosphorous (TP) was ~0.044 kg ha-1y-1. N-NO3 load increased for NT and CT in terms of surface runoff and leaching. Contrariwise RF, as well as CFR and NTR scenarios showed a reduction of N-NO3 losses. In particular CFR and NTR abated of ~20% surface runoff and leached N-NO3 load. Economically, RF was profitable in sloped areas while CFR and NTR were the best alternative in those hilly and flat. This suggested that RF may be implemented in combination with other practices to have a greater impact at the basin scale. BMP implementation requires significant investments (public and private). The results of this study provide the scientific basis for decision-making for agriculture and watershed management.
Reconstructing Pliocene environmental changes in the East Mediterranean: results from a new multi-proxy study on a lake sedimentary record from the central Jordan Valley
Authors: Greenlee John , Dean Silas , Hall Christine , Castañeda Isla , Waldmann Nicolas
Published: March 2022

The Pliocene (5.33-2.68 Ma) was the last significant warm period in Earth's climate history. Atmospheric carbon dioxide and global temperatures during this interval are comparable to those estimated for our planet’s future climate trajectory. Considering a comparable to present continental and oceanic positioning, it is possible to assume similar oceanic and atmospheric circulation patterns, and hence reliable Pliocene climate archives may serve as a strong analogue for future climate conditions of the planet. Current data on the Pliocene mostly focus on marine sediments with terrestrial data stemming from loess and paleosol records. Yet, there is a lack of information from continental lacustrine formations, especially from the East Mediterranean. The ‘Erk-el-Ahmar Formation (3.15-4.5 Ma) lies in the central Jordan Valley and includes a ~150 m succession of fluvio-lacustrine deposits (clay, silt, very find sand, and carbonate layers), with excellent preservation of freshwater mollusk shells, ostracods, micromammal bone fragments, and mammoth remains. This study will reconstruct the paleoenvironmental conditions of the region during this time interval using a multiproxy approach that includes physical parameters (grain size distribution, magnetic susceptibility), geochemical compositional data (X-ray fluorescence and total organic carbon/inorganic carbon), with preliminary results of ostracod and biomarker data from two push-cores (40 m) and the formation’s outcrop.

Our results show major fluctuations in the lake hypsometry, as evidenced by the different parameters, which might reflect the local hydro-climate conditions. An orbital-scale dry-wet climate cyclicity is well identified in the sedimentary record, which influenced the lake depth, redox conditions, sedimentary provenance, and the habitat for faunal species. The cores capture transitions between continuous shallow and deep lacustrine environments, with potential short intermittent events (perhaps seismic or climate-induced), indicating the sustainability of this perennial water body. Results from this study provide an important understanding of the hydrological conditions that may have dominated the region during a warm climate phase, challenging previous estimations.
On the feasibility of Paleomagnetic Euler Pole Analysis
Authors: Gallo Leandro C. , Domeier Mathew , Sapienza Facundo
Published: March 2022

Owing to the inherent axial symmetry of the Earth’s magnetic field, paleomagnetic data only directly record the latitudinal and azimuthal positions of crustal blocks in the past, and paleolongitude cannot be constrained. An ability to overcome this obstacle is thus of fundamental importance to paleogeographic reconstruction. Paleomagnetic Euler pole (PEP) analysis presents a unique means to recover such information, but prior implementations of the PEP method have incorporated subjective decisions into its execution, undercutting its fidelity and rigor. Here we introduce an optimization approach to PEP analysis that addresses some of these deficiencies---namely the objective identification of change-points and small-circle arcs that together approximate an apparent polar wander path. Equipped with a new analytical approach to PEP analysis we turn to consider its feasibility in terms of its potential in the context of the theoretical and practical limitations of paleomagnetic data. In this presentation, we will share some key insights that emerged through experimentation with randomly-drawn plate kinematic models.
The construction of the eLTER Pan-European research infrastructure to support multidisciplinary environmental data integration and analysis
Authors: Watkins John , Peterseil Johannes , Oggioni Alessandro , Minic Vladan
Published: March 2022

One of the major goals of the upcoming European integrated Long-Term Ecosystem  critical zone and socio-ecological Research Infrastructure (eLTER RI) is to provide reliable and quality-controlled long-term environmental data from various disciplines for scientific analysis as well as the assessment of environmental policy impacts. For this purpose, eLTER has been designing and piloting a federated data infrastructure for integration and dissemination of a broad range of in situ observations and related data.
Implementing such a pan-European environmental data infrastructure is a lengthy and complex process driven by user needs, shareholder requirements and general service and technology best practises. The European LTER community has laid the foundations of this eLTER Information System. For further improvements, user needs have recently been collected by (a) targeted interviews with selected stakeholders to identify requirements, (b) workshops mapping requirements to potential RI services, and (c) analysis work for designing the RI service portfolio for. The requirements collections are used to derive functional (i.e. the behaviour of essential features of the system) and non-functional (i.e. the general characteristics of the system) requirements for the IT infrastructure and services. These collected requirements revolve around the development of workflows for the ingestion, curation and publication of data objects including the creation, harvesting, discovery and visualisation of metadata as well as providing means to support the analysis of these datasets and communicating study results.
Considering that downstream analyses of data from both eLTER and other RIs are a key part of the RI´s scope the design includes virtual collaborative environments where different data and analyses can be brought together and results shared with FAIR principles as the default for research practice. The eLTER RI will take advantage of data stored in existing partner data systems, harmonised by a central discovery portal and federated data access components providing a common information management infrastructure for bridging across environmental RIs.
This presentation will provide an overview of the current stage of the eLTER RI developments as well as its major components, provide an outlook for future developments and discuss the technical and scientific challenges of building the eLTER RI for interdisciplinary data sharing.
Perspectives on the thermosphere response to extreme magnetic storms: Current status of neutral mass density modeling
Authors: Oliveira Denny , Zesta Eftyhia , Mehta Piyush , Licata Richard , Pilinski Marcin , Tobiska W. Kent , Hayakawa Hisashi
Published: March 2022

Orbits of human assets such as satellites, crewed spacecraft and stations in low-Earth orbit (LEO) are very sensitive to the highly dynamic environment in which they fly. Atmospheric drag caused by the interaction between the orbiting object and the local thermospheric neutral mass density affects the satellite’s lifetime and orbital tracking, which becomes increasingly inaccurate or uncertain with storm intensity. Given the planned increase of government and private satellite presence in LEO, the need for accurate density predictions for collision avoidance and lifetime optimization, particularly during extreme events, has become an urgent matter and requires comprehensive international collaboration. Additionally, long-term solar activity models and historical data suggest that the solar activity will significantly increase in the following years and decades. In this presentation, we briefly summarize the main achievements in the research of thermospheric density response to magnetic storms occurring particularly after the launching of many satellites with state-of-the-art accelerometers for density determination (CHAMP, GRACE, GOCE, Swarm). We argue that specification models (e.g., HASDM) perform reasonably well during storm main and recovery phases of extreme storms, but forecasting models (e.g., JB2008) do not perform well throughout the storm cycle. We will discuss how forecasting models can be improved by looking into two directions: first, to the past, by adapting historical extreme storm datasets for density predictions, and second, to the future, by facilitating the assimilation of large-scale data sets that will be collected in future events. We invite the community to the discussion on the possible use of several hundreds of satellites with lower resolution density measurements along with data assimilation schemes or the use of ~100 high precision tracked satellites as a more effective approach for future density determinations.
Constraining wet quartz rheology from constant-load experiments
Authors: Ghosh Subhajit , Stünitz Holger , Raimbourg Hugues , Précigout Jacques
Published: March 2022

Quartz rheology in the presence of H2O is crucial for modelling (numerical and geophysical) the deformation behavior of the continental crust and gives important insights into crustal strength. Experimental studies in the past have determined stress exponent (n) values for flow law between ≤ 2 to 4, while the values for activation energy (Q) vary from ~120 to 242 kJ/mol. Here, we investigated the quartz rheology under high-pressure and high-temperature conditions, using a new generation hydraulically-driven Griggs-type apparatus. In order to develop a robust flow law for quartzite, we performed constant-load coaxial deformation experiments of natural coarse-grained (~ 200 μm) high purity (> 99 % SiO2) quartzite from the Tana quarry (Norway). Our creep tests were carried out at 750 to 900 °C on the as-is (no added H2O) and 0.1 wt.% of H2O added samples under 1 GPa of confining pressure. In contrast to earlier strain rate stepping experiments, the constant-load procedure needs lower strain at each step (≤1−2%) to achieve steady-state conditions. As a consequence, there is a very low amount of recrystallization. Importantly, we can determine the Q-value independently of the stress exponent (n). Microstructures from the deformed samples were characterized using polarized light microscopy (LM), SEM-cathodoluminescence (CL), and Electron backscatter diffraction (EBSD).

Our creep results for both the as-is and 0.1 wt.% H2O-added samples yield Q = 110 kJ/mol and n = 2. Our microstructural analysis suggests that the bulk sample strain is accommodated by grain-scale crystal-plasticity, i.e., dislocation glide (dominantly in prism

Our new flow law predicts strain rates that are in much better agreement with the inferred natural values than the earlier flow laws. It further suggests that the strength of the continental crust considering quartz rheology is significantly lower than previously predicted.  
Characteristic of Source and Seismic Hazard Analysis of Majene Earthquake Mw 6.2, January 15, 2021
Authors: Prasetyo Retno Agung , Rohadi Supriyanto , Yuliatmoko Rahmat Setyo , Rahman Aditya , Perdana Yusuf Hadi , Riama Nelly Florida , Adi Suko Prayitno , Karnawati Dwikorita , Prayitno Bambang Setiyo
Published: March 2022

A major earthquakes struck the Majene Regency, in West Sulawesi province, Indonesia, on 15 January 2021 at 02.28 local time, the hypocenter is 2.97°S, 118.99°E, depth 38.0 km, with moment magnitude Mw 6.2 with an epicenter located about 6 km Northeast Majene, West Sulawesi. This large event causing extensive damage, great economic loss and casualties in the Majene city and surrounding region. The mainshock preceded by significant foreshock on 14 January 2021 at 14.35 local time, 3°S, 118.94°E, depth 10.0 km Mw 5.9, epicenter was located at about 4 km Northwest of Majene. The faulting orientation of the mainshock, and foreshock was strike = 330°, dip = 17°, and slip = 59°, and strike = 353°, dip = 29°, and slip = 61°, respectively, is possibly related to Mamuju-Majene thrust fault. Focal mechanism solutions for the earthquakes indicate rupture occurred thrust fault with low dip angle. The mainshock was followed by low aftershocks productivity may due to homogeneous faulting systems and relatively uniform stress state in that region. We use hypocenter relocation, stress drop, coulomb stress and seismic hazard (PSHA) to investigate the earthquake characteristics and seismic hazard analysis. The distribution of hypocenter relocations indicate aftershock ruptured northern extension of the mainshock. This result supports that the highest of acceleration is the north component of the three component recorded acceleration, this detect the components of directivity toward the north for the foreshock distribution.
Sediment Transport Modeling to Forecast Coastline Changes due to New Port of Fiumicino (Central Latium Coast, Italy)
Authors: Madonia Nicola , Bonamano Simone , Piazzolla Daniele , Scanu Sergio , Marcelli Marco
Published: March 2022

Anthropic impacts mainly affect the coastal areas by the building of ports and the changing of courses of rivers. These activities can potentially interact with the natural coastal dynamics which are ruled by complex climatic, hydrodynamic and sedimentary processes.

Preliminary studies on the environmental impacts are increasingly necessary because the potential disturbances could affect natural coastal system at different spatial and temporal scales. Hydrodynamics and sediment transport models use specific equations to be basing on depict actual phenomena and expect future scenarios.

The present study aims to predict the environmental impact of the building of the new port of Fiumicino (central Latium coast, Italy), in a stretch of coast extended from Capo Linaro to Capo Anzio interested by Tiber River dynamic. Using numerical models, we have been able to give a prediction of the coastline evolution before and after the port construction, with particular attention to the sediment dynamic in the coastal areas affected by high ecological values such as nurseries, seagrass meadows and coastal dunes.

The coastal morphology changes have been investigated using the LITPACK (Littoral Transport and Coastline Kinetics) module of the software MIKE0 developed by the Danish Hydraulic Institute (DHI), a one-dimensional model which describes the dynamic processes that determine the shoreline evolution. The model has been fed with morphology and granulometric data collected along the study area in the 1990, as well as the wave parameters achieved by the WAM model included in COPERNICUS catalogues. LITPACK model has been validated using short- and long-term simulations, comparing the results of the historical analysis of the coastline in the period 1990-2021.

Finally, future scenarios have been carried out to investigate the contribution of the effects of the new port building on the morphological coastline variation.
Analysis of Magnetohydrodynamic Perturbations in the Radial-field Solar Wind from Parker Solar Probe Observations 
Authors: Zhao Siqi , Yan Huirong , Liu Terry , Liu Mingzhe , Shi Mijie
Published: March 2022

We report analysis of sub-Alfvénic magnetohydrodynamic (MHD) perturbations in the low-ß radial-field solar wind employing the Parker Solar Probe spacecraft data from 31 October to 12 November 2018. We calculate wave vectors using the singular value decomposition method and separate MHD perturbations into three eigenmodes (Alfvén, fast, and slow modes) to explore the properties of sub-Alfvénic perturbations and the role of compressible perturbations in solar wind heating. The MHD perturbations show a high degree of Alfvénicity in the radial-field solar wind, with the energy fraction of Alfvén modes dominating (~45%-83%) over those of fast modes (~16%-43%) and slow modes (~1%-19%). We present a detailed analysis of a representative event on 10 November 2018. Observations show that fast modes dominate magnetic compressibility, whereas slow modes dominate density compressibility. The energy damping rate of compressible modes is comparable to the heating rate, suggesting the collisionless damping of compressible modes could be significant for solar wind heating. These results are valuable for further studies of the imbalanced turbulence near the Sun and possible heating effects of compressible modes at MHD scales in low-ß plasma.
Large-scale spatio-temporal variability of the Congo Basin surface hydrologic components from space
Authors: Kitambo Benjamin , Papa Fabrice , Paris Adrien , Tshimanga Raphael , Calmant Stéphane , Frappart Frédéric
Published: March 2022

Despite being the second-largest watershed and tropical forest worldwide, with significant impacts on the global water cycle and in regulating Earth’s climate, the Congo River Basin’s (CRB) hydroclimatology remains among the least studied worldwide due to the lack of situ observations. To better characterize CRB surface hydrology and the variability of its different components at large scale, we jointly used a trove of large records of in situ and satellite-derived observations, specifically, Surface Water Level (SWL) from radar altimetry (a total of ~2,300 virtual stations) and Surface Water Extent (SWE) from the Global Inundation Extent from Multi-Satellite (GIEMS) dataset. A good performance is found between SWL from multi- satellite missions and in situ water height of historical and contemporary observations at different locations. The root mean square error varies from 10 cm for Sentinel-3A to 75 cm for European Remote Sensing-2.  SWL annual amplitude exhibits large spatial variability across the basin, with Northern sub-basins varying more than 5 m while the central and the southern sub-basins vary in smaller proportions (1.5 to 4.5 m). The assessment of SWE also agreed relatively well over a ~25-year period with in situ discharge from sub-basin to basin scale. At the basin scale, SWE shows that cuvette centrale is flooded at its maximum in October/November. The northern part of the basin reaches its maximum in September/October, and the southern eastern one in January/February. Furthermore, SWL and SWE help capture the water travel time across the basin that varies from 0 to 3 months and the regional relative contribution to the flow at Brazzaville station characterized by a bimodal hydrological regime. Northern sub-basins and the cuvette centrale contribute much to the large peak in December-January while the southern sub-basins contribute to both peaks. We further combine these two datasets to estimate the variability of Surface Water Storage (SWS) in rivers, lakes, floodplains, and wetlands across the entire basin over the period 1992–2015. The CRB SWS shows an annual amplitude varying between ~74 km3 and ~112 km3. Moreover, the combination of SWS and the annual variations of GRACE/GRACE-FO-derived terrestrial water storage permits us to estimate the long-term variation of sub-surface water storage. The use of these new long-term satellite-derived observations are an invaluable source of information for hydrological modeling and will allow to properly characterize and reproduce the hydro-climate variability of the CRB, and a better representation of local and regional hydrological processes. These results ensure therefore an improved monitoring of CRB hydrological variables from space, and open new perspectives towards a better evaluation of the impact of climate variability on water availability in the region.
Lessons learned from a combined precipitation and shrub invasion manipulation experiment in a Mediterranean cork oak ecosystem
Authors: Haberstroh Simon , Werner Christiane , Lobo-do-Vale Raquel , Caldeira Maria C.
Published: March 2022

The impact of various environmental stressors, such as plant invasion and extreme drought is increasing in many ecosystems around the globe. Mediterranean ecosystems have especially been affected by both stressors in recent decades. Thus, we conducted a precipitation and shrub invasion manipulation experiment in a Mediterranean cork oak (Quercus suber L.) ecosystem in Portugal. The impact of both stressors (i.e. drought and invasion) as well as their interaction  on cork oak functioning was investigated, resulting  in four experimental treatments: 1) control trees, 2) trees with a rain exclusion of 45%, 3) trees invaded by the shrub Cistus ladanifer and 4) trees invaded by C. ladanifer combined with rain exclusion. Each of the four treatments was replicated in three spatially separated blocks. In total 36 trees (9 per treatment) and 18 shrubs (9 per treatment) were selected randomly for measurements between October 2017 and March 2020.

Invaded trees, independent of the rain exclusion, had lower leaf area index (LAI) and growth rates (trunk increment). Further changes in the relationship of pre-dawn and midday leaf water potential elucidated that competition by shrubs shifted the hydraulic behaviour of invaded trees to a more anisohydric strategy compared to non-invaded cork oaks during summer drought. These negative impacts of shrub invasion had also an effect on transpiration rates of trees, but the extent was dependent on annual precipitation. In the wet year 2018, transpiration rates of trees in all four treatments were similar due to replenished soil water resources. However, in 2019, when precipitation was strongly reduced (ambient: –25%, rain exclusion: –50%), trees under invasion and rain exclusion reduced their transpiration by 47% compared to control trees, which was stronger than the reduction caused by a single stressor (amplifying interaction). However, shrubs under the rain exclusion also suffered from the extreme drought and were not able to recover in the following autumn/winter period, releasing trees from a strong competition (buffering interaction). On the other hand, shrubs under ambient precipitation were highly competitive in the same recovery period and strongly delayed tree transpiration recovery (–51% compared to control). Consequently, extreme drought and shrub invasion interacted buffering in this recovery period after the extreme drought event. In conclusion, the lessons learned from this manipulation experiment are 1) that shrub invasion has a negative impact on the functioning of cork oak trees and 2) the magnitude of this negative impact is dependent on the predominant environmental conditions (i.e. precipitation amount), which can lead to amplifying, neutral or buffering effects of drought and invasion.