bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of three rainfall interception models with variable canopy cover fraction (c) and canopy storage capacity (S), from satellite-based leaf area index (LAI) data.
Authors: Eliades Marinos , Bruggeman Adriana , Djuma Hakan
Published: March 2022

The most common rainfall interception models (Rutter, Gash and Liu) require the knowledge of two canopy-related parameters, the canopy storage capacity (S) and the canopy cover fraction (c). Even though canopy cover changes over time, these parameters are treated as constants in most rainfall interception studies. The aim of this study is to evaluate the performance of these three interception models with the use of time-variable S and c with meteorological and throughfall data from a semi-arid Pinus brutia forest (Cyprus). Leaf area index (LAI) were acquired from the Copernicus global land service (https://land.copernicus.eu/global/products/lai). These data were interpolated with a cubic spline function to obtain a daily time series. Daily S and c values were expressed as one-parameter linear (S) and exponential (c) functions of the daily LAI values The model results with the variable S and c were compared with the model calibration and validation results obtained with constant S and c values. The interception losses computed with the three models ranged between 18 and 20% of the total rainfall. 
All three models showed high performance for both calibration and validation periods with Kling–Gupta Efficiency (KGE) above 0.90. However, the constant S and c models show equifinality, meaning that a range of combinations of the input parameters S and c will result in the same interception loss. The Gash model with the variable S and c resulted in higher KGE (0.968) and lower percent bias (0.8%) than the Gash model with constant S and c (0.956 KGE and 1.5% percent bias), during the calibration period. Rutter and Liu models with the variable S and c resulted in lower bias (-6 mm and -11 mm) than the models with constant S and c (17 mm and 27 mm). The models were all capable of capturing the inherently variable interception process. However, ground-based LAI data are needed to validate the satellite-based data. 
This research has received funding from the European Union's Horizon 2020 Research and Innovation programme, under Grant Agreement 641739 (BINGO Project) and from the Research and Innovation Foundation of Cyprus, through the Water Joint Programming Initiative (FLUXMED project).
Evaluation of varying spatial resolution in power system modelling
Authors: Roithner Maximilian , Zeyringer Marianne , Price James
Published: March 2022

Power system models are frequently used in academia and by policymakers to study different designs of country or continent-wide electricity systems. To have them remain computationally feasible, simplifications are made in many areas. When assessing the variability of renewable generation sources, weather data is an important input to such models. Yet, the spatial resolution of weather data (e.g., from reanalysis or satellites) is often more detailed than the resolution of the models using them. Hence, it is common to use averages or other aggregation techniques to use the weather data in the power system model.  

Using our power system model highRES, we compare the performance of an aggregated version (NUTS1 and 3- level) to an unaggregated grid cell level one based on ERA5 reanalysis data (30 km), to assess the benefits and drawbacks of this simplification: In the former, the aggregation is performed on the inputs already before handing them to the model (an hourly zonal average capacity factor for each technology is computed from all cells in that region before running the model), while the latter is allowed to pick and choose the grid cells that are to be used to deploy variable renewable generators in each region. The resulting grid cell model makes use of the high spatially resolved weather data. Using this framework, we seek to understand how varying spatial resolution impacts the cost and design of the power systems it produces, with different shares of renewable generation technology penetration.
Impact of the geological setting of the overburden on long-time series recorded at underground geophysical observatories: case study from the FSU Jena Geodynamic Observatory Moxa (Thuringia, central Germany
Authors: Kukowski Nina , Kasburg Valentin , Goepel Andreas , Schwarze Cornelius , Jahr Thomas , Stolz Ronny
Published: March 2022

To achieve very low ambient noise and thus very good conditions for long-term geophysical observations at a high level of instrumental accuracy in order to decipher also faint signals from Earth and environmental processes, sensors often are installed in the subsurface in galleries or in boreholes. This however, makes it necessary to consider the potential influence of the geological setting and properties of the surrounding rock formations and overburden.
Moxa Geodynamic observatory, located in a remote part of the Thuringian slate mountains, approximately 30 km south of Jena, provides an ideal setting to address this topic as it comprises two galleries, which are running perpendicular to each other. As the observatory is built at the toe of a relatively steep slope, coverage of the galleries varies along them. Further, the tectonic structure and hydrological settings of the overburden is rather complex.
Instruments sensitive to deformation, which include three laser strain meters measuring nano-strain, borehole tiltmeters and a superconducting gravimeter CD-034, together with other instruments, e.g. a node for the Global Network of Optical Magnetometers for Exotic physics (GNOME), are installed in various positions in the building of the observatory, close to the building, and in the galleries. The laser strainmeters record along three galleries in north-south, east-west and NW-SE directions. Further, information on fluid flow is gained from downhole temperature measurements employing an optical fiber and several groundwater level indicators, some of them installed in shallow boreholes. Additionally, information on environmental parameters is coming from a climate station and on the subsurface tectonic structure from various near surface geophysical data sets. 
Here, we present first results of an ongoing project which combines actual deformation recordings, structural and drillhole information to decipher how the tectonic structure of the and groundwater movement within the overlying slope on top of the observatory’s galleries may impact on the various instrumental recordings.
Physics-informed LSTM structure for recession flow prediction    
Authors: Istalkar Prashant , Kadu Akshay , Biswal Basudev
Published: March 2022

Modeling the rainfall-runoff process has been a key challenge for hydrologists. Multiple modeling frameworks have been introduced with time to understand and predict the runoff generation process, including physics-based models, conceptual models, and data-driven models. In recent years the use of deep learning models like Long Short-Term Memory (LSTM) has increased in hydrology because of its ability to learn information in the sequence of input. Studies report LSTM outperforms the well-established hydrological models (e.g. SAC-SMA), which led authors to question the need for process understanding in the machine learning era. In the current study, we claim that process understanding helps to reduce LSTM model complexity and ultimately improves recession flow prediction. Here, we used past streamflow information as input to LSTM and predicted ten days of recession flow. To reduce LSTM complexity, we used insights from a conceptual hydrological model that accounts for storage-discharge dynamics. Overall, our study re-emphasizes the need to understand hydrological processes.
The Face-Centered Finite Volume method for Geodynamic Modelling
Authors: Duretz Thibault , Räss Ludovic , Sevilla Rubén
Published: March 2022

The Face-Centered Finite Volume (FCFV) is a newly developed discretisation technique that has been applied to a variety of engineering problems. This approach is based on the hybridisable discontinuous Galerkin formulation with constant degree approximations. The FCFV is particularly attractive approach since it meets numerous essential criteria for successful geodynamic modelling. It offers full geometric flexibility, natural free surface boundary condition, second order accuracy velocity-field solutions, no oscillatory pressure modes, relatively low computational cost and adequate treatment of jump conditions at material interfaces. Here we present the implementation of Poisson and Stokes solvers in the Julia computing language. Here we present the implementation of Poisson and Stokes solvers using the performant Julia language. We discuss several solving strategies including direct-iterative and iterative pseudo-transient approaches, the latter executing efficiently on Graphical Processing Units. We extend the original FCFV Stokes formulation to account for discontinuous viscosity case and discuss the implementation of complex visco-elasto-plastic rheologies.
Cytotoxic and genotoxic effects of macro- and nano-form of heavy metals in Pisum sativum L. grown in soil
Authors: Chernikova Natalia , Kumari Arpna , Chokheli Vasiliy , Rajput Vishnu , Mandzhieva Saglara , Shuvaeva Viktoria , Tsitsuashvili Viktoria , Barakhov Anatoly , Nevidomskaya Dina , Kirichkov Michael , Timoshenko Alena
Published: March 2022

Improper dumps are one of the most common indicators of accumulated harm and are a source of a wide range of pollutants entering the environment. The waste of packaging materials, household chemicals, agrochemicals, used industrial catalysts, ash from thermal waste disposal, and other contaminants have been identified as sources of their introduction into soils from dumps. The accelerated applications of nano-forms of metals are one of the emerging concerns. Like other contaminants, the soil is the main sink for nanoparticles (NPs). Undoubtedly, in the last decade, metal NPs have been recognized for their numerous roles in research and development but due to their increasing amount in the environment, these emerging issues cannot be ignored. Therefore, with this background, the current work was proposed, in which, Pisum sativum L. was exposed to nano-disperse (30-50 nm) and macro-disperse (3-5 μm) forms of metal oxide viz., Cu, Zn, Cr, Mn, Cd, Ti, Ni, and Pb at the doses of 3, 30, and 90 background contamination (in mg/kg). After 3-4 days of exposure, the emerged roots were harvested, cleaned with distilled water, and fixed in Clark’s fluid (aceto-alcohol) for further analyses. For microscopic observations, slides were prepared using the squash technique. In this work, the mitotic index and frequency of chromosomal aberrations were recorded to depict the extent of cytotoxic and genotoxic effects, respectively. The experimental outcomes revealed that the maximal genotoxicity was found in all soil samples at the level of 90 background contamination, regardless of the macro- or nano-state of the metals. Besides, the commonly observed chromosomal aberrations were bridges and fragments. Also, cell ruptures at the metaphase stage, forming a metaphase plate was found but rarely. Thus, the current observation depicted the cytotoxicity and genotoxicity of different nano- and macro-disperse forms of metals, however further studies are needed to explore the responsible mechanisms for these toxicological vulnerabilities.  

This study was supported by Russian Science Foundation project no. 21-77-20089.
Source parameters of the 2021 Hovsgol earthquake (Mw 6.7) in Mongolia estimated by using Sentinel-1 and ALOS-2 DInSAR
Authors: Kim Taewook , Han Hyangsun
Published: March 2022

Understanding the mechanism of fault rupture is important to minimize earthquake damage and to estimate the impacts of future earthquakes. In this study, we observed surface displacements caused by the Hovsgol earthquake (Mw 6.7) in January 2021 using three Differential Interferometric SAR (DInSAR) pairs of Sentinel-1B at descending node and ALOS-2 at ascending and descending nodes, and then estimated the source parameters of the earthquake by the inversion of the observed displacement fields. The maximum surface displacement in the radar look direction was 21 cm at the Sentinel-1 descending node, and 32 cm and 26 cm at the ALOS-2 ascending and descending node, respectively. All differential interferograms showed three fringe patterns near the epicenter, which suggests that there were three rupture planes with different slips. We performed the inversion modeling of the DInSAR-observed surface displacements assuming three rupture planes with different slip magnitudes and directions. The values of normalized root mean square error (NRMSE) between the modelled and observed displacements were smaller than 4% for all DInSAR observations. The spatial distribution of modelled displacements was matched to the observed one. The source parameters of fault estimated by the inversion were closely consistent with the measurements by United States Geological Survey and Global Centroid Moment Tensor. The inversion results demonstrated that the assumption of our inversion modeling (three rupture planes) is reasonable.
Towards the resilience of Attica Region’s Provincial Road 3 in Greece, due to slope failure by applying civil engineering techniques and Rock Engineering System assessment
Authors: Tavoularis Dr. Nikolaos
Published: March 2022

Slope failures represent a major threat to human life and infrastructure in many countries all over the world and they often lead to significant and long-lasting disruptions of economic, social and ecological systems. This paper aims to describe civil engineering approaches to apply resilience assessment framework as well as a methodology using a model aiming to quantify slope instability. Regional Authority of Attica in Greece effectively works for their hazard affected communities. A particular case study where applied resilience civil engineering frameworks as well as a semi-quantitative methodology to engage with different stakeholders, is described from Attica Region, on Provincial Road 3 (Dekelias Street segment) near the stream Chelidonous in the Municipality of Kifissia.

A supporting study was carried out in the context of the restoration of the road surface and the stability of the stream slopes. The results of the geotechnical survey and study are presented in brief and the measures proposed by the study to support the slopes are described. The hazard of the existing condition of the encountered slopes adjacent to the roadway was confirmed using the Rock Engineering System (RES). Civil engineering approach and RES methodology provide targeted resilience strengthening investments and actions across, that are increasingly demanded in the context of climate change adaptation and sustainable development.
Information content of differential reflectivity columns for precipitation nowcasting
Authors: Evaristo Raquel , Reinoso Rondinel Ricardo , Crijnen Felix , Chen Ju-Yu , Trömel Silke
Published: March 2022

Columns of differential reflectivity, the difference between the horizontal and vertical reflectivity,
hereafter Zdr columns, are vertical columns of enhanced Zdr that extend above the environmental 0°C
level. These are easily identified when observed by polarimetric radars. Physically, these columns consist
of rain dominated by large drops that are being lofted above the freezing level and have been recognized
as a proxy for the location of updrafts. Their potential for nowcasting severe weather has been shown in
several past studies. We have developed an algorithm that identifies and tracks Zdr columns from
volumetric radar data along with 3D wind fields from MultiDoppler analysis to spatially correlate Zdr
columns with updrafts. Since Zdr columns are a manifestation of an updraft, different Zdr columns
properties for example Zdr column maximum height, volume, and area are expected to be related to
updraft intensity levels. In turn intensification of updrafts, as indicated by changes in the Zdr columns
properties, should be translated in intensification of observed precipitation at the surface. For the
estimation of rain rates, we used a radar-based polarimetric approach, which will allow us to monitor the
temporal evolution for a number of identified convective rain cells. These cells will be identified from
summer events observed by the C-band polarimetric German network. For each cell, the properties of Zdr
columns are correlated with rain rate values. Similarly, correlations are also calculated for updraft
volumes, updraft intensity, and other updraft properties. For the nowcasting of observed rain rates, an
extrapolation algorithm based on spatial and temporal properties of rain was used. Preliminary results
have shown that higher precipitation rates are generally associated with Zdr columns, and cells without a
Zdr column produce lower precipitation rates, as expected. Zdr column height and volume show a
positive correlation with precipitation intensity at the surface. The time lag between the intensification of
the Zdr column and associated increase in precipitation at the surface varies significantly between cells,
but it is generally short compared to previous studies, varying mostly between 5 to 15 minutes. An early
identification of cells associated with ZDR columns could benefit the skill of the nowcasting of localized
rain cells, which often are smoothed during extrapolation.
The Eurekan in eastern North Greenland: insights from thermochronology
Authors: Meier Katrin , O'Sullivan Paul , Monien Patrick , Piepjohn Karsten , Lisker Frank , Spiegel Cornelia
Published: March 2022

Eastern North Greenland is a key area for studying the reorganisation of the North Atlantic-Arctic Realm during the Cenozoic. Due to its crucial position at the intersection of Atlantic Ocean, Arctic Ocean, and the West Greenland Rift Basin this area was significantly involved in the Eureka Orogeny leading to intracontinental compression/transpression observed on the Svalbard-Barents margin and the Canadian Archipelago as well as Northern Greenland. In the Neogene the final breakup occurred in this area, leading to the deep-water connection of the Arctic and North Atlantic Oceans.

It is characterized by the Carboniferous-Paleogene deposits of the Wandel Sea Basin overlaying Mesoproterozoic to early Palaeozoic supracrustal rocks. They occur in a series of pull apart basins along a zone of NE-SW-oriented faults. These faults are part of the DeGeer Shear Zone, along which the lateral offset of Greenland and Spitsbergen occurred during the Eureka Orogeny. In accordance the deposits are deformed, but the timing and the structural context of the deformation is much debated. Also, some deposits show unusually high thermal maturities of which the origin and geodynamic context is unclear.

We took samples across the Tolle-Land-Fault-Zone from the coast in the NE into the Caledonian basement in SW and applied apatite fission tack analysis and (U-Th-Sm)/He thermochronology to reconstruct the thermal history of the respective segments of the fault zone and their thermal evolution in respect to the deformation and opening of the northern Atlantic. Preliminary results will be presented and the exhumation history and timing of deformation and thermal anomalies in eastern North Greenland and influence of the breakup will be discussed.
Properties and High-Resolution Topography of Subglacial Bedforms Beneath a West Antarctic Ice Stream 
Authors: Schlegel Rebecca , Brisbourne Alex , Murray Tavi , Booth Adam , Smith Andrew , Clark Roger , King Edward
Published: March 2022

Subglacial bedforms such as mega-scale glacial lineations and drumlins are commonly thought to form during active ice flow. They are often present in deglaciated areas with various elongation ratios, consisting of different materials , information which led to the development of different formation theories. However, these exposed examples were formed not only by subglacial processes during glaciation but also altered by processes during and after deglaciation. Here, we analyse in-situ properties and topography beneath Rutford Ice Steam, a fast flowing ice stream in West Antarctica to evaluate current theoretical models of bedform formation. We present a combination of seismic and radar data, including high-resolution 3D radar topography covering the upstream end of a bedform. Data acquisition and processing of the high-resolution 3D radar dataset result in a horizontal resolution of 24 m along- and across-track and a vertical resolution of 12 m. Using seismic acoustic impedance and calibrated radar reflectivity subglacial properties of the bedforms as well as the surrounding area are identified.

A depression around the upstream end of a 360 m wide, 50 m high and more than 13 km long bedform was observed for the first time analysing the high-resolution 3D radar topography.  The depression consists of a deepening up to 45 m deep and 360 m wide and is seen to extend around 10.5 km downstream. Radar reflectivity reveals that the material the depression is excavated into at least partly consists of low porosity material. Radar reflectivity and seismic acoustic impedance  along the bedform imply a stiffer upstream end which softens along flow. The subglacial topography and properties give evidence that the bedform and the depression are formed by a combination of  erosional and depositional processes. Both processes are likely interlinked, as implied by the comparable volume of the moat and the bedform at the upstream end of the bedform. Based on these observations we support or reject common bedform formation theories beneath Rutford Ice Stream.
Evaluating coastal flood impacts at the EU-scale: the ECFAS approach
Authors: Montes Juan , Duo Enrico , Souto Paola , Gastal Véra , Grigoriadis Dionysis , Le Gal Marine , Fernández-Montblanc Tomás , Delbour Sebastien , Ieronymidi Emmanouela , Armaroli Clara , Ciavola Paolo
Published: March 2022

Extreme marine storm events have the potential to produce coastal flooding among other hazards. Flood-related impacts are expected to intensify in the future due to climatological factors. Thus, forecasting the impacts generated by marine storms on coastal areas is a key aspect for risk management plans and cost benefit analysis of measures. An integrated approach for the evaluation of coastal flood impacts at the EU scale was developed in the framework of the ECFAS project (EU H2020 GA 101004211), whose main objective is to develop a coastal flood awareness system for the evolution of the Copernicus Emergency Management Service (CEMS).

The approach consists in the integration of literature-based methodologies that were adapted and/or improved to evaluate direct impacts on population, assets (buildings, roads, railways, agriculture, ecosystems, power and nuclear plants) and points of interest. The approach relies on publicly available EU-scale datasets of population, land use/cover, buildings, transport networks, and others. Micro-scale (object-based) and probabilistic methods were applied when data and model availability allowed it, in order to provide a reliable evaluation of the damage and its uncertainty. Otherwise, grid-based exposure methods were used.

A partial validation of the approach was performed by comparing the numerical results with reported qualitative and quantitative information on a few significant extreme events: Xynthia (2010) at La Faute-sur-Mer (France), Xaver (2013) at Norfolk (UK) and Emma (2018) at Cadiz (Spain). At this stage, the impacts were calculated using the LISFLOOD-FP flood maps produced in the framework of the ECFAS project. According to the analysis, this impact approach provides reliable results for the damage to buildings and roads, which represent two of the most important sectors when evaluating flood-related damages. Integrating the ECFAS awareness flood system, this approach will be extensively applied to provide impact results for flood scenarios (1-20 years return period) along the European coastal flood-prone areas.
Water Fountain Speed and Height at Strokkur Geyser, Iceland, derived from Video Camera Data
Authors: Karmacharya Sandeep , Eibl Eva P. S. , Shevchenko Alina , Walter Thomas , Hersir Gylfi Páll
Published: March 2022

Strokkur geyser in Iceland is located in the Haukadalur valley, Iceland. It exhibits frequent, jetting eruptions of hot water and non-condensable gases such as CO2. In earlier studies we found that Strokkur geyser erupts at regular intervals and passes through typical phases in an eruptive cycle. This eruptive cycle consists of the eruption, conduit refilling with water, gas accumulation in a bubble trap and regular bubble collapses at depth in the conduit. In this presentation we focus on the blue bulge that forms at the beginning of an eruption and the water fountain itself.

To study this, we use video camera data from 2017 and 2020 in comparison with a local broadband seismic network. We assess the bulge height, fountain height, the bulge rising speed, water fountain rising speed and the associated seismic amplitude. Particularly, ImageJ with the MtrackJ plugin was used to assess the bulge height and fountain height. We find that upto 0.5 m high water bulge forms within 0.7 s at an average speed of 0.6 m/s. Water is then expelled into the air at a speed of 10 m/s reaching heights of up to 40 m. We compare the speeds measured on the surface with (i) expected rising speeds of gas bubbles in water given a certain diameter and (ii) migration speeds derived from migrating seismic source locations. We discuss the derived height with respect to seismic amplitudes to constrain the tremor generation and to finally assess whether the seismic amplitude (e. g. RMS) has any predictive power when it comes to eruption forecasting.
Designing a Metric System for the evaluation of the Resilience due to Extreme Events in a Socio-Environmental System.
Authors: Jain Jagriti , Khare Deepak , Arriola Francisco-Munoz
Published: March 2022

Floods have become more frequent across the globe leading to loss in life and property. As per the 2021 World Meteorological Organization Atlas (1970-2019), there has been 58,700 deaths reported in the last 50 years due to extreme events.  The present work aims to improve governance for tackling the extreme events, floods, affected by the forces like social, physical infrastructure changes and the policies are responsible for the changes in the state of the system. It has been tried to capture the associated risk influencing metrics with these events by using remote sensing products, through the lens of socio-environmental approach where the human and natural system interactions were analysed. The objectives of this paper are: To characterise the indices ( or metrics) and the functionalities that causes change in state of the system required for the evaluation of the risk and resilience due to floods;
and to map the discrepancies persisting in the federal standards and policies of disaster risk management of floods and the regionalized flood prone areas. This will help us to better understand the resilience of the socio-ecological system and identifying the key areas of improvement in the administration at different levels.
The geomorphic response of river alternate bars to climate change
Authors: Redolfi Marco , Carlin Mattia , Tubino Marco
Published: March 2022

Understanding the possible geomorphic trajectory of rivers on the scale of decades is crucial for a successful design of river restoration interventions, especially in the contest of a changing climate. In this contribution we focus on river alternate bars, large bedforms that appear as a repeating sequence of diagonal depositional fronts and scour holes. Downstream-migrating alternate bars can spontaneously form due to a well-known process of riverbed instability and are frequently found in channelized river reaches. We considered two study reaches of the Alpine Rhine River in Switzerland, characterized by similar hydrological and sedimentological characteristics, but different channel width. Expected hydrological changes until 2100, depending on the Representative Concentration Pathways for greenhouse gases, were evaluated by considering the recents projections from the Hydro-CH2018 project. The bar evolution was reproduced through the novel mathematical model developed by Carlin et al. (2021), which allows for simulating the temporal variability of the reach-averaged bar height in the long-term. Model’s results clearly show that the expected response of the river bed strongly depends on channel conditions with respect to the relevant morphodynamics threshold for bar formation. The first reach, which is sufficiently wide to allow for a full development of migrating alternate bars, turns out to be weakly sensitive to the projected hydrological alterations. Conversely the second, narrower reach, which is currently close to the threshold conditions, is expected to experience a remarkable alteration in bar dynamics. Specifically, the average bar height is expected to significantly increase, while its variability during flood events will probably drastically reduce. Ultimately, this work reveals a noteworthy example of a more general property of near-threshold geomorphic systems, which are potentially fragile and highly susceptible to changes of their hydrological and ecological conditions, in contrast to systems that being far from threshold conditions are more likely to maintain their physical characteristics in the long term.
Modelling the post-seismic deformations measured by GNSS and InSAR, following the 2014 Iquique earthquake, Chile
Authors: Cresseaux Juliette , Socquet Anne , Radiguet Mathilde , Doin Marie-Pierre , Marsan David , Marchandon Mathilde , Huiban Flora , Molaro-Maqua Rémi
Published: March 2022

Large earthquakes are followed by a post-seismic period during which the stresses induced by the co-seismic phase are relaxed through different processes. This post-seismic phase participates to the redistributions of stresses in the earth, and understanding its mechanism is a key to understand interactions between earthquakes at different spatial and temporal scales. In subduction zones the most important terms are the afterslip and the visco-elastic relaxation. It is generally considered that the two mechanisms affect different spatial and temporal scales: the afterslip is prevalent the first months in the surrounding of the fault, while the visco-elastic relaxation process affects a larger area and lasts a longer time. The time-space pattern of the measured deformation can help to characterize the rheology of the underlying structure.

In this work we look at the processes involved after the Iquique earthquake.

 

To explore the processes driving the post-seismic deformation, we use a finite element model (FEM) (2D model, using the FEM software Pylith) that is constrained with InSAR and GNSS data. The GPS time series (processed with GipsyX) include 83 stations located in North Chile, Peru and Bolivia. The post-seismic signal is isolated using a trajectory model. The InSAR data consist in two Sentinel-1 time series (ascending and descending tracks) processed with the NSBAS chain, they include 514 interferograms, starting 7 months after the earthquake up to the end of 2019. In the model we impose a co-seismic displacement on the plate interface and explore the influence of the structure and the rheology on the predicted surface displacement.

 

Our tests reveal that the viscosity in the continental and the oceanic mantle both have an impact on the displacement produced at the surface. The difference between these viscosities controls the movements allowed at depth. The crust thickness and the presence of a cold nose have a clear impact on the wavelength and the location of the maximum of amplitude, respectively.

The afterslip is the major contribution at short time. At longer time, it affects weakly the near trench displacements. To fit the long-term data, we show that visco-elastic relaxation is needed. After 7 months, the InSAR data show a clear spatial wavelength with a strong signal 150 to 300 km from the trench which can be explained by the visco-elastic process.

We pointing out that these is a trade-off between the contribution of afterslip and visco-elastic relaxation. However, both processes affect different space and time, and the comparison with GNSS data and two InSAR tracks allows to strongly constrain the model and reduce the range of plausible models.
AI-enhanced drought forecasting: a case study in the Netherlands
Authors: Bertini Claudia , van Andel Schalk Jan , Corzo Perez Gerald , Werner Micha
Published: March 2022

Drought is a natural phenomenon linked to a temporary but significant reduction in the availability of water resources. Drought usually originates as a deficit in precipitation, with prolonged drought having substantial repercussions on the hydrological, agricultural and socio-economic sectors; making drought one of the most impactful natural hazards modern society faces. The ability to forecast the occurrence of drought events with sufficient lead time, however, allows for the implementation of strategies to reduce drought impacts. Although drought forecasting using both statistical and dynamic techniques has been widely studied, challenges still remain in predicting drought events, especially for sub-seasonal to seasonal forecasts. Because of the increased availability of Earth Observation data, advances in Artificial Intelligence, and progress in computing capabilities in the last decades, drought prediction has received a new impulse. Machine Learning, especially Deep Learning, techniques are now increasingly being used both to improve current weather forecasts and as an alternative to conventional predictions of extreme events.

In this contribution we explore the use of Machine Learning techniques to improve meteorological drought prediction through post-processing of weather forecast analogues. To this aim, we use both ECMWF extended and long-range forecasts, together with reanalysis data, to build a ML-based model that helps correcting forecasts. We then test the model to explore how much current forecasts can be actually improved with the use of AI-based techniques. We apply the method proposed, in the area of the Rhine Delta in the Netherlands, focussing on 1-month lead time predictions. This work is part of the CLImate INTelligence (CLINT) project, which aims at developing AI-enhanced Climate Services for extreme events detection, causation, and attribution.
A multi-model assessment of atmospheric composition in the UTLS with the IAGOS database, in the frame of the ACACIA EU project
Authors: Cohen Yann , Hauglustaine Didier , Bellouin Nicolas , Lund Marianne Tronstad , Matthes Sigrun , Petzold Andreas , Rohs Susanne , Skowron Agnieszka , Thouret Valérie , Ziereis Helmut
Published: March 2022

A wide variety of observation data sets are used to assess long-term simulations provided by chemistry-climate models (CCMs) and chemistry-transport models (CTMs). However, the upper troposphere – lower stratosphere (UTLS) is hardly assessed in the models because of uncertainties in remote measurements, a limited area for balloon-borne observations and a limited period for aircraft campaigns. Observations performed in the framework of the IAGOS program (In-service Aircraft for a Global Observing System) combine the advantages of in situ measurements in the UTLS with an almost global-scale area, a ~20-year monitoring period and a high sampling frequency. Few model assessments have been made using the IAGOS database, and none of them involved the whole cruise data set.

Cohen et al. (2021, GMD) proposed a method to project all the IAGOS data onto a model monthly grid, in order to make them ready for assessing global climatologies and seasonal cycles above several well-sampled regions in the North Hemisphere. This work has been extended to a daily resolution for an accurate separation between the upper troposphere and the lower stratosphere, and to other chemical species. In this study, we apply this method to a set of simulations generated by the following CTMs or CCMs: Oslo-CTM3, MOZART3, EMAC, UKESM, and LMDZ-OR-INCA, all involved into the ACACIA European Union program (Advancing the Science for Aviation and Climate) that focuses on the climate impact of the subsonic aviation emissions. The runs are generated following a common protocol, notably regarding the boundary conditions (e.g. emission inventories) and the chemical configurations, the latter including gaseous tropospheric and stratospheric chemistry, and heterogeneous chemistry. The multi-model assessment concerns the 1994 – 2017 period, and focuses on ozone, carbon monoxide, water vapour and reactive nitrogen (NOy) fields.
Multispacecraft wave diagnostics of the flapping motion of the magnetotail current sheet
Authors: Petrenko Bohdan , Kronberg Elena , Grigorenko Elena
Published: March 2022

The flapping motion of the magnetotail current sheet has a valuable contribution to magnetosphere dynamics. We have investigated features of flapping motions involving single- and multi-spacecraft methods using MMS and Cluster measurements. Velocities of dawn-dusk propagation of these motions and their types have been determined using Harris current sheet model and minimum variance analysis of the magnetic field. Dispersion features of such wavy motions using the phase differencing technique were explored.             
This work was carried out in accordance with the Target Comprehensive Program of the SRI NASU and SSAU in plasma physics with the support of grant no. 97742 of the Volkswagen Foundation (VW-Stiftung). 
The destructive 1928 fissure eruption of Mt Etna (Italy): surficial deformation revealed by field data and FEM numerical modelling
Authors: Russo Elena , Tibaldi Alessandro , Bonali Fabio Luca , Corti Noemi , Drymoni Kyriaki , De Beni Emanuela , Branca Stefano , Neri Marco , Cantarero Massimo , Pasquarè Mariotto Federico
Published: March 2022

The present research is aimed at evaluating the wide surficial deformation associated with the destructive 1928 fissure eruption on Mt. Etna, Italy: with its high effusion rates and the low elevation of the main eruptive vents, this eruption caused the destruction of the Mascali town. The main aim of our work is to reconstruct the geometry, kinematics and origin of the system of faults and fissures formed during the 1928 event. Our study has been performed through a multidisciplinary approach consisting of field observations, aerial photo interpretation and Finite Element Method (FEM) modeling through COMSOL Multiphysics® (v5.6). Field data consist of 438 quantitative measurements: azimuth values, opening direction and aperture of dry/eruptive fissures, as well as attitude and offsets of faults. Our detailed structural analysis allowed us to detect four different tectonic settings related to dike propagation scenarios, which, from west to east, are: 1) a sequence of 8 eruptive vents surrounded by a 385-m wide graben, 2) a 2.5-km long single eruptive fissure, 3) a half-graben up to 74-m-wide and a symmetric 39-m-wide graben without evidence of eruption, 4) alignment of lower vents along the pre-existing Ripe della Naca faults. 

As a next step, several numerical models have been developed to investigate the relationship between diking and surficial deformation. We performed sensitivity analyses, by modifying crucial parameters, such as a range of dike overpressure values (1-20 MPa), host rock properties (Young modulus ranging from 1 to 30 GPa), stratigraphic sequence, and layer thickness. Furthermore, the distribution of tensile and shear stresses above the dike tip has been evaluated. Results revealed the presence of temporary stress barriers, which consist of soft (e.g. tuff) layers, that control the surficial deformation above a dike propagating to the surface by suppressing the distribution of shear stresses.
A seasonal climatology of the upper ocean pycnocline
Authors: Sérazin Guillaume , Tréguier Anne-Marie , de Boyer Montégut Clément
Published: March 2022

Climatologies of the mixed layer depth have been provided using several definitions based on temperature/density thresholds or hybrid approaches. The upper ocean pycnocline (UOP) that sits below the mixed layer base, sometimes referred to as the transition layer or as the seasonal pycnocline, remains poorly characterised though it is an ubiquitous feature of the ocean surface layer. The UOP often consists in a rapid change in density with depth and enhanced vertical shear that connects the well-mixed surface layer to the stratified ocean interior. The UOP is important for the ventilation of the ocean as it represents a barrier to mixing between the upper ocean and the ocean interior.

Available hydrographic profiles (e.g., Argo, CTD on marine mammals) provide near-global coverage of the world's oceans and allow the characterisation of spatial and seasonal variations of the upper ocean vertical stratification, including the UOP. Based on these profiles, we estimate the depth, thickness and intensity of the UOP, and assess when and where the UOP can be considered as a layer with constant thickness. We provide monthly maps of the UOP complementing the available MLD climatologies and we compare the UOP characteristics with the depth and stratification of the mixed layer. We  aim at assessing the UOP intensity in winter and spring when the stratification is usually weak and submesoscale vertical motions can penetrate below the mixed layer base. During these seasons, the UOP intermittency must be taken into account because restratification may occur with intermittent events.
Assessment of hydrological extremes and water resources availability under climate change in the Main river basin, Germany
Authors: Pérez Ciria Teresa , Wood Raul , Gunnar Braun , Ludwig Ralf
Published: March 2022

Human-induced climate change is already impacting hydrometeorological extremes in every region across the globe (IPCC, 2021). In fact, changes in the climate system are projected to become larger with increasing global warming. This includes regional increase of frequency and intensity of heavy precipitation, hydrological extremes, agricultural and ecological droughts. Recent studies indicate that this problematic seems to be particularly relevant also in Central Europe, a region usually perceived as an area of comparatively low vulnerability to climate change due to its high adaptive capacity. The presented study focuses on the Main river basin, a tributary to the Rhine river in Germany: the watershed, covering an area of 21.519 km² (at Kleinheubach gauging station) with over four million inhabitants, is characterized by intense gradients of topography and climate, and diversified land use. The region already suffers from water scarcity and consequently water use conflicts are becoming more relevant recently, especially during summer months. This study presents results from a single hydrological model initial condition large ensemble (i.e. the spatially explicit process-based hydrological model WaSiM (Willkofer et al., 2020)) being driven by 50 members of the Canadian Regional Climate Model Vers.5 (CRCM5) over Europe (Leduc et al., 2019) for the time interval 1950-2099. A remarkable decline of mean annual runoff in the Main river basin is projected, while both frequency and intensity of extreme floods show strong increasing trends. This work is meant to tackle this challenge as a first step to achieve co-designing systemic solutions and science-driven technical and cross-sectoral innovations to build new climate-resilient development pathways for efficient water resources management.

The presented study is supported by results from the project ClimEx (www.climex-project.org), funded by the Bavarian State Ministry for the Environment and Consumer Protection, and the project ARSINOE (GA: 101037424), funded under EU’s Horizon 2020 research and innovation programme. 
Contribution of Direction-of-Arrival Observations for Geodetic Seafloor Positioning Using an Unmanned Surface Vehicle
Authors: Sakic Pierre , Chupin Clémence , Ballu Valérie , Coulombier Thibault , Morvan Pierre-Yves , Urvoas Paul , Beauverger Mickael , Lenhof Edgar , Royer Jean-Yves
Published: March 2022

Precise underwater geodetic positioning remains a challenging operation. Measurements combining surface positioning (GNSS) with underwater acoustic positioning are usually performed from research vessels. We present an alternative approach using a small Unmanned Surface Vehicle (USV) equipped with a compact GNSS/Acoustic experimental configuration, which is more cost-effective and easier to deploy. The positioning system included a GNSS receiver mounted above an Ultra Short Baseline (USBL) module integrated with an inertial system (INS) to correct the USV movements. The experiment conducted in the shallow waters (40 m) of the Bay of Brest, France, provided a data set to derive the coordinates of individual transponders from two-way-travel times and direction of arrival (DOA) of acoustic rays from the transponders to the USV. We tested different acquisition protocols (box-in circles around transponders and two static positions of the USV). Using a least-squares inversion, we show that DOAs improve single transponder positioning both in box-in and static acquisitions. From a series of short positioning sessions (20 min) over two days, we achieved repeatability of ~5 cm in the locations of the transponders. Post-processing of the GNSS data also significantly improved the two-way-travel times' residuals compared to the real-time solution.
Hyperconcentrated floods required to transport coarse bedload over the Gangetic Plains 
Authors: Quick Laura , Sinclair Hugh , Creed Maggie , Attal Mikael , Borthwick Alistair , Sinha Rajiv
Published: March 2022

The gravel-sand transition is a distinct morphological boundary in continental foreland basins characterised by an abrupt downstream reduction in grainsize and lowering of channel gradients. Tectonic convergence between foreland basins and mountain fronts results in the progressive migration of the gravel-sand transition into the basin. As a result, the stratigraphy of the basin fill records a vertical coarsening with an abrupt transition from sandstones to conglomerates. Analysis of this stratigraphic boundary enables insight into the long-term stability of the gravel-sand transition, and records evidence of extreme flood events that were able to transport gravel far out into the basin. Floodwaters sourced from mountain ranges transport and re-suspend finer sediment commonly resulting in them becoming ‘hyperconcentrated’, further increasing the ability to mobilise coarse bedload; however, observations of sediment transport during such extreme flood events are limited. Here, we combine sedimentological analyses of Miocene deposits from the front of the Himalaya, with sediment entrainment calculations. We record the sedimentological transition between the Middle Siwalik sandstones and the Upper Siwalik conglomerates exposed across the Mohand anticline in North West India; this stratigraphic transition records the gravel to sand transition in the Miocene Gangetic Plains. Rather than this being an abrupt, single stratigraphic boundary, it shows a series of thick, coarse conglomeratic beds that punctuate the sandstones beneath the boundary. We focus on these beds as examples of major sediment transport events, and demonstrate the transport of cobble and gravel-rich bedload, facilitated by hyperconcentrated flow conditions, tens of kilometres beyond the gravel-sand transition. Such extreme flow conditions require intense monsoon precipitation, and enhanced suspended sediment concentrations, which in the modern system would represent a 1 in 500 to 1000 year flood event.