bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-timescale response of the Filchner-Ronne Ice Shelf to climate change
Authors: Naughten Kaitlin , De Rydt Jan , Rosier Sebastian , Jenkins Adrian , Holland Paul , Ridley Jeff
Published: March 2022

A potentially irreversible threshold in Antarctic ice shelf melting would be crossed if the ocean cavity beneath the large Filchner-Ronne Ice Shelf were to become flooded with warm water from the deep ocean. Previous studies have identified this possibility, but there is great uncertainty as to how easily it could occur. Here, we show, using a coupled ice sheet-ocean model forced by climate change scenarios, that any increase in ice shelf melting is likely to be preceded by an extended period of reduced melting. Climate change weakens the circulation beneath the ice shelf, leading to colder water and reduced melting. Warm water begins to intrude into the cavity when global mean surface temperatures rise by approximately 7°C above pre-industrial, which is unlikely to occur this century. However, this result should not be considered evidence that the region is unconditionally stable. Unless global temperatures plateau, increased melting will eventually prevail.
Understanding household-level flood responses in Ho Chi Minh City: who acts what and why?
Authors: Yang Liang Emlyn , Garschagen Matthias
Published: March 2022

Ho Chi Minh City (HCMC) is characterized by rapid urbanization, socio-economic transitions and significant climate/environment influences at a low lying flood prone area, which in combination results in more frequent and intense floods. Accordingly, flood coping measures and adaptation actions have been carried out by various stakeholders for years, especially the diverse responses at household level. However, there is a lack of substantial understanding on the profiles of different households regarding their flood response measures, the driving factors, particularly with regards to dynamically changing socio-economic groups and the question of individual vs. collective action for flood risk reduction. Based on a large scale household survey conducted in HCMC in September and October 2020, the study classifies different flood coping/adaptation measures. A cluster analysis of multiple factors is carried out to clarify the major factors and to identify the features of households and their networks in each cluster. Specific data analysis indicates: 1) Majority of local people don’t receive external supports, due to the fact of moderate flood events and that they subjectively don’t concern much to the impacts (have got used to floods). 2) The most vulnerable groups did receive various supports, which indicates the existence of a basic flood-safe system in HCMC. 3) Long-term adaptation measures are not often applied, because vulnerable groups are not able to while rich people don’t need to. Findings of the study help to better understand the local status of flood responses against the backdrop of underlying socio-economic transformations.
The influence of a stratified core on Mercury's librations
Authors: Seuren Fleur , Triana Santiago Andres , Rekier Jérémy , Van Hoolst Tim , Dehant Véronique
Published: March 2022

Earth-based measurements of Mercury's libration amplitude have been used previously to establish the existence of Mercury's liquid core and to estimate its size. However these previous works have not yet taken into account the internal core flows that can be induced by rotational variations such as librations. In the present study, we use a numerical linear model to investigate the effect that these internal flows might have on Mercury's libration amplitude and other observables. In particular we find that the inclusion of a stably stratified layer at the top of the core – the existence of which has been suggested by thermal evolution and numerical dynamo models – in most cases prohibits the transmission of any motion from the top of the core to its deeper parts and vice versa.
The 2021 unrest phase of Vulcano volcano (Aeolian islands) detected by SAR,GNSS and GB-RAR
Authors: Francesco Guglielmino , Bonforte Alessandro , Puglisi Giuseppe
Published: March 2022

Starting from July 2021, a gradual unrest of Vulcano volcano was recorded by monitoring system managed by INGV, marked by a progressive change of many parameters from the multi-disciplinary networks.

The fumaroles located on the crater rim and along the flank of the cone shown temperature increase ( up to 350 degree Celsius) and  an increase of the flux of carbon dioxide and sulfur dioxide in gas emissions. Furthermore, the increase of the occurrence of with very-long-period (VLP) events was recorded by seismic network, and a rapid uplift of about 1 cm/month was recorded at VCRA GNSS permanent station located on the North slope of the “La Fossa” cone.

In order to image the ground deformation accompanying the unrest phase, we analyzed the 2020-2021 ascending and descending ESA-Copernicus Sentinel-1A and 1B C-band SAR (Synthetic Aperture Radar) acquired in TopSAR (Terrain Observation with Progressive Scans SAR) Interferometric Wide mode with A-DINSAR techniques. On October 2021 a new GNSS survey was performed on the ”Lipari-Vulcano” network. We integrated the SAR data and the GNSS data applying the SISTEM method, and the preliminary results are consistent with the Vulcano hydrothermal system dynamics, with a deformation pattern limited to the cone area.

In order to monitoring continuously and more in detail the change in ground deformation, on December 2021 we installed 4 additional GNSS mobile stations and a permanent GB-RAR (ground-based real aperture radar) on the island. The GB-RAR system was installed at the Lipari Observatory, at a distance of about 5 km from Vulcano, and it is able to image the whole Vulcano north area, with a rectangular pixel resolution of 3x30 m and a precision of the displacement along the line of sight of about 1 mm.

At time of this abstract no ground deformation have been recorded in the last month, the microseismic activity reduced but the fumarole temperatures at the crater and gas emissions of carbon and sulphur dioxide remained at high level.
On the present and future teleconnection to the Indian summer monsoon in CMIP6 models
Authors: Chakraborty Arindam
Published: March 2022

In a continuing warming climate, it is necessary to understand how the Indian summer monsoon (ISM) will respond to El Nino Southern Oscillation (ENSO) and other dominant Non-ENSO climate patterns. Using several coupled climate models participated in the CMIP6 simulations, we show that the frequency of droughts and floods is similar in these models either in the historical or future scenarios (ssp126, ssp245, ssp370, ssp585). This symmetry is unlike the observation where droughts are more frequent and vigorous than floods. We show that while the number of ENSO years is projected to increase with raised CO2 forcings, the fraction of ENSO and Non-ENSO years experiencing extremes of ISM remain relatively constant. However, the future scenarios indicate more frequent La Nina-related floods than the historical period. We show that most models do not capture the observed spatial maps of vertically integrated moisture flux during Non-ENSO ISM extreme years. While in the observation, a stronger role is played by the climate of the Arabian Sea and West Asia, most models are driven by the climate of the western North Pacific Ocean during non-ENSO ISM extremes. Our results indicate changes in the future teleconnection pattern during Non-ENSO related ISM extremes. These results call for special attention for model diagnosis and development for a better seasonal prediction.
Of mesh artefacts and electric fields: the bane of numerical global coronal modelling
Authors: Brchnelova Michaela , Zhang Fan , Perri Barbara , Lani Andrea , Poedts Stefaan
Published: March 2022

Global magnetohydrodynamic (MHD) computational fluid dynamics (CFD) simulations have become an important tool for solar weather research. These simulations use solar magnetogram data to compute structures in the solar corona. We have developed one such model based on the COOLFLuiD platform and validated it through comparison with other state-of-art codes and observations (Leitner et al., 2022, submitted). Currently, further physics is added to the solver to move it from ideal MHD to full MHD, such as radiation, coronal heating or conduction. Description of this physics and its results is what is most usually discussed in papers concerning coronal MHD CFD. 

However, physics is only one part of the solution when CFD is used. Actually, it is the numerics that is oftentimes the limiting factor, setting constraints on the accuracy and speed of these solvers. Many different problems can arise due to the finite discretisation of the domain or even due to the solver working with simplified ideal MHD equations instead of the full ones. It is rarely discussed what type of a computational grid should be used depending on the type of the simulations at hand, and it is mentioned even less often what type of errors and inaccuracies such an inappropriate grid type can cause. An unsuitable grid can also cause convergence problems and decrease the speed of the solver considerably (Brchnelova et al., 2022, submitted).

In our work, we investigate the sources of inaccuracies and errors which can compromise the global coronal MHD CFD results. We have observed that due to the large ranges of density magnitudes involved, spurious numerical fluxes can result on mesh cell interfaces when these cells are either highly skewed or the boundaries otherwise non-orthogonal. These spurious fluxes can create local errors of up to 40% in the velocity field in the most deformed portions of the computational grid. Further inaccuracies were observed also in the sharpness of the resulting velocity structures, this time due to artificially generated electric fields during the simulation. 

Thus, in our talk, we will summarize the most important of the issues observed, their causes and potential means of their mitigation. For controlling the errors due to the spurious fluxes while simultaneously optimizing the performance of the solver, we will show a trade-off between different grid topologies and what to expect in the results. Similarly, to enhance the sharpness of the features, it will also be discussed how to mitigate the generation of artificial electric fields via careful formulation of the initial state and boundary conditions.
SEismic imaging of the Ivrea ZonE (project SEIZE) reveals the 3D structure of the Ivrea body near Balmuccia, Italy
Authors: Wawerzinek Britta , Ryberg Trond , Bauer Klaus , Stiller Manfred , Haberland Christian , Zanetti Alberto , Ziberna Luca , Hetényi György , Weber Michael , Krawczyk Charlotte M.
Published: March 2022

The Ivrea-Verbano Zone (IVZ) located in the Italian Alps is known as one of most complete archetypes of continental crust–upper mantle section on Earth (e.g. Pistone et al., 2017). Because of its accessibility at the surface it can be used as natural laboratory to improve the understanding of the crust–mantle transition zone. Several geophysical observables indicate the presence of mantle rocks (high density, high seismic velocity) in the shallow sub-surface (~ 1 km), commonly known as the “Bird’s Head” or Ivrea body (Berckhemer, 1968; Diehl et al., 2009; Scarponi et al., 2021). 

The project SEIZE images and characterizes the shallow upper crust at the Balmuccia site (Italy) providing depth, extent and shape of the outcropping Ivrea body as well as its rock properties. Our tomographic study covers the crust down to about 3 km depth, while seismic reflection imaging is possible down to 6 km depth or deeper. With SEIZE we contribute to the comprehensive ICDP Drilling program in the Ivrea-Verbano ZonE (DIVE, www.dive2ivrea.org).

To tackle this task, a controlled source (vibroseis) seismic experiment was carried out in the region around Balmuccia in October 2020. The seismic survey comprised two crossing profiles with a total length of 28 km which ran along (NNE-SSW) and across (W-E) the Balmuccia peridotite. In total, 432 vibro points were acquired with a nominal distance of ~60 m which were recorded using a fix-spread (110 receivers, ~250 m spacing) and a roll-along setup (330 receivers, ~20 m spacing).

To obtain a structural image of the shallow upper crust various seismic techniques are applied: The fix-spread data set is used to recover the velocity structure down to 3 km depth. By using a 3D Markov chain Monte Carlo travel time tomography a shallow, distinct high velocity body is imaged in 3D near Balmuccia, at the proposed drill site. Reflection seismic processing is applied to the roll-along data set. However, the difficult terrain setting (deep mountain valleys) results in complex wave propagation that is challenging for conventional processing methods (e.g. static and dynamic corrections, CDP stacking). Therefore, pre-stack migration techniques are applied enabling the imaging of steeply dipping structures.
Deep learning, remote sensing and visual analytics to support automatic flood detection
Authors: Ghosh Binayak , Garg Shagun , Motagh Mahdi , Eggert Daniel , Sips Mike , Martinis Sandro , Plank Simon
Published: March 2022

Floods can have devastating consequences on people, infrastructure, and the ecosystem. Satellite imagery has proven to be an efficient instrument in supporting disaster management authorities during flood events. In contrast to optical remote sensing technology, Synthetic Aperture Radar (SAR) can penetrate clouds, and authorities can use SAR images even during cloudy circumstances. A challenge with SAR is the accurate classification and segmentation of flooded areas from SAR imagery. Recent advancements in deep learning algorithms have demonstrated the potential of deep learning for image segmentation demonstrated. Our research adopted deep learning algorithms to classify and segment flooded areas in SAR imagery. We used UNet and Feature Pyramid Network (FPN), both based on EfficientNet-B7 implementation, to detect flooded areas in SAR imaginary of Nebraska, North Alabama, Bangladesh, Red River North, and Florence. We evaluated both deep learning methods' predictive accuracy and will present the evaluation results at the conference. In the next step of our research, we develop an XAI toolbox to support the interpretation of detected flooded areas and algorithmic decisions of the deep learning methods through interactive visualizations.
Distributive justice principles for integrated assessment models: a comparative study on interregional justice
Authors: Akoluk Damla , Zatarain Salazar Jazmin , Verbraeck Alexander
Published: March 2022

Justice in the climate context has gained more attention in the last decade. One of the main reasons is the increasingly pervasive and aggressive impact of climate change on societies and economies. Existing inequalities and disparities between sectors, regions, and generations are often exacerbated by proposed or applied policies. Hence, protecting different groups’ rights becomes more and more necessary in the climate change adaptation and mitigation policies. It is therefore essential to understand the subjective notions of the ethical principles that underlie the policies, by categorically examining these principles before taking action.

For this reason, this study explored different distributive justice principles in integrated assessment models using a descriptive approach. It resulted in a classification of the five most common ethical principles: Utilitarianism, Rawlsianism, Egalitarianism, Prioritarianism, and Sufficientarianism. These principles have been operationalized to find the optimal climate policy for future emissions. The principles have been applied to the Regional Integrated Climate-Economy (RICE) model for a comparative analysis on interregional justice.
Significant amplification of instantaneous extreme precipitation with convective self-aggregation
Authors: Da Silva Nicolas , Muller Caroline , Shamekh Sara , Fildier Benjamin
Published: March 2022

Convective organization has been associated with extreme precipitation in the tropics. Here we investigate the impact of convective self-aggregation on extreme rainfall rates. We find that convective self-aggregation significantly increases precipitation extremes, for 3-hourly accumulations(+70%) consistent with earlier studies, but also for instantaneous rates (+30%). We show that this latter enhanced instantaneous precipitation is mainly due to the local increase in relative humidity which drives larger accretion rates and lower re-evaporation and thus a higher precipitation efficiency.

An in-depth analysis based on an adapted scaling of precipitation extremes, reveals that the dynamic contribution decreases (-25%) while the thermodynamic is slightly enhanced (+5%) with convective aggregation, leading to lower condensation rates (-20%). When the atmosphere is more organized into a moist convecting region, and a dry convection-free region, deep convective updrafts are surrounded by a warmer environment which reduces convective instability and thus the dynamic contribution. The moister boundary-layer explains the positive thermodynamic contribution. The microphysic contribution is increased by +50% with aggregation. The latter is partly due to reduced evaporation of rain falling through a moister near-cloud environment (+30%), but also to resulted larger accretion efficiency (+20%).

Thus, the change of convective organization regimes in a warming climate could lead to a significantly different evolution of tropical precipitation extremes than expected from thermodynamical considerations. Improved fundamental understanding of convective organization and its sensitivity to warming, as well as its impact on precipitation extremes, is hence crucial to achieve accurate rainfall projections in a warming climate.
Impact of Covid-19 lockdown on shipping underwater noise in the Mediterranean Sea
Authors: Lajaunie Myriam , Ollivier Benjamin , Ceyrac Laura , Dellong David , Le Courtois Florent
Published: March 2022

Marine traffic is an important noise contributor to the underwater soundscape. In addition to the growing marine traffic worldwide, the increase in both ship size and ship power tends to intensify the radiated noise, and thus the low-frequency noise level. Studies have shown that marine species can be impacted by the rapid growth of ambient noise levels. In particular, masking of communication or behavior changes in relation to noise exposure have been documented.

Shipping noise and its consequences on marine fauna are now monitored, and their evolution is of major concern for marine policies. Shipping noise modeling, based on Automatic Identification System (AIS) data is the most common approach to providing underwater noise levels at basin scales. Indeed, most ships are equipped with AIS transmitters, sending information concerning both the ship (ID, activity, length, etc.) and its navigation (position, speed, heading, etc.). This information is used to compute traffic density maps, and to model the ship’s radiated noise. The ambient noise is finally inferred by propagating noise sources in the environment.

In France, a first Covid-19 lockdown occurred from the 17th of March to the 11th of May 2020, reducing significantly the marine traffic. In particular, cruise ships, passenger vessels, vehicle carriers and containerships harbor callings have decreased by 27%, 13%, 7% and 2 % respectively in member states harbors from 2019 to 2020, according to the European Maritime Safety Agency (EMSA). This traffic decrease affected only specific categories of ships, and contributed to some extent to a decrease of the anthropogenic underwater noise.

This study aims to analyze the impact of the traffic density reduction due to the lockdown on the shipping noise in the occidental part of the Mediterranean Sea by use of AIS datasets from 2019 and 2020, and eventually to discuss the potential benefit of traffic density reduction as a mitigation measure.
Gamma-Flash: an Experiment to Detect Radiation and Particles in Thunderstorms
Authors: Ursi Alessandro ,   Gamma-Flash Team
Published: March 2022

Gamma-Flash is an Italian program devoted to the investigation of radiation and particles produced during lightning and thunderstorms. The project is funded by the Italian Space Agency (ASI) and led by the National Institute for Astrophysics (INAF), with the collaboration of numerous institutions and universities. The aim of the project is the study and development of an innovative gamma-ray and neutron detector, and correlative instruments, to be placed onground, at the Climatic Observatory "O. Vittori" on Mt. Cimone (2165 m a.s.l., Northern-Central Italy). In a second phase, the program foresees the development of another payload, to be placed on aircraft for observations of thunderstorms in the air. Gamma-Flash is designed to detect both short-duration transients, such as terrestrial gamma-ray flashes (TGFs), as well as longer-lasting gamma-ray emissions, such as gamma-ray glows, and associated high-energy particle emissions. Main targets of the program are the study of high-energy emissions in thunderstorms, which can have substantial impact in many fields, such as local/global climate change, environmental studies, and atmospheric plasma physics. In addition, the experiment is aimed at the estimate of the susceptibility of electronic systems and devices to TGF-induced ionizing radiation and particles. The investigation of thunderstorm-related high-energy emissions will be supported by a continuous monitoring of the correlated atmospheric scenario, by means of meteorological data analysis on a local scale. The Gamma-Flash group shares cutting-edge expertise in the field of atmospheric physics, high-energy particle and radiation instruments, radiation damage, data analysis, and simulations, taking advantage of more than ten years experience of the ASI AGILE satellite in the field of TGF studies. Gamma-Flash is currently in its design and development phase. The ground-based detector is on its way to the final implementation it will be operative starting from spring 2022. We present an overall description of the Gamma-Flash program, of its detectors, payload, and system design, and of its main scientific objectives.
ARTEMIS – An operational tool to manage the information provided by Persistent Scatterers Monitoring at a regional scale.
Authors: Bertolo Davide , Stra Michel , Thuegaz Patrick
Published: March 2022

The increasing diffusion of the PS (Persistent Scatterers) InSAR services across the world and the early adoption of PS-Monitoring techniques, provide to the civil protection authorities effective and objective tools for disaster risk prevention, empowering the capability to detect early-stage terrain deformations even in unpopulated areas.

More in detail, the PS Monitoring technique exploits the high temporal resolution provided by the recent satellite constellations (e.g. Sentinel 2), with revisitation times of about 14 days  detecting, at a regional scale, the so called “anomalies” (i.e.: the Persistent Scatterers which show acceleration trends compared to a given deformation trend). Considering that the deformation anomalies could be provoked by many factors not related to an incipient landslide, the so-called “false positives”, terrain investigations are usually required to assess a real landslide hazard .

Furthermore, to be effective, the terrain investigations aimed at validating a potential incipient landslide situation should be conducted within a short time, to allow an effective implementation of the safety measures by the civil protection authorities.

Many constraints such as the limited availability of human resources and terrain conditions usually hamper an extensive terrain validation of the anomalies provided by PS-InSAR monitoring services. It is thus necessary a fast and objective method to filter and prioritize the terrain deformation anomalies which have the highest probability to indicate an incipient landslide, and require an immediate terrain investigation.

To make that possible, we developed a semiautomated GIS-based information system, called ARTEMIS (Advanced Regional TErrain Motion Information System), which allows an objective and fast selection of the PS InSAR anomalies to be investigated, detected twice a month by the PS-Monitoring services.

The ARTEMIS is a multi-stage workflow operating a preliminary validation of the anomaly itself, followed by a danger assessment stage and a final risk-assessment stage. At the end of the process, a risk-rating score to prioritize the field investigation is provided. 

ARTEMIS is a flexible and scalable tool, which can be adapted to different geographical realities and PS-Monitoring services. Its workflow is openly available for non-commercial use.
Automated delimitation of rockfall runout zones using high resolution trajectory modelling at regional scale
Authors: Dorren Luuk , Moos Christine , Schaller Christoph
Published: March 2022

More than ten years ago, Swiss-wide rockfall modelling was carried out to indicate potential hazard areas and rockfall protection forests within the framework of the SilvaProtect-CH project. The forest effect itself was not included in these models and only one block size (1 m3) was calculated. The aim of our study was to model rockfall runout zones using Rockyfor3D for block size scenarios ranging from 0.05 – 30 m3 with explicit inclusion of the protective effect of the forest for an area of approx. 7200 km2 in Switzerland and Liechtenstein with a 2m-resolution. For the determination of the start cells as well as the slope surface characteristics, we used the terrain morphometry derived from a 1m-resolution digital terrain model as well as the Swiss TLM geodata and information from geological maps. The forest structure was defined by individual trees with their coordinates, diameters and tree type (coniferous or deciduous). These were generated on the one hand from detected individual trees and on the other hand from statistical relationships between the detected trees, remote sensing-based forest structure type definitions and stem numbers from field inventory data. Based on the latter, we generated forest strata in addition to the detected individual trees. The delimited rockfall runout zones automatically derived from the simulated reach probability maps were validated with 1554 mapped historical rockfall events. The results of the more than 78 billion simulated trajectories showed that 94% of the mapped silent witnesses could be reproduced by the simulations and 78% were within the delimited runout zones. The median of the volume of the non-reproduced silent witnesses was 0.1 m3, which led us to a hypothesis, that these mapped blocks could partly be deposited fragments from larger blocks. We conclude that a rockfall simulation with explicit consideration of the forest effect at 2m-resolution with plausible results is possible for very large areas.
Elemental behaviour of nitrogen and heavy noble gases in interstellar ice analogues and the implications for cometary bodies
Authors: Almayrac Matthieu , Broadley Michael , Bekaert David , Byrne David , Piani Laurette , Marty Bernard
Published: March 2022

Laboratory investigations of noble gases trapped in cometary ice analogues, exposed to photo-irradiation [1], have the potential to provide important information on the evolution of cometary matter under interstellar and solar system conditions. Historical studies on the capacity of amorphous water ices to trap and retain volatiles above their sublimation temperature [1, 2] failed to predict the noble gas elemental and isotopic composition of comets, as measured in ice sublimating from comet 67P/Churyumov-Gerasimenko [3]. However, these studies did not investigate the potential effect of irradiation on elemental fractionation, nor the isotopic fractionation that may occur during trapping and release of volatiles from cometary ice.

Here, we have developped an experimental setup to form cometary ice analogues from mixtures of water, nitrogen and noble gases. We aim at understanding the elemental and isotopic behaviour of nitrogen and noble gases trapped in amorphous water ice, when subject to conditions akin to those experienced by outer solar system bodies. In this experiment, we therefore form amorphous water ice at temperatures and pressures down to 25 K and 10-8 mbar, respectively). Upon heating, water structure changes from amorphous to crystalline ice at around 140K, with the liberation all gas that was initially trapped within the ice. This corresponds to the gas phase in the coma of comets, where both trapped gas and sublimating water are present. In the experiment, gases released from the ice are analysed using a quadrupole mass spectrometer.

We investigate the evolution of N2/Ar/Kr/Xe in the ice from their condensation temperature to their release into the gaseous phase, and the potential effects of this trapping mechanism on the isotope composition of noble gases carried in water ice. We found that reproducing the Ar/Kr/Xe ratios of the comet from a solar composition might be possible when the ice forms at “high” temperature around 70K. Additionnally, high 14N/36Ar measured in comet 67P/C-G [3] may also be replicated when the ice forms at high temperatures. A low temperature formation of around 30K for the comet, as previouslty suggested [4], thus requires a different (or additional) source than solar-type gas for both noble gases and nitrogen.

Taken together, these experimental investigations will ultimately help us to better understand the genesis and evolution of volatile elements within outer solar system icy bodies, and their role as precursors to the terrestrial atmopshere.

[1] Bar-Nun, A. and Kleinfeld, I., 1989. Icarus, 80 [2] Notesco et al., 2003. Icarus, 162 [3] Rubin et al., 2018. Science advances, 4 [4] Rubin et al., 2015. Science, 348.
Nitrogen isotopic inventory of the Lena River Delta 
Authors: Sanders Tina , Fiencke Claudia , Juhls Bennet , Ogneva Olga , Strauss Jens , Tuerena Robyn , Dähnke Kirstin
Published: March 2022

Permafrost-affected soils around the Arctic Ocean contain a large reservoir of organic matter including nitrogen, which partly reach the river after thawing, degradation and erosion of permafrost. After mobilization, reactive remineralised nitrogen is either used for primary production, microbial processing or is simply transported to coastal waters. With analyzing the natural abundance of the stable isotope composition in different form of nitrogen components, we aim to unravel the balance of transport and biological nitrogen turnover processes like remineralization or nitrification and in consequent the fate of the nitrogen. 

We have analyzed soil, suspended matter and dissolved inorganic and organic nitrogen for their contents and 15N stable isotope composition to create a baseline for a nitrogen inventory of the Lena River Delta in 2019/2020. We used samples from two transect cruises through the delta in March and August 2019, a monitoring program at Samoylov Island in the central delta (2019/2020), and different soil type samples from Samoylov and Kurunghak Island. Our aim was to determine nitrogen sources, sinks and transformation processes during transport in river and delta.

Our data shows that in winter the nitrogen transported from the delta to the Laptev Sea were dominated by dissolved organic nitrogen (DON) and nitrate, which occur in similar amounts of approx. 10 µmol/L. The load of nitrate, during the transect cruise, increased slightly in the delta, while we observed no changes to the isotope values of DON and nitrate indicating a lack of biological activity in the winter season and the lateral transport from soils was the likely source. In summer, nitrogen was mainly transported as DON and particulate nitrogen in the suspended matter and nitrate was mainly below 1µmol/L. 

The nitrogen stable isotope values of the different nitrogen components ranges between 0.5 and 4.5‰, and were subsequently enriched from the soils via suspended particulate matter (SPM)/sediment and DON to nitrate. These light values indicate soil nitrogen mainly originates from atmospheric nitrogen fixation. During transport and remineralization, biogeochemical recycling via nitrification and assimilation by phytoplankton led to an isotopic enrichment in summer. In the coastal waters of the Laptev Sea, the exported river waters are slowly mixed with marine nitrate containing waters from the Arctic Ocean, and a part of the riverine organic nitrogen is buried in the sediments.

 Our data provides a baseline for isoscape analysis and can be used as an endmember signal for modeling approaches.  
Insights on vadose zone hydrologeology within a carbonate setting: Preliminary results based on a new vadose zone monitoring system
Authors: Schembri Michael , Sapiano Manuel , Mamo Julian , Debattista Henry , Dahan Ofer
Published: March 2022

A new monitoring network was setup to adequatly assess the hydryogelogical condtions within the vadose zone in Malta. The installation of the monitoring equipment allows for the measurement of water content along the vadose zone from distinct points and along varying. Data on water content variation with time and depth was collected throughout the rainy season of 2021 and 2022 from two sites within this network. The lithology of both sites consists of alternate bands of carbonate sediments with varying levels of porosity. The data generated from these two sites allowed for the continuous tracking of water percolation within the vadose zone and therefore enabled the evaluation of water flow velocities. It was observed that the intensity and frequency of occurence of rain events controls the initiation and downward propagation of wetting fronts along the carbonate litholgical sequence within the vadose zone. The initiated wetting fronts exhibited significant variations in the velocity of the draininage process as a result of the varying lithological sequence. The velocity of the drainage process and the variations in water storage content within the vadose zone were utlised to calculate the rate of groundwater recharge for these two sites.
Determining the Optimal Location of Endangered Species Habitats Using Remote Sensing and Species Distribution Models to Protect Biodiversity in Indonesia
Authors: Al Faruqi Ismail , Santoso Cokro , Putri Adillah Kurnia , Nurlaila Syahid Luri , Dimara Sakti Anjar
Published: March 2022

 

Granted with the world's third-largest area of tropical rainforest, Indonesia is called a mega-biodiversity country with the second-highest level of biodiversity in the world. The diversity of flora and fauna in Indonesia is classified as rare and endangered due to forest fires, climate change, and anthropogenic factors. Strategies to protect biodiversity are required to address this situation. However, studies on conservation status are still lacking and limited to certain species because they have unique characteristics, so they do not always respond well to proposed strategies. Spatial modeling of potentially suitable habitats is essential in effective biodiversity conservation management. Using machine learning algorithms, more than 500 species points occurrence and ten environmental predictors consist of weather and climate aspects, topography, vegetation cover, air pollution, and fire prediction points from future climate model data to predict potential habitats for suitable species. From remote sensing data also analyzes the predictor variables that influence it. This study is resulting in predictions of flora and fauna habitat based on the Random Forest algorithm with suitable and unsuitable values. The novelty in the results of this study provides spatial modeling of the habitats of rare and endangered species so that policymakers can immediately take practical conservation actions to protect species from the threat of extinction.

Keywords: biodiversity, machine learning, remote sensing, and species distribution model.
Occurrence, distribution and behaviour of contaminants of emerging concern and regulated organic pollutants. Case study: the endorheic catchment of Fuente de Piedra Lagoon (Southern Spain). 
Authors: Llamas Marta , Jiménez-Martínez Joaquín , Vadillo Iñaki , Jiménez-Gavilán Pablo , Lara-Martín Pablo , Corada-Fernández Carmen
Published: March 2022

Contaminants of Emerging Concern (CECs) and regulated organic pollutants pose a serious threat to water quality and their spatial distribution is challenging to assess as it can be driven by several factors.

In the current work, we focus on the distribution of a wide range of regulated and non-regulated organic contaminants in groundwater of the Fuente de Piedra lagoon catchment, in Southern Spain. Groundwater samples were collected and they were analyzed for (I) 185 organic contaminants and (II) water ions and stable isotopes (δ2H, δ18O and δ13C). Target organic contaminants included pharmaceuticals, personal care products, polyaromatic hydrocarbons, pesticides, flame retardants and plastizicers.

The Fuente de Piedra lagoon is a hypersaline wetland located in an endorheic basin (150 km2) in which three main aquifer types, with an hydraulic connection, can be distinguished: (I) unconfined carbonate aquifers with low mineralized water corresponding to two mountain ranges; (II) an unconfined porous aquifer formed by Quaternary and Miocene deposits, more exposed to pollution from anthropogenic activities; and (III) a karstic-type confined aquifer developed in a massive accumulation of evaporites and gypsum (Upper Triassic). 

In total, 32 organic contaminants were detected, at least once. An attempt to evaluate the importance of the different factors affecting the spatial distribution of the organic contaminants have been conducted. Attention has been paid to the main physico-chemical properties of the pollutants (hydrophobicity and speciation), distribution of pollution sources and anthropogenic pressures in the area (including water management practices) and hydrogeological characteristics of the different aquifers. A geochemical model has been built to characterize water mixing processes in order to better understand transport and fate of these organic contaminants.
3D Evolution of a Restraining Bend: Insights from Physical Analogue Modelling
Authors: R. Nogueira Carlos , O. Marques Fernando
Published: March 2022

Restraining bends are tectonic structures related to strike-slip fault zones, a common mode of deformation in the crust. Frequently, they show complex 3D geometries and kinematics, which brings difficulties when analysing their evolution. We used physical analogue models together with sequential scanning of the surface deformation and imaging of internal deformation to better understand their deformation evolution. Perspex parallelepiped box was used with three lateral ﬁxed walls, one mobile that worked as a vertical piston and two parallel basal plates with a step contact, where one remained fixed and the other was mobile attached to the back vertical wall, creating a strike-slip displacement with a contractional step-over, a restraining bend. The mobile walls were pushed by a computer-controlled stepping motor at steady velocity, so deforming the models. Fine dry natural quartz sand from Fontainebleau was used as the analogue of brittle rocks. Sequential scanning of the model surface was performed during the model deformation and complemented with digital time-lapse image acquisition synchronized with LiDAR scanning, using an 18 MP camera orthogonally positioned to the model surface (top view), in order to monitor the structures development, their timing and in-plane displacements. Sequential slicing of the model at the end of each deformation step was performed to obtain the internal deformation evolution of the model. Therefore, we present in this work a 4D perspective (3D evolution) of a restraining bend, describing its geometry evolution, kinematics, and host-rock material accommodation. Model results are then compared with the structure of natural models of similar restraining bends.

Acknowledgements: CRN would like to acknowledge the financial support of FCT through grant SFRH/BD/71005/2010 and project UIDB/50019/2020 – IDL.
Hydropower capacity expansion in the African continent under different socio-economic and climate policy scenarios
Authors: Carlino Angelo , Wildemeersch Matthias , Giuliani Matteo , Castelletti Andrea
Published: March 2022

Hydropower and other renewable energy sources are experiencing new investments for capacity expansion to provide clean and accessible energy to a growing population in many world areas. As most of the untapped hydropower potential lies in developing countries, here, strategic dam planning is critical in supporting the design of capacity expansion with reduced impact on interconnected water, food, and climate systems.

This is true especially for Africa, where more than 300 new hydropower projects are under consideration, and future population growth projections and associated energy, water, and food demands are highly uncertain.

In this work, we investigate how to strategically plan hydropower capacity expansion at the African continental scale, providing an estimate of future hydropower capacity needs. Specifically, we model the energy system using The Electricity Base Model for Africa (TEMBA), based on the OSeMOSYS energy modelling framework, and we consider capacity factors for each hydropower project reported in the African Hydropower Atlas as derived from the hydrologic simulation of the SWAT model that accounts for irrigation demand. To explore different socio-economic and climate policy projections, we also downscale final energy demands projections at the country level from the SSP database. We then investigate two different planning approaches: first, using scenario analysis, we examine how the different individual projections influence hydropower and power system development; second, we adopt a two-stage robust optimization methodology to develop a robust capacity expansion plan common for all the socio-economic and climate policy scenarios until 2035. Finally, we hypothesize that uncertainty about the socio-economic scenario is resolved, and we model the adaptation of the capacity expansion strategy to each of the narratives considered in the period 2035-2050 by solving a new optimization problem.

Our results show that not all the 100 GW of hydropower projects considered in the African Hydropower Atlas are needed to satisfy the final energy demands. Furthermore, as we observe large variability in hydropower capacity expansion under different socio-economic projections, we produce a short-term robust plan extracting the most relevant hydroelectric projects via robust optimization. Finally, we show that adapting capacity planning decisions based on new information can strongly reduce the price of robustness.

Our work proposes a methodology for taking planning decisions in an integrated assessment context where scenarios are used to link different societal sectors and resources. When the uncertainty spanned by plausible future states of the world is large and diverging, a combination of robust optimization and adaptive planning can reduce the potential for bad societal outcomes.
Resolving thermomechanical ice flow on Alpine topography
Authors: Räss Ludovic , Utkin Ivan , Omlin Samuel
Published: March 2022

The evolution of glaciers and ice sheets depends sensitively on the processes occurring at their boundaries such as, e.g., the ice-bedrock interface or shear margins. These boundary regions share as common characteristics the transition from flow to no flow over a relatively short distance, resulting in a complex and fundamentally non-hydrostatic stress field. The localised intense shearing may further induce weakening of the ice owing to thermomechanical interactions, ultimately accelerating and potentially destabilising the bulk of the ice. Better understanding the sensitivity of these near-boundary processes is vital and challenging as it requires non-linear and coupled full Stokes models that can afford very high resolution in three-dimensions.

We present recent development of a thermomechanical coupled numerical model that leverages graphical processing units (GPUs) acceleration to resolve the instantaneous stress and velocity fields within ice flow over complex topography in three dimensions. We apply the model to various glaciers of the Swiss Alps resolving the complex flow field in three dimensions and at very high spatial resolution. We further use the model to assess the competition between basal sliding and internal sliding, the latter referring to the formation of a near-basal internal shear zone within the ice owing to thermomechanical feedback. We finally provide some insights in GPU-based high-performance computing model development using the Julia language and the ongoing development of efficient implicit iterative solvers based on the accelerated pseudo-transient method.
Origin of gabbro and anorthosite mineral clusters in Fagradalsfjall lavas
Authors: Wenrich William , Bali Eniko , Marshall Edward W. , Gudfinnssonn Gudmundur
Published: March 2022

The 2021 Fagradalsfjall lava brought a number of mineral clusters/xenoliths <6cm in diameter to the surface. Of the >40 samples collected from the field, eight xenoliths and one plagioclase megacryst were analyzed by stereo- and petrographic microscopes and the electron microprobe. In hand specimen, the xenoliths were sub-rounded to rounded, and were olivine and clinopyroxene bearing anorthositic gabbros and anorthosites. During thin section characterization, deformed and undeformed textural types were distinguished. In deformed xenoliths, deformation textures such as undulose extinction, deformed albite twinning, and triple junctions were observed in plagioclases. Plagioclase in deformed samples was typically unzoned and had bimodal crystal size distribution. Olivines had normal zoning where they were in contact with interstitial melt and more pronounced zoning was observed on the edges on the clusters. Undeformed samples did not show deformation features and had ophitic and poikilitic texture. Clinopyroxene in undeformed xenoliths was commonly observed interstitially as well as discrete subhedral crystals. The interstitial clinopyroxene resorbed the edges of plagioclase and olivine and had uniform extinction in all but one sample. 
Electron microprobe results show that the compositional variation of minerals within the xenoliths overlaps and exceeds the compositional variation of the host lava macrocryst cargo. Olivine forsterite, plag anorthite, Cpx Mg#, and Cr# content ranged from 80-89, 76-89, 82-87, and 6-18, respectively in mineral cores and 59-86, 65-86, 71-87, and 0.4-12, respectively, in zoned rims. Mineral compositions overlap in both deformed and undeformed samples. In general, undeformed samples cover a broader range compared to deformed ones, the latter being much more uniformly primitive. One deformed sample is an outlier with significantly lower forsterite (~73-79), anorthite (~66-71), and Mg# (~74) in clinopyroxene compared to the rest of the clusters and lava phenocrysts.
Plagioclases in most xenoliths contained devitrified silicate melt inclusions. Melt compositions after post entrapment corrections are in equilibrium with their host plagioclases according to Putirka (2008). The calculated temperatures based on plagioclase melt pairs indicate a difference in crystallization environment between the clusters that overlap the lava phenocrysts and the evolved outlier. The average crystallization temperatures for most xenoliths is 1222°C, whereas for the deformed one is 1191°C, respectively. With an error of ±23°C, these two temperatures could be from separate sources.