bluuebunny/crossref_metadata_2025 huggingface dataset:
Stress field in NW Galati seismotectonic area (Romania): insights from the inversion of earthquake focal mechanisms
Authors: Craiu Andreea , Diaconescu Mihail , Craiu Marius , Mihai Marius , Armeanu Iulia , Marmureanu Alexandru
Published: February 2023

An intense and unusually seismic activity, occurred during September-October 2013, in Galati-Izvoarele region, situated in the central-eastern part of Romania, between two main crustal faults, Sf. Gheorghe and Peceneaga Camena fault. With several hundred (~400) earthquakes recorded in a short time, the activity was considered as seismic swarm. The magnitude ML was always below 4, with three shocks of magnitude 3.9, accompanied by specific seismicity bursts and focal depths ranging from 1 and 40 km. The focal mechanism solutions of the studied earthquakes obtained from P-wave polarities generally show normal faulting, with an important strike-slip component in several cases. For the seismic source delineated in Galati-Izvoarele area, the stress field has an extensional stress regime (σ1 almost vertical), with maximum horizontal stress (SHmax) oriented in the NNW-SSE direction. The resulting SHmax orientation and normal fault regime with a radial component (R′=0.5) are consistent with the observed geological setting.The results of this study are useful for revealing the crustal stress field, and, as such, for assessing past and current tectonic activities and potential future earthquake generation.Also, transdisciplinary studies can trigger unexpected collaborations between researchers from diverse fields to understand the processes and conditions causing the initial stages of rock failure, and the interplay between mineral and tectonic scale processes.
The role of water management technologies in regulating iron-phosphorus interaction in rice rhizosphere
Authors: Celi Luisella , Martinengo Sara , Schiavon Michela , Romani Marco , Said-Pullicino Daniel , Seyfferth Angelia , Martin Maria
Published: February 2023

Phosphorus (P) availability to rice plants is influenced by its strong interaction with iron (Fe). In the rhizosphere microenvironment, the soil-plant interactions cause the formation of Fe-plaques that can retain porewater components, such as P. The Fe-P processes have been extensively described in paddy soils managed under continuous flooding, although, due to the increasing water scarcity, new water-saving techniques have been adopted. However, their effects on P retention/release mechanisms are largely unknown.   In order to assess the impacts of water-saving techniques on the rhizosphere Fe-P dynamics and P availability to rice, a macrocosm experiment was conducted to compare the effects of three different water management practices: continuous water flooding (WFL), alternated wet and dry (AWD), and delayed flooding (DFL). Three P fertilization levels were tested for each water management strategy. The concentrations of Fe and P in porewater were monitored until rice harvesting. The plant tissues were analyzed for P concentration, and the content of amorphous and crystalline Fe (hydr)oxides in root plaque was estimated via oxalate and dithionite extractions at mid-tillering, stem elongation, heading and harvesting. The molar P/Fe ratio in porewater and the formation of Fe plaques differed as a result of the combined effect of water management and P fertilization.  The WFL and DFL treatments led to a higher Fe plaque formation with respect to AWD, while in all water management treatments, Fe plaque formation was higher without P fertilization. The early rice development stages were characterized by a greater amount of amorphous Fe (hydr)oxides in root plaques. The proportion of crystalline Fe (hydr)oxides increased with plant development, despite the lower amount of total Fe plaques, suggesting a reduction of the poorly ordered fraction, especially when no P was supplied. Rice plants could be supposed to respond to P-limited conditions, exuding protons and/or organic acid anions that increase P availability through Fe plaque dissolution. This was confirmed by the negative correlation between porewater P concentration and the content of crystalline Fe in the plaques. These results indicate the complex spatio-temporal interconnection between P and Fe cycling at the root-soil interface. The amount of Fe plaques formed on the root surface and their crystallinity degree can explain the mechanisms that regulate their potential in P retention/release and the consequent effects on plant uptake. This study was funded by the PSR Lombardia 2014-2020 (“P-rice Fosforo in risaia: equilibrio tra produttività e ambiente nell'ottica delle nuove pratiche agronomiche”) 
Vertical pathways associated with a submesoscale density front in the Balearic Sea
Authors: Garcia-Jove Maximo , Mourre Baptiste , Santana Alex , Zarokanellos Nikolaos D. , Lermusiaux Pierre F. J. , Rudnick Daniel L. , Tintoré Joaquín
Published: February 2023

The CALYPSO research program, funded by the Office of Naval Research, aims to understand the coherent pathways from the surface ocean to the interior. In February and March 2022, the CALYPSO campaign surveyed the upper layers of the Balearic Sea (Western Mediterranean), providing high-resolution observations of mesoscale and submesoscale structures. This included submesoscale density fronts, stretching regions and small coherent eddies. In this work, we analyze the formation, evolution, and impact of these submesoscale structures in the development of vertical velocities and in the determination of three-dimensional pathways from the surface to the ocean interior. We combine multi-platform in-situ observations with high-resolution numerical simulations both in free-run and data-assimilative modes. In particular, the WMOP reanalysis  assimilates remote sensing observations of temperature and sea level anomaly as well as vertical profiles of temperature and salinity from floats, underway CTD and gliders obtained during the CALYPSO campaign. The simulations are shown to realistically reproduce the main characteristics of the Balearic front and some of the associated submesoscale patterns, providing an appropriate tool to analyze the processes responsible for vertical velocities development. Particle tracking analyses indicate pathways for vertical exchange of water between the surface and the ocean interior in the frontal region. Finally, the process of frontogenesis and the submesoscale structures play an important role in the development of the vertical velocities and the energy transfers.
Beyond fractions and pools: Radiocarbon distributions as a constraint for soil organic carbon models
Authors: Stoner Shane , Trumbore Susan , Schrumpf Marion , Doetterl Sebastian , Sierra Carlos
Published: February 2023

Laboratory quantification and computer modeling of soil organic carbon (SOC) and radiocarbon (14C) rarely align well. Diverse lab methods exist to separate SOC into “fractions” with operationally defined boundaries which include physical, chemical, and biological thresholds. Compartmental soil models, on the other hand, use homogeneous “pools” to group SOC by its rate of decay. However, the stochastic nature of organic matter decomposition makes it virtually impossible to isolate model pools through fractionation or to model fractions as pools. Radiocarbon is a powerful metric that integrates C fluxes in and out of a system, but fraction and pool 14C valuesrepresent an average which may be composed of widely different C ages. In order to advance and constrain our understanding of SOC dynamics, we need to go beyond mean 14C values of operationally defined pools and instead use radiocarbon distributions. Thermal (oxidative) fractionation of SOC produces continuous C data as a function of temperature (20˚C to 900˚C), and discrete 14C measurements by collecting evolved gas. By fitting splines to 14C data and weighing by C release over temperature, a continuous mass-weighted distribution of 14C can be estimated. Recent modeling advances can similarly estimate system 14C distributions, and models may thus be constrained for the first time by continuous lab data. This convergence is a first step beyond pools and fractions that may significantly increase constraining power. We will present lab and mathematical methods, limitations, and outlooks for advancing soil SOC modeling.
Lake Neusiedl wetland (Austria/Hungary) in a changing environment: anthropogenic versus anthropogenic effects
Authors: Draganits Erich , Weißl Michael , Zámolyi András , Doneus Michael
Published: February 2023

Lake Neusiedl and adjacent lakes at the Austrian/Hungarian boundary represent a unique wetland, situated at the geodynamical and geomorphological boundary between the Alps, Carpathians and the Pannonian Basin, and therefore represents an important transition zone concerning terrain, climate, vegetation and fauna. The more than 700 km2 large area is one of the flattest regions of Austria with less than 17 m relief variation. Today, Lake Neusiedl measures some 320 km2 with less than 1.8 m depth and a tectonic origin is widely accepted. East of the lake, about 30 shallow lakes still exist, of which the largest measures less than 2 km length and less than 1 m depth. At present, the water level of Lake Neusiedl shows the lowest values since 1965 and all the shallow lakes were dry during the summer 2022. We use high-resolution topographical, sedimentological, geomorphological as well as historical maps and historical charters to investigate the formation end evolution of Lake Neusiedl and adjacent lakes. Our data show that the present-day conditions and processes of Lake Neusiedl strongly diverge from conditions in the past. The earliest preserved record of modification of the lake´s hydrological conditions is from 1568, followed by increasing drainage efforts and the building of a dam road in the southeast, finished in 1780, which subsequently cut off the lake from its most important tributaries from the south. This palaeohydrological reconstruction of Lake Neusiedl and Hanság also implies an episodic lower salt content of the water compared to modern values, especially during flood periods. Therefore, it is not useful to compare the hydrological situation of Lake Neusiedl before 1780 (or even 1568) and after. The documented variation of the water level of Lake Neusiedl between desiccation and highest flood level is around 4.2 m. These variations affected enormous areas in this low-relief region, with a huge impact on the landscape, fauna, vegetation, human settlement patterns, land use, communication routes and even possible occurrence of malaria – which should be considered in regional archaeological, historical and biological interpretations. The numerous shallow lakes and presently dry basins, detected in the high-resolution airborne laser scanning data in the Seewinkel originally formed as thermokarst lakes during permafrost degradation after the end of the Last Glacial Maximum. In total, more than 370 enclosed depressions are visible. The depressions of eastern Austria represent one of the first Latest Pleistocene thermokarst lakes documented in central Europe. Although man-made climate change has a clear impact on the water balance of the lakes, they reinforce past hydrological modifications.
Water budget in the Rutor glacier area: results from multidisciplinary activities
Authors: Tamea Stefania , Corte Elisabetta , Camporeale Carlo
Published: February 2023

Due to global warming and glacial retreat, periglacial areas and headwater catchments are experiencing relevant changes in surface processes and in water budgets. The water cycle, altered by the changing snow accumulation/melting dynamics, ice ablation, higher altitude increasing rainfalls frequencies, is shifting towards larger average and peak runoff productions. These alterations have also an impact on sediment production, on geomorphological processes, on ecosystem dynamics. The goal of our research is to take advantage of multidisciplinary activities aimed at monitoring the glacial and peri-glacial area of the Rutor glacier, in the Aosta valley (north-western Italian Alps) to quantify its dynamics under climate change. The Rutor glacier is fast-retreating and has a terminus that moved more than 2 km since the mid-19th century: it is thus a perfect case study to investigate snow/ice dynamics and runoff production, considering also that the periglacial area is characterized by a number of lakes and channels that collect and convey the melt water, while dynamically responding to it. In this work, we present the results from a multidisciplinary collaboration that involves hydrologists, geophysicists, geomatics and water engineers with the goal of monitoring stream flows, water properties, lake water balance and runoff production. Thanks to the contribution of different disciplines, we could gain an advanced quantitative knowledge of the water budget in the area that will represent a starting point for further investigations of processes and interactions within this unique melting landscape.
The chlorine cycle on Mars: What do we know after three Mars years of observation with ACS on TGO?
Authors: Olsen Kevin S. , Trokhimovskiy Alexander , Fedorova Anna A. , Kleinbohl Armin , Lefèvre Franck , Montmessin Franck , Korablev Oleg I. , Alday Juan , Baggio Lucio , Belyaev Denis A. , Patrakeev Andrey S. , Shakun Alexey , Patel Manish
Published: February 2023

 The Atmospheric Chemistry Suite (ACS) on the ExoMars Trace Gas Orbiter (TGO) took its first science observation in April 2018, right before the onset of the Mars Year (MY) 34 global dust storm. One of the main objectives of the TGO mission is to search for as-yet undetected trace gases that can tell us about contemporary volcanism on Mars, or its present and past habitability. In the data collected those first months, heavily impacted by dust activity, the first novel trace gas was discovered: hydrogen chloride. MY 37 has just begun and we have recently finished observing our third full dusty season on Mars with TGO and ACS (around perihelion, spring and summer in the southern hemisphere). HCl in the atmosphere of Mars is a seasonal phenomenon, having appeared coincidentally with the start of dust activity in each MY. HCl was thought to be an indication of contemporary volcanism, but its widespread distribution across both hemispheres and recurring seasonality are suggestive of a photochemical source. Here, we present the climatology of HCl after three Martian perihelion periods, as well as a comparison with other parameters measured with ACS, such as water, temperature, and aerosols. From coincident measurements made with the Mars Climate Sounder (MCS) on Mars Reconnaissance Orbiter (MRO), we can also compare the climatology of HCl with those of dust and water ice. HCl is strongly correlated to water vapour, which is itself correlated to atmospheric temperatures. While HCl only appears in the presence of suspended dust aerosols, the measured abundances of these two quantities are poorly correlated. The disappearance of HCl towards the autumnal equinox may be related to changes in temperature. The cooling atmosphere removes water vapour from the gas phase, necessary for formation of HCl, and promotes ice formation, which HCl may adhere to. We will show the evolution of HCl abundance over three Martian years in both hemispheres, and show how they fit into the seasonality of Martian dust, the water cycle, and ice formation, and discuss the possible mechanisms of its formation and destruction.
An EPANET metamodel based on Simplicial Convolutional Networks
Authors: Kerimov Bulat , Tscheikner-Gratl Franz , Taormina Riccardo
Published: February 2023

Metamodels reproduce the response surface of physics-based models while significantly reducing simulation times. Such techniques are widely employed in water distribution system analysis since they enable the application of computationally expensive methods in designing, controlling, and optimizing water networks. Recent works proposed graph neural networks as candidates for metamodels. These models bear inductive biases as one can draw analogies between links and nodes in the graph with the pipes and junctions. This implies that new metamodels using this approach can be applied to an unseen water network topology without re-training. However, there is no evidence of the transferability properties of those metamodels so far. This work introduces Simplicial Convolutional Networks (SCNs), which offer the potential of developing transferable metamodels that can generalize across different systems.  We test the suitability of SCNs to estimate pipe flowrates and nodal pressures emulating steady-state EPANET simulations. We compare the accuracy of SCN metamodels against graph neural networks on several benchmark water networks available in the literature. Moreover, we show that SCNs are able to generalize better than graph neural networks by evaluating and measuring the performance of the metamodel in an unseen setting.
Variability of residual flow drivers in estuaries: numerical investigations
Authors: Garel Erwan , Khosravi Maziar , Fortunato André , Lopez-Ruiz Alejandro , Valle-Levinson Arnoldo
Published: February 2023

Residual exchange flows in estuaries can be either laterally sheared, vertically sheared, or a mix of both, depending on the competition between baroclinic and barotropic forcings. Observations of the residual flow structure at subtropical, semi-arid and temperate estuaries indicate that the dominant forcing (horizontal density gradient or tidal stress) may vary at a fortnightly to seasonal timescale. This work aims at characterizing the variability of residual flow drivers in estuaries based on process-oriented numerical simulations with simplified geometry. The hydrodynamic model (Delft3D) is constituted by a straight estuarine channel of 80 km in length and a Gaussian-shape cross-section of 1 km in width, forced by a semi-diurnal (M2) tide. The computational grid includes 240 and 15 nodes along and across the channel, respectively (about 333 m x 67 m resolution) and 20 uniform vertical layers. A total of 20 runs of 6 months were performed to explore the effects of various channel depths, river discharges and tidal amplitudes on the spatial structure of residual flows. The results show distinct cross-channel structures for each experiment and suggest a switch of the dominant driver (between tidally-driven and density-driven) along the channel in some cases. The spatial variability of residual flows is first examined against both the horizontal density gradient and the tidal velocity amplitude to characterize the competition between barotropic and baroclinic forcings. The dynamics of residual flow is then approximated by the tidally averaged momentum equation, applied at every grid point of the model domain, to derive dimensionless parameters (such as the densimetric tidal Froude number) for prediction of the dominant residual flow drivers both temporally and spatially (i.e., along the channel).
Combining Earth cryosphere microwave radiometry and radar to understand the properties of planetary ices
Authors: Bonnefoy Lea , Prigent Catherine , Soriot Clément , Kilic Lise
Published: February 2023

Interpreting microwave data on icy moons in terms of physical parameters is a key challenge offered by observations of Ganymede and Europa by both the current Juno (NASA) MicroWave Radiometer (MWR) and the future JUICE (ESA) Submillimeter Wave Instrument (SWI). From sub-millimeter to decimeter scale wavelengths, radiometry is sensitive to different depths and scatterer sizes: each frequency offers complementary information. Despite the large volume of available passive and active microwave satellite observations over the Earth cryosphere, physical interpretation of the co-variability of the multi-frequency observations is still challenging, especially when trying to reconcile radiometry and radar observations. To help interpret icy moon observations and improve our understanding of Earth’s ices, we assemble a multi-frequency active and passive microwave observation dataset from the SMAP (1.4 GHz, passive), AMSR2 (6 to 89 GHz, passive) and ASCAT (5 GHz, active) missions. The data are gridded over Earth’s land and ocean ices and averaged over 10 days, over two full years and then classified using a k-means method. We identify regions with microwave behavior analogous to that observed on icy moons and simulate them using the Snow Microwave Radiative Transfer (SMRT) model. Identifying structures responsible for given microwave signatures will help interpret the Juno MWR observations on Jupiter’s moons as well as the joint active/passive 2.2-cm Cassini data acquired from 2004 to 2017 on Saturn’s icy satellites. 
Including water quality in the water-energy-food nexus: An Upper White Nile case study
Authors: Schlemm Annika , Mulligan Mark , van Griensven Ann
Published: February 2023

The Upper White Nile basin plays a critical role in supporting essential ecosystem services and the livelihoods of millions of people in East Africa. The basin has been exposed to tremendous environmental pressures following extensive population growth, urbanisation, and land use change, all of which are compounded by the threats posed by climate change. The water-energy-food (WEF) nexus provides an integrated solution to sustainable development by minimising the trade-offs between water, energy, and food resources. We apply quantitative and qualitative methods to understand the most pressing WEF nexus challenges within the Upper White Nile basin, how these can be represented in indicators, and how existing WEF nexus modelling tools could address this. This research combines semi-structured stakeholder interviews with a Co$tingNature analysis in order to map the greatest environmental pressures within the basin and disentangle the likely drivers. The findings from these highlight the importance of declining water quality, aquatic and terrestrial ecosystem health, and fish populations as a result of deforestation, growing human population, intensifying pollution, and increasing agricultural intensity within the basin, with most stakeholders expressing concerns for the uncertain impacts from climate change. Furthermore, a review of current WEF nexus modelling tools reveals how existing tools are insufficient in addressing the most pressing environmental challenges within the basin, with a significant gap regarding the inclusion of nuanced water quality and aquatic ecosystem indicators. Subsequently, these findings are combined in order to guide the development of holistic WEF nexus indicators that have the potential to spatially model the trade-offs within the WEF nexus in the Upper White Nile basin under climate change and land use change scenarios. This work demonstrates the use of a novel decision framework for WEF nexus indicator development, which ensures that outputs are fit-for-purpose and respond to the actual needs of stakeholders and policymakers. The outputs aim to strengthen water management decisions that enhance water quality, energy production, food production, and aquatic biodiversity within the Upper White Nile basin.
The effect of Arctic sea-ice loss on extratropical cyclones
Authors: Hay Stephanie , Priestley Matthew , Yu Hao , Catto Jennifer , Screen James
Published: February 2023

We use a Lagrangian objective feature tracking algorithm with the PAMIP experiments to determine the response of extratropical cyclones to sea-ice loss and consequent weakening of the equator-to-pole near-surface temperature gradient. The wintertime storm tracks are found to shift equatorward in the North Atlantic and over Europe, and eastward in the North Pacific. In both regions, cyclones become weaker and slower, particularly on the poleward flank of the storm tracks. On average, there are fewer individual cyclones in the extratropics each winter, they last longer, are weaker, and propagate more slowly. These changes are greatest for Arctic cyclones, but still statistically significant in the midlatitudes despite being small compared to internal variability. Inter-model spread in cyclone responses is comparable to the magnitude of the multi-model mean response. Little change in summertime equator-to-pole near-surface temperature gradient or in extratropical cyclones is found. Separately, we determine the response to extratropical cyclones to future SST change and compare to the response found in the CMIP6 simulations in order to place our conclusions within the broader context of climate change.
Quantifying provenance of soil originated from mass movement on soil reservoir-bank using rare earth elements
Authors: Ran Guang , Li Tian , Xu Xiangzhou
Published: February 2023

Abstract：The reservoir-bank collapse has caused soil erosion and bank expansion in the lower Yellow River, which seriously affects the ecological environment and agricultural development. Understanding the processes of mass movement occurred on reservoir-bank is important to predict and control bank expansion. However, little research exists concerning how to accurately quantify the process of bank collapse and trace the source of sediment. In this study, a reservoir-bank model with the gentle slope of 3°, steep slope of 40° and abrupt slope of 70°, was constructed according to geomorphological characteristics of the soil reservoir-bank in Xiaolangdi Reservoir, in which rare earth elements were used to trace the provenance of sediment originated from mass movement on reservoir-bank under different rainfall conditions, and quantify the soil loss from the bank contributed to sediment deposition in reservoir. The results show that the sediment in reservoir mainly comes from steep slope, and the percentage contribution of abrupt slope to the total soil loss increases significantly in rainstorms with the precipitation larger than 60 mm. Under the rainstorms, the contributions of the gentle slope, steep slope and abrupt slope to soil loss were 10%, 55% and 35%, respectively. Without rainstorm, the contributions of the gentle slope, steep slope, and abrupt slope to soil loss were 4%, 72% and 24%, respectively. Meanwhile, sediment deposition in reservoir also mainly derived from steep slope and abrupt slope. The contribution of steep slope and abrupt slope to sediment deposition were 49% and 40% under the rainstorms, and the contribution of steep slope and abrupt slope to sediment deposition without rainfall were 67% and 28%, respectively. In addition, most of the sediment generated from the lower abrupt slope accumulates near the reservoir-bank, while the sediment generated from the steep slope accumulates at a distance from the reservoir-bank. Under the rainstorms, the contribution of upper steep slope to sediment deposition was 54% at 240 cm from the reservoir-bank, while the contribution of lower steep slope to sediment deposition without rainfall was 70% at 180 cm from the reservoir-bank. Whether with or without rainfall, the contribution of lower abrupt slope to sediment deposition was all about 54% at 40 cm from the reservoir-bank. Thus, in the near future, engineering measures such as grid protected slope may be used in the reservoir area to protect the steep slope of reservoir-bank, which can effectively reduce soil erosion and bank expansion in the reservoir area.Keywords: Bank collapse; Mass movement; Xiaolangdi Reservoir; REEs; Rainstorm
Risks of space radiation exposure to exploration astronauts: limitations in predictions based on the ground experiments and possible solutions
Authors: Khaksarighiri Salman , Wimmer-Schweingruber Robert , Guo Jingnan , Zeitlin Cary , Berger Thomas , Matthiä Daniel
Published: February 2023

Future expeditions into interplanetary space, and in particular to the Moon and Mars, will expose astronauts to very high levels of cosmic radiation, which are known due to years of research and instruments that have been sent to space. It is, however, a limitation in understanding the risks of this radiation for the human body due to difficulties in simulating the complex space environment on Earth or complex human phantom and the inability to extrapolate human clinical outcomes based on animal models or simulation results. As human spaceflight continues on its path to success, we need to develop appropriate and effective mitigation strategies for future missions to improve our understanding of the space radiation risk by identifying the constraints of radiation research on the Earth and finding possible solutions based on the existing technologies to be closer to the reality as much as possible and better understand human physiology in space.  As part of this paper, we have identified several factors that hinder our understanding of radiation risks for human crews and have identified ways to cope with these restrictions for a better understanding and preparation for human spaceflights in the future.
Response of coral reefs and mangroves to Holocene sea-level changes: insights from Belitung Island, Indonesia
Authors: de Gelder Gino , Solihuddin Tubagus , Isik Frida , Husson Laurent , Rhomadana Meggi , Agusta Vera Christanti , Utami Dwi Amanda , Erkan Dilruba , Cahyarini Sri Yudawati
Published: February 2023

Coral reefs and mangroves are important yet vulnerable coastal ecosystems, especially given strong anthropogenic pressure such as the projected 21st century sea-level rise. Despite the symbiotic relationship of reefs and mangroves within the context of sea-level changes, few studies provided a synchronous assessment of both systems, especially on timescales beyond a few decades. We focus on the response of coral reefs and mangroves in Belitung Island (Indonesia), where previous studies have already provided initial constraints on Holocene relative sea-level history. Along 3 different coastal transects within a distance of ~40 km, we surveyed and sampled 8 sedimentary cores of 1-3 m length, containing coral fragments, mangrove mud/sands and other types of coastal sediment. The three cross-sections evidence a surprisingly variable responses to the same sea-level history: 1) at Sidjuk, a mid-Holocene (~6 ka) coral reef within a former embayment was slowly filled up with sediments providing the substrate for estuarine mangrove development, 2) at Batu Itam, ~500 m of open coast mangroves prograded on top of a mid-Holocene reef, currently occupying around one third of the area within the intertidal zone and 3) at Mendanau, ~ 1 km of open coast mangroves prograded directly on top of basement rocks, with fossil corals seemingly sparse and isolated compared to the other sites. These results demonstrate how reef and mangrove response to sea-level changes may be extremely local in nature, and directly dictated by physical parameters such as sedimentation, wave erosion and reef construction rates. The spatial heterogeneity on the scale of a few 10s of kilometers emphasizes the need for tailored solutions with regards to future sea-level rise.
A review of deep learning for weather prediction
Authors: Thümmel Jannik , Butz Martin , Goswami Bedartha
Published: February 2023

Recent years have seen substantial performance-improvements of deep-learning-basedweather prediction models (DLWPs). These models cover a large range of temporal andspatial resolutions—from nowcasting to seasonal forecasting and on scales ranging fromsingle to hundreds of kilometers. DLWPs also exhibit a wide variety of neural architec-tures and training schemes, with no clear consensus on best practices. Focusing on theshort-to-mid-term forecasting ranges, we review several recent, best-performing modelswith respect to critical design choices. We emphasize the importance of self-organizinglatent representations and inductive biases in DLWPs: While NWPs are designed to sim-ulate resolvable physical processes and integrate unresolvable subgrid-scale processes byapproximate parameterizations, DLWPs allow the latent representation of both kinds ofdynamics. The purpose of this review is to facilitate targeted research developments andunderstanding of how design choices influence performance of DLWPs. While there isno single best model, we highlight promising avenues towards accurate spatio-temporalmodeling, probabilistic forecasts and computationally efficient training and infer
Study of clear air turbulence (detection, observation, generation) in the Tropical Upper Troposphere-Lower Stratosphere (UTLS)
Authors: Pitois Clara , Wilson Richard , Podglagen Aurélien , Hertzog Albert , Corcos Milena , Plougonven Riwal
Published: February 2023

The role played by turbulent mixing in the vertical transport of constituents in the UTLS is still poorly understood: there is a lack of knowledge of turbulence due to the limited number of observations in this region as well as to the limitations of current observation techniques.The first part of the present work deals with the detection of small-scale turbulence in the tropical upper troposphere - lower stratosphere from in-situ meteorological measurements collected under super-pressure balloons (SPBs). Eight SPBs were launched during the first Strateole-2 campaign, from November 2019 to March 2020 and flying for several weeks (∼ 3 months). Turbulence detection methods relies on the quasi-periodic vertical oscillations (∼ ±15 m) of the SPBs around their equilibrium positions, such oscillations inducing large fluctuations of measured quantities (pressure, temperature, positions) and inferred quantities (density, potential temperature). A first method of detection is based on correlations between the increments of potential temperature δθ and the vertical displacements of the balloons (i.e. of the sensors) δz. Such correlations are expected to be null as ∂θ/∂z → 0 in case of turbulent mixing. A second method relies on the Richardson number criterion, Ri < 0.25. Ri is deduced from the vertical gradients of measured quantities (T , u, v), estimated from covariances between the increments of the considered quantities and the vertical displacements δz. Turbulence indexes (true of false) to describe the different states of the flow encountered by the SPBs during their flights (laminar or turbulent), are evaluated. These different indexes, based on independent measurements and on various methods, correlations or linear regressions, are found to be consistent: they differ for less than 3% of the cases. The flow is observed to be turbulent for about 5% of the time, with strong inhomogeneities along the longitude.The second part of the present work aims to improve our understanding of turbulence, and its impacts, in the tropical UTLS by studying small- to meso-scale processes, i.e. atmospheric waves, deep convection and associated observed turbulence. These are all key processes of the dynamics of the equatorial UTLS. One can evaluate the probability of turbulence occurrences as a function of the distance to deep convection. Such a distance seems to be a good proxy of wave activity generated by deep convection. The occurrence frequency of turbulence is significantly larger when the distance to deep convection is small, i.e. smaller than ~ 200 km.This research should contribute to a better parametrization of these processes in climate models, and to a better estimation of their impact to vertical transport in the tropical UTLS.
Colloidal properties of clays related to the erosion and sedimentation behaviour of bentonite in fractures
Authors: Alonso Ursula , Missana Tiziana , Garcia-Gutierrez Miguel , Sellin Patrik
Published: February 2023

Smectites are selected as barriers in deep geological repositories for high-level radioactive waste repository due to their high swelling capacity and contaminant retention ability. Erosion of the clay barrier can affect repository safety and eroded particles may facilitate radionuclide migration within the host rock fractures. These processes depend on the physicochemical characteristics of the clay, on its structural properties and are affected by the chemical equilibrium established with the groundwater from the geological formation.In order to assess the relationship between clay colloidal properties and the erosion and sedimentation behaviour in fractures, this study correlates the erosion behaviour of a compacted bentonite barrier, under repository conditions, simulating expansion and sedimentation in artificial fractures with physicochemical macroscopic properties (viscosity, turbidity,...) of different smectite suspensions. Studies are carried out under different geochemical conditions.Results showed that sodium smectites had the highest viscosities, all showing similar behaviour: at low ionic strengths the viscosity remained constant and around 10 mM increased significantly. In spite of forming smaller particles, their expansion and sedimentation is hindered by their high viscosity. In contrast, clays with dominant bi-trivalent cations in their structure, has lower viscosity values, independent on the water ionic strength. Due to their higher particle size and lower viscosity, higher sedimentation in rock fractures is expected.Turbidity measurements over time were done to assess sedimentation behaviour. It was observed that sodium smectites remained stable over time, even at high ionic strengths, as observed in viscosity studies. With calcium clays, turbidity decreased rapidly, indicating fast sedimentation occurred.The study contributes to predict the erosion behaviour of the clay barrier in the fractures of the geological formation of a deep geological repository, starting from the colloidal properties of each clay.This work was partially supported by the Swedish Nuclear Fuel and Waste Management Co, SKB (Sweden) and by the Spanish Ministry of Innovation and Science (PID2019-106398GB-I00, ARNO Project).
Rates of High Mountain Asian Glacier Ice Loss from ICESat-2 Observations
Authors: Hassan Javed , Colgan William , Abbas Khan Shfaqat
Published: February 2023

The importance of glaciers in High Mountain Asia (HMA) is significant in sustaining mountain hydrology and the runoff of several river systems that originate from these glaciers. The availability of numerous remote sensing products provides an opportunity to assess the current regional glacier mass balance comprehensively. We updated and presented recent glacier mass loss from the HMA and regional variability using Ice, Cloud, and Land Elevation Satellite (ICESat-2) data from October 2018 to December 2021. The HMA experienced accelerated mass loss in recent years of -62.62 ± 11.81 Gt a-1, (-17.11 ± 2.89 m w.e a-1). All 22 regions of HMA lost mass during the study period, regional mass loss range between -0.28 ± 0.47 m w.e. a-1 in the Western Kunlun Shan and -1.71 ± 0.22 m w.e. a-1 in the Hengduan Shan. The highest mass loss occurred at Hengduan Shan, East Tibetan Mountains, and Nyainqentanglha. Glaciers within the altitude range up to 4000 m a.s.l experienced the most negative mass balance. In recent years glacier mass loss increased by more than two-fold compared to previous studies even in the regions where glaciers were previously in balance or less negative mass balance such as Western Kunlun Shan (-0.28 ± 0.47 m w.e. a-1), Eastern Pamir (-0.47 ± 0.374 m w.e. a-1), and Karakoram (-0.61 ± 0.40 m w.e. a-1). The complex regional pattern of variable glacial mass balance and recent mass loss can be attributed to heterogeneous climate change signals and changes in meteorological conditions over the regions.
Assessing distribution and pattern of the earthquake-related deformation caused by large continental normal earthquakes using optical image correlation
Authors: Andreuttiova Lucia , Hollingsworth James , Vermeesch Pieter , Mitchell Tom
Published: February 2023

Earthquakes on normal faults in the continental setting are relatively uncommon. The scarcity of surface-rupturing events underpins an absence of surface displacement measurements. It is a common practice to use surface offset as a proxy to understand the fault structure at depth. Hence, the lack of comprehensive surface data impedes the subsurface reconstruction of seismogenic normal faults and prohibits the thorough assessment of earthquake hazards. To supplement the available surface displacement measurements and to make statistically significant inferences, we apply optical image correlation (OIC) methods to historical images from three large continental normal earthquakes in the western United States (1954 Dixie Valley (Mw 6.8) - Fairview Peak (Mw 7.1) earthquake sequence, the 1959 Mw 7.2 Hebgen Lake earthquake and the 1983 Mw 6.9 Borah Peak earthquake). The results of this study are displacement maps with three components of deformation from which we extract high-resolution 3-d measurements everywhere along the surface rupture.  The high-resolution 3-d data are used to quantify the magnitude and direction of the earthquake-related offset, the percentage of off-fault damage as well as the width of the fault zone. These parameters represent the fault maturity, geometric complexity and subsurface structure of the fault. Our observations confirm behaviours previously observed along strike-slip faults (e.g. magnitude of off-fault deformation is proportional to the rupture complexity). In addition, a comparative assessment of the results from the three study areas demonstrates that features such as excess slip detected close to the fault scarp are not unique and can be found along multiple dip-slip faults. Consequently, this study documents the variation of the quantifiable parameters along the normal faults. It suggests that while some parameters are a universal reflection of the fault characteristics, others vary according to the geology or topography in the area and should not be accepted without further investigation.
Random Forest approach to forecast onset date and duration of rainy season in Tanzania
Authors: Nielsen Kristian , Troccoli Alberto , Roy Indrani , Mliwa Meshack
Published: February 2023

In the SADC region of Eastern Africa the onset and duration of the rainy season is of high importance to the agriculture and general water resource management. The planting time, selection of crops and success of different crops is linked to how skillfully this date can be forecasted.   As part of the Horizon 2020 project called FOCUS-Africa, in order to forecast this specific onset-date and duration for a specific location in Tanzania, we have constructed a statistical model utilizing the Random Forest algorithm. This is being trained using a mix of observation of past teleconnection indices such as IOD and ENSO3.4 from recent months that from earlier studies have shown to be connected to the onset date and dynamical seasonal forecast of precipitation with a daily temporal resolution. At this stage three dynamical models are included. Finally, the observed precipitation of the previous months is being used as predictors as well.   The first results have shown an improvement of the statistical model over using climatic information such as mean onset date as the reference forecast. This can be achieved 2-3 months ahead of the onset date. Furthermore, a relatively large importance of the seasonal forecast systems and the teleconnection indices seems to be present several months ahead of the observed onset date. This also indicates the importance of mixing observations and dynamical models in order to optimize the best possible overall skill of the system in predicting the onset date of the rainy season and thereby supporting local agriculture. 
Observation of VLF transmitter induced electron precipitation of up to 400keV
Authors: Neubüser Coralie , Battiston Roberto , Follega Francesco Maria , Burger William Jerome , Piersanti Mirko , Recchiuti Dario
Published: February 2023

Ground-based very low frequency (VLF; 10-30kHz) transmitters have been found in previous studies to emit whistler waves that can re- sonate with high-energy particles (>100keV) in the radiation belt, causing energetic electron precipitation via pitch angle scattering. In the attempt to find a similar mechanism responsible for electron precipitation due to EM waves emitted during seismic events, we ha- ve analysed three years of data (2019-2021) from the China Seismo- Electromagnetic Satellite (CSES) and the NOAA POES satellites. We found enhanced electron fluxes due to the 19.8kHz waves of the NWC transmitter in Australia at L-shell values of about 1.5 and 1.8 at energies up to 400keV in the data of the CSES and NOAA POES-19 sa- tellite, respectively. The enhanced fluxes can be followed along the drift shells from Australia eastwards, and are observed to be lost in the the South Atlantic Anomaly (SAA) due to the interaction with the atmosphere. The high energy resolution of the HEPP-L detector on board CSES of 11keV from 0.1 to 3MeV allows a detailed study of the signal and we will present the expected energy-dispersed wisp struc- ture in L-shell. Finally, we will present our latest results on the identification of isolated electron bursts and the assignment to dif- ferent VLF transmitters, which includes the correlation of VLF wave measurements from ground and space-based instruments to determined on/off periods of the transmitters.
Management Options to Improve Drought Resilience in Sugar Beet
Authors: Santos Pires Sabrina , Bodner Gernot , Stumpp Christine
Published: February 2023

Weather-extreme events are increasingly common due to climate change, with longer periods of drought and periods of strong rainfall. Drought periods are a problem in agriculture with several crops suffering from qualitative and quantitative yield reduction depending on the crop growth stage. Sugar beet (Beta Vulgaris) makes up 20% of sugar production worldwide and is the main source of sugar in temperate regions, with a recent increase in its use for biofuel production. The search for drought-resistant varieties of sugar beet with lower water requirements is expanding, however substantial variability in drought resistance regarding yield and quality has not been found so far. The goal of this study was to develop strategies to improve yield security in sugar beet cultivation under low water availability conditions. Therefore, two field experiments were established at sites representative of Austrian sugar beet production (Oberhausen, Marchfeld; Guntersdorf, Weinviertel) over the course of two years, 2020 and 2021. The experiments involved combining breeding strategies (variety selection) with agronomic approaches (soil management, land cover, irrigation, fertilization) to investigate the sugar beet's response to water stress and assess the performance of different sugar beet varieties, leading to a more climate-resilient sugar beet crop. Direct methods of measuring soil hydraulic properties (e.g. via soil moisture sensors) and plant properties (e.g. stomata density and conductance) with stable isotope analysis for carbon and water were combined. As a result, a significant yield increase was found in irrigated plots. Nitrogen fertilization had a detrimental effect when applied extensively. A yield increase was obtained by soil coverage with wooden chips in both years and sites. Furthermore, the choice of variety also played an essential role, especially regarding the trade-off between drought resistance and yield.