bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium and amorphous silica in Arctic soils: Estimating Pan-Arctic availabilities and importance for CO2 production
Authors: Stimmler Peter , Schaller Joerg
Published: February 2023

Future warming of the Arctic not only threatens to destabilize the enormous pool of organic carbon accumulated in permafrost soils, but may also mobilize elements such as calcium (Ca) or silicon (Si). Little is known about the effects of Si and Ca on carbon cycle processes in soils from Siberia, the Canadian Shield or Alaska. We incubated five different soils for six months with different Ca and amorphous Si (ASi) concentrations. Our results show a strong decrease in soil CO2 production for all soils with increasing Ca concentrations. The ASi effect was not clear across the different soils used, with soil CO2 production increasing, decreasing or not being significantly affected depending on the soil type and if the soils were initially drained or waterlogged. Including Ca as a controlling factor for Arctic soil CO2 production rates may therefore reduce uncertainties in modelling future scenarios on how Arctic regions may respond to climate change. To project how biogeochemical cycling in Arctic ecosystems will be affected by climate change, there is a need for data on element availability. For this we analysed ASi, Si, Ca, iron (Fe), phosphorus (P), and aluminium (Al) availability from 574 soil samples from the circumpolar Arctic region. We show large differences in element availability among different lithologies and Arctic regions. We summarized these data in pan-Arctic element maps focussing on the top 100 cm of Arctic soil. Furthermore, we provide values for element availability for the organic and the mineral layer of the seasonally thawing active layer as well as for the uppermost permafrost layer. Our spatially explicit data on differences in the availability of elements between the different lithological classes and regions now and in the future will improve Arctic Earth system models for estimating current and future carbon and nutrient feedbacks under climate change.
Coseismic and Early Postseismic of 23 November 2022 Mw = 5.9 Düzce Earthquake with InSAR and GNSS Measurements
Authors: Farımaz İlay , Doğan Uğur , Ergintav Semih , Çakır Ziyadin , Zabcı Cengiz , Özarpacı Seda , Özdemir Alpay , Ayruk Efe Turan , Eskiköy Figen , Belgen Alpay , Çakmak Rahşan
Published: February 2023

The North Anatolian Fault (NAF) was broken over the last century by a series of Mw > 7 earthquakes, most of which migrated westward, starting from the 1939 Erzincan Earthquake and ending with the 1999 Izmit and Düzce Earthquakes.  For 23 years the area remained silent for destructive earthquakes but also produced relatively small seismic activities until November 23, 2022 Düzce Earthquake, Mw 5.9.In this study, we aim to investigate the source mechanism for the 23rd November 2022 Düzce Earthquake and associate it to the ruptures of 1999 Izmit and Düzce Earthquakes. For this purpose, in the same day that the earthquake occurred, our team established 8 new continuous GNSS sites covering the area to monitor the postseismic deformation and surveyed the historical sites to estimate coseismic field. Additionally, a stack of interferograms has been interpreted from Sentinel-1 data to densify the deformation fields.Based on our first order analysis, the earthquake occurred at the overlap of the rupture zones of 1999 Izmit and Düzce Earthquakes (west of Eftani Lake on Düzce segment). Our GNSS and InSAR monitoring showed that the coseismic deformation is around <6 cm in the near field and ~33% of the InSAR coseismic deformation field is related with postseismic deformations.   Keywords: Düzce earthquake, Coseismic and early postseismic deformation, InSAR, GNSS
Simple self-shadowing in precise orbit determination of Copernicus Sentinel satellites
Authors: Arnold Daniel , Peter Heike , Jäggi Adrian
Published: February 2023

Numerous non-gravitational accelerations (NGAs) – due to radiation or gas-surface interactions – act on a typical satellite in low Earth orbit. The modeling of these accelerations is a key aspect of (reduced-)dynamic satellite precise orbit determination. Opposed to a purely empirical estimation of NGAs, especially orbit solutions with a high dynamical stiffness require an explicit NGA forward modelling. This is most important, e.g., for altimetry satellites which require utmost orbit accuracy especially in radial direction.For explicit NGA modelling, a commonly employed strategy is to describe the satellite body in terms of a relatively simple macro model, i.e., a geometry composed of a number of elementary shapes like flat plates, spheres or cylinders, each of which with a specific size, orientation and surface property. During orbit integration, for each individual elementary surface NGAs are then computed based on analytical expressions and the sum over all surfaces yields the total NGA of the satellite at integration epoch. Often each of the elementary surface of the satellite macro model is treated fully independent from the other surfaces and interactions, in particular the (partial) occultation or shadowing of one surface by other surfaces is neglected. In case of satellites with significant non-convex shapes (like the altimetry satellite Sentinel-6A) this can lead to a marked degradation of NGA modeling. On the other hand, very detailed satellite geometry models together with techniques like ray tracing can provide highly accurate NGAs, however, at the price of significantly increased processing times.In this contribution we assess the performance of a relatively simple self-shadowing algorithm for satellites described by a collection of flat convex polygons. Based on the relative plate locations, for each plate we analytically determine the amount of shadow cast by the other plates. We quantify the cost in terms of processing time and the impact on dynamic orbit solutions for the Copernicus Sentinel satellites in terms of empirical orbit parameters, observation residuals as well as other orbit quality metrics. We compare the so-derived NGAs and orbit solutions to results obtained with different other macro models and alternative approaches to take self-shadowing into account.
Carbon allocation in banana plants – the effects of drought stress and suckers
Authors: Vantyghem Mathilde , Beelen Eline , Hood-Nowotny Rebecca , Merckx Roel , Dercon Gerd
Published: February 2023

Banana is a perennial crop that propagates vegetatively through the formation of so-called suckers. Suckers are photosynthetically active, but remain connected to the mother plant. Their initial formation is driven by a carbon flux from the mother plant, but it is not known to which extent this flux persists once the sucker develops further. Drought stress is one of the most important limitations to banana production. Nonetheless, the effect of drought stress on the integrated system of mother plant and suckers remains unknown. In a greenhouse experiment, we aimed to quantify carbon fluxes in banana plants and assess the effects of drought stress and suckers on carbon allocation. We labeled banana mother plants with and without suckers with 13CO2, while the suckers were sealed gas tight. An optimal and suboptimal watering treatment were applied. The label was then traced in the phloem sap, in the leaves of mother plant and sucker and in the underground corm for a period of two weeks. Most of the label was either lost through respiration (37.5 ± 3.0 %) or allocated to the mother plant leaves (35.6 ± 2.2 %). Plants without suckers did not invest more in the growing mother plant, but instead, had higher respiratory losses. In plants with suckers, 3.1 ± 0.7 % of 13C assimilated by the mother plant was translocated to the sucker. Drought stress reduced the allocation to the sucker. On average, 5.8 ± 0.4 % of the label ended up in the corm, which connects all leaves and plant parts but also serves as a storage organ, by accumulating starch. Both drought stress and sucker presence increased overall translocation to the corm. Starch accumulation also increased under drought stress or in the presence of a sucker. However, when drought stress and a sucker were both present, starch accumulation was severely reduced. Finally, 17.2 ± 1.1 % of the label ended up in the wrapped leaf sheaths of the mother plant, that form the structurally important pseudostem. The pseudostem as well serves as a source of carbohydrates for future fruit and sucker development. Sucker presence increased carbon allocation to the pseudostem. In conclusion, it seems that suckers and drought stress affected carbon dynamics in banana plants similarly, namely by increasing carbon allocation to storage tissues. Their combination, however, resulted in an imbalance between carbon supply and demand and hence the plants’ investment in sucker growth, as well as in long-term storage were reduced.
What is the source of CO2 and CH4 at 150 meters depth? Studying CO2, CH4 and N2O concentrations and carbon isotopic signatures in the air of the Vadose Zone in Spain
Authors: Echeverría Martín Enrique , Fernández-Cortés Ángel , Kowalski Andrew S. , Serrano-Ortiz Penélope , Pérez Sánchez-Cañete Enrique
Published: February 2023

It is crucial to understand the cause-effect relationships of greenhouse gas (GHG: CO2, CH4 and N2O) concentrations and quantify their sources and sinks in natural systems, including their main reservoirs. This is particularly important when it comes to the vadose zone, which has the potential to store large amounts of GHGs in its pores. Currently, GHG measurements are mainly limited to the top few meters of soil, ignoring transport and storage processes in deeper areas. As a result, the vadose zone, with high concentrations of GHGs and a significant capacity for gas storage, is an enormous but unknown GHG reservoir.  
To improve knowledge of GHGs in the vadose zone, the air column of boreholes, soils and the atmosphere were sampling over the course of a year, with three sampling campaigns, generating depth profiles of GHG concentrations down to 150 meters. This study shows the behavior of GHG concentrations found in the vadose zone of several sampling campaigns carried out in boreholes of different aquifers in the south of Spain. Also, we focus on two with results showing fluctuating concentrations of CO2 (419-8452 ppm), CH4 (0.56-63 ppm) and N2O (0.33-1504 ppm). The carbon isotopic signature for CO2 was -9 and -10 ‰ for the atmosphere, between -22 and -25 ‰ for the soil and between -10 and -22 depending of the air column of the borehole. The isotopic composition of CO2 from sectors closer to surface results from a mixing process between the soil-derived CO2 and the local atmosphere. The 13C enrichment of CO2 in some deeper sector of the air columns denotes the CO2 contribution by outgassing of water reservoirs within the vadose zone that has experienced a high interaction with the host-rock. The carbon isotopic signature for CH4 was especially surprising with values fluctuating between -9.76 and -100 ‰. The 13C enrichment of CH4 with concentrations above 50 ppm CH4 may indicate a particular case in which intense production coexists with a high consumption by methanotrophic bacteria and the 13C depletion of CH4 shows a biotic generation of methane. Although the complexity of these values may involve other processes that will be discussed.
These results reveal great variability in concentration and origin of the underground atmosphere, indicating the need for further investigation in order to accurately characterize this significant reservoir of greenhouse gases.
This work was supported by the OAPN through the project PN2021-2820s (IBERALP).
Evidence of frequency-dependent directivity effects from non-ergodic ground motion modelling of Spectral Acceleration in Central Italy
Authors: Colavitti Leonardo , Lanzano Giovanni , Sgobba Sara , Pacor Francesca , Gallovič František
Published: February 2023

Rupture directivity and its potential frequency dependence is an open issue in the seismological community, especially for small-to-moderate earthquake. Directivity itself is the focusing of the radiated seismic wave energy due to the rupture propagation along the direction of the fault.In this research, we calibrate a non-ergodic ground motion model for the ordinates of the 5% acceleration response spectra (computation interval 0.04-2 sec) and we analyse, earthquake by earthquake, the azimuthal dependence of the aleatory component, i.e. the residual terms corrected for systematic source, site and path contributions. The final aim is the calibration of a prediction model including directivity effects that can be used for engineering purposes such as seismic hazard assessment and shaking scenarios generation.The study area is the Central Italy, which was affected by several seismic sequences in the last 20 years, occurred on normal fault systems. The dataset we used is composed by almost 300,000 seismic recordings of 456 earthquakes in the magnitude range from 3.4 to 6.5 within the time frame 2008-2018. We find that about one-third of the analysed events are directive, characterized by unilateral ruptures along the Apennine faults direction.Directivity effects occur over a wide frequency band and can be described by spectral curves peaked in different frequency ranges according to the event magnitude: the stronger the earthquake, the lower the frequency at which these effects are visible. Vice versa, we find no correlation between the amplitude of such peaks and the events magnitude. When normalized to the peak, the directivity curves can be grouped into families characterized by similar amplification trends variable with frequency, with the exception of 16 events, which we classify as "super-directive", that differ markedly from the others generating broadband amplifications.Preliminary results suggest that is possible to obtain similar shapes of directivity curves for defined frequency families and that they can consequently be modeled for non-ergodic ground motion model and predictive shaking scenarios.
Observing Sediment Transport in Taiwan's National Wetlands by Satellite Images
Authors: Chuang Shu-Ping , Chien Hwa , Chen Yen-Ti , Li Shin-Hui , Tseng Kuo-Hsin
Published: February 2023

Alluvial estuaries along the west coast of Taiwan play as habitats for several endangered species. Wetlands are widely scattered over the coastline, including two international-level and forty national-level sites. To understand their evolutions of erosion and siltation processes associated with coastal current and hydrological regime, we analyze 21 major wetlands by observing their interannual changes exhibited in the multiyear satellite images. We utilize Sentinel-2 multispectral data for digital elevation model (DEM) inversion. All low cloud-coverage images are first collected, and the intertidal topography is calculated through waterline detection, image stacking, and marking the tidal range by the DTU16 tide model. Temporal changes in topography are revealed by the reconstruction of DEM on a two-year rolling update. The quality of DEM is verified at an accuracy of sub-meter level, by the multibeam echosounder during high tide. We find that the groin effect and artificially nourished beach are the main causes of sedimentation, while the erosions commonly co-exist near the upstream of the ocean current.
Seven years of research on process-based, mechanistic modeling of aggregation and its drivers
Authors: Prechtel Alexander , Zech Simon , Ray Nadja
Published: February 2023

Advanced imaging techniques now allow to take snapshots of soils even down to the nanoscale. Nevertheless, assessing the temporal evolution of elemental distributions, distinguishing different liquid phases and identifying dynamic microbial processes is experimentally still challenging. Consequently mechanistic models operating at the pore scale facilitate the study and understanding of phenomena shaping soil structures as, e.g., carbon turnover, and vice versa.We present an overview of a versatile hybrid discrete continuum modeling approach combining cellular automata and partial differential equations, which integrates the complex coupling of biological, chemical, and physical processes. Dynamic liquid and gaseous phases, diffusive processes for solutes, mobile bacteria transforming into immobile biomass, and ions are prescribed by means of partial differential equations. Furthermore the solid phase is dynamic, e.g. through aggregation of soil particles, the addition and decomposition of particulate organic matter, or the mechanical influence of roots and their exudates. The virtual soil structures rely on micro-CT images or particle libraries derived from dynamic image analysis of water-stable aggregates.Applications include structure formation of clay minerals, the interplay between soil structural dynamics and organic matter turnover, or the impact/importance of liquid phase connectivity and substrate supply. Finally the mathematical homogenization technique is used to show a way how to incorporate information from the pore scale to macroscale models, e.g. by coupling microscale carbon turnover to profile-scale CO2 transport.
Using remotely sensed data to understand global lake colour variability
Authors: Liu Shuang , Glamore William , Liu Yi , Johnson Fiona
Published: February 2023

Water colour can reflect waterbody health and environmental conditions of inland waterbodies. As a result, changes in water colour may be associated with environmental dynamics resulting from either climate or catchment changes or both. In the absence of long term, spatially comprehensive global databases of lake water quality, satellite-derived water colour can be used to understand water quality variability. Here we analyse the spatial-temporal variability of water colour for nearly 200,000 inland waterbodies around the world using Landsat 5, 7, and 8 images for 35 years. We investigated the spatial variability in the baseline water colour and temporal patterns of water colour across 41 climate reference regions. We found that the mean dominant wavelengths of small waterbodies were constantly higher (less blue) than larger waterbodies. We also found that most waterbodies became increasingly bluer, with an average change of -14.5 nm ± 0.15nm over the 35-year study period. The exception were waterbodies in north-eastern Russia which tended to shift towards red wavelengths. The waterbodies were grouped based on their inter-annual water colour change and intra-annual variation (standard deviation) in water colour. Intra-annual variability increased for two thirds of the waterbodies over the study period. Around 20% of the waterbodies have tended to shift to redder wavelengths accompanied by increased intra-annual variation, which may indicate they are more vulnerable to environmental stresses. The findings from this work provide a strong baseline understanding of historical global lake water quality variability with which future projected climate change impacts can be compared.
Long-awaited and delayed Transportable Highest grade of Fiber Optic Gyroscope for Seismology
Authors: Guattari Frédéric , Lenogue Guillaume , Gautier Kevin , Frenois Arnaud , Couderette André
Published: February 2023

First announced at EGU2021, and said to be “released soon”, the 1C rotation seismometer which complements the blueSeis product line on the high performance segment, will be finally disclosed at EGU2023.2019 and 2020 results have been shared about large mockup of giant Fiber-Optic Gyroscope from iXblue, having diameter as large as 1.2 meters, and the development road to reach an industrial product had been drawn. But several critical additional issues raised on the track.Keeping in mind all the requirement of the instrument, the need for a transportable, and easily deployable instrument, the calibration capability, the possibility to push the performance pilling up the sensors, and the need for an optional orthogonal structure, we finally come to an instrumental solution with high versatility at expected performances.The full development story will be shared, and the tests results of first production units of blueSeis-1C will be disclosed. Explanation about the various way to use it will be offered too.Perspectives and applications using this long-awaited sensor will be presented, from ocean-bottom system tilt denoising to improved inversion of the seismic source.
Simulating wildfire impacts on boreal forest structure over the past 20,000 years since the Last Glacial Maximum in Central Yakutia, Siberia
Authors: Glückler Ramesh , Gloy Josias , Dietze Elisabeth , Herzschuh Ulrike , Kruse Stefan
Published: February 2023

Even though wildfires are an important ecological component of larch-dominated boreal forests in eastern Siberia, intensifying fire regimes may induce large-scale shifts in forest structure and composition. Recent paleoecological research suggests that such a state change, apart from threatening human livelihoods, may result in a positive feedback on intensifying wildfires and increased permafrost degradation [1]. Common fire-vegetation models mostly do not explicitly include detailed individual-based tree population dynamics. However, setting a focus on patterns of forest structure emerging from interactions among individual trees in the unique forest system of eastern Siberia may provide beneficial perspectives on the impacts of changing fire regimes. LAVESI (Larix Vegetation Simulator) has been previously introduced as an individual-based, spatially explicit vegetation model for simulating fine-scale tree population dynamics [2]. It has since been expanded with wind-driven pollen dispersal, landscape topography, and the inclusion of multiple tree species. However, until now, it could not be used to simulate effects of changing fire regimes on those detailed tree population dynamics.We present simulations of annually computed tree populations during the past c. 20,000 years in LAVESI, while applying a newly implemented fire module. Wildfire ignitions can stochastically occur depending on the monthly fire weather. Within the affected area, fire intensity is mediated by surface moisture. Fire severity depends on the intensity, with scaled impacts on trees, seeds and the litter layer. Each tree has a chance to survive wildfires based on a resistivity estimated from its height and species-specific traits of bark thickness, crown height, and their ability to resprout. The modelled annual fire probability compares well with a local reconstruction of charcoal influx in lake sediments. Simulation results at a study site in Central Yakutia, Siberia, indicate that the inclusion of wildfires leads to a higher number of tree individuals and increased population size variability compared to simulations without fires. In the Late Pleistocene forests establish earlier when wildfires can occur. The new fire component enables LAVESI to serve as a tool to analyze effects of varying fire return intervals and fire intensities on long-term tree population dynamics, improving our understanding of potential state transitions in the Siberian boreal forest.References:[1] Glückler R. et al.: Holocene wildfire and vegetation dynamics in Central Yakutia, Siberia, reconstructed from lake-sediment proxies, Frontiers in Ecology and Evolution 10, 2022.[2] Kruse S. et al.: Treeline dynamics in Siberia under changing climates as inferred from an individual-based model for Larix, Ecological Modelling 338, 101–121, 2016.
Improving solid-phase extraction of dissolved organic matter (DOM)
Authors: Waska Hannelore , Füssel Jessika , Paetz Katharina , Renken Marit , Dittmar Thorsten
Published: February 2023

In current dissolved organic matter (DOM) research, solid-phase extraction (SPE) with Bond Elut PPL resins is the gold standard for desalination and concentration. This method routinely recovers 50-65% of marine and terrestrial DOM. However, in unusual samples, for example from hydrothermal vents, early-stage microalgal cultures, the sea-surface microlayer, or sediment leachates, DOM recovery drops to 20% or less, presumably because the prevalent organic compounds are outside the polarity or molecular size window of the PPL sorbent. Here, we adjusted individual steps of the standard protocol, such as acid type, acid strength, and solvent polarity to increase DOM yields in notoriously low-recovery samples. We compared acidification of a coastal marine sample with either HNO3 or HCl at pH 1 and pH 2. From samples of the sea-surface microlayer, the underlying seawater, and macroalgal and intertidal sediment leachates, we performed two subsequent extractions at environmental pH and at pH 2. Following DOM extraction, we compared several eluents, including methanol, acidic methanol, tetrahydrofuran, and dichloromethane. We evaluated the different approaches by determining dissolved organic carbon (DOC) and dissolved black carbon (DBC) yields as well as changes in molecular DOM composition using ultra-high resolution mass spectrometry.Lowering the pH from 2 to 1 increased the DBC yield but resulted in slightly lower DOC recoveries, indicating a shift in molecular composition of the retained compounds rather than expansion of the SPE window. HNO3 may furthermore cause nitration, nitrosation and oxidation of DOM. However, combining sequential extraction at neutral and acidic pH with a series of eluents increased DOC recoveries substantially in comparison to the standard protocol. The inter-sample differences in the molecular composition (as detected via ultrahigh-resolution mass spectrometry on a molecular formula level) of the extracted DOM exceeded those caused by variations in the protocol and followed similar trends compared to the standard procedure. The co-variance of molecular degradation indicators with PPL performance emerged as a general trend: Recoveries with the standard protocol increased with the DOM degradation state. We conclude that PPL is much more versatile than its regular use indicates and encourage exploring a larger bandwidth of experimental setups for a better representation of natural DOM from a wide variety of sources.
Unsupervised Segmentation Of Microwave Brightness Temperatures To Study The Changes In The Water Cycle
Authors: Sambath Vibolroth , Viltard Nicolas , Barthès Laurent , Martini Audrey , Mallet Cécile
Published: February 2023

Due to climate change, understanding the changes in the water cycle has become a pressing issue. It is increasingly important to study prolonged periods of intense precipitation or dry spells to better manage water supply, infrastructure and agriculture. However, obtaining fine-scale precipitation data is challenging due to the intermittent nature of rain in time and space. Ground-based instruments could have mismatches between different regions due to spatial distribution, calibration, and complex topography. On the other hand, space-borne observations have uncertainties in their retrieval algorithms. This study proposes to deal directly with microwave images from space remote sensing, as this type of data makes it possible to study the evolution of the atmospheric water cycle on a global scale and with a temporal coverage of several decades by avoiding the uncertainties from retrieval methods. In recent years, convolutional neural networks have shown promising capabilities in identifying cyclones and weather fronts in large labelled climate datasets. However, these models required large labelled datasets for training and testing. The present study aims to test unsupervised segmentation approaches of microwave images, which are thus segmented into different classes. Instead of focusing only on one aspect, for example, precipitation, the obtained classes contain many physical properties. This is due to the fact that microwave brightness temperatures contain essential information relative to the atmospheric water cycle that can be used to derive many products such as rain intensity, water vapour, cloud fraction, and sea surface temperature. The unsupervised segmentation model consists of blocks of fully convolutional networks serving as feature extractors. Without labels, pseudo-targets from the feature extractors are used to train the model. The performance of the model in terms of intra-class and inter-class distances is compared with those of simpler models such as Kmeans. A major challenge in the unsupervised approach is validating and interpreting the resulting classes. Most of the obtained cluster patterns provide geographically coherent regions whose mode of variability of geophysical quantities can be highlighted. The presented study will then explore how the different classes computed by the unsupervised methods can be labelled and how the properties of the said classes change through time and space.
iMPACt-erosion: A robust and accessible model for a long-term effective management of agricultural soil erosion
Authors: Peñuela Andres , Vanwalleghem Tom
Published: February 2023

Soil erosion represents a serious challenge for agricultural production and for the environment. Soil erosion impacts, such as reduction of fertile soil, alteration of the carbon cycle and pollution and eutrophication of water bodies, represent a significant management concern for the European Union. Modelling can help define efficient and targeted mitigation strategies by identifying the long-term controlling factors and the areas where, and periods during which, soil is at high risk of erosion. However, to define such strategies, there remains a lack of modelling approaches a) able to provide with longer term baseline information which to measure the success or otherwise of mitigation strategies at the catchment scale and b) accessible and robust enough to be used, understood and trusted by users with more or less expertise, including researchers, land managers and policy makers. In response, this project will improve the robustness and accessibility of quantitative methods for supporting agricultural land management. The objectives of this project are: (i) to develop an accessible soil erosion model, iMPACt-erosion, based on interactive Jupyter Notebooks, to support agricultural land management at the catchment scale, (ii) to apply a robust model evaluation based on the use of both long-term soil loss observations and global sensitivity analysis to achieve greater confidence in model predictions and (iii) to identify the soil erosion controlling processes and vulnerable areas and periods to define targeted and effective mitigation strategies until 2100. We present the model and the first model evaluation results, which show that simulations are consistent with observed soil loss rates (estimated from both fallout radionuclides and tree mound measurements) in the last 60 years in olive orchard catchments in South Spain.
The role of urban trees in water cycle restoration
Authors: Marrazzo Giacomo , Raimondi Anita
Published: February 2023

Urban development leads to an increment of impervious cover that drastically reduces infiltration rates and increases the risk of stormwater floods, also reinforced by the rise of extreme events due to climate change.In this context, urban trees represent a valid system for sustainable stormwater management. They decrease the runoff discharged in the sewer network and/or in the receiving water bodies.Trees impact the hydrological cycle through the processes of interception, evapotranspiration and infiltration strictly depending on several factors such as tree features, soils properties, climate, and storm event characteristics.The objective of the study is to propose an analytical-probabilistic approach to model the contribution of urban trees to the restoration of the water cycle, with particular focus on the evapotranspiration component.
Evolution of the Off-Fault Deformation during experimental strike-slip earthquakes
Authors: Visage Sarah , Souloumiac Pauline , Cubas Nadaya , Maillot Bertrand , Klinger Yann
Published: February 2023

Large continental strike-slip earthquakes produce spectacular surface deformations. However, ground displacements are only partially measured in comparison with the amount of slip inferred at depth. Relatively few estimates of the proportion of surface deformation accumulated on faults and deformation distributed regionally around faults are available. However, new technological advances such as state-of-the-art space imaging techniques now greatly improve the quality of surface rupture measurements. Their application has revealed that a significant amount of deformation is accommodated as diffuse deformation in an area of several hundred meters around the fault. This distribution is suggested to depend on the fault complexity. It is therefore essential to understand this distribution and its relation with fault segmentation to study the impact of fault complexities in a seismic context, we recently developed an innovative experimental prototype using some granular materials in layers similar to the earth's crust. They consist of a basal layer of rubber powder that stores elastic energy provided by the displacement of a basal plate sliding parallel to a second, fixed plate. The second layer is made of raw, twice broken rice that brings the stick-slip behaviour required for locking the slip between ruptures, and a third layer of sand with the frictional behaviour of cold shallow sediments at the surface. The surface sand layer allows following the evolution of the fault surface trace from the R-shears stage to the anastomosed fault zone composed of a succession of segments separated by zones of complexities. Using image correlation, we analyse the surface displacements. Since the rice layer causes a stick-slip behaviour, the analysis of the surface displacement is done on several seismic cycles: if the surface displacement is lower than the displacement imposed by the motor, it is an inter-seismic period, if the surface displacement is faster than the displacement imposed by the motor then it is a seismic event.Once this catalog of events is established, the analysis of the gradient of the displacement Ux parallel to the basal enables us to quantify the deformation: localized (On-Fault Deformation) or distributed (Off-Fault Deformation).At the R-shear stage, we measure [50~80] % of Off-Fault Deformation. Once the strike-slip fault is formed, the percentage of OFD drops between 20 to 30 %. These results are comparable to measurements made by experiments devoid of a stick-slip behaviours (with only of sand). Moreover, if we compare these values to the proportions of OFD estimated for natural earthquakes, we find the same distribution.These experiments show that the more mature the fault, the more it will rupture seismically, in time as in space.
Radar altimetry for the detection of ship traffic: an improved byproduct of satellite radar altimetry
Authors: Scozzari Andrea , Grasso Raffaele
Published: February 2023

The detection of vessels is considered an attractive byproduct of satellite radar altimetry, because it may complement the conventional tracking systems with the possibility to build long-term global statistics of ship traffic based on relatively small and manageable datasets of freely available data. Satellite radar altimetry was initially conceived and applied to the observation of ocean topography, being later extended to the coastal zone and to the observation of inland water.The potentiality of SAR altimetry for the detection of ships has already been demonstrated with Cryosat2, and today Sentinel-3 is the first operational mission offering global SAR coverage with a constellation of two satellites.Thanks to the enhanced azimuth (along-track) resolution available in the synthetic aperture radar (SAR) mode, the radar altimeter on board the Sentinel-3 satellite could be beneficial to other applications than ocean topography. In particular, this work studies the performance of algorithms for the automatic detection of ship targets from SAR mode data. In addition, the pre-processing of altimeter data by reliable detection algorithms, filtering out signal outliers from the sea surface response, largely contributes to enhance geophysical products that are typical in ocean topography studies (e.g. mean sea level).  Thus, altimeter data of today could be regarded as an additional non-cooperative source for vessel traffic monitoring or to map global traffic patterns over long periods of time.This work proposes a processing chain based on mathematical morphology filtering and robust statistics to estimate the structured background and detect target signatures from radargrams. The detection stage is followed by an additional binary morphological filtering phase that is useful to estimate target characteristics, such as the height. The study shows that robust statistics outperform non-robust ones, in terms of target signal to background ratio and of rejection of false alarms. The study finally provides a first attempt to validate the analysis comparing detected target contacts with automatic identification system (AIS) data. 
Towards explainable marine heatwaves forecasts
Authors: Prasad Ayush , Mazumder Swarnalee
Published: February 2023

In recent years, both the intensity and extent of marine heatwaves have increased across the world. Anomalies in sea surface temperature have an effect on the health of marine ecosystems, which are crucial to the Earth's climate system. Marine Heatwaves' devastating impacts on aquatic life have been increasing steadily in recent years, harming aquatic ecosystems and causing a tremendous loss of marine life. Early warning systems and operational forecasting that can foresee such events can aid in designing effective and better mitigation techniques. Recent studies have shown that machine learning and deep learning-based approaches can be used for forecasting the occurrence of marine heatwaves up to a year in advance. However, these models are black box in nature and do not provide an understanding of the factors influencing MHWs. In this study, we used machine learning methods to forecast marine heatwaves. The developed models were tested across four historical Marine Heatwave events around the world. Explainable AI methods were then used to understand and analyze the relationships between the drivers of these events.
Impacts of drought on European inland transportation – insights from the European Drought Impact Inventory 2.
Authors: Blauhut Veit , Stephan Ruth , Stahl Kerstin
Published: February 2023

Drought is one of the most disastrous natural hazards in Europe, affecting a broad range of systems directly and indirectly, tangible and intangible. The complex nature of the hazard drought, its associated and cascading risks and the occurrence of compound hazards often hinder a precise assignment and quantification of drought impacts. Especially for the case of inland transportation, where different types of drought affect the strongly interconnected modes of transport, only little is known on the effects of drought. This contribution presents an analysis of the effects of drought on European inland navigation, road, and rail transport based on the European Drought Impact report Inventory 2.0 (EDII). The EDII is a standardised collection of drought impact information from a variety of sources. Impact information is classified to one of >100 drought impact types, referenced in space and time and complemented with additional reported impact information such as secondary impacts and response measures where applicable. The second public version of the EDII extends the initial database until 2021. The results show strong effects on inland navigation, in particular along major navigable European rivers. Especially cargo transport is impacted by drought, but impacts on public transport via ferries (rivers and lakes) have also been reported. For road and rail traffic, drought induced land degradation and soil shrinkage are reported as causes for damaged roads and deformation of rail tracks. Furthermore, heat waves associated with drought can lead to “melting of road surfaces” and road blow-ups, as well as track deformation and buckling. Moreover, forest and embankment fires are reported as short-term impacts on rail traffic, whereas information on secondary impacts and compound effects are generally scarce. Drought impacts on inland navigation (reduced cargo) are reported to raise market costs of goods and increase traffic on roads and rails. The results also highlight strong spatial disparity in the occurrence of drought impacts on inland transport, which either are a results of strong differences in national drought risks, reporting behaviour or information collection practice. In order to increase the resilience of transport systems to drought, a comprehensive overview on the direct and indirect impacts of the past is essential. Thus, there is a need for a common pan-European investigation of impacts on inland transportation to inform a central database.
Comparison of fluvial and aeolian sedimentary environments based on morphological analysis of their mineral components
Authors: Gresina Fruzsina , Farkas Beáta , Fábián Szabolcs Ákos , Szalai Zoltán , Varga György
Published: February 2023

The relationship between depositional environments and transportation processes associated with the general properties of formed siliciclastic sediments has been of great interest to researchers. The recent spread of high-resolution analytical methods has allowed researchers to quickly examine grain shape properties of a large number of individual mineral grains. We investigated mineral particles of two sediment types from different depositional environments (wind-blown sand, floodplain and channel deposits [n=11]) from the Carpathian Basin (Central Europe) by using automated static image analysis (Malvern Morphologi G3SE-ID). Our aim was to determine the key variables that can help us distinguish fluvial and aeolian environments. During the analysis and data processing (e.g. hierarchical cluster analysis, Wilks’ λ, Kruskal-Wallis, MANOVA, PCA) we examined four variables related to grain shape which were the following circularity (form), convexity (surface texture), solidity (roundness) and elongation (form).The objective and the quantitative study revealed that the solidity parameter proved to be an effective variable for separating sediments with similar convexity values (mean: 0.95-0.99) like in our case, the aeolian and fluvial sediments. Fluvial sediments had lower solidity (mean: 0.95-0.97) values compared to the aeolian sands (mean: 0.97-0.98). This major difference (p<0.001; α=0.05) resembles that the investigated fluvial sediments are not as much rounded as aeolian sands. Associated with circularity (form) result, it can be deduced that grains from fluvial sediments (low circularity; mean: 0.76-0.84) spent less time in the transport media or transported at lower energy level than aeolian grains (high circularity; mean: 0.82-0.87). Our research supports the previously established theory that aeolian transport is more effective in rounding the grains than an aqueous environment.Support of the National Research, Development and Innovation Office (Hungary) under contract FK138692, ÚNKP-22-3 and RRF-2.3.1-21-2022-00014 are gratefully acknowledged.
Soil carbon in CMIP6 Earth System Models
Authors: Varney Rebecca , Chadburn Sarah , Burke Eleanor , Cox Peter
Published: February 2023

The response of soil carbon represents one of the key uncertainties in future climate change due to competing soil carbon driven feedbacks. The ability of Earth System Models (ESMs) to simulate both present day and future soil carbon is therefore vital for reliably estimating global carbon budgets required for Paris agreement targets. In this presentation, the simulation of both present day and future soil carbon is investigated within CMIP6 ESMs.The ability of CMIP6 ESMs to simulate present day soil carbon is evaluated against empirical datasets, where a lack of consistency in modelled soil carbon remains from the previous generation of models (CMIP5). This underestimation is particularly dominant in the northern high latitude soil carbon stocks. The results suggest much of the uncertainty associated with modelled soil carbon stocks can be attributed to the simulation of below ground processes, and greater emphasis is required on improving the representation of below ground soil processes in future developments of models.Projections of soil carbon during the 21st century are also evaluated to quantify future soil carbon changes in CMIP6 ESMs and to assess the uncertainty of the soil carbon induced feedback to climate change. The response of soil carbon is broken down into changes due to increases in Net Primary Productivity (NPP) and reductions in soil carbon turnover time (τs), with the aim of isolating the differing responses which influence changes in future soil carbon storage. A reduction in the spread of soil carbon projections is identified in CMIP6 compared to CMIP5. However, similar reductions are not seen in the components due respectively to changes in NPP and τs. The relationship between the induced soil carbon changes due to NPP and τs is investigated and their overall effect on the future soil carbon response is presented.
Quasi exhaustive synthetic spectra of the aurora and spectrometers measurements
Authors: Barthelemy Mathieu , Robert Elisa , Sequies Thierry
Published: February 2023

Studying the auroral emission is of strong importance since they are created in an atmospheric layer (80-300 km) where in situ measurements are complicated. They represent a good proxy of the particle precipitations into atmosphere.The spectrum of the aurora is complex made of both atomic and molecular lines. The intensities of these emissions vary with the activity, especially the particle precipitations.Transsolo is the kinetic code which solve the transport equation of the electrons along a vertical or a magnetic field line. It allows to obtain the particles fluxes at different energies, angles and altitudes. From this, the code is able to calculate the related emissions.The emission modules have recently been updated by including the vibrational structures of the molecular bands. Several atomic lines have also been added. We can consider that we include more than 95% of the full emission spectra. From this, it is now possible to obtain some almost complete synthetic spectra of the aurora parametrized by the mean energy of the particle fluxes at the top of the atmosphere and the total precipitated energy.Recently Robert et al. show that it is possible to reconstruct the energetic precipitation from the N2+ 427 nm line. However, it remains clear that multiplying the number of considered lines, will allow to get more accurate measurements of these particle fluxes. Moreover, a large number of auroral monitoring instruments are done with filters with variable widths. Such synthetic spectra can help to identify the possible perturbation of the measurements due to wavelength coincidences. For example, the green line at 557 nm is in coincidence with several O2+ and N2 bands in a +/- 5 nm range. Calculating the relative ratio of these lines in different conditions is then crucial.In parallel, we are developing a series of calibrated high sensitivity spectrometers to validate the data and enhance the quality of particle precipitation reconstructions.In this presentation, we will detail the links between these instruments and these synthetic spectra.