bluuebunny/crossref_metadata_2025 huggingface dataset:
GEE and Machine Learning for mapping burnt areas from ESA’s Sentinel-2 demonstrated in a Greek setting
Authors: Tselka Ioanna , Detsikas Spyridon E. , Demertzi Isidora Isis , Petropoulos George P. , Triantakonstantis Dimitris , Karymbalis Efthimios
Published: March 2022

Climate change has resulted to an increase in the occurrence and frequency of natural disasters worldwide. An increased concern today is wildfire incidents, which constitute one of the greatest problems due to the ecological, economical and social impacts. Thus, it is very important to obtain accurately and robustly information on burned area cartography. Recent advances in the field of geoinformation have allowed the development of cloud- based platforms for EO data processing such as Google Earth Engine (GEE). The latter allows rapid processing of large amount of data in an efficient way, saving costs and time since there is also no need to locally download and process the EO datasets in specialized software packages committing also own computing resources. In the present study, a GEE-based approach that exploits machine learning (ML) techniques is developed with the purpose of automating the mapping of burnt areas from ESA’s Sentinel-2 imagery. To demonstrate the developed scheme, as a case study is used one of the largest wildfire events occurred in the summer of 2021 in the outskirts of Athens, Greece. A Sentinel-2 image, obtained from GEE immediately after the fire event, was combined with ML classifiers for the purpose of mapping the burnt area at the fire-affected site. Accuracy  assessment was conducted on the basis of both the error matrix approach and the Copernicus Rapid Mapping operational product specific to this fire event. All the geospatial analysis was conducted in a GIS environment. Our results evidenced the ability of the synergistic use of Sentinel-2 imagery with ML to map accurately and robustly the burnt area in the studied region. This information can provide valuable help towards prioritization of activities relevant to the rehabilitation of the fire-affected areas and post fire management activities. Last but not least, this study provides further evidence of the unique advantages of GEE towards a potential an automation of burnt area delineation over large scales.

KEYWORDS: GEE, Machine Learning, Sentinel-2, Burnt area mapping, Copernicus
Can digital twins incentivise good modelling practice?
Authors: Guillaume Joseph
Published: March 2022

It has been said that culture eats strategy for breakfast. The effect of legacy over adequacy in modelling practice exemplifies the difficulty in changing behaviours to improve modelling outcomes. Ideally, good modelling practice would be incentivised by the systems in which modellers operate, and moreover, that modelling practice would have a learning orientation that gradually improves over time, seeking an ever closer alignment with organisational and societal needs.

Digital twins institutionalised within organisational operations provide a possible opportunity to incentivise these behaviours. A digital twin is a time-varying representation of a system that brings together observed information and predictive model capabilities. Juxtaposing model predictions with other sources of information forces models to demonstrate their value, in continually changing conditions. Operational use of a digital twin means that models need to be fit for purpose. The need to prioritise investment across a digital twin means that the model suite needs to address a broad range of purposes and model augmentation is more likely to be driven by consideration of value of information and prioritisation of efforts to reduce uncertainty over time.

These theoretical benefits are explored with example use cases in the context of cross-scale catchment water resource, landscape, and irrigation management, drawing on preliminary experiments in Australia.
Robustness of precipitation Emergent Constraints in CMIP6
Authors: Ferguglia Olivia , Palazzi Elisa , von Hardenberg Jost
Published: March 2022

Climate models are fundamental tools to understand the complexity of the climate system, to study  the processes at work and to provide credible future climate projections. Unfortunately, models often disagree significantly in the amplitude of different climate change signals and in their representation of the role of important feedbacks. In the past years the “Emergent Constraints” methodology has been developed for reducing uncertainties in climate-change projections. An Emergent Constraint (EC) is a statistical relationship between the inter-model spread of a measurable aspect of the present-day climate (predictor) and the inter-model spread of a variable projection (predictand), under a climate change scenario. If a significant correlation is found, observations of the predictor can be used to constrain model projections of the predictand and the uncertainties in climate model outputs can be narrowed. 

In the last two decades, ECs have been identified in different branches of climate science although just a limited number of these ECs is related to the hydrological cycle. Recently, a relevant number of EC in the literature was discovered to lack a satisfying physical explanation and many, developed and tested with CMIP5 ensemble, seem to be not-significant in the new CMIP6 ensemble. However, the analysis regarding ECs related to the hydrological cycle is still incomplete. The aim of this work is to test three ECs related to mean-precipitation and extreme precipitation events, originally identified in CMIP3 or CMIP5 data, and to evaluate if their statistical significance survives also in the CMIP6 ensemble: (a) global hydrological sensitivity used to constrain future changes in local extreme precipitation: we find this relationship not to be robust in CMIP6 models; (b) future changes in the Indian summer monsoon precipitation, constrained by Western Pacific mean precipitation: this relationship is not robust with the new ensemble; (c) changes in future extreme tropical precipitation, constrained by the same variable calculated in the past: we find this EC to be robust both in CMIP5 and CMIP6.
Remote sensing detection of climate-smart practices: Enhancing farm resilience in Austria
Authors: Laso Bayas Juan Carlos , Hofer Martin , McCallum Ian , Bodner Gernot , Lamare Maxim , Danylo Olha , Maus Victor , Luger David , See Linda , Fritz Steffen
Published: March 2022

Climate-smart agricultural practices are techniques that help crops to endure “extreme” weather events. Practices such as minimum or no tillage, crop rotations, and cover crops reduce wind and rain-driven erosion, enhance soil physical quality, and enable soil to store water for a longer time. Climate change has already led to an increased frequency of “extreme” weather events including prolonged dry spells and intense rain. From a farmer’s perspective, a clearer and more spatially explicit demonstration of how these practices can enhance the resilience of farms would support their accelerated uptake and thus result in increased food security. From a policy maker’s perspective, knowing the extent of adoption and location of these more resilient farms would enable them to produce policies that facilitate and promote the adoption of these practices, which can buffer the effects of climate change. The use of remote sensing to detect these practices would, therefore, benefit this process. Several existing remote sensing-derived indicators, such as the Normalized Difference Vegetation Index (NDVI), are already in use. They inform farmers and policy makers on, e.g., crop and nutrient status. A combination of existing and new remote sensing-derived indices is needed to facilitate and streamline the detection and promotion of climate-smart practices, but a lack of in-situ data to date has prevented the development and verification of new models of detection. The “SATFARM services” project, which brings together expertise in agriculture, remote sensing, and data analysis, aims to connect a large agricultural time-series data set, provided by the Austrian Chamber of Agriculture, with various remote-sensing derived indicators. The goal is to detect and track climate-smart practices and to display the results on a platform (https://apps.sentinel-hub.com/eo-browser/) accessible to farmers, researchers, and policy makers. This presentation will showcase the methodology employed, the initial results and the display of these indicators on the platform.
Simulation of Permeability Changes by Reactive Transport in a Geothermal Doublet
Authors: Wuttke Manfred W.
Published: March 2022

The performance of a geothermal plant is controlled by the permeabilities in  the geothermal reservoir. Hydrothermal systems often consist of porous sand- or limestone with high salt content. Most important minerals in this context are halite and calcite. During the operation of the geothermal plant the circulating fluid changes locally the chemical equilibrium which leads to changes of the permeability by dissolution and precipitation processes. To investigate these processes we have set up a numerical code on the basis of a general C++ Library, which is developed and maintained at LIAG for the solution of mathematical models of coupled thermal, hydraulic and chemical processes. The code concept is introduced and first numerical studies of the dissolution, transport and precipitation of halite and calcite in a geothermal doublet system are presented.
Retrieval of Ice Cloud Properties from Sentinel-5 Precursor and Sentinel-4 Measurements
Authors: del Águila Ana , Lutz Ronny , Molina García Víctor , Romahn Fabian , Loyola Diego
Published: March 2022

The study of ice clouds properties is of central importance to further understand the role of ice clouds in climate system processes. Therefore, it is crucial to perform accurate ice cloud retrievals in satellite-based systems in order to provide reliable information about the cloud microphysical, macrophysical and optical properties. Current and future satellite missions like Sentinel-5 Precursor (S5P), Sentinel-4 (S4), and Sentinel-5 (S5) are designed to monitor the air quality and greenhouse gases. The cloud retrieval algorithm used operationally for these missions is ROCINN (Retrieval Of Cloud Information using Neural Networks) which retrieves the cloud top height (CTH), cloud optical depth (COD) and cloud albedo (CA) from measurements in the NIR in the O2 A-band (755-771 nm). ROCINN considers two cloud models: Clouds as Reflecting Boundaries (CRB) and Clouds As scattering Layers (CAL). In this work we will present the latest developments including the ice cloud retrieval performed using the VLIDORT radiative transfer (RT) model containing ice cloud parametrization. This study investigates the performance of ROCINN for ice cloud retrieval for several test scenarios adapted from Level 2 operational data. The selected datasets contain partially and fully cloudy scenarios for ice clouds placed at different CTH and for different COD. The retrieved CTH and COD for ice clouds are evaluated for the TROPOMI/S5P and S4 satellites.
The impact of aerosols on the temperature inversion in the boundary layer over southwest China 
Authors: Jiang Mengjiao , Yang Yinshan , Ni Changjian , Chen Qiying
Published: March 2022

The Sichuan Basin, which is located in southwest China, has become one of the most polluted regions in China. The frequency of atmospheric boundary layer in the Sichuan Basin are analyzed based on radiosonde profile from 2014 to 2016. The occurrence probability of multi-layer temperature inversions is about 46.86% in winter over the Sichuan Basin. The radiosonde data are divided into four equal parts according to the previous 12-hour average visibility and PM2.5 mass concentration. As the PM2.5 mass concentration increases (visibility decreases), the surface-based inversion frequency increases more consistently in the morning, while the elevated inversion increases more consistently in the evening. The mechanisms of the aerosol radiative effect on the boundary layer temperature inversion are further investigated by using the radiometer, the Mie scattering lidar, and the microwave radiometer in Chengdu. 1D-SBDART simulation is performed to better clarify the mechanisms. The simulation results show that: from clean to heavy pollution conditions, in clear-sky the surface shortwave radiation reduces by 135.04 w·m-2 and the heating rate increases by 0.75 k·d-1; in cloudy sky the surface shortwave radiation reduces by 46.15 w·m-2 and the heating rate increases by 0.35 k·d-1. Aerosols can enhance the boundary layer temperature inversion at both daytime and nighttime due to the radiative effect, while clouds mitigate the enhancement by aerosol effects. 
The bioporosphere and its role in soil functioning
Authors: Bottinelli Nicolas
Published: March 2022

Along with roots, soil macrofauna such as earthworms, ants, termites, beetles and myriapods dramatically alter the physical architecture of soil with strong effects on the distribution and connectivity of pores, and therefore on key ecological functions such as water dynamics, gas exchanges, soil organic matter decomposition or storage. While most of the literature has focused on the properties of galleries and show their large variability, much less is known about the other pores produced by soil fauna (e.g., those agented between or within biogenic aggregates or those located around galleries).

Using examples from studies carried out in tropical and temperate soils, I show that the ‘trait-based’ approach in soil biology offers interesting perspectives for understanding the properties of biopores, and as a consequence of the impacts of soil fauna on water dynamics and biogeochemical cycling. Second, I show that galleries are not as stable as we imagine, indicating the need to quantify their dynamics. Finally, I show that macrofauna influence also the architecture of small pores with consequences on the dynamics of soil organic matter and other properties. To conclude, I introduce the “bioporosphere” as a new concept to integrate the complex effects of soil fauna on its functions.
Aftermath of catastrophic flooding of a desiccated ocean basin
Authors: Amarathunga Udara , Hogg Andrew , Rohling Eelco , Roberts Andrew , Grant Katharine , Heslop David , Hu Pengxiang , Liebrand Diederik , Westerhold Thomas , Zhao Xiang , Gilmore Stewart
Published: March 2022

5.33 Million years ago, a mile-high marine cascade terminated the Messinian Salinity Crisis due to partial collapse of the Gibraltar arc/sill that isolated a largely desiccated Mediterranean from the Atlantic Ocean. Atlantic waters may have refilled the basin within 2 years. Prevailing hypotheses suggest that normal marine conditions were established across the Mediterranean immediately after the catastrophic flooding. Here we use new proxy data and modelling to show that normal conditions were likely for the western Mediterranean (wMed), but that flooding caused massive wMed salt transfer to the eastern Mediterranean (eMed), which became a hyper-salinity-stratified basin. Hyper-stratification inhibited deep-water ventilation, causing anomalously long-lasting organic-rich (sapropel) sediment deposition. Model:data agreement indicates that hyper-stratification breakdown required 26,000 years. Testing an alternative hypothesis—reconnection of a largely refilled Mediterranean—reveals hyper-stratification in both the wMed and eMed, which would have left sapropels in both basins, in disagreement with observations. Our findings offer novel insight into the processes involved in re-establishing normal marine conditions following abrupt refilling of a previously desiccated ocean basin.
Inference of velocity and pressure field of GravityCurrents using Physic Informed Neural Networks
Authors: Mickaël Delcey , Yoann Cheny , Jean Schneider , Yvan Dossmann , Sébastien Kiesgen De Richter
Published: March 2022

LEMTA - UMR 7563 CNRS-UL - Universite de Lorraine, Nancy, France

Gravity currents [Ungarish, 2009] are common finescale structures in coastal areas, where they are involved in the vertical transport of physical and biogeological tracers. These stratified flows frequently carry a suspended solid phase that controls the average properties of the flow, such as the geometry, velocity and apparent viscosity leading to a rich dynamic whose optimization/prediction remains a major scientific issue.

A better understanding of the particle-flow coupling requires an accurate characterization of the particle volume fraction, fluid density, velocity and pressure fields. The experimental apparatus available at LEMTA allows high accuracy instantaneous measurements of density fields in laboratory experiments with the light attenuation technique (LAT) as described in a companion presentation, while the joint measurement of velocity and pressure fields remains beyond the reach of known metrological techniques.

To address this issue we propose an original approach based on the Physics Informed Neural Network (PINN) technique [Raissi 2020], which extracts the complete hydrodynamic variable set from the sole observation of the density field. The accuracy of this approach is evaluated against the well-documented test case of the lock-exchange configuration in both laminar and turbulent regimes. As a validation step, the PINN technique is applied on numerical simulations outputs with the well-established Nek5000 flow solver with convincing results. Then, an application on experimental data from LAT experiments will be shown, illustrating the robustness of this promising paradigm.
Simultaneous Cross-energy Ion Response and Wave Generation after An Interplanetary Shock: A Case Study
Authors: Li Yuxuan , Yue Chao , Zong Qiugang , Zhou Xuzhi
Published: March 2022

Interplanetary (IP) shocks in general have strong impact on particles and electromagnetic field. In this study, we have examined the dynamics of cross-energy ions and plasma waves observed by the Van Allen Probe B satellite which was located near the equator at the noon sector after the impact of an IP shock on 27 Feb, 2014. We found that the ULF waves and electromagnetic waves are induced and the differential fluxes of protons with different energies increased or decreased after the IP shock arrival. For low energy ions (10-100eV), the perpendicular flux increased intensively due to ExB drift and betatron acceleration. These adiabatic processes also accounted for the special behavior of 10~200 keV ions, which are due to the positive gradient in phase space density before the IP shock arrival. In addition, the short-lived ultra-low frequency waves triggered by the IP shock interacted with the ~100 keV protons and resulting in the stripes in pitch angle distribution. Meanwhile, the anisotropic ions of ~50-300 keV generate EMIC wave at higher L shell after the shock arrival. This study reveals that an IP shock event can cause comprehensive responses of different energy ions and drive several plasma waves at the same time.
High-resolution imaging of subduction zones through SKS splitting intensity tomography: first results from test on numerically modelled complex settings
Authors: Baccheschi Paola , Confal Judith M. , Pondrelli Silvia , Faccenda Manuele , VanderBeek Brandon P. , Huang Zhouchuan
Published: March 2022

Measurements of seismic anisotropy provide a lot of information on the deformation and structure of the upper mantle, as well as flow in the Earth’s interior. High-resolution seismic anisotropy in the upper mantle can be obtained with several methods that may catch anisotropy at different depths depending on the nature of used seismic waves, including analyses based on surface waves and SKS splitting measurements. Taken together, these anisotropic measurements yield insights into the structure and dynamics of the crust and upper mantle. Nevertheless, mantle images resulting from surface waves result in poor lateral resolution. On the other hand, nearly vertically propagating SKS waves, when interpreted in a ray-based framework, have little or no depth resolution, not allowing to easily image the distribution of the anisotropy through depth. Albeit seismic anisotropic structure of the upper mantle has been demonstrated by a wealth of observational research, most of standard teleseismic body-wave tomography studies overlook P- and S-wave anisotropy, thus producing artefacts in tomographic models in terms of amplitude and localization of heterogeneities. To overcome this problem much effort has been done to implement tomographic methods for inverting SKS splitting observations for anisotropic structures, based on finite-frequency sensitivity kernels that relate elastic model perturbations to splitting observations. A promising approach to track the seismic anisotropy distribution with depth is the splitting intensity (SI): this seismic observable is a measure of the amount of energy on the transverse component of the waveform. At first order, SI is linearly related to the elastic perturbations of the medium through the 3-D sensitivity kernels, and therefore can be inverted allowing a high-resolution image of the upper-mantle anisotropy. The advantage of using splitting intensity is that its amplitude is related directly to the back azimuth, so fast polarization direction and time delay can be determined by fitting the azimuthal variation of splitting intensities with a sine function, with amplitude and phase shift respectively related to delay time and fast velocity direction. Here we present an application of the splitting intensity tomography approach to a synthetic subduction setting. Starting from synthetic SKS waveforms, we first derived high-quality SKS synthetic SI measurements; then we used the obtained results as input for the tomographic inversion based on the algorithm of Chevrot (2006) and Montellier & Chevrot (2011). This approach enables high‐resolution tomographic imaging of upper‐mantle anisotropy through recovering vertical and lateral changes in anisotropy and represents a propaedeutic step to the imaging of real cases of subduction settings.
Inspecting internal magnetic field gradients in volcanic rocks
Authors: Chibati Nadjib , Geraud Yves
Published: March 2022

Nuclear magnetic resonance (NMR) is being used since 1990 in the petroleum industry. NMR is a powerful tool for petrophysical properties estimation (porosity, permeability, pore size distribution, and irreducible saturation). Despite its large success in the conventional carbonate and sandstone reservoirs, some tight sandstones, volcanic and metamorphic rocks, contain a high amount of paramagnetic and clay minerals, which can complicate the interpretation of NMR results. These complications are due to the inhomogeneities of the internal magnetic field generated by the magnetic susceptibility contrast between the pore-fluid and the matrix. The magnitude of the internal gradients depends on the strength of the background magnetic field, magnetic susceptibility contrast, and pore size.

Many studies are focused on the investigation of the effect of clay and paramagnetic minerals on the internal gradient and their implications on the NMR-derived petrophysical properties mainly of the high magnetic susceptibility sandstones. The primary goal of this analysis is to investigate the magnitude of the internal magnetic gradient of volcanic rocks with different alteration grad and its relationship with the rock properties (magnetic susceptibility, iron, and manganese content, pore type, and pore size).

The data were collected using the Minispec q10®, with Larmor frequency of 10 MHz, on the water-saturated samples with magnetic susceptibility between 26.8 10-3 and -0.4 10-3 SI. The average effective internal gradient was calculated from the slope of the mean log relaxation rate (T2gm-1) versus the squared echo time (TE2). The preliminary results show that samples presented a multi-distribution of T2 peaks corresponding to the different pore types observed for these samples (micro, meso, and macropores). The average effective internal magnetic field gradient calculated from the slope of T2gm-1 vs TE2 ranges from 0 to 43.16 T.m-1. The average effective internal gradient increases with the increase of magnetic susceptibility and decreases as the T2gm increase, suggesting that the pore size also impact internal gradient magnitudes. However, No clear relation exists between iron content and average effective internal gradient.
Snow depth mapping over large, high-alpine regions by airplane photogrammetry 
Authors: Bührle Leon , Marty Mauro , Eberhard Lucie , Stoffel Andreas , Bühler Yves
Published: March 2022

Abstract.

Snow depths are traditionally determined by point measurements at automatic weather stations or field observations, which cannot capture the complexity of snow depth distribution in alpine terrain. Therefore, remote sensing techniques have become key tools for spatially continuous snow depth mapping. Only satellites, airborne laser scanners (ALS) or photogrammetry from piloted aircrafts are capable of covering large regions of more than 100 km². However, the accuracy of satellite data does not match/achieve the requirements for exact snow depth mapping yet. In comparison to ALS, photogrammetric methods are considerably more economic, but have the disadvantages of light and weather dependence as well as the lacking ability to penetrate high vegetation. Nevertheless, previous studies of photogrammetric snow depth mapping on a large scale have already proven the accurate implementation, but those studies were either limited to only one recording or characterized by a spatial resolution of around 2 m. These properties limit the comparison of snow depth distribution and the analysis of small-scale features.

In our study we apply airborne imagery from the current state-of-the-art survey camera Vexcel Ultracam acquired during the annual peak of winter for the five years from 2017 to 2021 in an area of approximately 300 km2 around Davos, Switzerland. This enables the calculation of outstandingly improved annual snow depth maps. The high spatial resolution of the snow depth maps (0.5 m) in combination with the high-resolution orthophoto (0.25 m) enables the identification of small-scale snow depth features. Additionally, the development of masks for high-vegetated and settled areas in combination with the high accuracy of the unmasked snow depth values (root mean square error of around 0.15 m) represents a significant step forward for reliable snow depth mapping of large alpine regions with photogrammetric methods. Our study focuses on the consistent workflow used for processing the snow depth maps, demonstrates the special characteristics of the snow depth distribution and presents the potential for investigations and applications based on this unique snow depth time-series.
Integrating satellite remote sensing data and hydrological models by data assimilation for a near real time estimation of the soil water content at local scale.
Authors: Moradi Shirin , Mengen David , Vereecken Harry , Montzka Carsten
Published: March 2022

Climate change affects the Earth system at all levels (IPCC et al., 2007). The Monitoring and prediction of droughts and flood events, agricultural production, and analysis of energy and water will continue to gain importance, accordingly. Especially agricultural systems are of the main affected by rising temperatures, extreme precipitation events, and droughts, all of which can lead to crop failures (Lobell et al., 2011). Approximately 40% of the world's crop production comes from irrigated agriculture (Vereecken et al., 2009), the future expansion of which will continue to provide adequate food for the population. However, efficient irrigation must be ensured to prevent unnecessary groundwater depletion (Richey et al., 2015). To increase efficiency and safeguard yields, novel technologies need to be developed for innovative, real-time water management strategies that will allow farmers to make management decisions at the right time (OECD, 2010). Predicting the overall water supply and its components (e.g., soil water content and groundwater) for plants growth and at each growing stage would assure a sustainable irrigation. Therefore, the aim of this study is to predict the root zone soil water content which is one of the main components of the total water supply for plant growth. For this purpose, spaceborne remote sensing data from C- and L-band Synthetic Aperture Radar will be used. These data provide valuable information about the surface soil moisture only. But by integration into a hydrologic model in a data assimilation framework the soil moisture of the root zone as well as the groundwater recharge can be estimated to identify the actual irrigation requirements and resources. 
Transport and Composition of Terrestrial Organic Matter at the Sediment-Water Interface of the Kara, Laptev and East Siberian Shelf Seas
Authors: Madaj Lina , Keskitalo Kirsi , Gustafsson Örjan , Tesi Tommaso , Semiletov Igor , Dudarev Oleg , Martens Jannik , Vonk Jorien
Published: March 2022

Around 65% of the Arctic coastline consists of permafrost soils which are currently thawing on an accelerating rate due to rising global air temperatures. The uncontrolled and rapid thaw of permafrost soils leads to increased coastal erosion and input of large amounts of organic carbon (OC) into the coastal ocean. Here, the OC can either be degraded (leading to production and emission of greenhouse gases that strengthen climate warming) or be sequestered over short or long timescales (attenuating climate warming). A major proportion of permafrost-derived OC quickly settles upon coastal release and therefore the sediment-water interface is the crucial zone for determining the trajectory of thawed OC and whether it deposits or remains in suspension. However, there is little data available from these so-called flocculation (i.e. nepheloid) layers, particularly in the Arctic shelf seas.

Here, we investigate the composition of suspended sediment within the flocculation layer at the sediment-water interface as well as the shallow surface sediments to shed light on the degradation state and fate of terrestrial OC, and additionally, characterize its lateral and vertical variability upon transport offshore. All samples were collected during ISSS-2020 expedition in late summer (Sept-Oct) of 2020 onboard R/V Akademik Msistlav Keldysh in the Kara Sea (n=2), Laptev Sea (n=8), and East Siberian Sea (n=4). We present first results of elemental, isotopic, and sedimentological analyses of suspended and surface sediments (C/N values, δ13C, Δ14C, surface area). With these data, we want to better understand how transport and degradation processes of terrestrial OC vary across the vast Siberian shelves.
Manure and crop rotation affect water retention under dry conditions in long term experiments 
Authors: Arthur Emmanuel , Fu Yuting , Paradelo Marcos , de Jonge Lis Wollesen
Published: March 2022

Crop rotation and manure application are agricultural practices that are regularly used to improve soil quality and crop yields, and long term experiments (LTEs) provide an excellent platform to assess their impact. There is a large volume of literature on the benefits of these practices on soil structure, organic matter contents, soil nutrient levels, and other soil chemical properties. There is, however, little to no information on the impact of manure application and crop rotation on water retention at low matric potentials (pF > 5.0; <−10 MPa) as occurs under dry conditions. The study utilizes LTEs (20 to 127 years) from Denmark, Sweden, Germany, Spain and the UK that includes manure application and various crop rotation sequences. The sites vary in soil texture, organic matter content, and manuring rates. We measured water vapour adsorption and desorption isotherms covering the range from −10 MPa to −465 MPa (pF 5.0 to 6.8) on soil samples from the LTEs. The presentation will discuss the interactive effect of soil texture, manure and crop rotation on the magnitude of water sorption, its hysteresis, and the specific surface area.
PSP observations of the solar wind coherent structures from MHD to sub-ion scales at 0.17 AU
Authors: Vinogradov Alexander , Alexandrova Olga , Maksimovich Milan , Artemyev Anton , Mangeney Andre , Vasiliev Alexei , Issautier Karine , Moncuquet Michel , Petrukovich Anatoly
Published: March 2022

First perihelion Parker Solar Probe magnetic field measurements (MAG and SCM merged data) allow to resolve the fluctuations on a wide range of scales: from MHD to ion plasma scales and smaller. We trace the cascade of the fluctuations and investigate the structures formed. Using the total energy of magnetic fluctuations in time and scales, we show that coherent structures cover all the observed scales. The filling factor of the structures is a few percents. We analyze the magnetic fluctuations at different frequency ranges. We observe the coexistence of events at MHD, ion and sub-ion scales in the form of sharp discontinuities and/or vortex-like events. The approach of selecting structures by total energy alone is not complete, as it can miss structures with change in magnetic field modulus. For completeness, we perform the same analysis on longitudinal magnetic fluctuations.
The architecture of the lithospheric mantle controlled the emplacement of the Central Atlantic Magmatic Province
Authors: Boscaini Andrea , Marzoli Andrea , Bertrand Hervé , Chiaradia Massimo , Jourdan Fred , Faccenda Manuele , Meyzen Christine , Callegaro Sara , Serrano Durán Lina
Published: March 2022

Large Igneous Provinces (LIPs) represent exceptionally brief (<1 Ma) voluminous magmatic events that punctuate Earth history, frequently leading to continental break-up, global climate changes and, eventually, mass extinctions. Most LIPs emplaced in continental settings are located near cratons, begging the question of a potential control of thick lithosphere on mantle melting dynamics. In this study we discuss the case of the Central Atlantic Magmatic Province (CAMP), emplaced in the vicinity of the thick lithospheric keels of the Precambrian cratons forming the central portion of Pangea prior to the opening of the Central Atlantic Ocean. In particular, we focus on CAMP magmas of the Prevalent group, ubiquitous all over the province, and of the Tiourjdal and High-Ti groups, emplaced (respectively) at the edges of the Reguibat and Leo-Man shields in north-western Africa, and the Amazonian and São Luis cratons in South America. As imaged by recent tomographic studies, there is a strong spatial correlation between most CAMP outcrops at surface and the edges of the thick cratonic keels. Geochemical modelling of trace element and isotopic compositions of CAMP basalts suggests a derivation by partial melting of a Depleted MORB Mantle (DMM) source enriched by recycled continental crust (1-4%) beneath a lithosphere of ca. 80 km. Melting under a significantly thicker lithosphere (>110 km) cannot produce magmas with chemical compositions similar to those of CAMP basalts. Therefore, our results suggest that CAMP magmatism was produced by asthenospheric upwelling along the deep cratonic keels and subsequent decompression-induced partial melting in correspondence with thinner lithosphere. Afterwards, lateral transport of magma along dykes or sills led to the formation of shallow intrusions and lava flows at considerable distances from the source region, possibly straddling the edges of the cratonic lithosphere at depth. Overall, the variations of the lithospheric thickness (i.e., the presence of stable thick cratonic keels juxtaposed to relatively thinner lithosphere) appear to play a primary role for localizing mantle upwelling and partial melting during large-scale magmatic events like the CAMP.
Increasing trend in the Greenland blocking Index: can causal inference help to explain discrepancies between observations and models?
Authors: Di Capua Giorgia , Beckmann Johanna , Coumou Dim , Davini Paolo , Donner Reik V. , Rousi Eftychia
Published: March 2022

Changes in the Greenland Blocking Index (GBI) present a threat to both the mass loss of the Greenland ice sheet, potentially leading to increased sea level rise, and downstream regions, such as the European continent and Mediterranean Basin that may be affected by associated changes in the frequency and characteristics of weather patterns. While a consistent increase in the summer GBI has been detected in (several) observational and reanalysis datasets, global climate models and seasonal prediction systems so far have failed in capturing this historical trend. The question whether the observed trend is real and not reproduced by models or an artifact of multidecadal variability (and, hence, a transient phenomenon) has so far not been answered. Here we apply the Peter and Clark momentary conditional independence (PCMCI) causal discovery tool to (i) unravel essential causal drivers of the GBI in a set of selected atmospheric fields at intraseasonal (weekly and 3-day averages) time scales in observations and (ii) compare the latter with those found in the ECMWF SEAS5 seasonal forecasts. Observed causal links well reproduced by the dynamical model would be considered indicative of the trend in GBI found in observations more likely emerging because of the selected time frame. By contrast, any differences between the two sets of causal drivers in observations and models would support the hypothesis that some key mechanisms are not appropriately represented in the forecast model, preventing it from correctly reproducing the observed trend.
Vegetation as a remedial measure against erosion and shallow landslides in steep soil slopes
Authors: Ånäs Mikael
Published: March 2022

The Swedish Civil Contingencies Agency, the Swedish Geotechnical Institute, the Swedish Road Administration and the Swedish University of Agriculture have together been involved a project named “Vegetation as a mean for slope stabilisation”. The aim of the project was to introduce soil-bioengineering methods in Sweden through demonstration projects and to obtain experiences regarding the function and effect of plants on slope stability within Swedish conditions.

In three selected areas, the plant- and soil conditions were studied, with tests commencing in the spring of 2004 and in the beginning of 2005, respectively. The project ended in 2007 in a report containing recommendations, based on the experiences from the project, for the continued use of soil bioengineering methods.

In the test site Bispgården, a new road was built in 2004 through a gully area. The soil consists of highly erodible silt and sand material. Hedge- and brushlayers with grass seeding were selected to protect the soil from erosion in one slope. Equipment for measurements of pore pressure and precipitation were installed in the summer of 2004. Studies of the plant conditions were conducted several times during the first two years of the project.

In the test site Bydalen, a reconstruction of a country road was conducted in 2005, as the road was plagued with annually recurring erosion along it’s existing silty-till slopes. These slopes were to be restabilised during reconstruction. All together nine existing slopes were stabilised in early 2005 by different soil bioengineering methods proposed by the project group. The group analysed the function of the plants together with automated recordings of precipitation.

In the test site Näsåker, steep slopes of a country road were repaired in 2005-2008, due to continuing erosion and landslides in the silty soil slopes along the existing road. The slopes were stabilised with soil bioengineering and soil nailing.

Different soil bioengineering methods have been used in some new production sites, following this demonstration project. The methods may also be implemented in future projects.

The results from the demonstration in project sites, will be described in this presentation.
Plants maximize the conductive efficiency of the xylem 
Authors: Franklin Oskar , Fransson Peter , Hofhansl Florian , Joshi Jaideep
Published: March 2022

In vast areas of the world, the growth of forests and vegetation is water-limited and plant survival depends on the ability to avoid catastrophic hydraulic failure. Therefore, it is surprising that plants take high hydraulic risks by operating at water potentials (ψ) that induce partial failure of the water conduits (xylem) 1, and which makes them susceptible to drought mortality under climate change 2. Here we present an eco-evolutionary optimality principle for xylem design that explains this phenomenon - xylem is adapted to maximize its effective conductivity. A simple relationship emerges between the xylem intrinsic tolerance to high negative water potential (ψ50) and the environmentally dependent minimum ψ, which explains observed patterns across and within species. The theory provides a fundamental conduit-level principle that complements previously described principles at higher organizational levels, such as hydraulic-network scaling and drought-avoidance behavior. The new optimality principle may be universally valid, from within-individuals to across-species, and thus improve our basic understanding of drought tolerance of plants and forests globally.   
Numerical modelling of fluid-induced fault slip reactivation,application to Geo-Energy systems
Authors: Jiang Jinlin , Dublanchet Pierre , Passelègue Franҫois , Bruel Dominique , Pellet Frederic
Published: March 2022

Geothermal energy is one of the most promising techniques to exploit renewable energy resources from the Earth and to limit emissions of greenhouse gas. Deep geothermal exploitations are associated with long term fluid circulation and pressure perturbations at great depth, in fractured and faulted zones and are likely associated with a risk of triggering earthquakes. Such earthquakes are usually interpreted as the reactivation of rapid (m/s) shear slip on critically stressed faults caused by fluid flow and poroelastic stress changes. In some cases however, slow aseismic slip (m/d) can take place on faults in response to fluid flow. How fluid pressure perturbations reactivate aseimic or rapid slip still remains poorly understood. A better understanding of the hydromechanical processes controlling fault slip is therefore crucial to mitigate seismic hazards associated with geothermal exploitation.

In this framework, our study aims at constraining the influence of stress state, fluid injection rate, diffusivity and frictional failure criterion on the reactivation of slip on pre-existing faults through mechanical modelling of a set of laboratory experiments. The experiments consist of a fluid injection into a saw-cut rock sample loaded in a triaxial cell. Fault reactivation is triggered by injecting fluids through a borehole directly connected to the fault. This experimental setup is modelled by a 3D Finite Element Method (FEM) coupled with a solver of the fluid diffusion. The sample fault is modelled as a contact surface obeying slip-weakening Mohr-Coulomb friction law. This approach allows to compute slip and stress evolutions, as observed during the laboratory experiment. The FEM model is calibrated and is able to reproduce the experimental results. We show that fluid injection triggers a shear crack that propagates varying from 1 to 300 m/d along the fault. This approach can be used to investigate the relationship between fluid front and slip front during reactivation, which is an important issue to control the effects of fluid injections at depth.
Impact of elevated CO2, temperature, and drought on summer ecohydrological moisture cycling and water transit times in montane grassland
Authors: Radolinski Jesse , Wachter Herbert , Birk Steffen , Brüggemann Nicolas , Herndl Markus , Kahmen Ansgar , Kübert Angelika , Schaumberger Andreas , Stumpp Christine , Vremec Matevz , Werner Christiane , Bahn Michael
Published: March 2022

Rapid alteration of Earth’s climate amplifies concerns over the future quantity and quality of freshwater resources. Earth’s warming atmosphere is known to store and transport more water vapor at higher velocities than historic climatic conditions, augmenting the magnitude and frequency of extreme weather events like intense rainfall and droughts. Warming can accelerate evapotranspiration by elevating vapor pressure gradients, whereas atmospheric CO2 enrichmentcan suppress transpiration as plants preferentially close their stomata. Despite the potential hydrological implications, no study to date has comprehensively explored how these global change factors, when combined, impact the transit of moisture through the soil-plant-atmosphere continuum. In a montane grassland we tracked an extensive deuterium-labelled rainfall event following a severe experimental drought period under current versus simulated future (+300 ppm CO2 and +3°C warming) conditions. We monitored stable isotopes of water in soil and evapotranspiration vapor, to partition signatures of evaporation, transpiration, drainage and soil pore water and quantify transit times through each ecohydrological compartment. Preliminary results suggest that under future conditions (+300 ppm CO2 and 3°C) drought can drastically increase the retention time of water in the rootzone, which intermittently forces plants to return older water to the atmosphere. We intend to use these findings to directly quantify the water age preference of evaporative and drainage fluxes under a range of climate scenarios.
Analysis of high-resolution decadal prediction of drought events in the Department of Chocó-Colombia
Authors: Toro Ortiz Yenny Marcela , Gámiz Fortis Sonia Raquel , Castro Díez Yolanda , Palomino Lemus Reiner , Esteban Parra María Jesús , Córdoba Machado Samir
Published: March 2022

Agriculture and livestock represent 21% of the economic sector of the Department of Chocó (Colombia), being drought and flood events one of the main difficulties. Although this Department has the largest records of annual precipitation, in some seasons with scarce precipitation, it shows great drought problems and crop deterioration.

Consequently, several institutes use short-term decadal climate simulations using general circulation models (GCM), which consider climate warming as well as the predictable climate signal associated with the initial climate conditions to inform water resource managers.

This work analyzes the potential use of the decadal predictions of precipitation from the Japanese model BCC-CSM2-MR to predict of drought events in the Department of Chocó through the analysis of the hindcasts in the period 1960-2018. The choice of this model is based on its suitability to reproduce the main patterns of climate variability that affect the study area. Drought events will be characterized by the Standardized Index of Precipitation (SPI) on different time scales.

Since the resolution of this GCM is very vast and does not allow to solve regionalized characteristics, such as topographic factors, land-sea distribution, or vegetation types, etc., a statistical downscaling of the decadal hindcasts for precipitation will be carried out from which the SPI will be calculated. These results will be compared with those obtained from the observational database "Global Precipitation Climatology Centre (GPCC)”.

Keywords: drought, Colombia, SPI, decadal predictions, GCM, statistical downscaling.

Acknowledgments: Y.M. Toro-Ortiz acknowledges the Colombian Ministry of Science, Technology, and Innovation for the predoctoral fellowship (grant code: 860). This research was funded by the Spanish Ministry of Economy and Competitiveness project CGL2017-89836-390R, with additional support from FEDER Funds, by FEDER/Junta de Andalucía-Consejería de Economía y Conocimiento, project B-RNM-336-UGR18, and by FEDER/Junta de Andalucía-Consejería de Transformación Económica, Industria, Conocimiento y Universidades (project P20_00035).