bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistence of S-metolachlor at the catchment scale investigated by compound-specific isotope analysis (CSIA)
Authors: Payraudeau Sylvain , Droz Boris , Drouin Guillaume , Lohmann Jenna , Guyot Benoît , Imfeld Gwenaël
Published: February 2023

Pesticide pollution of agriculturally impacted ground and surface water is ubiquitous with concentrations exceeding drinkable water limits or environmental quality standards (EQS). In this context, Compound-Specific Isotope Analysis (CSIA) opens novel opportunities to follow-up pesticide persistence and degradation from agricultural soil to rivers at the catchment scale. While CSIA has been used for decades to investigate in situ degradation of legacy compounds at contaminated aquifers, its application to evaluate pesticide degradation and transport in soil and surface water is mostly lacking due to analytical and conceptual challenges. Here we show that degradation estimates of the herbicide S-metolachlor at the catchment scale based on a classical mass balance, accounting for the different catchment’s compartments, were similar to those based on CSIA data. S-metolachlor CSIA based on carbon isotope ratios was carried out from soil samples collected monthly across the 120-km² Souffel catchment (Bas-Rhin, East of France) and from flow-proportional river samples collected at the outlet of the catchment from March 1 to October 1 2019. Based on CSIA data, 98% ± 20% of the S-metolachlor was degraded over agricultural season. This converged with estimates of S-metolachlor degradation (98.9 ± 4.7%; mean ± SD) obtained using the classical mass balance. Interestingly, degradation mainly occurred in soil, while only 12.3 ± 3.1% of S-metolachlor degraded in river on a total river length of 79 km. The wastewater treatment plants (WWTPs) contributed to 52 ± 18% of the total input mass of S-metolachlor in river. However, similar isotope signatures of S-metolachlor for diffuse and WWTP sources hampered the identification of pesticide sources. From 0.04 to 0.12% of the S-metolachlor applied was exported from the catchment during the agricultural season, which is similar to previous S-metolachlor exports estimated in other catchments. Although a little fraction of S-metolachlor was exported, 81% and 93% of the river samples exceeded the drinkable water limit (0.1 µg.L-1) and the EQS for S-metolachlor (0.07 µg.L-1), respectively. Overall, we anticipate that pesticide CSIA deployed systematically in agricultural catchments could help water managers to estimate pesticide persistence and sources to address regulatory and monitoring strategies. 
Late Cenozoic sedimentary systems offshore West Greenland providing new insights to ice-ocean interactions during periods of enhanced climate warming
Authors: Knutz Paul , Perez Lara , Nielsen Tove
Published: February 2023

The need for constraining future climate scenarios requires a better understanding of how the cryosphere responded to ocean-climate conditions that were warmer than present. The Greenland shelf margins store thick sedimentary packages that may offer detailed information pertaining to ice-ocean-climate dynamics and Arctic ecosystems. A wealth of seismic data acquired since the early nineties has generated numerous subsurface maps and geomorphic studies of expanded sedimentary archives located proximal to the Greenland Ice Sheet. While paleoclimate reconstructions of ice sheet and ocean dynamics have largely been based on North Atlantic deep-water records, the Greenland continental margin will be the focus of forthcoming International Ocean Discovery Program missions such as Exp. 400, NW Greenland margin. The aim of this presentation is to provide an update of the late Cenozoic marine successions that form key targets for understanding cryospheric behavior during warm climate periods, in particular the Miocene-Pliocene interval characterized by contourite drifts and hemipelagic sequences. The significance for pushing knowledge frontiers on Northern Hemisphere climate evolution and Earth System modelling will be discussed. 
Analysis of IMF penetration into Mercury’s Magnetosphere
Authors: Pump Kristin , Heyner Daniel , Masters Adam , Zomerdijk-Russell Sophia , Plaschke Ferdinand
Published: February 2023

Mercury is the smallest an innermost planet of our solar system and has a dipole-dominated internal magnetic field that is relatively weak, very axisymmetric and significantly offset towards north. Through the interaction with the solar wind, this field leads to a magnetosphere. Compared to the magnetosphere of Earth, Mercury’s magnetosphere is smaller and more dynamic.A semi-empirical magnetospheric model can capture the large-scale magnetospheric structures. Using the residuals between in-situ data and the model prediction we further seek to improve our understanding of the Hermean magnetosphere. To first order the magnetopause completely separates the magnetosphere from the magnetosheath and thus no magnetic field may penetrate this boundary. In reality, the magnetosheath field may diffuse across the very thin boundary within a finite time. Here, we investigate this penetration and compare the different interplanetary field (IMF) components by their ability to enter into Mercury’s Magnetosphere. For this, we use in-situ MESSENGER magnetic field data to estimate the IMF for the time frame with the probe located inside the magnetosphere. The amount of penetration is found by least-square fitting to magnetospheric model results.First statistical results indicate that the penetration is stronger under southward IMF conditions.
Using a regional model as intermediate between in situ airborne measurements and Sentinel 5P δD column retrievals
Authors: Thurnherr Iris , Sodemann Harald , Trent Tim , Werner Martin , Bösch Hartmut
Published: February 2023

The isotopic composition of water vapour is a natural tracer of moisture cycling and moist processes such as rain-out efficiency in the atmosphere. The abundancy of deuterium (denoted as δD) in atmospheric water vapour can be studied using a variety of observational platforms that have a wide range of spatial and temporal resolutions. Recently, high-resolution and high-frequency δD total column retrievals from the Sentinel 5P satellite have become available, and need validation from in situ measurements. While satellite-retrieved products of δD in water vapour allow to study δD variability on spatial scales of several 1000km every 12-24h, the few available in-situ water vapour measurements of δD are at a much higher temporal resolution (seconds) and cover a more limited spatial extent (10s of km). In this study, we present a methodology for comparing datasets with different scales to each other. Thereby, it is important to take the principal time and length scales of water vapour δD features into account. To this end, we use model simulations with the isotope-enabled weather prediction model COSMOiso as an intermediate to bridge the scales between the newly developed retrieval of water isotopologues for the Sentinel 5P satellite, based on the University of Leicester Full Physics retrieval algorithm, and in-situ vertical profiles of δD from ultralight aircraft acquired during the L-WAIVE campaign in June 2019. We illustrate that the assessment of spatial and temporal δD correlated patterns in COSMOiso can serve as a proxy for spatial representativeness, and as such guides towards an unbiased comparison of datasets. Overall, we demonstrate that the combination of in-situ measurements and COSMOiso simulations with satellite-retrieved δD can help to better constrain vertical δD gradients and to understand the temporal evolution of large scale δD patterns and associated moist processes. From our findings, we also derive more general recommendations for future comparison studies of in-situ measurement, satellite products, and model-simulated δD.  
Atmospheric environment change in a summertime O3 pollution event over the North China Plain under the influence of recent-year anthropogenic emission reduction
Authors: Luo Yuehan , Zhao Tianliang
Published: February 2023

The air pollutant emissions play a decisive role in the control of air quality. In recent years, the anthropogenic emission reduction measures have effectively reduced the PM2.5 levels over China improving air quality in China. However, due to the complex physical and chemical processes in atmospheric environment, O3 pollution events still occur frequently. To assess the impact of recent-year emission reduction of emissions on variations of summertime O3 pollution in the North China Plain, this study conducted the simulations with the air quality model WRF-Chem by using China's Multiresolution Emission Inventory (MEIC) with 0.1° resolution in 2012 and 2019, and we understand the characteristics of summer O3 pollution in the NCP under the scenario of anthropogenic emission reduction. The results show that the anthropogenic emissions of PM2.5, PM10, SO2, CO, black carbon (BC), and organic carbon (OC) in the NCP region decreased significantly from 2012 to 2019, while the emissions of NMVOCs (non-methane volatile organic compounds) increased distinctly in urban areas, and NOx emissions decreased in urban and increased in rural, reflecting the uneven emission reduction of anthropogenic air pollutants in North China. The control of anthropogenic pollutant emissions induced an elevated concentrations of atmospheric oxidants (O3 and multiple free radicals) in the NCP region, enhancing the atmospheric oxidation capacity, and then strengthening the chemical conversions of SO2 and NOx to generate sulfate, nitrate, and other secondary particles. As a result, the proportion of secondary PM2.5 in urban and rural areas markedly raised , especially during the O3 pollution period, offsetting the reduction of primary PM2.5 emissions. In addition, these emission reduction measures promote the transformation of O3 generation mechanism in the NCP from VOC-control to NOx-control. This study reveals the complex effects of anthropogenic emission reduction altering the atmospheric physical and chemical processes on atmospheric environmental change.
Elements of emerging concern: The “old” new contaminants in water and sediments of a Mediterranean wetland (the Albufera Natural Park, Valencia, Spain).
Authors: Andreu Vicente , Gimeno-Garcia Eugenia , Campo-Velasquez Julian , Pico Yolanda
Published: February 2023

In recent years increasing attention has been paid to a to a group of inorganic elements widely used but not well known, mainly in their toxicological aspects. Because of this lack of knowledge their possible toxic levels have not been regulated for many of them in the different environmental compartments. It is for these reasons that they have been included in the group of “emerging contaminants” or “contaminants of emerging concern”.In this work, the presence and spatial distribution of 15 elements (Al, As, B, Be, Bi, La, Li, Mo, Rb, Se, Sr, Ti, Tl and V), considered as emerging contaminants and most of them scarcely studied, in waters and sediments of the Natural Park of L’Albufera of Valencia (Spain) have been studied, together with the influence of the environment (land uses, water sources, etc.). The Natural Park of La Albufera (Valencia, Spain), is one of the most important marshland of Europe, included in the RAMSAR agreement, but it suffers impacts derived from the high human and industrial occupation, and of the hydrological contributions from the connected irrigation systems. It includes a coastal lagoon, marshlands, dunes and pinewoods, surrounded by rice fields, orchard and citrus crops in its not urbanized part.In this study area, 57 sampling zones were selected covering the different water sources and agricultural types. Total concentrations of the selected 15 elements were evaluated. Standard analytical methods were used to measure water physical and chemical properties. Total content of the elements in water and sediment samples were extracted by microwave acid digestion and determined by ICP-OES-MS.Taking in to account that for many of these elements there are not regulations or even benchmarks, Al, Li, Sr and Tl showed levels above the stablished legislation for waters with maximum values of 5182.14, 77.83, 4310.03 and 11.37 µg/L, respectively. For sediments values above the existent legislation or benchmarks were observed for As, Sb and Se with maximums of 40040.25, 17.03 and 22.17 mg/kg. Water channels that irrigates rice crops at the south of the target area, and surrounding the lake showed the highest levels in almost all metals.This study can be a solid base to assess the state of water quality of this wetland area, extrapolable to others in the Mediterranean, and to help in the knowledge of the dynamics of metals scarcely known such as Be, Mo, Se, Sr, Ti or Tl.AcknowledgementsThis work has been supported by the Generalitat Valenciana (Spain) through the project with reference CIPROM/2021/032.
A model of forced folding controlled by syn-orogenic clastic deposits in a foreland fold and thrust belt. The case of the Jaca Basin, South Pyrenean Zone.
Authors: Bonnel Cédric , Menzer Lionel , Aubourg Charles , Callot Jean-Paul , Hoareau Guilhem
Published: February 2023

The nature and rate of syn-orogenic sedimentation play an important role in the tectono-stratigraphic evolution of foreland basins. Recent works have shown syn orogenic evaporites at the transition between underfilled and overfilled conditions in the Sivas basin (Turkey) have strongly influenced the subsequent structural and sedimentary evolution of the foreland fold and thrust belt (Legeay et al., 2020).In the western South Pyrenean Zone, the Jaca basin exhibits the classical stratigraphic succession of a pro-foreland basin systems. This was filled during Eocene-Oligocene with siliciclastic sediments derived from the erosion of the Pyrenees and deposited in a marine to continental environment. During Bartonian, a derivation in the sediment routing system and decreasing subsidence rate resulted in the deposition of a km-thick shale unit forming the transition between marine and continental conditions.The “bed-to-bed” mapping of the syn-orogenic units at the basin-scale using high-resolution DEM together with the reinterpreted seismic lines were used to build three cross-sections that highlight the structural style of the western South Pyrenean Zone. These illustrate the tectono-sedimentary evolution of a transitional shallow-marine to continental foreland basin.From end-Bartonian, the deposition of the Orosia-Cancias conglomerates in the north-eastern basin margin is coeval with the onset of the folding of the Basa anticline forward. During Priabonian, this were subsequently welded and forward-tilted coevally with the development of an imbricate in Hecho turbidites beneath, that can be linked to the emplacement of the Gavarnie thrust-sheet. At this time, the Orel alluvial fan was deposited westward at the termination of the Basa anticline and was associated with the growth of the second, shale-cored Atarès anticline folding ahead. This was in turn welded during Rupelian at the time of deposition of the San Juan conglomerates at its western termination, coevally to the Botaya anticline folding downstream.The tectono-sedimentary evolution of the Jaca fold-and-thrust belt is thus resulting from complex interactions between the deformation of mobile shale and syn-orogenic alluvial sedimentation both at local and regional scale. This example highlights the influence of the syn-orogenic sedimentation and especially the deposition of a decoupling layer at the transition between marine and continental conditions during the evolution of foreland fold and thrust belts as well as thein mountain building processes.
Semi-brittle deformation of Carrara marble: snapshots during strain accumulation
Authors: Qu Tongzhang , Brantut Nicolas , Wallis David , Harbord Christopher
Published: February 2023

Semi-brittle deformation arises as the manifestation of combined microphysical mechanisms dominated by pressure (including dilation, fracturing, frictional sliding) and temperature (including intragranular diffusion of matters, dislocation motion and annihilation, twinning, and grain-boundary sliding). Although each of the deformation mechanisms is individually relatively well understood, the combination and interaction between the two sets of processes remain poorly known.In order to have a better understanding of the semi-brittle behavior in the lithosphere, we conducted a series of uniaxial compression experiments on samples, cored from Carrara marble – polycrystalline calcite with low porosity and isotropic texture, at confining pressure of 400 MPa in gas pressure medium, temperature of 200 ºC and constant strain rate of 1 × 10-5 /s. Ultrasonic waves were transmitted through the specimen by a pair of piezoelectrical crystals to monitor the in-situ microstructural states of the sample. The focus of this work is to investigate the contribution of each mechanism as a function of strain accumulation. Accordingly, deformation is ceased at a different stage in each experiment, including the onset of inelastic behavior (at ~0.3% strain) and yield point (at ~1.1% strain) and stages after the yield point (at 1.8%, 3.8% and 7.5% strains).The mechanical testing results from the 5 runs are essentially reproducible before yielding, and after yielding the difference among the experiments is at most ~20 MPa in stress at the same strain. Strain hardening occurred in the later three specimens deformed to relatively large extent with stress increasing, for example, from 140 to 300 MPa in the sample deformed by 7.5%. The wave velocity, occasionally increasing at the start of deformation in some experiments, generally decreases with increasing strain. Preliminary observations by scanning electron microscopy and EBSD on deformed samples show pervasive distribution of fractures, twins and high misorientation within individual grains, confirming that all the aforementioned mechanisms in semi-brittle regime have potentially contributed to the deformation at such experimental conditions. Further analysis quantifying the evolution of fracture density, twin density and intracrystalline plastic strain with increasing deformation is currently being undertaken.
Spatial vs temporal variability in German river water quality
Authors: Schauer Linus S. , Jawitz James W. , Cohen Matthew J. , Musolff Andreas
Published: February 2023

River water quality is degraded by a multitude of diffuse and point sources impeding ecosystem functioning and constituting a severe risk for human water security all over the world. Monitoring campaigns are the basis of evaluating water quality by characterizing probability of concentrations in time and space, allowing to identify solute source zones and flow paths. This knowledge can then aid in the development of effective water quality management strategies. However, it is not clear, whether current monitoring approaches provide sufficient information to allow to soundly characterize concentration probability over time and localize pollution sources in space. We propose a space-time variance framework to characterize spatial and temporal variation in river water quality and analyze its interplay. Specifically, we assess for discharge and two contrasting solutes (anthropogenic: NO3-, biogenic: DOC) by analyzing time series data across 1386 stations in Germany (Ebeling et al. 2022) . Variability is quantified by using the Coefficient of Variation (CV) of mean temporal and spatial variation of subsets of catchments. We find a large span of both spatial and temporal CV for discharge, NO3- and DOC. Overall, variability of discharge was considerably higher in time and space than the variation of NO3- and DOC. Differences between CVs of NO3- and DOC were smaller than expected from their different landscape sources. Apart from analyzing national to continental-scale data records, we plan to analyze archetypal patterns of solutes by utilizing a stochastic modelling approach. Ultimately, the aim is to inform stakeholders whether monitoring strategies such as synoptic sampling are viable approaches and to disentangle anthropogenic and natural drivers to illuminate their role for spatial and temporal variation in river ecosystems.Ebeling, P., Kumar, R., Lutz, S. R., Nguyen, T., Sarrazin, F., Weber, M., Büttner, O., Attinger, S., and Musolff, A.: QUADICA: water QUAlity, DIscharge and Catchment Attributes for large-sample studies in Germany, Earth Syst. Sci. Data, 14, 3715–3741, https://doi.org/10.5194/essd-14-3715-2022, 2022.
Underestimation of Arctic warming trends in sub-seasonal forecasts
Authors: Tietsche Steffen , Vitart Frederic , Mayer Michael , Weisheimer Antje , Balmaseda Magdalena
Published: February 2023

The Arctic has warmed substantially over the last decades and will continue to do so owing to global warming in conjunction with polar amplification. The changing mean state poses many challenges to the construction, evaluation and calibration of subseasonal-to-seasonal forecasting systems, because it puts into question the representativeness of the system's retrospective forecasts (reforecasts). Furthermore, any inconsistencies with observed trends degrade the forecast skill and point to deficiencies in either the physical modelling or the initialization methods. Here, we assess the consistency of boreal winter trends of surface air temperature (SAT) in the Eurasian Arctic between the ERA5 reanalysis and ECMWF sub-seasonal reforecasts initialised from ERA5, for the 35-year period 1986-2021. We present methods to quantify robustness and importance of the observed trends, and to quantify the consistency of reforecast trends with these observed trends. We find that, in large parts of the marine Arctic, the reforecasts clearly underestimate the reanalsyis warming trend of about 1 K per decade at lead times beyond two weeks. For longer lead times, the reforecast trend is less than half of the reanalysis trend, with very high statistical significance. We present a series of numerical experiments to investigate potential reasons for the trend underestimation. These concern the sea-ice thermodynamic coupling to the atmosphere, impact of sea surface temperatures, and possible remote atmospheric influences from the North Atlantic and the Tropics. The outcome of these experiments provides guidance for future improvements in the physical forecast model and data assimilation methods needed to faithfully represent and predict Arctic climate variability and change.
Carbon, sulphur, and mercury geochemistry in a crater lake in the Siberian Traps
Authors: Svensen Henrik H. , John Timm , Polozov Alexander G. , Callegaro Sara , Jones Morgan T. , Newton Robert J. , Fristad Kirsten E. , Planke Sverre
Published: February 2023

In the Siberian Traps Large igneous province (LIP), the emplacement of magma in sedimentary strata led to explosive release of volatiles and the formation of large pipe structures with explosion craters. Of the hundreds of pipes present, several still have preserved crater lake sediments, representing the only known end-Permian sedimentary archive proximal to the Siberian Traps. Here we present new data from a core from the best studied crater lake section, the October pipe/crater located west of Bratsk in East Siberia. The S26 core contains 505 meters of sediments and in order to investigate the geochemical processes in the lake and the possible role of brine influx from the breccia pipe below, we have analysed carbon isotopes, the mercury content, δ34S and δ56Fe in pyrite and δ56Fe in magnetite, from the breccia pipe and crater sediments. In addition, reference samples from two other breccia pipes and relevant sedimentary strata from the Tunguska Basin were analysed for comparison. Our previous work has shown that the lake was saline, stratified and anoxic/euxinic, with up to 4 wt.% TOC, and abundant framboidal pyrite. The sediments are dominated by sandstone and siltstone, sourced from the material ejected during the pipe formation, and have not experienced heating above ca. 50 °C. The basal deposits are coarse and contain reworked magnetite-apatite ore that originally precipitated from hydrothermal fluids within the upper parts of the pipe. The sediments are calcite-cemented and the volcanic minerals altered to clays and zeolites, with occasional oxidized zones showing that the water level fluctuated, in accordance with rapid subsidence resulting from dissolution of deeper-seated Cambrian evaporites. New results show a marked shift in the isotope systems from the breccia pipe and into the basal lake deposits. The δ34S shifts from background sedimentary values (+20-30‰) in the pipe breccia, to -7-0‰ in the lower half of the lake sediments followed by an increase to +20 ‰ towards the top of the lake. The trend is evident in the δ56Fe in magnetite as well, with a 0.4 ‰ negative shift from the breccia and into the lake sediments, followed by an upward increase in the stratigraphy. We suggest that basinal brines rich in iron and sulphate were partly reduced in the stratified lake, leading to pyrite precipitation and isotope fractionation. The data shows the interplay between lake processes and fluid seepage from a hydrothermal system, making these deposits unique for understanding the consequences of LIP formation.  
Modelling grain size segregation in geophysical mass flows: bridging particle-level forces and continuum models
Authors: Liu Meng , Jing Lu
Published: February 2023

Geophysical mass flows typically consist of a granular solid phase having a broad grain size distribution and an interstitial fluid phase. During the flow, particles of larger sizes tend to segregate in the flow and thereby accumulate in the flow surface and front, resulting in dramatic changes in the flow and deposition characteristics, such as enhanced runout distances and stratified deposit patterns. However, current hydro-mechanical modeling of geophysical mass flows often does not consider grain size segregation and the resulting internal heterogeneity of the flow, which can largely compromise the predictability of existing hydro-mechanical models. A major challenge lies in the multiscale nature of grain segregation and its effects on the flow mobility, which requires detailed characterization of segregation mechanics at both the particle and flow levels. Here, we first review recent advances in a multiscale framework in which the driving and resistive forces of segregation on a single intruder particle or a collection of large particles have been formulated based on discrete element method simulations and theoretical analysis. Then, we discuss how these particle-scale forces can be derived toward a continuum formulation for segregation flux modeling and be connected with the flow dynamics in a two-way coupling manner. These physics-based force formulations reflect the micromechanics of segregation and lead to enhanced predictive modeling of particle size dynamics in the granular flow. Finally, we discuss the potential of extending the proposed framework to consider the effects of interstitial fluids and other mechanisms in upscaled hydro-mechanical modelling for more realistic geophysical mass flows.
Effect of elevated CO2 and soil nitrogen availability on plant C allocation and soil C turnover from a whole-plant mesocosm experiment
Authors: Yang Hye In , Schrumpf Marion , Zaehle Sönke
Published: February 2023

Elevated atmospheric carbon dioxide (CO2) concentrations can have a positive effect on plant growth, and are also expected to alter the plant belowground allocation of photosynthetically fixed carbon (C). The release of root-derived exudates can potentially stimulate soil microbial activity and the turnover of existing soil C. However, soil organic matter decomposition response to elevated CO2 may vary depending on the level of available nutrients, particularly nitrogen (N), which is the most limiting nutrient. To investigate the combined effect of CO2­ and available N on rhizodeposition and soil C turnover, a greenhouse mesocosm experiment was conducted. A total of 64 hornbeam (Carpinus betulus L.) trees were exposed to ambient (400 ppm, aCO2) or elevated (580 ppm, eCO2) concentrations of CO2 at 13C-enrichment of 100 permil, in order to trace C in the system. Two levels of N were applied to the soils in the form of 15N-labelled ammonium nitrate (NH4NO3). Above and belowground C fluxes were continuously monitored for partitioning of soil heterotrophic and autotrophic respirations. After one growing season, the trees and soils were destructively harvested. The trees were separated into buds, leaves, branches, stem and roots, which were analysed for CN and their respective isotopic compositions. Soils were separated into rhizosphere and bulk soils, and were analysed for CN, isotopic compositions, microbial biomass and enzyme activities. We observed an increase in the belowground C allocation under eCO2 and trees showed a higher active fine root growth response to eCO2. Consequently, the overall microbial biomass in the rhizosphere as well as the fraction of microbial biomass C derived from roots increased under eCO2. Enzyme activities, especially those of β-Glucosidase and N-acetyl-β-d-glucosaminidase, increased, while phosphatase and peroxidase activities decreased under eCO2. Despite the stimulated microbial activities, changes in soil C were not observed. Furthermore, we did not find any interactive effect of available N with eCO2, which suggested that N availability did not strongly influence belowground C allocation by trees.
Exploring the asymmetric dependence in hydrologic extremes
Authors: Deidda Cristina , Engelke Sebastian , De Michele Carlo
Published: February 2023

The issue of dependence and causality is fundamental for the study of compound events. Dependence measures are largely exploited in literature to study the interconnections among hazards and drivers. Classical dependence measures are symmetric, dependence in one direction is considered equal as the dependence in the other direction. Nevertheless, there are many situations in which there can exists a directionality on dependence. Considering the extremes in river network case study, there exists a physical link between upstream and downstream river sites, and this must be reflected in their dependence relationships. Upstream influences downstream more that in the other direction. In this work, we want to explore the concept of asymmetric dependence considering the extremes and the possible existing link with causality effects. A conditional version of the Kendall’s tau has been proposed and investigated to give some information about the directionality of the dependence.As case study we use the UK river network considering daily discharge data and a POT analysis approach. Exploring the issue of asymmetry in the statistical pairwise dependence, it could provide a new tool/perspective to address the joint statistical behaviour of dependent variables. 
Continuous observations of CO2 and CH4 exchange from East-African rangelands
Authors: Merbold Lutz , Odongo Vincent , Dowling Thomas , Fava Francesco , Glücks Ilona , Vrieling Anton , Wooster Martin , Leitner Sonja
Published: February 2023

Semi-arid rangelands in Sub-Saharan Africa (SSA) are an important source of food security and nutrition but are under increased anthropogenic pressure by a growing population. These rangelands are characterized by nutrient poor soils and distinct wet and dry season(s). Due to the soil and climate combination, conventional crop agriculture is rarely feasible without irrigation and mineral fertilizer amendments, which in turn are limited by prohibitively high fertilizer prices and lack of water. Instead, pastoral livestock keeping is a valuable option to use these marginal lands and – under the right management – can be a sustainable form of food production and biodiversity protection given that most of these landscapes have co-evolved with megafauna over millennia. Despite the global role of livestock systems on climate change, there is still limited understanding on the role of SSA rangelands. At the same time, livestock systems emit greenhouse gases (GHG) and can promote global warming. But despite the impact of livestock systems on climate change, our understanding of the role of SSA rangelands is limited. To date, a thorough assessment that includes continuous GHG exchange measurement in combined wildlife-livestock systems on the African continent has not been undertaken. Here we provide the first eddy covariance (EC) measurements of CO2/CH4/H2O fluxes from the ILRI Kapiti Wildlife Conservancy - a benchmark rangeland site in East Africa that is grazed by livestock and wildlife. Our results show continuous ecosystem CO2 uptake from the wet to dry seasons with considerable CO2 emission pulses following precipitation events after long dry periods that turn the landscape into short-term net CO2 emitters. In contrast to CO2, CH4 fluxes are highly variable and depend particularly on wildlife and/or livestock being present in the fetch of the EC tower. In addition to EC measurements and given the need for scaling of our results, we relate CO2 and CH4 fluxes to simple remote sensing measurements of vegetation greenness derived from phenological cameras. Our results show good agreement between the two approaches. Yet, more observations across a climatic gradient and along varying management intensities are needed to reduce existing uncertainties in the effect of SSA rangelands on climate change. To build a complete GHG budget, hot spots of greenhouse gas emissions such as from livestock enclosures or water bodies as well as soil carbon sequestration have yet to be accounted for.
Methodological improvements and processing software of SO2 fluxes from UV cameras
Authors: Brenot Hugues , Friedrich Martina , Theys Nicolas , Merlaud Alexis , Hermans Christian , Fayt Caroline , Van Roozendael Michel
Published: February 2023

With its high temporal and spatial resolution, SO2 UV cameras are very attractive tools for monitoring emission and estimating fluxes (volcanic or anthropogenic sources). Their measurements can also contribute to warning systems (e.g., in the mitigation of volcanic crisis and its impact on aviation).The first part of this contribution will briefly review the methodology with the pros and cons of this technique. In the calibration process (to obtain SO2 amounts by using a collocated spectrometer as a part of our EnviCam3 SO2 UV camera), we show means to mitigate some of the effect on UV light propagation (i.e., dilution and saturation) by using a multi-window DOAS analysis approach. We will show some tests of the saturation effect for sets of SO2 concentrations (from 10 to 10000 ppm.m) obtained in our laboratory (device with a vacuum pump). In the second part, we will present a new GUI Python software developed at BIRA, for both fast analysis during field campaigns and more detailed post-processing analysis of SO2 fluxes. The functionalities of this software consist of: 1) automatic or manual correction of X/Y shifts between the images from the two cameras; 2) correction of the vignetting effect in each image; 3) automatic detection of spectrometer field of view by correlation with time series of QDOAS retrieved SO2 slant columns for calculating the conversion factor to SO2 concentrations  4) estimation of the plume speed using optical flow computing; 5) retrievals of SO2 fluxes (box, traverse or delta-M methods).Data measured in the harbour of Antwerp (in 2022 and 2023), at Etna (in 2022) and Nyiragongo (in 2017) volcanoes will be shown.
Multi-angular airborne thermal observations: A new hyperspectral setup for simulating thermal radiation and emissivity directionality at the satellite scale
Authors: Langsdale Mary , Middleton Callum , Wooster Martin , Grosvenor Mark , Schuettemeyer Dirk
Published: February 2023

Land Surface Temperature (LST) is a key parameter to the understanding and modelling of many Earth system processes. Viewing and illumination geometry are known to have significant impacts on remotely sensed retrieval of LST, particularly for heterogeneous regions with mixed components. However, it is difficult to accurately quantify these impacts, in part due to the challenges of retrieving high-quality data for the different components in a scene at a variety of different viewing and illumination geometries over a time period where the real surface temperature and sun-sensor geometries are invariant. Previous field studies have attempted this through observations with aircraft-mounted single-band thermal cameras to further understanding of real-world conditions, but these sensors have limited accuracies and cannot be used to consider the angular variability of emissivity or to simulate multi-band satellite observations.To redress this, the National Centre for Earth Observation’s Airborne Earth Observatory (NAEO) have developed and manufactured a modified mount for their state-of-the-art commercial pushbroom longwave hyperspectral airborne sensor, the Specim AisaOWL (102 narrowband channels across the 7.6 – 12.6 µm region). When mounted in standard mode, the field-of-view of the OWL sensor is 24° (± 12°), however the modified mount enables off-nadir measurements up to 48°. This has the potential to evaluate both thermal radiation and spectral emissivity directionality up to and beyond the view angles of most thermal satellite sensors. With LST now classified as an Essential Climate Variable, this work is particularly relevant as it will help to improve the accuracy of retrievals from current and future satellites (e.g. LSTM, SBG, TRISHNA).In this presentation, we first present an overview of the design modifications that enable these high-angle observations and preliminary results from test flights before detailing how this setup will be used in an upcoming joint ESA-NASA campaign dedicated to quantifying and simulating thermal radiation directionality over agricultural regions at the satellite scale.
The integrated use of LiDAR and photogrammetric techniques by the UAS platform for the mapping of rockfall processes in Ischia Island (Italy)
Authors: De Novellis Vincenzo , Alvioli Massimiliano , Barone Andrea , Bonfante Antonello , Buonanno Maurizio , Castaldo Raffaele , De Matteo Ada , Fiorucci Federica , Pepe Susi , Reichenbach Paola , Santangelo Michele , Solaro Giuseppe , Tizzani Pietro , Vitale Andrea
Published: February 2023

The following work focuses on the surveys that were carried out using optical sensors (photogrammetry) and LiDAR mounted on UAS platforms. The processing of the acquired images provided the necessary information for the development of high-precision digital terrain models that can be used as a basis for the subsequent modeling of the stability analysis of collapse phenomena with STONE, a three-dimensional rockfall simulation model. These surveys allowed us to localize the possible detachment sources and the inclusion of scenario-based seismic shaking as a trigger for rockfalls.The areas filmed fall almost exclusively along the north-western slope of Mt. Epomeo and more precisely in the areas identified as locality Falanga (32 ha) and locality Frassitelli (123 ha) in the territory of the Municipality of Forio (Napoli) and only marginally in the Municipality of Serrara Fontana (Napoli). The slope surveyed has two distinct morphologies: 1) the north-west oriented sector (Falanga) delimited by extremely steep walls and by cliffs with variable vertical development, at the base of which there is a large sub-flat area delimited to the north by a new sudden jump in slope; 2) in the west sector (Frassitelli) the slope is instead more rounded, even if in various points there are areas with steep slopes and strongly fractured cliffs; this side is characterized by the presence of numerous tuff blocks, even of large dimensions, which have stopped at various altitudes after having detached themselves from the overlying sub-vertical walls.We also used data from the Geoportale Nazionale Italiano managed by the Ministry of Environment and provided different kinds of spatial data. In particular, the archive contains an extensive LiDAR survey covering a substantial portion of Italy, with data stored at the intermediate processing level. For this research, we selected point clouds covering the Ischia island and we interpolated separately the two point clouds, using the module specifically designed to perform surface interpolation from vector points mapped by splines, within the GIS platform.In conclusion, we interpreted the point-to-point difference between DSM and DTM as due to vegetation and exploited this information to infer modifications of ground parameters relevant to the simulations with Stone. We partially took into account disturbances due to the presence of anthropic structures and buildings using additional land cover data, which we correlated with point-to-point DSM – DTM differences.
Reversing the impact chain
Authors: Pfleiderer Peter , Sillmann Jana , Lamboll Robin , Rogelj Joeri , Schleussner Carl-Friedrich
Published: February 2023

Climate impacts have been studied intensively and our understanding of changes in climate impacts due to anthropogenic activity is impressive (see IPCC AR6). There is, however, a gap between the physical understanding of changes in climate impacts and availability of information that could directly be used by adaptation planners. We argue that this gap is to a large extent a result of the usual modeling chain that is based on a handful of representative emission scenarios.Most climate change studies take a small, predefined set of emission scenarios (SSP2-45, SSP1-26, SSP5-85 etc.) and calculate the global and regional climate impacts resulting from these. Focusing on a limited set of emission scenarios allows us to compare results from different modeling groups and lets us run detailed climate models on each scenario. However, this modeling approach does not align with relevant research questions such as: “How much can be emitted to avoid a certain impact?” Or “what are the emission constraints to limit the probability of experiencing a certain event until 2050 to 10%?”The presented reversal of the impact chain would help to answer these questions. The idea is to start from a clearly defined impact and evolve uncertainties backwards into the emission space. Doing so, we take the perspective of practitioners who know very well what impacts are of relevance and would like to know how these impacts are related to greenhouse gas emissions.
Simulated tree-grass competition in drylands is modulated by CO2 fertilization
Authors: Verbruggen Wim , Schurgers Guy , Meunier Félicien , Verbeeck Hans , Horion Stéphanie
Published: February 2023

Interannual variability in climatic drivers can have a strong impact on dryland ecosystem functioning globally. While interannual variations in dryland ecosystem processes are mainly driven by rainfall, other global change drivers such as CO2 fertilization and rising temperatures can play an increasingly important role for these ecosystems. Yet, the high complexity of dryland ecosystems makes it difficult to unravel the individual and compound impacts of these different drivers. In this work we study the impacts of interannual climatic variability on the dryland ecosystems of the Sudano-Sahel region for the period 1981–2019. By using a dynamic vegetation model (LPJ-GUESS v4.0), we show that the year-to-year variability in dryland ecosystems that originates from interannual variability in rainfall is modulated by effects of CO2 fertilization, which can strongly impact woody encroachment and resource competition between vegetation types. We also show that this response varies with aridity subtype, depending on the amount and type of woody cover. By untangling the impacts of climatic drivers on dryland vegetation, this study helps us to understand the different sensitivities of dryland ecosystems to climatic variability.
A modeling approach to address building energy consumption and thermal comfort under urban climate change
Authors: Blond Nadège , Breton Florentin , Micolier Alice , Mendez Maxence
Published: February 2023

The urban environment and climate change are essential factors to consider for applications involving urban planning and human health. Although these factors influence estimations of energy consumption and thermal comfort, buildings in France are still generally designed and renovated without accounting for these specific conditions but by considering present rural weather conditions. The first objective of this study is to develop an approach to explore building design and renovation choices while accounting for the urban environment and climate change. The second objective is to find which design and renovation choices are relevant to improve thermal comfort and reduce energy consumption (and therefore GHG emissions).First, we use observations and simulations of weather conditions in several cities of France (representing different climatic zones), for the present and future climate (2050), to analyze urban conditions and estimate energy consumption. Second, we run building simulations for rural and urban situations, and for present and future climate conditions, to investigate the effect of the urban environment and climate change on the operation of buildings, and the effect of building scenarios on the urban climate.
Numerical simulation of the atmospheric CH4 increase and the corresponding decrease of δ13C(CH4) after 2007
Authors: Nickl Anna-Leah , Winterstein Franziska , Jöckel Patrick
Published: February 2023

The global atmospheric CH4 growth rate stagnated between 2000 and 2007, and has continued to grow since 2007. This renewed CH4 rise has been analysed with respect to a 2007 onward decline in  δ13C(CH4), indicating changes in the relative contribution of CH4 sources. However, this is still subject to debate and a variety of hypotheses have been put forward. In our work, we present numerical sensitivity simulations that investigate the impact of different inventories of methane emission fluxes on the globally averaged δ13C(CH4) signature. We apply the state-of-the-art global chemistry-climate model EMAC and use a simplified approach to simulate methane loss. We include methane isotopologues and take the kinetic isotope effects in physical and chemical processes into account. We further consider regional differences in the isotopic signatures of individual emission source categories, such as, for example, the differences between signatures of tropical and boreal wetlands emissions. Based on recent emission inventories and isotopic source signatures from the literature, our chemistry climate model reproduces the actual atmospheric methane and δ13C(CH4) distribution adequately. We show that our setup is suitable to constrain the individual influence of different CH4 sources on the global average δ13C(CH4). We further present an approach to optimize the global methane level with respect to station measurements probing for a strategy to include the isotopic information into such an optimization process.