bluuebunny/crossref_metadata_2025 huggingface dataset:
Burned area and fire emissions according to the fifth version of the Global Fire Emissions Database (GFED)
Authors: van der Werf Guido , Randerson James , van Wees Dave , Chen Yang , Vernooij Roland , Giglio Louis , Hall Joanne , Morton Douglas , Barsanti Kelley , Yokelson Bob
Published: March 2024

Quantifying burned area and associated fire emissions is paramount to understand how changing fire patterns affect radiative forcing and air quality. It is now well established that many fires are too small to be detected by coarse resolution satellite burned area products on which the Global Fire Emissions Database (GFED) relied. In the fifth version of GFED (GFED5) we therefore combine burned area derived from mapped coarse-resolution burned area from the MODIS sensor -which excels in detecting larger fires- with small-fire burned area. The latter is derived from MODIS active fire detections scaled to burned area using ratios constrained by higher-resolution burned area datasets from Landsat and Sentinel-2 for selected regions. Burned area in cropland regions was based on the Global Cropland Area Burned (GloCAB) dataset. Total global burned area is 61% higher than in GFED4s. We converted burned area to emissions using a simplified version of the CASA model used in previous GFED versions, but which now runs at a 500 m spatial resolution. This allows for better constrained modeled fuel loads based on field measurements. Although GFED5 emissions are aggregated to a 0.25 degree grid due to the statistical nature of deriving our burned area, we can now account for heterogeneity in fire processes within these large pixels. Emissions (3 Pg carbon per year) are roughly 50% higher than in GFED4 and we show how diverging trends in grassland versus forest ecosystems impact trends in total emissions. Finally, we show how converting fire carbon losses to trace gas and aerosol emissions is now better constrained due to the addition of several new emission factor measurement campaigns. In the savanna biome we now account for spatial and temporal variability in emission factors.
Projected changes in compound dry-hot events in South Asia
Authors: Saleem Farhan , Weber Torsten , Remedio Armelle
Published: March 2024

South Asia is one of the hotspot regions for extreme weather and climate events such as heatwaves, droughts, and extreme precipitation. This work aims to present a comprehensive analysis of the future changes (2071-2100) in the frequency and duration of compound dry-hot extremes in South Asia. Given the current gap in specific data for such compound events in this region, our approach involves utilizing state-of-the-art regional climate models from the Coordinated Output for Regional Evaluations (CORE) project embedded in the Coordinated Regional Climate Downscaling Experiment (CORDEX) framework. The focus will be on understanding the interplay between dry and hot days conditions, and how their concurrent occurrence may exacerbate environmental and socio-economic challenges. We will analyze an ensemble of regional climate projections to identify potential trends in these compound events by the end of the 21st century. The outcomes of this study are expected to provide valuable insights into the evolving nature of compound climate extremes in South Asia, thereby informing policy and adaptation strategies for enhanced regional resilience.
Dispersion in heterogeneous networks under linear and non-linear flow conditions
Authors: Dentz Marco , Kordilla Jannes , Hidalgo Juan
Published: March 2024

The understanding and prediction of dispersion phenomena in natural and engineered media are key issues in different fields of science and engineering, with applications ranging from groundwater management to geological energy storage. Spatial variability in the physical medium properties and flow conditions leads to scale effects in the flow and dispersion processes. Here we study the mechanisms of dispersion in two- and three-dimensional heterogeneous networks under linear and non-linear flow conditions, that is, for flows in which the flow rate is a non-linear function of the pressure gradient. Such non-linear relationships have been found for the flow of non-Newtonian fluids, for multiphase flow and inertial flows in porous, fractured and karstic media. We study transport under steady flow using a Lagrangian approach. The flow fields are characterized statistically in terms of the distribution of Eulerian and Lagrangian flow velocities and their correlation properties. Longitudinal dispersion is measured in terms of particle breakthrough curves. We observe broad distributions of particle arrival times, which are manifestations of memory processes that occur due to broadly distributed flow velocities and mass transfer rates. These behaviors are analyzed in terms of the Eulerian and Lagrangian flow statistics, medium structure and flow conditions. Based on this analysis, we propose a stochastic time domain random walk approach to quantify the impact of the network heterogeneity and flow conditions on large-scale dispersion.     
Formation of chemically stratified layer in Ganymede’s ocean: implications for upcoming JUICE mission
Authors: Pinceloup Mathis , Bouffard Mathieu , Vance Steven , Melwani Daswani Mohit , Styczinski Marshall
Published: March 2024

Chemically stratified layers in the deep oceans of icy moons may strongly influence the oceans’ dynamics, thermal and chemical evolution, and therefore their habitability. Such layers can form during the differentiation of the refractory cores as they heat up due to the decay of long-lived radioactive elements. In the case of Ganymede, salts could be transported through the high-pressure ice layer to form a denser salt water layer at the base of the ocean. Such a layer would inhibit ocean convection, limiting chemical and thermal transport. It is therefore crucial to understand how these layers form and what specific signatures they may leave in geophysical observations of future space missions. The present work describes numerical simulations of the formation of stratified layers and the predicted observables that could be detected by instruments on the JUICE spacecraft.3-D numerical simulations of Ganymede’s rotating ocean are performed with the PARODY code. Rayleigh-Bénard convection is imposed. We investigate the effect of either a constant flux of heavy salts or a fixed composition at the base of the ocean. Two regimes are identified by varying the dimensionless chemical Rayleigh (buoyancy over viscosity) and Schmidt numbers (viscosity over diffusivity). In the first regime, heavy salts are entrained and mixed in the convective region. In the second regime, the entrainment is too weak and a chemically stratified layer develops, eventually filling the entire ocean.Extrapolation to Ganymede suggests the current existence of a chemically stratified layer at the base of the ocean with a thickness close to 30 km. By considering different stratifications in Ganymede’s ocean in the PlanetProfile and ForcedTides codes, we show that signatures of stratified layers might be detected in the gravity field, induced magnetic field, and tidal deformation responses. The problem of non-uniqueness in the individual observations points to the need to jointly invert these datasets from the JUICE mission to constrain the existence and properties of stratified oceanic layers.
Overview of the shallow magma reservoir, conduit properties and effusion style throughout the 2021 eruption near Fagradalsfjall, Iceland
Authors: Eibl Eva P. S. , Moreland William M. , Thordarson Thorvaldur , Höskuldsson Ármann , Gudnason Egill Árni , Hersir Gylfi Páll , Ágústsdóttir Thorbjörg
Published: March 2024

The 2021 Geldingadalir eruption is the first of four eruption events that have taken place since volcanic activity resumed on the Reykjanes Peninsula, SW Iceland, after an 871-year repose. It lasted from 19 March to 18 September 2021 and featured (i) continuous effusion, (ii) episodic effusion on a minute scale, and (iii) episodic effusion on an hour to day scale. The eruption transitioned between these states several times, making it the most diverse eruption on record. We provide an overview of the eruptive processes during the entire eruption using video camera footage and seismic tremor data.Our aim is to image the changes in the subsurface structure, to identify the driving processes, and to interpret the dynamics of the volcano. We will present our view on the most striking questions: What triggered the transition between these different states? What do these different effusion states mean in the context of the conduit and the shallow magma reservoir? What can we learn from the tremor amplitude, tremor duration and repose time of such episodic events?
Half of the unprecedented global soybean production failure in 2012 is attributable to climate change.
Authors: Hamed Raed , Lesk Corey , Shepherd Theodore G. , M.D Goulart Henrique , van Garderen Linda , Van den Hurk Bart , Coumou Dim
Published: March 2024

The United States (US), Brazil, and Argentina collectively produce about 75% of the world's soybean supply. In 2012, soybean crops failed in these three major producing regions due to spatially compound hot and dry weather across North and South America. This led to unprecedented shortages in the global supply, resulting in record-high market prices. Despite the severity of this event, the role of historical and future anthropogenic warming in influencing such occurrences remains unknown. Here, we present different impact storylines of the 2012 event by imposing the same seasonally evolving atmospheric circulation in a pre-industrial, present day (+1°C above pre-industrial), and future (+2°C above pre-industrial) climate. We use so-called nudged atmospheric simulations and train a statistical model to estimate yield losses from meteorological conditions. While the drought intensity is rather similar under different warming levels, our results show that anthropogenic warming strongly amplifies the impacts of such a large-scale circulation pattern on global soybean production, driven not only by warmer temperatures, but also by stronger heat-moisture interactions. We estimate that 51% (47-55%) of the global soybean production deficit in 2012 is attributable to climate change. Future warming (+2°C above pre-industrial) would further exacerbate production deficits by 58% (46-67%), compared to present-day 2012 conditions. This highlights the increasing intensity of global soybean production shocks linked to similar atmospheric conditions with warming and thus requires urgent adaptation strategies.
Maximal reachable temperatures for Western Europe in current climate
Authors: Noyelle Robin , Zhang Yi , Yiou Pascal , Faranda Davide
Published: March 2024

Human bodies, ecosystems and infrastructures display a non-linear sensibility to extreme temperatures occurring during heatwave events. Preparing for such events entails to know how high surface air temperatures can go. Here we examine the maximal reachable temperatures in Western Europe. Taking the July 2019 record-breaking heatwave as a case study and employing a flow analogues methodology, we find that temperatures exceeding 50 ∘C cannot be ruled out in most urban areas, even under current climate conditions. We analyze changes in the upper bound of surface air temperatures between the past (1940–1980) and present (1981–2021) periods. Our results show that the significant increase in daily maximum temperatures in the present period is only partially explained by the increase of the upper bound. Our results suggest that most of the warming of daily maximum surface temperatures result from strengthened diabatic surface fluxes rather than free troposphere warming.
Evaluation the efficiency of different application method of Fe aminochelates compared to FeSO4 on yield and quality traits of oleic Sunflower (Helianthus annuus L.) in a calcareous soil
Authors: Alipour Babadi Mina , Norouzi Masir Mojtaba , Moezzi Abdol Amir , Taghavi Mehdi , Rahnama Afrasyab , Razavi Bahar S.
Published: March 2024

In modern and sustainable approaches, it is necessary to address the nutrient deficiencies that limit agriculture productions.­ Routine inorganic fertilizers such as FeCl2 and FeSO4, are not effective in correcting iron (Fe) deficiency due to their chemical nature and rapid conversion of soluble Fe forms into unavailable Fe (III)-oxide or hydroxide forms, particularly under lime conditions. Recently, organic complexing agents such as amino acids have been considered important due to increasing nutrient bioavailability in the soils as well as improving plant stress tolerance for more yield. It is hypothesized that the use of ecofriendly Fe (II)-amino acid chelates can increase Fe uptake by plant as such products have the potential to form relatively stable complexes with minerals as "aminochelates". Aminochelate fertilizers are the latest novelties regarding plant nutrition in agricultural production systems. Amino chelates provide higher bioavailability and absorption of micronutrients due to effective ingredients with no environmental side effects. Here, we investigate the effects of Fe aminochelates as Fe sources on the yield of sunflower (Helianthus annuus L.) plants in field condition. We made use of synthesized Fe (glycine)2 [Fe (Gly)2] and Fe (methionine)2 [Fe (Met)2] amino chelates for seed priming, fertigation and foliar application on plant leaves. This experiment showed that all methods of Fe aminochelates application, especially foliar feeding, can increase shoot iron content and improve nutritional quality of sunflower in Fe-deficient soils. We observed the higher effectiveness of Fe aminochelates compared to FeSO4 on increasing plant growth parameters, grain and oil yield, biomass production and activity of antioxidant enzymes. Overall, our results suggested that application of Fe aminochelates can be considered as an effective approach to overcome the plant Fe deficiency and improve the yield of plant in calcareous soil. Future experiments will investigate the effects of aminochelates on soil biological parameters and soil enzymes activity in rhizospheres using imaging techniques. Key words: Aminochelates; antioxidant enzymes; grain yield; iron deficiency; nutrient uptake 
Climate Change impacts on hydrological and plant resources in the agro-pastoral Sahel
Authors: Collet Lena , Demarty Jérôme , Etchanchu Jordi , Ollivier Chloé , Maïnassara Ibrahim , Farhani Nesrine , Raynaud-Schell Brune , Chahinian Nanée
Published: March 2024

The Sahel is a semi-arid region where the majority of the population depends on subsistence farming. This region is considered as a hotspot for climate change with an expected warming of 3 to 4°C by 2100. Indeed, climate projections show that dry periods are likely to be longer and extreme rainfall will be more frequent. These changes could have a major impact on hydrological and vegetal resources. This study aims to assess these impacts on a typical Sahelian agro-pastoral ecosystem dominated by millet crops and shrubby savannah in South-Western Niger. Climate scenarios are constructed from a local set of observed climate data combined with CMIP6 and other climate scenarios dedicated to Sahelian region. These scenarios are used to constrain SiSPAT SVAT (soil-vegetation-atmosphere transfer) model in order to simulate the surface water and energy fluxes. Results show that both energy and water balances are deeply influenced by temperature and air humidity changes. Temperature increase mainly affects the sensible heat flux (H), e.g., H decreases by 38% for a 3°C of temperature increase. Moreover, results show that the impact of temperature and humidity changes on evapotranspiration, partly compensate each other; higher temperature in the rainy season, leads to higher evapotranspiration values, contrarily to the impact of humidity increase. The surface water balance is mostly influenced by the rainfall regime modification, e.g., intensification of extreme rainfall leads to 59% increase in drainage. It also generates more runoff (+ 500 %), that would increase the risk of flooding but could cause a rise in groundwater levels, which is called the Sahelian paradox. Finally, it also increases the soil water storage, which could lead to a longer vegetation cycle. For this aim, coupling with crop and/or hydrological modelling would be useful to quantify the impacts of climate evolution on vegetal and water resources dynamics. It would allow to find efficiently adapted strategies for crop and water management.
Increased N2O emissions by the soil nematode community cannot be fully explained by enhanced mineral N availability
Authors: Hu Junwei , Kong Meng , Françoys Astrid , Yarahmadi Farideh , Mendoza Orly , Hassi Ummehani , Gebremikael Mesfin T. , Wesemael Wim , Sleutel Steven , De Neve Stefaan
Published: March 2024

Soil nematodes, being the most abundant soil fauna, can significantly impact soil N mineralization via interaction with soil microorganisms. As a consequence, nematodes likely also influence soil N2O production and emissions but the very few studies on this matter were carried out in simplified setups with single nematode species and in (highly) disturbed soil conditions. Here we measured soil N2O emissions in a 74-day incubation experiment in the presence or absence of the entire soil nematode community with minimal disturbance of the soil microbial community and soil nutrients. This was e.g. evidenced by readily recovery of nitrifiers after the mild and selective sterilization and soil powder inoculation. N2O emissions increased in the presence of nematodes, varying between soils +747.7 % in a loamy sand, +55.8 % in a loam, and +51.9 % in a silt loam cropland topsoil, in line with nematode abundance in these soils. In particular, the loamy sand soil showed an atypical N2O emission peak at the time of high nematode abundance. Soil nematodes also increased net N mineralization by +8.4, +6.8 and +4.75 %, in these respective soils and to a smaller extent C mineralization as well. The extra soil nitrate buildup and the overall net stimulation of N mineralization by nematodes could not or just slightly explain the observed increased N2O emissions. This research revealed the important role of soil nematodes in regulating N2O emissions, and further stresses the need to consider the change in community composition and activity of denitrifiers, and connectivity of soil pores, rather than the stimulation of N mineralization as potential explanations for this role of nematodes.
Waveform tomography of the upper mantle beneath the North Atlantic region using regional seafloor and global data.
Authors: de Laat Janneke I. , Lebedev Sergei , Bonadio Raffaele , Thsekhmistrenko Maria , Celli Nicolas L. ,   SEA-SEIS Team
Published: March 2024

The Iceland hotspot and its interaction with the Mid-Atlantic Ridge have strongly influenced the structure and evolution of the North Atlantic region. The Iceland hotspot has been linked to the presence of the underlying Iceland plume, rising from the deep mantle below Iceland. Due to the sparsity of the seismic data coverage in the North Atlantic Ocean, the structure and dynamics of the underlying plume, as well as its influence on the surrounding North Atlantic region, remain a topic of debate. As part of the project SEA-SEIS (Structure, Evolution And Seismicity of the Irish offshore), a network of ocean bottom seismometers was deployed across a large part of the North Atlantic Ocean—from Ireland and Britain to near Iceland—in September 2018. Over a period of 19 months, they recorded seismic data on the seafloor. 14 OBSs were retrieved in May 2020, of which 12 successfully recorded 19 months of seismic data. The data was thoroughly preprocessed, including the reduction of compliance and tilt noise on the vertical-component waveforms of teleseismic events. These waveforms were individually inverted for surface, S- and multiple S-waves using the Automated Multimode Inversion (AMI), extracting structural information on the lithosphere and underlying mantle.Here, we combine this new seafloor seismic data with a massive global dataset of waveform fits for almost 1.5 million seismograms, with the coverage maximised in the hemisphere around the North Atlantic, and compute a new seismic waveform tomography model of the North Atlantic upper mantle: NA24. The tomography capitalises on the improved data coverage and reveals both the S-wave velocity and the azimuthal anisotropy structure below the Iceland hotspot, the adjacent mid-ocean ridge, and the entire North Atlantic region at a new level of detail. It shows low seismic velocities below Iceland and the adjacent Reykjanes Ridge and Kolbeinsey Ridge down to ~260 km depth, below which they merge into one low-velocity body located west of Iceland at around 330 km depth. Around 410 km depth, the low-velocity body is present below eastern Greenland where it remains throughout the transition zone. This observation implies that the Iceland plume is located below eastern Greenland in the transition zone, moving eastward as it rises in the upper mantle. In the shallow upper mantle, a strong ridge-parallel azimuthal anisotropy structure is revealed along the full length of the Reykjanes Ridge. This implies a strong channelled horizontal flow from the Iceland plume towards the south below the ridge axis, while any sign of a radial outward flow of the plume is absent.
Near-surface effects in seismic wavefields at Krafla volcano (NE Iceland): characterization and mitigation. 
Authors: Maass Regina , Bean Christopher J. , Li Ka Lok
Published: March 2024

Seismic imaging of small-scale geological features in volcanic regions is challenging due to the often heterogeneous subsurface, causing extensive wave scattering and limited coherence in the wavefields. A well-known example that illustrates this problem is the unexpected encounter of magma at 2.1 km depth at Krafla (NE Iceland) during geothermal drilling in 2009. Despite numerous geophysical studies, the magma body remained undetected prior to drilling. In the summer of 2022, we deployed ~100 short-period seismic nodes in a reflection seismic configuration at Krafla. Using the known reflector as a guide, our goal is to investigate and enhance seismic imaging in complex geological settings. Analyses of ~300 local earthquakes (magnitudes < 1.5) show that the wavefields at Krafla are largely dominated by wave scattering and reverberations within the uppermost ~100m of the subsurface, causing little coherency in the data even among neighbouring stations spaced at 30 meter intervals. Using auto – and cross-correlation techniques, we address the reverberations and construct transfer functions characterising the seismic response of the sites at each station. This is followed by time-dependent deconvolution. The deconvolved wavefields show increased coherency, as the influence of the near-surface could be considerably reduced. Coherent phases emerge in the wavefields which were previously obscured by reverberating waves. Different imaging techniques such as common-depth-point (CDP) binning and stacking will be applied to the cleaned wavefields in order to resolve potential layer boundaries and magma pockets, ultimately improving our understanding of the Krafla geothermal system.
Effect of tectonic stress on isotopic systems in dating minerals
Authors: Chen Xin , Wang Yu
Published: March 2024

Temperature is recognized as the only dominant factor that affects the opening and closing of isotope system, based on which thermochronology has well developed. However, there are some research shows that stress could also matter. The muscovite K-Ar ages of Sanbagawa (Japan) schists are consistently younger with increasing deformation extent (Tetsumaru, 1988), which revealed that tectonic deformation can have influence on isotopic ages. On a microscopic scale, elements like Pb can redistribute in zircon lattice during dislocation (Piazolo,2015). The behaviors of isotopic systems in dating minerals under stress involve the fundamental problem of isotopic chronology. The application of it can be very wide, it allows us to get the deformation age directly if we choose the right deformed minerals in the right way. Some of the works such as fault, fold and ductile shear zone dating by our lab has been published (Yu Wang, 2010, 2016, 2020). What role does stress play in isotope diffusion which in turn affects ages is what we are eager to know. We designed a set of experiments using three axles press to work on undeformed K-feldspars with known age (126Ma) to test the effects. Rock mechanics experiments, field observation and isotopic dating are combined to give us an insight to it.
The effect of grid resolution on sub-ice shelf circulation in the Energy Exascale Earth System Model
Authors: Vaňková Irena , Asay-Davis Xylar , Comeau Darin , Price Stephen , Wolfe Jonathan
Published: March 2024

Global ocean models are typically too coarse to explicitly resolve physical processes, such as mesoscale eddies, that transport heat into ice-shelf cavities and contribute to melting. As a result, mesoscale processes around Antarctica in such models need to be parameterized. Here we investigate the performance of these parameterizations in the Energy Exascale Earth System Model (E3SM), specifically focusing on the heat transport into an ice shelf cavity, the strength and direction of sub ice shelf circulation, and the rate of basal melting. Taking advantage of E3SM’s variable-resolution capabilities we set up a sequence of configurations with nominal grid sizes of 12, 8, 4, 2, and 1 km in the southern Weddell Sea, such that with increasing resolution, less eddies are parameterized and more resolved explicitly. The analysis is focused on the Filchner-Ronne Ice Shelf, because it is oceanographically interesting, it is important for sea level projections, and there are relatively abundant datasets from this region available for model validation.
Examining the influence of forest changes on drought across time scales in Europe through multiple regional climate model simulations
Authors: Li Yan , Huang Bo , Tan Chunping , Liu Yi , Rust Henning W.
Published: March 2024

Land cover changes, notably forest alterations, have been observed across Europe due to extensive land management policies. These changes have significant influence on local climates through diverse biophysical mechanisms, given the crucial role of forests in the land ecosystem. While modeling studies have emphasized the impact of forest changes on regional temperature and precipitation in recent decades, their effects on drought conditions in this region remain largely unexplored. To address this gap, our study analyzes multiple simulations with regional climate models to comprehensively investigate how forest changes impact drought across various timescales in Europe. Specifically, we explored seven models, each simulated two extreme scenarios: maximum forest coverage and grass coverage in the region. The comparison between extreme forest coverage and grass coverage serves to evaluate the impact of deforestation on drought. The Standardized Precipitation Evapotranspiration Index was chosen as our metric to assess drought conditions. Our findings reveal considerable variation among the models in depicting the response to deforestation in terms of drought, particularly notable in Scandinavia and Eastern Europe. Our results suggest an increase in aridity on the Iberian Peninsula following deforestation. In Scandinavia the response varies during the year: winter months tend toward increased dryness, while summer months display a tendency toward greater wetness post-deforestation. Our primary objectives encompass quantifying the potential impacts of deforestation in Europe, identifying resilient model responses, and unraveling the sources of uncertainty within these simulated impacts. Through a meticulous analysis of model responses across regions and timescales, we aim to offer insights into the nuanced effects of forest change on drought conditions. This exploration is crucial in guiding future land management policies and devising strategies to mitigate potential adverse impacts of deforestation on regional drought susceptibility in Europe. Ultimately, our study seeks to contribute to informed decision-making regarding land use practices and their implications for climate and ecosystems.
Application of Machine-Learning Based Models for Prediction of Suspended Sediment Load in the Indian Peninsular River Basin
Authors: Kundu Soumya , Swarnkar Somil , Agarwal Akshay
Published: March 2024

Suspended sediment load in rivers has a crucial impact on the river water quality, soil erosion, irrigation activities, and dam or reservoir operations. Dam construction in a river reduces the runoff, which increases the deposition of suspended sediment on the river course and ultimately leads to a change in the river channel morphology. Thus, suspended sediment load prediction is significant for planning and sustainable management of the riverine ecosystem. Researchers have used various physical models, such as sediment rating curves (SRC), SWAT, HEC-RAS, HEC-HMS, etc., for predicting suspended sediment load. Recently, researchers have used machine learning models to predict suspended sediment load in different hydroclimatic regions worldwide. In this study, we used five different machine learning models, such as ElasticNetCV, Multi‑Layer Perceptron (MLP) Regressor, Extreme Gradient Boosting (XGB) Regressor, Light Gradient-Boosting Machine (LGBM) Regressor and Linear Regression (LR), for predicting suspended sediment load in a downstream station of Godavari River Basin (GRB). The GRB is the largest Indian peninsular river basin, covering more than 0.3 million square kilometers of area. We used the 'Lazy Predict' Python library to achieve better results for machine-learning modeling. The data was collected for the period of 1970–2018 and divided into two parts, viz. pre-1990 and post-1990, to consider the dam effects on the downstream regions of the GRB. Performance evaluation revealed that the Multi‑Layer Perceptron (MLP) Regressor performed very significantly, with an r-square value of 0.71 and 0.74, respectively, for pre-1990 and post-1990. The developed models offer a valuable resource for decision-makers, environmental scientists, and water resource managers seeking to proactively manage sediment-related issues in river systems, ultimately fostering sustainable water quality and ecosystem health.
Identifying Heterogeneous Landslides using Multi-modal Deep Learning
Authors: Tang Xiaochuan , Fan Xuanmei , Catani Filippo
Published: March 2024

Automated detection of landslides is an important part of geohazard prevention. In dense vegetation covered area, identifying landslides is a challenging problem. Various types of landslide monitoring technologies have generated heterogeneous data, such as optical imagery, SAR imagery, and LiDAR point clouds. Different types of landslide monitoring methods have their advantages and drawbacks. An ideal landslide detection model should utilize their advantages. However, the complementary information of multi-source landslide monitoring data has not been fully understood. To deal with this problem, we study how to use multi-source data for developing better landslide detection models. First, a multi-modal deep learning model is introduced for landslide detection using multi-source landslide monitoring data. Second, representation learning networks are proposed for extracting landslide detection features from optical imagery and LiDAR-derived data. In addition, an attention-based data fusion network is proposed for merging the feature maps of different data sources. Finally, to improve the explainability of the proposed neural network, a new loss function with domain knowledge constrains is proposed. The proposed multi-modal deep learning method is compared with the existing machine learning-based landslide detection methods. Experimental results demonstrated that the proposed method outperformed the state-of-the-art landslide detection methods, and is able to simultaneously identify earthquake-triggered new landslides and forest-covered ancient landslides. The reason is that optical imagery is appropriate for identifying new landslides, while LiDAR-derived data is able to remove forest cover and suitable for identifying ancient landslides. It can be seen that the complementary information of multi-source data is helpful for improving the performance of landslide detection.
Can long-term tropical land carbon-climate feedback uncertainties be constrained from interannual variability?
Authors: Liu Laibao , Fisher Rosie , Douville Hervé , Padrón Ryan , Berg Alexis , Mao Jiafu , Alessandri Andrea , Kim Hyungjun , Seneviratne Sonia
Published: March 2024

Whether tropical land carbon sink will persist in the future to slow climate change remains elusive in Earth System Model (ESM) projections, largely due to carbon-climate feedback uncertainties. Unraveling drivers of interannual variability (IAV) of the land carbon cycle can inform tropical land carbon-climate feedbacks. Here we utilize two generations of factorial ESM experiments to show that the IAV of the tropical land carbon uptake under both present and future climate is consistently dominated by terrestrial water variations in ESMs. The magnitude of this interannual sensitivity of tropical land carbon uptake to water variations (γIAV,W) under future climate shows a large spread across the latest 16 ESMs (2.3 ± 1.5 PgC/yr/Tt H2O). Based on the identified significant emergent relationship between γIAV,Wunder future climate and present climate, the mean and spread of future γIAV,Ware reduced by about 41% and 44%, respectively (1.3 ± 0.8 PgC/yr/Tt H2O), using observations and the emergent constraint methodology. However, the long-term tropical land carbon-climate feedback uncertainties in the latest 16 ESMs can no longer be directly constrained by land carbon cycle IAV compared with previous generations of ESMs, given that additional important processes such as tree mortality are not well represented in IAV but could determine long-term tropical land carbon storage. This result highlights the importance of recommended out-of-sample testing for validating previously diagnosed emergent constraint. In summary, our results suggest the limited implication of IAV for long-term tropical land carbon-climate feedbacks and help isolate remaining uncertainties with respect to the effects of water limitation on tropical land sink in ESMs.
Empirical and computational study on conservative tracer migration through a single fracture
Authors: Pandey Snigdha , Sharma Pramod Kumar
Published: March 2024

The escalation of industrialization and population growth in recent decades has increased the prominence of groundwater pollution in environmental concerns. However, accurate prediction of the contaminant migration through the fractured aquifer is still an arduous task. The current research is dedicated to evaluating the predictive accuracy of three models: the Advection Dispersion Equation (ADE), Advection Dispersion Equation with Retardation (ADE-R), and Single Rate Mobile-Immobile (MIM) model. Constant dispersivity is assumed for all the models. These models were employed to predict the migration of the solute, particularly NaCl, within a single fracture characterized by a 0.3 cm aperture and 1000 cm length and filled with fine sand. The study maintained non-Darcian flow conditions throughout the experimental runs. The simulated BTCs exhibited a non-Fickian trend and were subsequently subjected to fitting using the ADE, ADE-R, and MIM models. Notably, the MIM model proved the most adept at fitting the simulated BTCs, effectively capturing both early arrival and long tails. Conversely, the ADE-R model excelled in predicting the early arrival but fell short in fitting the long tails of the BTCs.Keywords: ADE model; ADE-R model; Breakthrough curves; filled-single fracture; MIM model; non-Darcian flow
From subsidence to uplift at Campi Flegrei, with an eye to Vesuvio
Authors: Crescentini Luca , Amoruso Antonella , Gualandi Adriano
Published: March 2024

Geodetic data measure deformation of various origins (e.g., tectonic, volcanic, hydrological, human-induced). To attempt separating the different signals underlying the observations, data can be analysed as in a blind source separation (BSS) problem. A common technique to tackle BSS problems is the Independent Component Analysis (ICA), which decomposes the dataset into a set of independent components (ICs) under the assumption of a linear mix of the non-moving sources.We use a variant of ICA (vbICA, variational Bayesian ICA; Choudrey and Roberts, 2003) to analyze ground displacement time series from ERS-ENVISAT SAR images in a large area including Campi Flegrei and Vesuvio volcanoes (Italy) between 1993 – 2010. The time series, which have gaps, were obtained through the SBAS technique and provided to us by IREA-CNR.Our analyses evidence two significant ICs. Their spatial and temporal features indicate that one of the ICs (IC1 in what follows) is related to Campi Flegrei only and describes the subsidence occurred before 2000, the mini-uplifts started in 2000 and 2005, and a post-2005 uplift. The other significant IC (IC2 in what follows) is related to the subsidence occurred at Vesuvio after 2001 (Amoruso & Crescentini, 2023) and an additional (with respect to IC1) post-2001 Campi Flegrei dynamics.The IC1 spatial pattern confirms the results in Amoruso et al. (2014): it is satisfied by the joint effects of two pressurized sources embedded in an elastic layered half-space, i. e. a sill at a depth of about 3.5 km and a small spheroid at a depth of about 2 km; the two sources satisfy large-scale and local (Solfatara fumarolic field) deformation, respectively.The IC2 spatial pattern is consistent with Amoruso & Crescentini (2023) as regards Vesuvio. As for the Campi Flegrei area, it is quite complex and difficult to ascribe to a single source, even as general as a moment tensor. If the whole IC2 spatial pattern is inverted for small (with respect to depth) pressurized spheroids (point sources), two deep sources (depths larger than about 8 km) acting in the Campi Flegrei area are needed in addition to the deflating source beneath Vesuvio. The three sources appear inactive before 2000; afterwards the two deep sources beneath Campi Flegrei show opposite behaviour.We show that the scenario outlined by our results is consistent with geophysical (e.g., gravity) and petrological data. It is also consistent with subsequent pressurization of a sill-like source at about 8 km depth, inflating at least since 2015 (Amoruso & Crescentini, 2022).ReferencesAmoruso et al. (2014), J. Geophys. Res: SE, 119, 858–879.Amoruso, A., and Crescentini, L. (2022). Remote Sens., 14, 5698.Amoruso, A., and Crescentini, L. (2023). Remote Sens., 15, 3038.Choudrey, R., and Roberts, S. (2003). Neural Computation, 15(1), 213-252. 
Mapping snow depth in the Arctic with public satellite elevation datasets, a case study in Iceland with ICESat-2 and the ArcticDEM
Authors: Deschamps-Berger César , Belart Joaquin , Gunnarsson Andri , Revuelto Jesus , Aðalgeirsdóttir Guðfinna , Lopez-Moreno Juan Ignacio
Published: March 2024

Satellite datasets are especially useful to monitor the cryosphere in vast and remote environments, such as the Arctic, where seasonal snowpack controls permafrost distribution, surface runoff, plant growth and animal survival rate. The recent availability of free, high-precision and high-resolution elevation datasets show promises to map snow depth on a large scale, a key bulk variable of the snowpack. Here, we mapped the snow depth distribution across Iceland (65°N) using elevation data from ICESat-2, a photon-counting laser altimetry satellite, and the ArcticDEM, a large set of digital elevation models from satellite stereoimages. The snow depth was retrieved through comparison of acquisitions with snow-on conditions (ICESat-2, ArcticDEM) and snow-free (summer ArcticDEM). Despite the heterogeneous spatial coverage of the two datasets, negative impacts of clouds, polar night and a shallow snowpack often close to the limit of detection, we successfully retrieved snow depth from 2018 to 2023, at monthly resolution. By leveraging large publicly available datasets, this approach is promising to further monitor the snowpack in other regions of the Arctic.
Assessment of ecohydrological response of Himalayan Forest ecosystems to  forest fires
Authors: Ge Nagashree , Sharma Ashutosh
Published: March 2024

Himalayan forests boast an incredible biodiversity, harboring a wide range of flora and fauna and playing a significant role in regulating water resources. Forest fires are one of the disturbances which constitute a major force influencing, even determining, the structure and functions of ecological components-populations, communities, and ecosystems. The ability to withstand disturbance is defined as resistance whereas resilience is the capacity to recover from disturbance. These two terms define the ecohydrological response to forest fire. This study insights on how remote sensing technique can be utilized for the measurement of ecohydrological response of a large extent of region subjected to forest fire based on resistance-resilience framework and how further implementation of these measures would help to know the changes in the interaction been vegetation and water cycle. Normalized burn ratio (NBR) is used to quantify the response.  The outcome of the study reveals that deciduous needled leaf forests are subjected frequently to forest fires compared to other classes of forests during 2002-2022. The regions considered for study showed moderate to high range of resistance but low resilience, signifying the region has gained and lost vegetations in the post-fire. There was a variation in rainfall and run-off occurred during the post-fire year for different burn severities. The present approach has the potential to quantify the response of ecosystems to the forest fire and related effects on hydrology of the region.
Delineation of the thermal plume associated with a standing column well system
Authors: Champagne-Péladeau Laurence , Pasquier Philippe
Published: March 2024

Due to their potential for reducing energy consumption and greenhouse gas emissions, ground heat exchangers (GHE) coupled with heat pumps are now more commonplace. In urban areas, interference between neighboring GHEs can be a cause for concern, as it can affect average ground temperature and the long-term efficiency of heat pumps. Standing column wells, which use groundwater as a heat transfer fluid, are particularly suited to urban contexts as they do not require a productive aquifer or large areas of land. Unlike open-loop systems, groundwater is mainly recirculated in SCWs. However, to improve their performance, a fraction of the recirculation flow can be diverted to an injection well (IW), enabling the development of a thermal plume around the SCW and IW. Therefore, the delineation of the thermal plume for SCW systems is important to prevent environmental disturbances and maintain their thermal efficiency. A case study is conducted on a real system consisting of five SCWs and one IW installed in a productive fractured aquifer in the city of Mirabel, Canada. Using a 25-day hydraulic tomography, geophysical logs, drilling reports and thermal profiles, a 3D numerical model coupling heat transfer and groundwater flow was developed and calibrated. Using this calibrated model, numerical simulations were used to generate a 3D thermal plume and assess the environmental impact of the SCW system. The results indicate that the impact of SCW on this particular aquifer is limited, and that the system alone can be operated for 10 years without significant loss of efficiency or environmental impact.
Limited role of discharge in global river plastic transport 
Authors: Roebroek Caspar , Teuling Adriaan , Van der Ploeg Martine , Van Emmerik Tim
Published: March 2024

Global plastic pollution in the environment is of widespread concern. Rivers have been recognised as an important transport pathway, leading to the spatial redistribution of land-based plastic, and as a key source of plastic in the world’s oceans. Several global models have been developed to estimate the transport, accumulation and export of plastics into the ocean. Many, if not all, of these attempts formulate the river plastic transport dynamics based on estimates of land-based plastic pollution and river discharge. However, the direct relationship between discharge and the river plastic flux is put into question by river plastic pollution observations, which have largely failed to obtain any significant correlation between discharge and the plastic flux at non-extreme discharge levels. Here, we seek to explain these counterintuitive findings and provide a new perspective on how the riverine plastic research and models could improve. We address this by separating the driving forces of plastic transport into the transport capacity (transport), and the potential plastic load (supply). This perspective provides an explanation of the absence of generalizable correlations between discharge and the riverine plastic flux observations. We also highlight the need to broaden the focus of plastic research to include not only the flux in the river, but also the current plastic stocks and fluxes of the whole river systems and their relationship to human behaviour. 
Time-dependent deformation behavior of Opalinus Clay: A triaxial multi-step creep study under fully drained conditions
Authors: Gotzen Lina , Winhausen Lisa , Jalali Mohammadreza , Khaledi Kavan , Amann Florian
Published: March 2024

Ensuring the long-term integrity of deep geological repositories for nuclear waste, i.e., safety and sustainability, remains a critical concern for disposal solutions. Reliable predictions on long-term rock mass behavior require a precise characterization and understanding of time-dependent phenomena such as creep and consolidation. While consolidation involves changes in effective stress, creep is characterized by continuous deformation even under minimal to zero effective stress changes. Parameters which describe the drained creep behavior under fully-saturated rock mass conditions and the long-term strength boundaries (i.e., creep failure) of low-permeable clay shales are limited mainly due to the significant amount of time required for laboratory tests. Creep mechanisms may lead to tunnel convergences and delayed failure, but may also favor self-sealing, even under stress conditions below the short-term peak strength. Consequently, a comprehensive understanding of creep mechanisms is necessary for long-term safety analyses and associated precautionary measures.In this context, we performed hydro-mechanically coupled triaxial creep experiments using samples of the shaly Opalinus Clay obtained from the Mont Terri Underground Research Laboratory in Switzerland. These tests were conducted on fully saturated and consolidated specimens with bedding orientations parallel and perpendicular to the axial loading direction. We applied step-wise, strain-controlled increases in differential stress under drained conditions, succeeded by creep stages at constant effective stresses. Two different multi-stage stress paths were used. The procedure allows observing deformations related to creep mechanisms for different sample geometries and quantifying the influence of the stress path on the creep behavior.The study findings reveal the occurrence of both primary and secondary creep even at low differential stresses, along with a distinct anisotropic creep behavior related to the bedding orientation. Increased differential stresses generally result in accelerated secondary creep rates, ultimately leading to creep failure below the short-term strength. The strain-rate data allow a subdivision into a stress-insensitive and a stress-sensitive creep behavior depending on the stress conditions, indicating a difference in the dominating creep mechanisms. Our study also shows that the long-term strength and the creep rates depend on the multi-step stress paths. For smaller incremental increases in differential stress, we find a decreased long-term strength and higher creep rates for the same differential stress.Our results provide insights into the creep behavior of clay shales and yield crucial parameters for incorporating drained creep as a distinct, time-dependent phenomenon into a constitutive model for Opalinus Clay.