bluuebunny/crossref_metadata_2025 huggingface dataset:
PETRI-MED: Advancing Satellite-Based Monitoring for Microbial Plankton Biodiversity in the Mediterranean Sea
Authors: Tinta Tinkara ,   PETRI-MED
Published: March 2024

The assessment and monitoring of microbial plankton biodiversity are essential to obtain a robust evaluation of the health status of marine environments. The PETRI-MED project addresses this imperative by developing novel strategies to monitor the microbial plankton community composition and function, based on satellite observations. PETRI-MED will focus on the Mediterranean Sea as a global biodiversity hotspot with profound ecological and cultural importance. The primary objectives of PETRI-MED project encompass (i) the development of innovative satellite-based indicators to determine the biodiversity status and trends of microbial plankton community, (ii) the identification of spatio-temporal patterns in microbial plankton distribution and diversity, and (iii) the elucidation of key controls of biodiversity patterns, including ecological connectivity, natural and human-related forcings, by focusing on key indicators of ocean’s health and/or biogeochemical state. To do so, PETRI-MED will largely rely on satellite optical radiometric measurements (i.e, Ocean Colour, OC), exploiting the combined temporal and spatial characteristics of latest OC European datasets (i.e., Copernicus Sentinel-3 and European Space Agency OC-CCI) with state-of-the-art remote sensing observations and biogeochemical models (as provided by Copernicus Marine), marine currents modelling, and genomic techniques. To achieve the ambitious goal of merging remote sensing, biogeochemical/physical modelling, and in situ omics measurements, PETRI-MED will rely on Artificial Intelligence (AI). The overarching goal of PETRI-MED is to empower policymakers and stakeholders with the necessary knowledge to adopt prioritization approaches for ecosystem management based on quantitative, real-time metrics. This includes the design and implementation of protection strategies and policies to safeguard biodiversity, quantifying the impact of implemented actions at various levels, and enabling systematic, fact-supported management of Marine Protected Areas (MPAs), Key Biodiversity Areas, and Ecologically or Biologically Significant Marine Areas. Furthermore, PETRI-MED seeks to evaluate the viability of MPA management in response to climate change, ensuring adaptive strategies for the conservation of marine ecosystems in the face of environmental challenges. In summary, PETRI-MED represents a comprehensive and innovative approach to advancing our understanding of microbial plankton biodiversity in the Mediterranean Sea. Through the integration of satellite technology, omics techniques and AI, the project contributes valuable insights and tools for effective marine ecosystem management and conservation strategies.
Sen12Landslides: A Multi-modal, Large-scale, Multi-temporal Benchmark Dataset for satellite-based Landslide Monitoring
Authors: Höhn Paul , Heidler Konrad , Behling Robert , Zhu Xiao Xiang
Published: March 2024

Landslides, with their devastating impact on communities and infrastructure, present a pressing challenge for accurate and timely detection. Effective monitoring is therefore essential, not only to understand the process of landslides, but also to provide comprehensive risk assessments for future planning and to mitigate the consequences of such events. In addition, timely mapping of these hazardous events is essential to gain an overview and coordinate rescue efforts, while also addressing the geoscientific component of how these processes evolve over space and time, including potential acceleration due to climate change. To address this critical need, our study presents a large-scale, multi-temporal dataset that uniquely combines time-series data from the Sentinel-1 and Sentinel-2 satellites to improve landslide monitoring. Our initiative aims to create a globally standardized dataset that will overcome the challenges of transferring existing algorithms and facilitate the development of more effective models. This innovative and still growing dataset, which already includes over 7500 landslides from 16 global regions, offers a unique opportunity to advance machine learning methods for landslide detection. Using time-series analysis of Sentinel-1 radar data, we have successfully identified the onset and end dates of landslide events. Complementing this, Sentinel-2 optical data analyzed by NDVI change provide detailed land cover information critical for accurate landslide labelling. Our methodological approach is rigorously validated by manual expert review to ensure the reliability and accuracy of our results. By incorporating temporal context and combining the cloud-penetrating capabilities of Sentinel-1 with the rich multispectral resolution of Sentinel-2, this research represents a significant advance in the use of satellite data for landslide monitoring and serves as an invaluable resource for both the remote sensing and machine learning communities. It supports both object-based landslide identification and granular pixel-level analysis through semantic segmentation, extending its versatility for various environmental research applications. In our initial benchmarks, we evaluated existing state-of-the-art models such as UNet3D, U-TAE, TSViT and U-ConvLSTM to better understand their individual advantages for landslide monitoring. This process highlights the potential of our dataset to provide a reliable benchmark for future developments in landslide detection research.
A field trial study on long-term effects of organic farming on the retention of plant available soil water
Authors: Hofbauer Michael , Šípek Václav , Dvořák Petr
Published: March 2024

With regard to an increasing intensity and frequency of drought and heavy rainfall, there is a need to adapt arable farming to these climatic changes. In this respect, organic agriculture has a higher adaptation potential than conventional agriculture, since organic farming leads to an enrichment of soil organic carbon and a stimulation of soil biological activity in the long term. As a result, an improvement of soil structure, water infiltration and soil water retention can be expected as compared to conventional agriculture.In April 2023, a study of soil hydraulic properties after 15 years of recognised organic management was commenced in the Czech Republic. The objective is to compare an organic farming system to a conventional farming system in terms of retention of plant available soil water. The hypothesis is that the retention of plant available soil water is higher in the organic farming system than in the conventional farming system.The studied site is a long-term field trial on a clay loam soil in Praha-Uhříněves (P = 584 mm, T = 8.3 °C). In either farming system inversion soil tillage is carried out by mouldboard ploughing to a depth of 20 cm. For either farming system two plots with summer wheat (Triticum aestivum L.) are sampled in 2023 and 2024. In order to analyse soil water retention functions, saturated hydraulic conductivity, and soil organic carbon content, soil samples are taken in 10 cm and 30 cm soil depth each year in spring, summer, and autumn. In order to unravel the sources of plant available water, further soil samples are taken bimonthly in 10 cm, 30 cm, and 45 cm soil depth. The soil water’s isotopic composition (δ2H, δ18O) of these samples is analysed and compared to the rainwater’s isotopic composition. The volumetric soil water content is continuously recorded in 10 cm, 30 cm, and 45 cm soil depth.Preliminary data from the first experimental year indicate that the volumetric soil water content in the organic farming system is higher than in the conventional farming system. In contrast, soil water retention and soil organic carbon content do not show differences between the two systems. However, for robust results with statistical validation, further data and analyses need to be waited for. Therefore, reliable conclusions regarding the hypothesis of a better retention of plant available soil water in the organic system will be possible in the course of the project.This project is funded by the institutional support of the Czech Academy of Sciences (RVO: 67985874) and by the Faculty of Environmental Sciences of the Czech University of Life Sciences Prague (IGA grant No. 2023B0042).
The Thermal Plasma Sensor (TPS) for the Geospace Dynamics Constellation (GDC) mission
Authors: Anderson Phillip
Published: March 2024

GDC is a six-satellite constellation, designed to investigate the dynamics of the coupling between the ionosphere and thermosphere. The mission will provide multipoint observations of both the energy inputs and the ionosphere-thermosphere system response with sufficient spatial and temporal resolution to finally unravel the physical processes underlying the observed system-level dynamical responses. A critical component of the measurement requirements are the characteristics of the thermal plasma. TPS is a multi-sensor instrument designed to measure the three components of the ion drift, the ion density and temperature, and the mass fractions of the major constituent ions. We present an overview of the instrument, the methods by which the measurements are made, and the science questions to be addressed.
Dynamical controls of mesoscale water vapor variability in the tropical western Pacific
Authors: Tompkins Adrian , Casallas Alejandro , Vianca De Vera Michie
Published: March 2024

Idealized simulations of radiative-convective equilibrium (RCE) with cloud resolving models have been used as a numerical laboratory to understand how diabatic processes can drive convective clustering, which in turn leads to significant drying of the free troposphere and increase in spatial humidity variability.  These processes, such as feedbacks between radiation, clouds and water vapor have been found to have relevance for numerous large-scale modes of convective organization, such as the width of the upward branch of the Hadley cell, ENSO and the Madden Julian Oscillation.  However, the controls of water vapor associated with convective variability on the sub-1000km mesoscale are less well known.  We adopt a simple multivariate analysis technique previously used to assess convective organization in RCE, and apply it to analyze convective organization and its impact on column integrated humidity (precipitable water, PW) variability for order 106 km2 mesoscale-size boxes in the tropical western Pacific warm pool region lying on or to the north of the equator.  We find that during the boreal summer/autumn periods, when sea surface temperature (SST) gradients are very limited in the target regions, convection remains mostly random and the horizontal PW gradients are small on these scales, this despite the action of diabatic feedbacks such as LW-cloud feedbacks and surface latent heat fluxes that are acting to  force clustering of convection. In stark contrast, during the other months of the year, when the zones are subject to a weak meridional SST gradient of SST (> 10-3 K km-1), convection is mostly aggregated over the warmer SSTs, with much larger PW gradients associated with an increase of clear sky OLR exceeding 10 W m-2. However, this situation is regularly disturbed by intermittent, multi-day episodes of more homogeneous convection distribution and limited spatial PW gradients. During these periods the SST-PW relationship flips, and the convecting regions are found over the coldest SSTs.  By using an index based on the SST-PW covariance, we construct a composite of 44 such events over a 4 year period which shows that they are associated with a westward-propagating, convectively-coupled Rossby wave like mode that is symmetric about the equator.  An independent multivariate (SST-PW) rotated EOF analysis confirms this, indicating the robustness of the result. We hypothesize that the longer-term variations in an convective organization index which was directly related to the tropics-wide energy budget (Bony et al. 2020) may be driven by the frequency of occurrence of these westward propagating modes, that seem to act as a primary control on mesoscale water vapor variability in the warm pool region in the boreal winter and spring months.
Managing Large-Scale Geologic Storage of CO2 in the United States: Geomechanical Impacts, Basin-Scale Coordination, and Regulatory Implications
Authors: Birkholzer Jens , Guglielmi Yves , Cihan Abdullah , Rutqvist Jonny , Glubokovskikh Stanislav , Reagan Matt , Jordan Preston , Mital Utkarsh , Cao Meng , Tounsi Hafssa
Published: March 2024

After decades of research on geologic carbon storage (GCS), the world seems to be moving from pilot tests and demonstration experiments to industrial-scale implementation. In the United States, the Bipartisan Infrastructure Law passed in 2021 contributes $2.5 billion for carbon storage commercialization in addition to similarly large investments in point-source carbon capture as well as direct air capture. These federal investments, combined with new tax credits provided by the 2022 Inflation Reduction Act, provide a significant push towards GCS deployment over the coming years and decades, likely creating multiple large storage projects or clusters of integrated projects across hydrogeologic basins. These projects will likely involve injection volumes that may result in large-scale pressure increases in the subsurface and may cause unwanted geomechanical effects, such as generating seismic events and seal integrity concerns per reactivation of critically stressed faults.Here, we will focus on such large-scale deployment hurdles and discuss related regulatory challenges, using the United States permitting framework as an example. We will begin by illustrating basin-scale pressure impacts expected from geologic carbon sequestration at scale, based on regional modeling studies of future GCS scenarios. With regards to geomechanical implications, we will briefly present lessons learned from two recent field tests—one being a controlled fluid (water and CO2) injection fault slip and leakage experiment in a clay (sealing) formation, the other a CO2 storage demonstration site where micro-seismicity has occurred along pre-existing basement faults. We will then introduce ongoing work to transfer the knowledge derived from these experiments to larger injection volumes and scales so that ultimately geomechanical effects can be assessed and coordinated at the scale of large storage complexes. In terms of regulatory implications, we will review the regulatory framework for CO2 storage wells in the United States and discuss how suitable it is (or not) for permitting a GCS future where sedimentary basins with interconnected reservoirs might host multiple large storage projects. Lastly, we will propose a hierarchical permitting approach for such situations, which would add a general permit for regional coordination of subsurface resources to the existing framework for permitting of individual CO2 storage projects.
Simulating 3D calving dynamics at Thwaites Glacier
Authors: Wheel Iain , Benn Douglas , Crawford Anna
Published: March 2024

Recent advances in the Elmer/Ice modelling suite have allowed 3D simulation of unrestricted calving geometries at tidewater glaciers such as Jakobshavn Isbrae. We present the first use of this model in an Antarctic setting. The more stochastic nature of calving at Antarctic ice sheets when compared to a Greenlandic setting has discouraged the development of calving laws and models. For shorter term calving simulations, it is sufficient to determine the local attractor or pinning point where the terminus stabilises following a transient period of retreat or advance. Importantly, this can only be achieved through a position-based law, as a positional attractor is independent of velocity.Using a deterministic position-based crevasse depth calving law it is possible to simulate the observed calving behaviour at the western ice front of Thwaites Glacier. The calving law identifies the attractor point beyond which ice will calve following a variable but short delay. The geometric attractor is defined by local topography along with grounding zone dynamics. Beyond this point there are a lack of lateral or basal pinning points, so any downstream ice is effectively lost from the system. More generally, across the floating extensions of Thwaites Glacier, the model reliably predicts regions of crevasse formation. Accurately simulating crevasse formation on ice shelves along with determining the attractor within the glacier retreat and advance cycle is the first step towards a reliable Antarctic calving law. 
A regular clock for the solar cycle variation of sunspot and geomagnetic activity
Authors: Chapman Sandra , Dudok de Wit Thierry
Published: March 2024

Sunspot records reveal that whilst the sun has an approximately 11 year cycle of activity, no two cycles are of the same duration. Since this activity is a direct driver of space weather at earth, this presents an operational challenge to quantifying space weather risk. The sunspot number record can be used to map the variable cycle length onto a regular 'clock' and this mapping reveals in each cycle a clear active-quiet switch-off and quiet-active switch-on of activity, with around 2% of extreme space weather events occurring within the quiet intervals of the cycles over the last 155 years [1]. Some of the most extreme geomagnetic storms have occurred around the switch-on and switch-off times, rather than at solar maximum, motivating their determination and prediction. The times of the switch-on/off can be approximately determined directly from the sunspot time-series [2] so that future switch-on and switch-off times can be directly identified in model predictions for future solar activity as characterized by sunspot number. The clock supports charting – a tool to integrate observational estimates of risk (observed events and their likelihood) with narrative reports of impacts on technological systems to improve our understanding of space weather hazard. The sunspot number Hilbert transform phase is found to correspond to solar-cycle scale evolution of sunspot latitudinal bands, so that there is a direct relationship between the well known sunspot ‘butterfly pattern’ and the intensity and character of geomagnetic activity and its switch-on/off [3].[1] S. C. Chapman, S. W. McIntosh, R. J. Leamon, N. W. Watkins, Quantifying the solar cycle modulation of extreme space weather, Geophysical Research Letters, (2020) doi:10.1029/2020GL087795 [2] S. C. Chapman, Charting the Solar Cycle, Front. Astron. Space Sci. - Space Physics,  (2023) doi:10.3389/fspas.2022.1037096[3] S. C. Chapman, T. Dudok de Wit, A solar cycle clock for extreme space weather (preprint, 2024) doi:10.21203/rs.3.rs-3672243/v1 
Exploiting Pseudo Wells in a Synthetic Sedimentary Basin: a simulation in the Santos Off-Shore Basin in the Southeast Atlantic portion of Brazil, using synthetic TOC for k-means classification.
Authors: Carreira Victor , Silva Milena , Venancio Igor , Belem André , Viegas Igor , Spigolon André , Albuquerque Ana Luiza , Vitor Pedro
Published: March 2024

Shales are important rocks that store a significant amount of Organic Content. In this work, we present applications of realistic synthetic simulations using real-scaled geological sections. The case of the study is Santos Sedimentary Basin, a well-known and well-studied Geologic Basin. This synthetic data improves the performance of our IA for TOC estimators. Besides, it reduces costs and resources concerning data acquisition for IA simulations. The work consists of reconstructing a pseudo-well formed in a fracture zone modelled through an accurate 2D geological section. To simulate the effects of a fracture zone on geophysical logging data, we present the law of mixtures based on well-drilling concepts, whose objective is to impose geometric conditions on the set of subsurface rock packages. We generated four rock packs belonging to two mixed classes. Tests with noisy synthetic data produced by an accurate geological section were developed and classified using the proposed method (Carreira et al., 2024). Firstly, we go for a more controlled problem and simulate well-log data directly from an interpreted geologic cross-section. We then define two specific training data sets composed of density (RHOB), sonic (DT), spontaneous potential (SP) and gamma-ray (GR) logs,  and  Total Organic Carbon (TOC), spontaneous potential (SP), density (RHOB) and photoelectric effect (PE) all simulated through a Gaussian distribution function per lithology. Acquiring the sonic profile is essential not only for estimating the porosity of the rocks but also for in-depth simulations of the Total Organic Content (TOC) with the geological units cut by the synthetic wells. Since most wells Exploitation does not have this profile well and it is not economically viable to make a new acquisition, resorting to the nonlinear regression models to estimate the sonic profile showed that it is an important feature. We estimate the observed Total Organic Carbon (TOC) measurements using Passey and Wang's (2016) methodology to input data into the k-means classification model. The synthetic model proposed showed promissory results indicating that linear dependency may underscore k-means shale classification. 
Universal microbial reworking of dissolved organic matter along soil gradients
Authors: Freeman Erika , Emilson Erik , Dittmar Thorsten , Braga Lucas , Emilson Caroline , Goldhammer Tobias , Martineau Christine , Singer Gabriel , Tanentzap Andrew
Published: March 2024

Soils lose a large amount of carbon annually to freshwaters as dissolved organic matter (DOM), which, if degraded, can undermine climate change mitigation. The degradation state of DOM in aquatic ecosystems can reflect the distance from its source, with DOM increasingly dominated by similar compounds as degradation proceeds. However, the processes underlying the degradation of DOM and its generality across environments are poorly understood. Here we found DOM changed similarly along two soil-aquatic gradients irrespective of environmental conditions. We tracked DOM across soil depths and hillslope positions in forest headwater catchments using ultra-high-resolution mass spectrometry and related its composition to soil microbiomes and physical chemistry. Along both gradients, carbohydrate-like and unsaturated hydrocarbon-like compounds increased in mass, suggestive of microbial reworking of plant material. Most of the variation in the abundance of these compounds (>56%) was related to the expression of genes important for breaking down plant-derived carbohydrates. Our results highlight the value of high-resolution molecular data in understanding global carbon cycles, directly implicate microbial processing in shifting DOM towards universal compounds in soils, and suggest that this process is generalizable across ecosystems and spatiotemporal scales. This consistent degradation process could provide insights for estimating the state of DOM in different environments and inform the management of soil-to-stream carbon losses.
Overview of the DECOVALEX Initiative - Building Confidence Via Model Comparison
Authors: Birkholzer Jens , Bond Alex
Published: March 2024

Here we provide an overview of an international research collaboration for advancing the understanding and modeling of coupled thermo-hydro-mechanical-chemical (THMC) processes in geological systems. The creation of the international DECOVALEX Initiative, now running for more than 30 years, was motivated by the recognition that prediction of these coupled effects is an essential part of demonstrating the performance and safety of radioactive waste disposal and other subsurface engineering applications. DECOVALEX emphasizes joint analysis and comparative modeling of state-of-the-art field and laboratory experiments, across a range of host rock options and repository designs. Participating research teams are from radioactive waste management and other organizations, national research institutes, regulatory agencies, universities, as well as industry and consulting groups, providing a wide range of perspectives and solutions to these complex problems. The most recent phase of the initiative, referred to as DECOVALEX-2023, started in 2020 and ended in December 2023. Modeling teams from 17 international partner organizations participated in the comparative evaluation of seven modeling tasks involving complex experimental and modeling challenges. The presentation provides examples of research contributions made within DECOVALEX-2023 and illustrates how these have helped building confidence in long-term performance predictions. These examples range from the modeling of large-scale in situ heater tests representing mock-ups of nuclear waste disposal tunnels, the analysis of gas transport tests in clay-based materials, the prediction thermal and gas pressure rock fracturing, to the comparison of performance assessment models.The main characteristic of DECOVALEX is the close collaboration on analyzing and simulating state-of-the-art field and laboratory experiments, which provides a wide range of experiences, perspectives and solutions to these complex problems and allows for detailed comparison of analysis and modeling results. Much insight can be gained through this cooperative comparison of results from different research teams using different model approaches, not only on the effects of complex THMC processes, but also on the strengths, weaknesses, and adequacies of the various approaches and predictive models used by these research teams. We make the case in this presentation that DECOVALEX has contributed, and continues to contribute, to enhancing confidence in the technical adequacy of radioactive waste disposal, by improving our collective understanding of complex subsurface perturbations and coupled processes, by developing and comparing predictive models for these processes, by evaluating their uncertainties, by recognizing areas for additional research, and by emphasizing means of learning from each other and knowledge sharing. The insight and scientific knowledge gained would not have been possible if individual groups had studied these data alone rather than within a truly collaborative setting.
Air-Sea Flux Influences on Extratropical Cyclone and Atmospheric River Mesoscale Development and Upstream Temporal Clustering
Authors: Crespo Juan , Naud Catherine , Luna-Niño Rosa , Booth James , Posselt Derek
Published: March 2024

Latent and sensible heat fluxes (LHF and SHF, respectively) within the marine boundary layer are believed to play a significant role in the genesis and evolution of Extratropical Cyclones (ETCs) and Atmospheric Rivers (ARs, often associated with ETCs in the midlatitudes). However, consistent observations of air-sea interactions with in-situ observatories are limited in both time and space, and traditional polar orbiting satellites may miss large swaths in the lower midlatitudes due to their orbits, leading to daily gaps in coverage where the most robust fluxes often occur and change rapidly. Satellite missions like CYGNSS (Cyclone Global Navigation Satellite System) have filled in data gaps by providing improved observations over the lower midlatitudes of air-sea interactions. These improved observations of air-sea processes, coupled with observations of cloud and precipitation structure within ETCs and ARs from other satellites, like GPM and MODIS, can help one begin to link the correlations between surface heat fluxes to changes of the mesoscale features within these synoptic-scale systems. Previous studies have shown the correlation of observed surface heat fluxes to precipitation and cloud thickness increases along the frontal regions. Still, they have only looked at the connections between ETCs and ARs when LHF and SHF were at their strongest or the peak intensity of the system, not during its early formation (or just before formation) when they may be at their strongest. Additionally, recent studies have examined through idealized models how surface heat fluxes within an ETC can impact the development of ETCs and ARs upstream of the primary cyclone and lead to multiple ETCs in succession, often called a family or temporal clustering of ETCs and ARs. This clustering can lead to significant and excessive precipitation over parts of the globe, such as the United States West Coast in early 2023, with successive ARs over one month. Improved observations of real-world conditions can help us better understand the interplay within these systems. This presentation will highlight the role air-sea interactions may have during the genesis and early evolution of ETCs and ARs, the correlations to cloud and precipitation structure changes, the upstream impacts, and setting the groundwork that will be able to show that air-sea interactions directly impact the development of these systems.
SWM: a Stochastic Weather Model for precipitation-related hazard assessments using ERA5-land data
Authors: Whitehead Melody , Bebbington Mark
Published: March 2024

Long-term hazard and risk assessments are produced by combining many hazard-model simulations, each based on a slightly different set of inputs to cover the uncertainty space. While most input parameters for these models are relatively well-constrained, atmospheric parameters remain problematic unless working on very short-time scales (hours to days). Precipitation is a key trigger for many natural hazards including floods, landslides, and lahars. This work presents a stochastic weather model that takes openly available ERA5-land data, and produces long-term (e.g., decadal), hourly, spatially varying precipitation data that mimics the statistical dimensions of real-data. Thus, allowing precipitation to be robustly included in hazard-model simulations.The stochastic weather model (SWM) comprises three steps: Data conversion, block construction, and stochastic weather generation. Due to the relative simplicity of the model and exploiting some coding efficiencies in the R package dplyr, 10 years of hourly data can be generated across a 10 by 10 cell grid (~110 km by 110 km) on a standard desktop computer in < 5 seconds.
Surface geochemistry controls 'hot-spots' of dust emission at Etosha Pan, Namibia
Authors: Wiggs Giles , Wallum Natasha , Bryant Robert , Reynolds Richard
Published: March 2024

Dust emissions from ephemeral playas are characterized by considerable spatiotemporal variability.  It has proven extremely difficult to resolve the complex dynamics between climatic conditions and surface crust characteristics that control aeolian dust emissivity.  In this study we used multitemporal satellite remote sensing and model reanalysis data to determine the climatic environments, surface sediment mineralogy, and hydrological context associated with the formation of ‘hot-spots’ of dust emission at Etosha Pan, Namibia. A twenty-year record (2000–2022) of dust source locations was established from MSG-SEVIRI and MODIS data, which enabled the identification of clusters of dust sources (‘hot-spots’). Using a time-series of Landsat 8-9 data we identified the surface mineralogical characteristics associated with the development of these ‘hot-spots’ of dust emission. These analyses were validated using reflectance spectroscopy and XRD analyses of sediment samples collected from the field. Linear spectral unmixing was applied to map the relative proportions of identified evaporite and clay mineral spectral endmembers from pixel spectra of Landsat image time-series. Results show that the development of emissive ‘hot-spot’ dust sources are associated with the formation of evaporite mineral crusts through the process of salt efflorescence initiated by wet season flooding events. Field experimentation using a portable wind tunnel combined with remote sensing analysis demonstrates that high winds in the dry season can break down this mineral crust exposing large quantities of fine and highly emissive sediments that are extremely susceptible to aeolian entrainment. Surface crust geochemistry, influenced by flooding history, therefore offers a first-order control on the development of ‘hot-spots’ of dust emission (Figure 1). The approach described here could be used at other ephemeral playas that are significant dust sources to elucidate hydrological and mineralogical controls on aeolian dust emission and to enhance regional-scale dust emissions modelling.Figure 1. Landsat 8 OLI image time-series and linear spectral unmixing model outputs showing changes in crust mineralogy (abundance of saponite, montmorillonite, and thenardite) influenced by the flooding history of the surface and determining the location of emissive ‘hot-spots’ of dust emission (outlined) at Etosha Pan for the 2018 winter dust season (May to September). 
Cook glacier-Ocean Antarctic Past Stability (COLLAPSE) project preliminary results from geophysical and oceanographic data analysis
Authors: De Santis Laura , Accaino Flavio , Accettella Daniela , Bensi Manuel , Colleoni Florence , Cova Andrea , Donda Federica , Facchin Lorenzo , Kovacevic Vedrana , Martellucci Riccardo , Mauri Elena , Ursella Laura , Zgur Fabrizio
Published: March 2024

The glaciers terminating in the Cook Ice Shelf and the Ninnis Glacier drain most of the Antarctic marine ice sheet covering the Wilkes Subglacial Basin (WSB), whose ice volume is equivalent to 3-4 m of global sea level rise. Long-term climate projections and multiproxies studies of ice records suggest that ice sheet retreat in this area, thought to be colder and more stable, may be triggered by warm ocean water intrusion.During the 2022 campaign of the Italian Programma Nazionale delle Ricerche in Antartide (PNRA) with the icebreaker L. Bassi, the project COLLAPSE (Cook glacier-Ocean system, sea LeveL and Antarctic Past Stability) mapped two systems of canyons and hills located at the mouth of suspected glacial valleys off Cook and Ninnis glaciers. The combination of geomorphological, seismic, oceanographic, and sedimentary data (see abstract from Torricella et al.) allowed identification of a variety of processes active on the seafloor today and in the late Quaternary. The geophysical data show evidence of slope instability offshore of the presumed major glacial troughs. Sediment drifts controlled by bottom currents grow on channel-levees and slope terraces. This information will help, albeit indirectly, to reconstruct the dynamics of different glaciers in relation to paleoclimatic changes and ocean circulation, and to estimate their respective contributions to global sea-level rise.In addition to the co-authors listed in this summary who are involved in the analysis of the geophysical and oceanographic data, the project PNRA COLLAPSE includes a large group of scientists for the analysis of the sediment cores, from the Universities of Trieste, Siena and Milan-Bicocca, CNR-ISP e ISMAR, INGV (I), Univ. Bordeaux, Grenoble and LOCEAN, Paris (F), CSIC (E), Colgate Univ. (USA), Australian National University and Univ. of Tasmania (AUS), Russian FSBI VNIIOkeangeologia, (RU), Alfred Wegener Institute (D), GNS (NZ).
Assessment of different CMIP6 regional wind wave climate downscaling approaches – From a global to a local perspective
Authors: Meucci Alberto , Lorenzo Matteo , Liu Jin , Syktus Jozef , Trenham Claire , Hernaman Vanessa , Hoeke Ron , Onorato Miguel , Young Ian
Published: March 2024

Wind waves play a crucial role in coastal dynamics and can significantly impact coastal sea levels, especially during extreme events. Ocean winds are changing as the Earth is warming, and hence the waves. The Australian Climate Service (https://www.acs.gov.au/), recognised wind waves as a crucial element to support future coastal climate mitigation and adaptation strategies. Wind wave climate future projections are, however, plagued by uncertainties. One of the primary sources of uncertainty originates from the resolution of the Coupled Model Intercomparison Project (CMIP) General Circulation Model (GCM) surface wind speed products. We hereby assess different approaches to regional wind wave climate modelling, to understand the impact of the CMIP6 GCM wind speed resolution. We evaluate the Southeast Australia wave climate results from an unstructured grid regional wave model nested in a global wave model. We compare 30 years (1985-2014) of historical wave climate simulations using wind vectors from the CMIP6 Meteorological Research Institute (MRI) CMIP, AMIP, and HighResMIP experiments (nominal resolutions of ~150 km for CMIP and AMIP, and 25 km for HighResMIP). We then compare these results with the wave model forced by the MRI CMIP surface winds dynamically downscaled with the Conformal Cubic Atmospheric Model (CCAM) (~12.5 km resolution). The findings indicate that the wind wave climate models yield divergent results, particularly at the extremes where the most interest lies for future coastal sea level projections. We discuss the reasons for the differences and propose the best way forward for developing regional wind wave climate projections.
Abrupt transitions between drought and pluvial events becoming more widespread and intense
Authors: Yang Yuheng , Lu Xixi , Xiao Xue
Published: March 2024

Droughts and floods, as individual hazards, pose significant challenges, but their consecutive occurrence can trigger catastrophic cascades of disasters. Therefore, it is crucial to understand these extreme events, known as drought-pluvial (DPAT) and pluvial-drought abrupt transitions (PDAT), to mitigate their risks and potential impacts effectively. Our study utilizes historical records spanning from 1940 to 2022 to identify DPAT and PDAT events, investigating their frequencies, durations, intensities, and underlying causes. Additionally, we analyzed the frequency, duration, and intensity of these events under projected future scenarios. Globally, there has been an increasing trend in the frequency of DPAT and PDAT events, with significant upticks observed in Eastern North America, South Asia, East Asia, the Middle East, Africa, and Australia. In the 2010s, these disasters impacted over 100 million people, predominantly in less economically developed countries. Our findings enhance the current understanding of DPAT and PDAT, thereby contributing to the development of more effective mitigation and adaptation strategies against their impacts.
Characterizing Lithospheric Transverse Isotropy via Non-double Couple Components of Moment Tensors
Authors: Kawakatsu Hitoshi
Published: March 2024

The seismic moment tensor, which represents the equivalent body-force system of the seismic source (Backus and Mulcahy, 1973), may exhibit non-double couple components (NDCs) when the earthquake occurs on a planer fault if the source medium is anisotropic (Aki and Richards, 1981; Kawasaki and Tanimoto, 1981). Kawakatsu (1991, GRL) reported that the NDCs of the moment tensors for shallow earthquakes from the Harvard CMT catalog (Dziewonski et al.,1981; predecessor of GCMT) exhibit a systematic characteristic dependent on faulting types. Specifically, the sign of NDC on average systematically switches between normal-faulting and reverse-faulting. The average NDC parameter ε (Giardini, 1983) is negative for thrust faulting and positive for normal faulting. This behavior can be explained if the source region is transversely isotropic with a vertical symmetry axis (radially anisotropic). In fact, the transverse isotropy model of PREM at a depth of 24.4 km predicts the observed systematic NDC pattern, although the magnitude is slightly underestimated, indicating the potential to enhance our understanding of the lithospheric transverse isotropy using the NDC of the moment tensors.To investigate the lithospheric transverse isotropy structure utilizing the NDCs of the moment tensors, we propose a novel inversion scheme, building upon the approaches employed by Vavrycuk (2004) and Li, Zheng, et al. (2018) for deep and intermediate-depth earthquakes, but with necessary modifications to address shallow sources (Kawakatsu, 1996, GJI). Synthetic tests conducted under conditions of random faulting indicate the potential to constrain the S-wave anisotropy (ξ) and the fifth parameter (ηκ; Kawakatsu, 2016, GJI). However, in realistic scenarios where a predominant stress regime influences earthquake occurrence to limit the diversity of faulting types, a significant correlation between these two parameters is anticipated, especially in regional-scale cases. Preliminary application of this method to real data sourced from the GCMT catalog suggests that the lithospheric transverse isotropy of PREM serves as a suitable initial model. However, some adjustments may be necessary, particularly regarding the fifth parameter, to enhance the model's fidelity in representing observed NDCs of the moment tensors.
Temporal and Spatial Distribution Characteristics of Short-Duration Heavy Rainfall in Ganzi Prefecture of Eastern Slope of Tibetan Plateau
Authors: Maoshan Li , Xu Yuan
Published: March 2024

 Short term heavy rainfall is often caused by small and medium-sized systems, and its occurrence and development are very rapid, with strong locality, drastic changes, and complex causes. Monitoring, forecasting, and early warning of it have always been a hot and difficult point in meteorological forecasting services. Using hourly precipitation observation data from 18 benchmark (basic) meteorological stations and 489 regional meteorological stations in Ganzi Prefecture from April to October 2012 to 2021, the spatial and temporal distribution characteristics of short-term heavy precipitation in Ganzi Prefecture on the western Sichuan Plateau were statistically analyzed. The results showed that: 1) The total frequency of short-duration heavy rainfall during the flood season in Ganzi Prefecture from 2012 to 2021 was 1906 times, with an average of 190.6 times per year, and the frequency decreased exponentially with increasing magnitude, with 15-25mm/h short-term heavy precipitation accounting for more than 84%. 2) The diurnal variation of short-duration heavy rainfall showed a bimodal pattern, with the peak occurring from 20:00 to 22:00 Beijing time, and the highest peak at 22:00, followed by 20:00. Short-duration heavy rainfall is more likely to occur from the afternoon to the first half of the night. The monthly variation showed a unimodal pattern, with the most occurrences in July (30.16%), followed by June and August. The interannual variation was uneven, with an average total frequency of 190 occurrences per year. The frequency of short-duration heavy rainfall in 2012 was the lowest, with only 38 occurrences, while in 2020, it was the highest, with 336 occurrences. 3) The frequency of short-duration heavy rainfall was higher in the southern and eastern regions compared to the northern and western regions, indicating an uneven spatial distribution.The highest frequency occurred in the southern part of Luding County, followed by the southern part of Jiulong County, which are the high-incidence areas of short-duration heavy rainfall in the entire prefecture. Short-duration heavy rainfall mainly occurred at an altitude of 1100-3900m, with the most occurrences at an altitude of 1100-1900m, and the maximum peak rainfall intensity of 63.3mm/h occurred in the altitude range of 1100-1300m. Short-duration heavy rainfall in Ganzi Prefecture is closely related to altitude, which is the result of the interaction between complex terrain and regional circulation.
Developing a Distributed Real-time Streamflow Forecasting Framework for Use in Highly Regulated Basins
Authors: Fang Yuan-Hao , Zhang Xingnan , Qian Rui , Zhang Tao , Qin Pingshan
Published: March 2024

As a non-engineering measure for flood control, real-time forecasting provides valuable information like the magnitude and occurrence time of flood peak, which is essential for decision-making. In China, many reservoirs are built and operated in major river including ChangJiang River Basin. Operations of reservoirs pose new challenges for real-time forecasting. For example, (1) it’s difficult to calibrate model parameters due to human-impaired streamflow series, (2) the leading time of real-time forecasting is much shorter.To address these challenges, we propose a distributed real-time streamflow forecasting framework using the Xin’anjiang (XAJ) hydrological model. We evaluate different scale of computational units of the XAJ model to better characterize the runoff processes, land surface characteristics, and meteorology factors. We then develop a set of models to calculate model parameters from land surface characteristics, which reduce the calibration requirement. We also develop an algorithm to correct the bias of precipitation forecasts, which is coupled with real-time forecasting framework. This helps to extend the leading time of real-time forecasting.Our proposed framework is tested and validated at Upper Changjiang River Basin and get promising feedbacks.
An observation-based estimate of the Atlantic meridional freshwater transport from 2004 to 2012
Authors: Zheng Huayi , Cheng Lijing , Pan Yuying , Zhu Chenyu
Published: March 2024

Meridional freshwater transport in the Atlantic Ocean (AMFT) plays a vital role in the Atlantic meridional overturning circulation and global climate change, but an accurate estimate of AMFT time series remains challenging.This study uses an indirect approach that combines the observation of ocean salinity, surface evaporation and precipitation observations to derive AMFT and its uncertainty from 2004 to 2012, by solving the ocean freshwater budget equation. The method provides an independent estimation of AMFT, complementary to array observation and model/reanalysis data. The climatology, interannual and trend of AMFT based on indirect method are analyzed.Climatologically, there is a strong southward AMFT between 18.5°S and 33.5°S, and a shift to northward from 18.5°S to 66.5°N. The highest transport occurs at 3.5°S (-0.29±0.09 Sv) and 39.5°N (-0.52±0.08 Sv). The estimation based on direct observation and reanalysis data are compared to give a clear understanding of AMFT climatology.The interannual variability of AMFT exhibits meridional coherence from 33.5°S to 66.5°N, except for the lag propagation near 44ºN, the boundary of the subpolar and subtropical North Atlantic. The peaks and valleys of AMFT align with El Niño-Southern Oscillation (ENSO) variation. In the south of 44.5ºN, a southward anomalous AMFT appears during the La Nina events, such as January 2006 (-0.13 Sv), January 2008 (-0.16 Sv), and November 2010 (0 Sv) for 20ºS-44.5ºN mean. Conversely, northward AMFT increases when ONI peaks, 0.07Sv and 0.17Sv for 20ºS-44.5ºN mean in November 2008 and January 2010, respectively. The corresponding relationship between ENSO and AMFT suggest a potentially remote impact of ENSO on the Atlantic Ocean.The derived time series indicates that, throughout the Atlantic Ocean, there is an increasing trend of northward AMFT from 2004 to 2012 when AMOC weaken, resulting in a freshwater divergence in the South Atlantic and subtropical North Atlantic, as well as a freshwater convergence in the subpolar North Atlantic.Additionally, we discuss the definition of freshwater transport, considering its dependence on reference salinity. Analyzing the impact of reference salinity on MFT estimation based on a theoretical model, we find that the choice of reference salinity has little impact when there is no net volume transport. Therefore, reference salinity does not significantly affect the AMFT discussed in this study.