bluuebunny/crossref_metadata_2025 huggingface dataset:
Climate Indices of Extreme Rainfall in the South Asian Monsoon Domain using a Bayesian Hierarchical Model
Authors: Früh Dexter , Strnad Felix , Goswami Bedartha
Published: March 2024

Intraseasonal variability of extreme rainfall events (EREs) during the South Asian Summer Monsoon season is modulated by the Boreal Summer Intraseasonal Oscillation (BSISO), a convective system of organised heavy rainfall that moves periodically from the Indian Ocean to the Western Pacific over the subcontinent. The BSISO, in turn, is typically characterised using indices obtained from the leading components of an Empirical Orthogonal Analysis (EOF) of outgoing longwave radiation (OLR) and lower and upper troposhere wind data from the region [1] ). A primary motivation for using OLR and wind data is that the EOF-analysis is not well suited for heavy-tailed data such as precipitation. Here, we propose to estimate climate indices directly from EREs in the South Asian Summer Monsoon by applying the Hidden Climate Index (HCI) - framework introduced by Renard et al. (2022) [2]. The method is designed to work with binary, event-like data and utilizes a Bayesian hierarchical model incorporating spatial Gaussian process priors, to capture spatial and temporal interdependencies by sampling from a Bernoulli distribution.Using the HCI framework, we estimate latent variables that underlie the ERE dynamics in the South Asian Monsoon domain, and show that these are related to large-scale modes of climate variability., We demonstrate that the ERE-based HCIs correlated well to the BSISO and in addition, we find relationships between the observed large-scale spatial ERE patterns  to the El Nino Southern Oscillation and the Silk Road Pattern. [1] Kikuchi, K., Wang, B. & Kajikawa, Y. Bimodal (2012). Representation of the tropical intraseasonal oscillation. Clim. Dyn. 38, 1989–2000.[2] Renard, B., Thyer, M., McInerney, D., Kavetski, D., Leonard, M., & Westra, S. (2022). A Hidden Climate Indices Modeling Framework for Multivariable Space-Time Data. Water Resources Research, 58
Atmospheric and Soil Moisture Monitoring in Agriculture Using GNSS: First Results from the MAGDA Project
Authors: Gatti Andrea , Fumagalli Alessandro , Barindelli Stefano , Realini Eugenio
Published: March 2024

The Meteorological Assimilation from Galileo and Drones for Agriculture (MAGDA) project aims to advance the integrated use of satellite-borne, drone-borne, and in-situ sensors, enhancing irrigation optimisation and weather hazard mitigation in agriculture. At its core, MAGDA employs low-cost Galileo-enabled GNSS ground stations for retrieving atmospheric water vapour and soil moisture. This data, combined with information from other technologies, is intended for assimilation into numerical weather prediction and hydrological models.MAGDA’s demonstration sites are strategically located in three diverse agricultural regions of Europe: fruit plantations in Italy’s Piedmont, vineyards in France’s Burgundy, and mixed crops in Romania’s Braila county. Each of these sites is equipped with three low-cost GNSS stations, operational since mid-2023, providing valuable data for testing the efficacy and adaptability of GNSS technology in different agricultural and climatic conditions.In addition to the three demonstration sites, MAGDA leverages data from pre-existing GNSS permanent stations across these countries. A comprehensive dataset from 397 stations in the Italy-France domain and 74 stations in the Romania domain has been downloaded. This data is specifically designed for the assimilation of GNSS-derived water vapour data, covering the entire weather model domains, complementing the localised information from the project’s targeted low-cost stations.GNSS data processing utilises GReD’s proprietary Breva software, capable of analysing multi-frequency and multi-constellation observations. Atmospheric water vapour estimates are obtained through an undifferenced and uncombined batch least squares Precise Point Positioning (PPP) approach. This method has been employed to analyse six weather events that significantly impacted agricultural operations at the demonstration sites, two events per site.Soil moisture results have been obtained by a newly developed module of Breva software that applies GNSS reflectometry based on the analysis of SNR measurements influenced by the humidity of the superficial soil. The methodology has been tested and validated at various previously studied sites, as well as directly at the low-cost GNSS stations established by the MAGDA project.This work presents the preliminary results achieved in the first half of the MAGDA project, outlining encountered limitations and future development plans related to the analysis of MAGDA’s GNSS stations.
NDVI trends observed over 30 years for different land cover types and biogeographical regions in Europe based on the novel TIMELINE NDVI product
Authors: Eisfelder Christina , Asam Sarah , Hirner Andreas , Reiners Philipp , Bachmann Martin , Holzwarth Stefanie
Published: March 2024

Remote sensing allows for spatially and timely continuous monitoring of the Earth’s surface. The analysis of remote sensing time-series can help to understand ongoing environmental changes. Especially the monitoring of past and current vegetation status and phenology may allow to identify possible long-term patterns and trends, which might be related to climate change. The availability of multi-decadal remote sensing time-series, such as from the Advanced Very High Resolution Radiometer (AVHRR), can be used to analyze long-term vegetation change over large areas. In the TIMELINE project (TIMe Series Processing of Medium Resolution Earth Observation Data assessing Long-Term Dynamics In our Natural Environment) of the German Remote Sensing Data Center (DFD) at the German Aerospace Center (DLR), a time-series of daily, 10-day, and monthly NDVI composites based on AVHRR data at 1 km resolution covering Europe and northern Africa has been generated. In this study, we used the TIMELINE monthly NDVI composites from the 30-year period 1989-2018 to derive long-term vegetation trends using Mann-Kendall trend test and Theil-Sen slope estimator. We analyzed annual and seasonal trends for spring, summer, and autumn for different land cover classes within the individual biogeographical regions in Europe. Our results show different NDVI trends for individual regions and land cover classes in Europe. The novel TIMELINE NDVI product allows to analyze European-wide trends at a spatial resolution of 1 km. The results of this study can thus assist to further understand vegetation dynamics and possible impacts of climate change on different land cover classes and within different regions in Europe.
Persistent Mobile and Toxic Contaminants in Urban Stormwater: the case of Barcelona Municipality
Authors: Chierchini Filippo , Santana Viera Sergio , Labad Francesc , Teixido Marc , Perez Sandra
Published: March 2024

Challenges posed by rapid urbanization, climate change, and the increased frequency of extreme weather events are forcing cities to adapt a new urban water management. Stormwater harvesting represents a prospective local resource, particularly in densely populated arid regions marked by severe water scarcity. Among these, deployment of stormwater blue-green infrastructure (BGI) is a promising practice to mitigate flood risk, while recharging aquifer and reducing combined sewer overflows. However, it is acknowledged that stormwater, highly impacted by anthropogenic contaminants, is a significant carrier of contamination.Despite legacy and (un)regulated contaminants (e.g., pesticides, drugs, anti-corrosion agents, plasticizers) have already been detected in various water sources, there is still a lack of scientific knowledge on the source, transport and fate of new chemicals of concern (i.e., absence of comprehensive monitoring) in the urban water cycle. For instance, blue-green infrastructure may not ineffectively remove persistent, mobile, and toxic (PMT) organic compounds, allowing them to potentially enter ground and surface waters.Herein, “first flushes” of urban stormwater (including rainwater) from nearly 30 sites over 3 districts across the municipality of Barcelona, were collected during the period March to April 2022. Sampling design included conventional and pedestrian streets runoff, and BGI inlet/outlets. The results showed that conventional streets were the most polluted areas. More than 30 targeted urban contaminants were investigated using a LC-MS/MS method, 14 of them included in the UBA PMT list. In this preliminary analysis, we observed that all targets were detected in at least one sample, among them 5 chemicals as benzenesulfonamide, 1,3 diphenylalanine, Di-n-butyl phosphate, tolytriazole and TCPP, resulted to be the more ubiquitous (with frequencies >70%) and showed median concentrations higher than 100 ng L-1. Moreover, BGI effluents showed lower overall PMT concentrations compared to influent runoff waters, highlighting the removal capacity of these stormwater treatment schemes. Results will eventually undergo thorough analysis to identify PMT sources, occurrence, and fate in a spatiotemporal domain. PMTs substances impacting urban stormwaters must be monitored in order to prevent spread in surface and ground waters and enable safe use for water supply.
Radial Distribution of Electron Quasi-thermal Noise in the Outer Heliosphere
Authors: Li Yi-Lun , Chen Ling , Wu De-Jin
Published: March 2024

The Voyager 1 and 2 are only the two spacecraft that have arrived and passed through the heliospheric boundaries. Based on the plasma data from Voyager 2 spacecraft, the electron quasi-thermal noise (QTN) is investigated by using of the electron population model consisting of a core with Maxwellian distribution and a halo with kappa distribution. The power spectra of the electron QTN is calculated at different heliocentric distances from 1 AU to 110 AU. The parametric dependence of the QTN power spectra and the effective Debye length on the model parameters, such as the density ratio and temperature ratio of the halo to the core, kappa index and the antenna length, are discussed further. The results show that the electron QTN spectrum consists of a plateau in the low frequency band f < fpt, a prominent peak at the plasma frequency fpt, and a rapid decreasing part in the high frequency band f > fpt. The QTN plateau level basically falls down outwards until the termination shock crossing at about 84 AU, after which the plateau rebounds a little near the heliopause. Although the model parameters can be very variable, the QTN plateau level does not present more than the double change in a fairly wide range of the model parameters. The presented results can be useful for future deep-space explorations in the heliosphere and can provide valuable references for the design of onboard detectors.
Merging Process of the Great Whirl and the Socotra Gyre in 2019
Authors: Dai Lingxing , Jiang Xingwei , Xia Yifan , Wang Minyang , Tang Shilin , Du Yan
Published: March 2024

The Great Whirl (GW) and the Socotra Gyre (SoG), two prominent anticyclonic eddies in the western Arabian Sea, exhibit strong dynamic interactions. This study reports a case of the merging of the GW and the SoG recorded by Argo floats in September 2019. Combined with satellite observations and a state-of-the-art ocean reanalysis, we show that the merging process was first detected at the subsurface layer (~150 m depth) rather than the surface. As the original water inside the GW is cooler than the SoG, the merging created a baroclinic structure between the eddies. The density gradients associated with the baroclinic structure drive strong subsurface geostrophic currents following the thermal wind relationship, leading to the fast merging at 100-200 m depth. Energy analysis shows that the predominant energy source for the merged eddy was the barotropic and baroclinic instability. The dissipative processes caused the rapid decay of the merged eddy. The merging process induced sub-mesoscale activities and promoted ocean vertical exchanges south of Socotra Island.
Slowing down the tidal flood wave is the key to reducing tidal flood risk in estuaries worldwide
Authors: Prasojo Octria Adi , Hurst Martin D. , Williams Richard D. , Naylor Larissa A. , Toney Jaime
Published: March 2024

Estuaries worldwide are expected to suffer increasing tidal flood risk due to climate change. Climate change is causing sea-level to rise and storm frequency and severity to increase, inducing more frequent tidal floods in estuaries, where most of the world’s largest cities are located. The key to mitigating this flood risk is by reducing tidal propagation from offshore to onshore. Flood alleviation in an estuary requires slowing down the passage of water coming into an estuary, rather than creating space for flood water. There is a nearly infinite supply of water flooding an estuary and thus, in contrast to terrestrial rivers, making space is not an effective solution for flood risk mitigation. To test this hypothesis, we investigate the effectiveness of natural tidal flood interventions for reducing water surface elevations along estuaries by performing sensitivity analyses on a 1D analytical model of tide propagation for estuaries worldwide, considering the impacts of future sea level rise. We find that increasing estuary bed roughness is the most efficient tidal flood intervention, whereas adding space for flood water has minimal impact on water surface elevations. A more focused  2D numerical model experiment simulating the hydrodynamics of the Clyde Estuary, Scotland, also reveals that roughening the estuary bed and banks significantly slows down the passage of water by absorbing tidal wave energy, delaying the tidal wave peak arriving from offshore and consequently reducing water surface elevation and tidal flood extent. However, the 2100 SLR projection consistently reduces the effectiveness of all such interventions, highlighting the challenges of implementing the most effective solutions for alleviating future tidal flood risk.
Quantifying the relation betwen jet meandering and extreme events
Authors: Aviv Erez , Kaspi Yohai
Published: March 2024

The Eddy-driven jet meandering has been hypothesized to increase due to climate change. This meandering frequently induces slow-moving patterns of low and high pressure anomalies, potentially causing extreme weather events such as droughts, flooding, heat waves and cold spells. However, the quantitative link between the jet’s meandering and storms development is still lacking, as well as a conclusive mechanism for the effect of climate change on the jet’s meandering. In this study, we first separate the physical components in the atmospheric complex system using an idealized global circulation model. We outline the connection between the decreasing equator-to-pole temperature gradient due to Arctic amplification and the meandering of the jet. As the meridional temperature gradient decreases, the eddy-driven jet slows and its meridional layout widens. By Lagrangian tracking cyclones and anticyclones, we link the jet meandering to the formation of cyclones and anticyclones. Looking at more realistic simulations, using CMIP6 data and applying a similar analysis we find analogous linkage between the meandering of the jet and storm genesis under the SSP585 scenario. We will present both our new methodology and results connecting jet meandering and extreme events.
A New Method to Compile Global Multi-Hazard Event Sets
Authors: Claassen Judith , Koks Elco E. , Tiggeloven Timothy , de Ruiter Marleen C.
Published: March 2024

This study presents a new method, the MYRIAD-Hazard Event Sets Algorithm (MYRIAD-HESA), that compiles historically-based multi-hazard event sets. MYRIAD-HESA is a fully open-access method that can create multi-hazard event sets from any hazard events that occur on varying time, space, and intensity scales. In the past, multi-hazards have predominately been studied on a local or continental scale, or have been limited to specific hazard combinations, such as the combination between droughts and heatwaves. Therefore, we exemplify our approach by compiling a global multi-hazard event set database, spanning from 2004 to 2017, which includes eleven hazards from varying hazard classes (e.g. meteorological, geophysical, hydrological and climatological). This global database provides new scientific insights on the frequency of different multi-hazard events and their hotspots. Additionally, we explicitly incorporate a temporal dimension in MYRIAD-HESA, the time-lag. The time-lag, or time between the occurrence of hazards, is used to determine potentially impactful events that occurred in close succession. Varying time-lags have been tested in MYRIAD-HESA, and are analysed using North America as a case study. Alongside the MYRIAD-HESA, the multi-hazard event sets, MYRIAD-HES, is openly available to further increase the understanding of multi-hazard events in the disaster risk community. The open-source nature of MYRIAD-HESA provides flexibility to conduct multi-risk assessments by, for example, incorporating higher resolution data for an area of interest.
Evaluating the demand for water for agricultural use for adaptation to climate change at the subbasin level (AGUAGRADA)
Authors: Jimenez-Aguirre Maite , Galea Carmen , Garde-Cabellos Sofía , Ribas-Tabares David , Soriano Barbara , Esteve-Bengoechea Paloma , Blanco-Gutierrez Irene , Lisazo Jon , Díaz-Ambrona Carlos H , Pérez David , Rodriguez-Sinobas Leonor , Ruiz-Ramos Margarita , Bardají Isabel , Tarquis Ana M
Published: March 2024

Given the decrease in water availability for agriculture caused by climate change (CC) in Mediterranean environments, it is necessary to use water efficiently in food production. As stated in the PNACC (National Plan for Adaptation to Climate Change), knowing the water demand for agricultural use before and after adaptation to CC is essential. In turn, for this, it is necessary to optimize the monitoring of the basins. To this end, AGUAGRADA proposes a monitoring and modeling system at the sub-basin scale and scalable to higher order basins, capable of quantifying the water demand for agricultural use under different climate, management scenarios (compatible with the CAP), and socio-economic and economic conditions of policies. The results of present and future water demands are expressed in PNACC indicators since the project aims to contribute directly to its implementation.The general objective of this project is to develop and apply a method for evaluating water demand for agricultural use applicable at the sub-basin and basin scale before and after adaptation to climate change (CC). To achieve this, the following specific objectives are defined:Design an optimal methodology for monitoring water demand for agricultural use applicable at the sub-basin and basin scale using PNACC indicators, replicable and scalable to other regions and even at the national level.
Co-create with stakeholders/farmers the selection of agricultural practices and CC adaptation measures to optimize water demand for agricultural use at the sub-basin and basin scale and ensure environmental and socio-economic sustainability. Analyze possible incentives for their inclusion in eco-regimes or CAP agri-environmental programs and study the best implementation routes (multidisciplinary approach).
Analyze water demand for agricultural use in the future without and with climate change adaptation.The actions as the advances achieved in this project will be explained.
Acknowledgements:Fundación Biodiversidad del Ministerio para la Transición Ecológica y el Reto Demográfico, a través de la Convocatoria de subvenciones para la realización de proyectos que contribuyan a implementar el Plan Nacional de Adaptación al Cambio Climático (2021-2030) (CBIO230220C063)
Bringing the human dimension into the measurement of greenhouse gases emissions
Authors: Zavala-Rojas Diana , Blanco Bosco Agustin
Published: March 2024

Given the growing concern about climate change and its impact on the lives of citizens, it is more necessary than ever to study their attitudes towards the environment and policies to mitigate it, especially in more polluted places such as cities. The Pilot Application in Urban Landscapes (PAUL) project, within the Integrated Carbon Observation System (ICOS Cities) network and in collaboration with the European Social Survey European Research Infrastructure Consortium (ESS ERIC), aims to introduce the social aspect of pollution measurement by conducting a three-wave panel survey in Paris and Munich to explore citizens' attitudes towards public policies to mitigate climate change, urban air quality, energy use and transport, among other topics. The presentation will cover the design of the survey, preliminary results from the first two waves, and how survey data can be mixed with environmental data to improve the findings and help understand social perceptions of climate change in cities.
Validation of CPM’s wind and precipitation field against observations and the highresolution reanalysis dataset SPHERA
Authors: Cesarini Luigi , Fosser Giorgia
Published: March 2024

The correct representation of fine-scale atmospheric processes, like convection, is vital for predicting extreme weather events and CPMs have already shown to provide more reliable representation of extreme precipitation. However, in most cases their validation is limited to the precipitation field and based on sparse in-situ observations or coarser resolution observational gridded dataset. In this study, we first explore whether high-resolution (i.e., grid spacing 2.2km) reanalysis product SPHERA provides a realistic representation of the in-situ observations, thus offering  a comprehensive overview of the atmosphere at fine scale and functioning as a reliable reference dataset for CPMs evaluation. Then the sub-daily precipitation and wind fields of the CPMs ensemble from the CORDEX Flagship Pilot project on Convective Phenomena over Europe and the Mediterranean (FPS Convection) is validated against both in-situ observation and SPHERA. The validation focuses on extreme quantiles, spatial variability and event representation with a quantile based approach (i.e., the event starts when atmospheric variables are above a certain quantile, and ends when it goes below). Results show a general good agreement between in-situ observations and SPHERA, that is found to be a good reference dataset to evaluate the CPM models. When looking at the extreme quantiles, the CPMs well represent  both wind and precipitation fields, although they underestimate heavy precipitation in summer (i.e., June-July-August). Similarly, the spatial distribution of precipitation and wind is well represented for all the season, with a decrease in the spatial variability and spatial correlation for the heavy precipitation in the summer. Finally the CPMs underestimate the number of the events when precipitation and wind are treated singularly, while they substantially overestimate the number of compound events of rainfall and winds. The analysis shows the capability of CPMs to represent the precipitation and wind fields and highlights the possibility of using high-resolution reanalysis into the evaluation of convection-permitting models. Moving from point-based measurements to high-resolution gridded observational datasets opens the path to the use of SPHERA for advanced bias correction methods that could take into account the full 3D dimension of the atmosphere and the processes within it.
Stability of abandoned pit slopes - how groundwater and lake water control may support safety while flooding
Authors: Pahlowan Ershad Ud Dowlah , Braun Anika , Fernandez-Steeger Tomas Manuel
Published: March 2024

In Europe's move towards decarbonization, renewable energy emerges as a key player, with its swift expansion crucial for cutting carbon emissions. Addressing the modern energy scenario, an innovative energy storage solution: transforming abandoned open-pit mines into large-scale facilities using pumped-hydro power storage (PHS) technology. This system operates by elevating water during periods of low demand and releasing it to produce electricity when demand peaks, mirroring the function of traditional hydropower plants. A significant hurdle in this transformation is the initial flooding of the mine pit to form the lower reservoir of the PHS system. This phase is marked by complex geotechnical challenges, especially in terms of mine slope stability, influenced by the difference in water head between the groundwater and the reservoir. A key aspect is to ensure an effective hydraulic head, particularly when the upper reservoir is positioned in areas with minimal head difference from the lower reservoir. Our approach revolves around managing the head difference between lake water and groundwater effectively, safeguarding mine slope stability for PHS operations. To achieve this, we compare two different approaches to maintaining the head difference between lake water and groundwater and assess the slope stability for different stages of flooding using the Limit Equilibrium Method (LEM). These approaches are aimed at refining the hydraulic head difference, thereby maximizing the energy generation capacity and promoting efficient, sustainable energy solutions, while ensuring safe operation in terms of slope stability.
Application of beta regression for the prediction of landslide areal density in South Tyrol, Italy 
Authors: Moreno Mateo , Opitz Thomas , Steger Stefan , van Westen Cees , Lombardo Luigi
Published: March 2024

The concept of landslide hazard entails evaluating landslide occurrence in space (i.e., where landslides may occur), in time (i.e., when or how often landslides may occur), and their intensity (i.e., how destructive landslides may be). At regional scales, data-driven methods are implemented to separately analyze the spatial component (i.e., landslide susceptibility) and the temporal conditions leading to landslide occurrence, such as rainfall thresholds. However, assessing how large a landslide may develop once triggered is seldom conducted and poses a persistent challenge to satisfying the complete definition of landslide hazard.So far, only a few publications have addressed this issue by predicting the total areal extent of landslides based on certain mapping units, such as slope units. Limitations arise since the total areal extent of landslides within a mapping unit is strongly influenced by the size of the mapping unit, leading to larger mapping units being more likely to encompass larger total landslide areas. To tackle these challenges, this study aims to predict the landslide area proportion per slope unit in South Tyrol, Italy (7,400 km²). Our approach built upon past landslide occurrences from 2000 to 2020, systematically related to damage-causing and infrastructure-threatening landslide events. The method involved delineating slope units, filtering the landslide inventory, designing the sampling strategy, removing trivial areas, and aggregating the environmental variables (e.g., topography, lithology, land cover, and precipitation) to the slope unit partition. We tested a generalized additive beta regression model to estimate statistical relationships between the various static predictors and the target landslide areal density. The resulting spatially explicit predictions are evaluated through cross-validation from multiple perspectives. Applications and shortcomings of the approach are discussed.The proposed method is anticipated to provide valuable insights and alternatives to assessing landslide intensity and moving toward landslide hazard in a data-driven context. The outcomes associated with this research are framed within the PROSLIDE project, which has received funding from the research program Research Südtirol/Alto Adige 2019 of the Autonomous Province of Bozen/Bolzano – Südtirol/Alto Adige.
Interannual variability of Sea Surface Salinity in North-Eastern tropical Atlantic: influence of freshwater fluxes
Authors: Thouvenin-Masson Clovis , Boutin Jacqueline , Echevin Vincent , Lazar Alban , Vergely Jean-Luc
Published: March 2024

​​​​​In tropical regions, the fresh water flux entering into the ocean originates primarily from precipitations and, in a lesser extent, from continental rivers. Nevertheless, at regional scale, river flows can have a significant impact on the surface ocean dynamics. Riverine fresh water modifies salinity, and therefore density, stratification and circulation in the surface layer. The eastern Southern North Tropical Atlantic (e-SNTA) region off Northwest Africa, with its particular coastline, relatively high cumulative river discharge and the vicinity of ITCZ, is a particularly interesting location to study the linkage between precipitations, river flows and Sea Surface Salinity (SSS). In particular, the effect of river flows interannual anomalies on SSS have been unexplored in this region.In this work, we focus on the regional SSS interannual variability, and their relations to river discharge and rainfall. We quantify the impact of these forcings on surface salinity and dynamics, combining informations coming from the CROCO regional ocean model and from SSS remote sensing.  Several simulations forced by different interannual and climatological forcings are analyzed. We compare the simulated SSS with satellite (ESA CCI product), in-situ (Argo, ships and Melax mooring datasets), and Glorys reanalysis. The mixed layer salinity budget is investigated to better understand the dynamics driving SSS variability.Overall, the simulations are in good agreement with the observations, with a slight statistical improvement in the river plume regions when using ISBA interannual runoff and IMERG precipitation. We find that interannual SSS variability depends on surface circulation, river discharge, precipitation and wind variability.  Strong anomalies are mostly linked to strong precipitation anomalies. The impact of river discharge is highly dependent on surface currents. This highlights the importance of properly constraining river runoff and precipitation to simulate realistic sea surface salinities. This study shows the value of satellite salinity data for validating ocean models, and highlights the potential contribution of future L-band radiometric missions for coastal ocean observation.
Influence of the fluid pressure ratio on accretionary wedge evolution over long timescales
Authors: Neuharth Derek , Behr Whitney , Holt Adam , Ruh Jonas
Published: March 2024

Accretionary wedges are regions of off-scraped and underplated sediment and oceanic crustal materials formed along subduction zones. Many modeling studies investigate accretionary wedge mechanics on a crustal scale, or on a larger scale using kinematic boundary conditions. However, in fully dynamic systems subduction velocity can change through time in response to variations in large-scale subduction dynamics (e.g., as the slab travels rapidly through the upper mantle vs. slower sinking through the transition zone). How this time-dependence affects an evolving accretionary wedge and subduction interface properties, and the resulting effect on subduction speeds, is not well understood.To understand how accretionary wedges evolve during different stages of subduction, we develop fully dynamic 2D subduction models using the finite element code ASPECT. The visco-plastic model setup consists of a dense subducting plate and a buoyant overriding plate coupled with a 6-km thick wet quartzite sediment interface. A fluid pressure ratio profile is prescribed within the sediment that varies from 0.4 at the surface to 0.9 at depths greater than 4-km. Between 50 to 100 km depth, the fluid pressure ratio is linearly tapered from 0.9 to 0. We run models for 30 Myr where we vary 1) the initial sediment thickness, 2) frictional strength, and 3) the depth needed to reach the maximum fluid pressure ratio. We explore how these parameters affect the thickness of the accretionary wedge, the amount of sediment that enters the subduction channel, and the resulting subduction speed.Preliminary results suggest that an accretionary wedge will initially frontally accrete as the wedge thickens. Over time, the faults forming these slivers are rotated towards vertical and moved towards the subduction zone along a basal decollement. Eventually, a second decollement forms along the overriding plate interface and links to the first decollement through backthrust faulting, creating a series of accretionary wedge blocks that are underthrust into the subduction interface. Increasing the depth to the maximum fluid pressure ratio leads to a larger accretionary wedge, and a deeper basal decollement. A deeper decollement results in greater sediment underplating due to the backthrust faulting, resulting in more sediment within the subduction interface.
Contiguous Space-time TEC Enhancements in JPL GIMs - Seasonal, Latitudinal and Activity dependence
Authors: Cafolla Martin , Chapman Sandra , Watkins Nick , Meng Xing , Verkhoglyadova Olga
Published: March 2024

The variability of GPS positioning and timings impacts navigation, communication and other low-Earth orbit satellites and is affected by space weather. Ground GNSS observations of Total Electron Content (TEC) with 100 − 200 ground stations are used to compile global maps of TEC to monitor ionospheric response to space weather events. We consider Global Ionospheric Maps (GIMs) available at a 15-minute cadence and a spatial resolution of 1 × 1 degree longitide/latitude bins from the Jet Propulsion Laboratory (JPL). These are available over 2 solar cycles, providing an extensive data set covering both seasonal variation and quiet/active times. Our study uses feature extraction to identify regions of enhanced TEC that are contiguous in both space and time. For each map, we identify spatially contiguous High Density Regions (HDRs) as the region on the TEC map within which the level is exceeded by the top 1% of TEC values. We then apply a tracking algorithm over consecutive timestamps to obtain a set of labelled coherent space-time TEC HDRs. Extracting and following these HDRs over multiple years allows us to explore their statistical dependencies upon geomagnetic activity, latitude and season. Given a set of geomagnetic indices (Dst, Kp and/or F10.7) at some date-time, we can determine the locations of HDRs, how long they last and their size/brightness. Our analysis detects, labels and tracks HDR origin, path, areas, TEC intensities and duration. TEC estimation in the JPL data has higher accuracy over the continental US and Europe than in other areas. We consider how this non-uniform distribution of ground stations affect our results.
Changing risk from extratropical windstorms in Europe
Authors: Catto Jennifer , Priestley Matthew , Little Alexander
Published: March 2024

Future projections of European windstorms and the resultant socioeconomic losses are subject to large uncertainties associated with model differences, internal variability, and emissions scenarios. Here we have used a dataset of objectively identified extratropical cyclones from reanalysis and a multi-model ensemble of climate models under different future warming scenarios. We have applied two storm severity indices; one that is only a measure of the severity of the windstorms; and one that takes into account the population (and its projected future changes) to better understand projections of losses from windstorms. Over northern and central Europe the storm severity itself more than doubles, but the losses estimated from the population-weighted index more than triple due to projected population increases. We also consider an idealised adaptation scenario, where future damage thresholds are used that take into account the increasing future wind speeds. This indicates that adaptation can only partially offset the increased losses. Considering different emissions scenarios, future increase in risk is reduced when following a lower emissions scenario. We show that to understand the future changing risk associated with European windstorms, there is a need to go beyond physical hazard modelling to consider risk and adaptation from a socio-economic perspective.
Detached Tonga slab in the mantle transition zone imaged by stress variations of deep-focus earthquakes
Authors: Hrubcová Pavla , Rastjoo Ghazaal , Vavryčuk Václav
Published: March 2024

Tonga is a part of Tonga-Kermadec, the 2,550 km long subduction system in SW Pacific. It represents a convergent plate boundary and the outcome of the Pacific plate submerging underneath the Australian plate. The Tonga slab subducts steeply into the mantle and is the fastest converging and the most seismically active deep subduction system in the world. In the mantle transition zone, especially at depths greater than 500 km, the geometry of the slab becomes complex, forming separated slab segments. Moreover, it undergoes strong deformation and sharp bending in the north, which results in significantly different course of the southern and northern Tonga slab.We focused on the mantle transition zone in the southern part of Tonga (south of latitude 22°S). We performed stress analysis by inverting focal mechanisms of deep earthquakes available in the Global Centroid Moment Tensor catalog. We focused on depths ranging from 400 to 680 km, where seismic activity forms two subparallel bands of events, in the west and east. We revealed two distinct stress regimes that characterize this deep Tonga double seismic zone and distinguish two slab segments. The stress orientation in the eastern slab segment matches the down-dip compressional stress regime of the subducting slab. However, the stress orientation of the western slab segment is different, with the maximum compression in the vertical direction. This suggests that the western slab segment is no longer connected to the subducting slab. Such findings are also supported by the horizontal westward detachment of the western slab segment at 520 km depth and by substantially different fault orientations in both slab segments. This points not only to the retention of the southern Tonga slab in the mantle transition zone but also to its detachment at the base of the upper mantle with a remnant slab no longer connected to the younger actively subducting slab.
A Bayesian approach to reconstructing quantitative climate using geochemical lake sediment data 
Authors: Boyall Laura , Lincoln Paul , Parnell Andrew , Martin-Puertas Celia
Published: March 2024

Palaeoclimate reconstructions from proxy data provides the opportunity to extend the instrumental climate record over the last few millennia. This extension allows the identification of climate trends which are not observed in the short observational period, contextualise current changes in the climate system, and be used in climate model sensitivity tests to strengthen future projections. The skill in reconstructing accurate palaeoclimate on centennial to millennial timescales using proxy data has increased over the past decades, however reconstructions at high temporal resolutions (1 to 10 years) are limited. This is mostly due to the sampling resolution of available proxy records and/or uncertain chronologies. Micro X-ray Fluorescence (m-XRF) core scanning data provides multivariate information about the changing geochemical composition of a sediment sequence. When combined with a tightly resolved chronology, such as one from a varved sediment sequence, m-XRF data can be used as a proxy for past changing environmental and climate conditions at an annual to sub-annual timescale. However, despite this, the reconstructions are only semi-quantitative and therefore only used to assess relative changes in climate and environmental variability.We have developed a novel approach which transforms XRF core scanning data into a quantified climate reconstruction using a Bayesian statistical approach. This method uses a calibration period measuring the relationship between the different geochemical elements and a climate parameter, as well as measuring the covariance and non-linear responses between the different geochemical elements. This learnt statistical relationship is then applied on the proxy data through time with quantified uncertainties calculated at each timestep.We present the simplification of this approach in a user-friendly R package (SCUBIDO, Simulating Climate Using Bayesian Inference with Proxy Data Observations) which provides functions for the stages of model calibration, application, and validation. We demonstrate this approach using the annually laminated lake sediments of Diss Mere (UK) to reconstruct annual mean temperature for the past 10,000 years. The temperature reconstruction reveals good consistency from the proxy data to the TraCE-21k transient climate simulation, and other palaeoclimate reconstructions from the surrounding region.
IEA Wind Task 51 – Minute and Seasonal Scale Forecasting Workshops for the Weather Driven Energy System
Authors: Giebel Gregor , Draxl Caroline , Frank Helmut , Zack John , Möhrlen Corinna , Kariniotakis George , Browell Jethro , Bessa Ricardo , Lenaghan David
Published: March 2024

The energy system needs a range of forecast types for its operation in addition to the narrow wind power forecast. Therefore, the notionally largest group world-wide discussing renewable forecasts, IEA Wind Task 51 “Forecasting for the Weather Driven Energy System” is reaching out to other IEA Technology Collaboration Programmes such as the ones for PV, hydropower, system integration, hydrogen etc. The three existing Work Packages (WPs) on NWP Improvements (WP1), Power and Uncertainty Forecasting (WP2) and optimal use of Forecasting Solutions (WP3), are complemented by thirteen work streams in a matrix structure. The three work packages span three distinct areas of challenge in forecasting for the weather driven energy system. The first area is the continuing effort to improve the representation of physical processes in weather forecast models through both new high performance initializations and tailored parameterizations. The second area is the heterogeneity of the forecasters and end users, the full understanding of the uncertainties throughout the modelling chain and the incorporation of novel data into power forecasting algorithms. A third area is representation, communication, and use of these uncertainties to industry in forms that readily support decision-making in plant operations and electricity markets.
Task 51 focuses on facilitating communication and collaborations among international research groups engaged in the improvement of the accuracy and applicability of forecast models and their utility for the stakeholders in the wind industry, in the power sector and in the energy system.

The collaboration is also structured in work streams, more targeted around a particular topic and potentially spanning several work packages [1]. Two of those work streams are aligned around forecasting horizons, the one on Sub-seasonal to Seasonal (S2S) forecasting and the one on minute-scale forecasting. Both work streams had public workshops. The Seasonal Forecasting workshop was in Reading (UK) in May 2023, while the Minute Scale Forecasting workshop  was on 10/11 April 2024 in Risø (DK). While the S2S workshop was done in conjunction with WMO, the Minute Scale workshop had people from several other IEA Wind Tasks (Lidars, Wind Farm Flow Control and Hybrid Power Plants) as well as representatives of IEA PVPS Task 16 for the solar side in the committee. The poster will discuss the results of both workshops.
 Reference: [1] https://www.iea-wind.org/task51/   The Task website, last accessed 10 January 2024
Coupling a Functional-Structural Plant Model with a Rhizosphere Model To Gain Multiscale Insights into Plant-Soil-Atmosphere Interactions for Water and Carbon Cycles
Authors: Giraud Mona , Sircan Ahmet , Lobet Guillaume , Streck Thilo , Leitner Daniel , Pagel Holger , Schnepf Andrea
Published: March 2024

To assess the impact of agricultural practices on water and carbon cycles within specific Genome-Environment-Management combinations, understanding the interactions across the Soil-Plant-Atmosphere continuum (SPAC) is crucial.Indeed, soil water conditions influence carbon concentration and transport, impacting soil carbon physical and biochemical reactions.The soil water and carbon status affect, in turn, the plant water and carbon dynamics directly via the plant-to-soil water or carbon gradient, and indirectly via plant water status, influencing its inner balance of water (uptake, transpiration and flow) and carbon (assimilation, usage for maintenance and growth, storage, respiration, rhizodeposition, and transport).Reciprocally, plant water and carbon balances affect the soil carbon cycle in the short term through root water uptake and rhizodeposition. Those rhizodeposits are, for the most part, made of exudates and mucilage. Root exudates are low molecular weight organic compounds that are mainly passively diffused, while mucilage is a fluid made of polymers with high molecular weight created from starch via an active process.Modelling plant and soil water and carbon processes, along with their interactions, can help to understand better and represent the effects of the underlying feedback loops. In this study, we therefore coupled the Functional Structural Plant Model (FSPM) CPlantBox with the rhizosphere model TraiRhizo, implemented using the porous medium flow and transport solver DuMux.The overall coupled model and multiscale framework includes a module of 3D plant architecture development, and modules to represent flow and transport within the plant, the soil and the perirhizal zone around each root segment. Flows between compartments are solved implicitly via fixed-point iteration, using parallel computation for both the 3D soil and rhizosphere models.We present a case study in which we simulated the growth of a C3 monocot and observed how changes in soil water content, due to root water uptake, influenced dissolved carbon concentration and (de)activation of the soil microbial communities during a dry spell.In the future, the model will be applied to assess the impact of small dry spells at various stages of plant development against a baseline scenario. In time, this model could support plant breeding efforts to find root traits that aim for more drought-resistant plants in specific pedoclimatic environments.