bluuebunny/crossref_metadata_2025 huggingface dataset:
Cascading Hazards – the challenges to understand interactions
Authors: Keiler Margreth
Published: March 2024

Cascading hazards come into focus of hazard and risk research in the last 15 years and is strongly connected to studies on multi-hazards and compound hazards. Unexpected cascading events and related casualties and losses of properties draw the attention to consider the possible amplified risks induced by cascading hazards.The contribution will focus in the first part on key concepts in relation to cascading hazards and will address briefly the challenges which may occur due to the general terminological ambiguity because the term cascading hazards tends to be used interchangeably with multi-hazards, cascading events, cascading disasters, or compound hazards or events. The main focus is on the analyses of different types of interactions which may occur during a cascading hazard events and their dependency on time and space. In the second part, the main question addresses the influence of climate and environmental change on cascading hazards including the occurrence of cascading hazards, changes of types of cascading hazards or interactions within the cascading hazard event. Current challenges regarding the approaches used to analyse and better understand cascading hazards are presented as well as first ideas to answer the questions what is missing, what is needed and how it can be used for hazard and risk analysis/management. 
Magnetic Fabric Analysis of Sheared Rocks along the Alaknanda-Dhauliganga Valley: Insights into the Structural Deformation and Evolution of the Main Central Thrust in the Himalayan Region
Authors: Borgohain Asha , Bhatt Sandeep , Banerjee Sayandeep
Published: March 2024

Magnetic fabrics derived from the anisotropy of magnetic susceptibility (AMS) depict the preferred alignment of grains and crystal lattices in minerals contributing to magnetic susceptibility. These fabrics serve as reliable indicators of strain in deformed terrains. Early research primarily focused on rocks lacking visible fabrics, such as granites and quartzites. However, there has been a recent surge in the application of magnetic fabric analysis to Himalayan rocks, particularly for insights into tectonic activity. In the present study, structural and magnetic data along the Alaknanda-Dhauliganga valley is presented majorly focusing on the sheared rocks of the MCTz. The aim of the present work is to elucidate the utility of magnetic fabrics in resolving the ambiguity of the MCT, distinguishing between the Munsiari Thrust (MCT-I) and Vaikrita Thrust (MCT-II). The analysis shows a gradual change in compactional oblate fabric along with the parallel alignment of thrust-induced magnetic fabrics, reflecting its geometry and proximity to intense deformation zones. Here, a notable change in the degree of anisotropy (Pj) is also observed as the rocks transition towards the thrust zones. This transition is accompanied by a shift to a quantitatively more prolate fabric, indicating a change in nature of strain. The study observes an anisotropy degree (Pj) ranging from 1.1 to 3.2, with mostly positive shape parameter (T), except near MCT where negative values are noted. Additionally, we also investigate contributors of magnetic fabric by estimating the mean magnetic susceptibility (Km) for all the samples and cross-verify the results with petrographic and magneto-mineralogy studies. Vibrating Sample Magnetometry (VSM) was also employed to identify magnetic carrier types. This study also shows a strong correlation between macroscopic features and magnetic fabrics indicating dominance of structural deformation (independent of magnetic mineral assemblages) in the region. In conclusion, the study highlights that strain within the studied area varies with distance from areas of intense deformation, and these variations are distinctly characterized by changes in magnetic fabrics.
Mapping km-scale global extreme rainfall onto mesoscale convective systems lifecycle, frequency and dynamics 
Authors: Fildier Benjamin , Carenso Maxime , Roca Rémy , Fiolleau Thomas
Published: March 2024

Mesoscale convective systems are the building block of tropical precipitation, as more than 40% of global precipitation and more than 80% of extreme rainrates are produced by these organized systems. However, when investigating the sensitivity of global rain extremes, the behavior and morphology of organized storm systems are typically ignored and corresponding dynamics are instead interpreted using the textbook framework of a convecting parcel. Indeed, despite rich observational and case studies describing the internal dynamics and structures of MCSs, no conceptual framework exist to this day to bridge the gap between global hydrologic sensitivity and MCS behavior.This work introduces new approaches to link extreme precipitation rates in the tropics to the occurrence, internal dynamics and lifecycle of individual MCSs. Individual storms are idenditifed based on by the Lagrangian tracking algorithm TOOCAN which tracks storm anvils over their lifecycle, and which has been applied to satellite observations and to global storm resolving models in the DYAMOND experiment. We first use this rich dataset to develop a numerical interface that maps the occurrence of extreme precipitation rate onto the MCS cloud shield. We then introduce a novel conceptual framework to decompose the sensitivity of precipitation extremes to the change in storm occurrence and change in internal dynamics within this cloud shield. Results are threefold. We demonstrate a robust phasing in the timing of global extreme rainrates within the storm lifecycle, robustly occurring at 25-30% of the storm's lifetime for the models and regions analyzed. The analytical decomposition confirms that in a given climate state, variability in the heaviest rainrates across regions mostly occur through changes in MCS frequency, rather than changes in their efficiency at producing rain. We finally argue that the sensitivity of extremes to climate state may occur through both a change in occurrence and a change in internal MCS dynamics.
The Challenge of Non-Markovian Energy Balance Models in Climate
Authors: Watkins Nicholas Wynn , Calel Raphael , Chapman Sandra , Chechkin Aleksei , Klages Rainer , Stainforth David
Published: March 2024

Hasselmann’s paradigm, introduced in 1976 and recently honoured with the Nobel Prize, can, like many key innovations in the sciences of climate and complexity, be understood on several different levels, both technical and conceptual. It can be seen as a mathematical technique to add stochastic variability into pioneering energy balance models (EBMs) of Budyko and Sellers. On a more conceptual level, it used the mathematics  of Brownian motion to provide an  abstract superstructure linking slow climate variability to fast weather fluctuations, in a context broader than EBMs, leading Hasselmann to posit the need for negative feedback in climate modelling.Hasselmann's paradigm itself has much still to offer us [e.g. Calel et al, Naure Communications, 2020], but naturally, since the 1970s a number of newer developments have built on his pioneering ideas. One important one has been the development of a rigorous mathematical hierarchy that embeds Hasselmann-type models in the more comprehensive Mori-Zwanzig (MZ) framework  (e.g.  Lucarini and Chekroun, Nature Reviews Physics, 2023). Another has been the interest in long range memory in stochastic EBMs, notably Lovejoy et al’s Fractional Energy Balance Equation [FEBE, discussed in this week’s Short Course SC5.15 ]. These have a memory with slower decay and thus longer range than the exponential form seen in Hasselmann’s EBM. My presentation [based on Watkins et al, in review at Chaos] attempts to build a bridge between MZ-based extensions of  Hasselmann, and the fractional derivative-based FEBE model.  I will argue that the Mori-Kubo overdamped Generalised Langevin Equation, as widely used in statistical mechanics, suggests the form of a relatively simple stochastic EBM with memory for the global temperature anomaly, and will discuss how this relates to FEBE.
Bedrock erosion by hyperconcentrated flows: A quantitative analysis and implications for effective gorge formation
Authors: Stammberger Verena , Jacobs Benjamin , Krautblatter Michael
Published: March 2024

Deeply incised bedrock channels can be found in mountain landscapes across the whole globe. The processes controlling this incision and subsequently gorge formation in bedrock have been discussed in the scientific community but have not been directly observed in an actualistic way. Here, we show the results of an unprecedented LiDAR dataset deciphering the erosive power of a 60,000 m3 hyperconcentrated flow (transition of flood and debris flow). We were able to quantify the lateral bedrock erosion in a narrow limestone gorge with channel widths between 1 and 15 m and a total length of 900 m. The flow laterally eroded up to 1 m massive limestone and widened sections by up to 15 %. The influence of sinuosity, convergence and gradient were tested but found not to influence the local erosivity pattern of the rock walls. We show that single hyperconcentrated flows similar to this one could have a major influence on the effectiveness of bedrock incision in comparison to turbulent flows. Here, we provide a new explanation of the processes of rock gorge formation due to mechanically excited breakout of rock fragments in a massive limestone gorge.
How to balance the voids? Tackling rapid ice loss in western Austria
Authors: Fischer Andrea , Stocker-Waldhuber Martin , Hartl Lea , Seiser Bernd , Helfricht Kay , Gschwentner Andreas , Bertolotti Giulia
Published: March 2024

The extreme melt during the years 2022 and 2023 resulted not only in up to 3 m w.e. ice loss, but also to rapid shrinkage of glacier area. As a result of thinning in all altitudes, an increase in pace of area loss can be expected for the next years. The area loss for long term mass balance glaciers reached up to 10% in 2023 for Jamtalferner. This similar to the area loss of the last decade and rises the question, how significant the tracking of the area loss influences the accuracy of in situ mass balance, as we traditionally calculate mass balance based on the area of the previous year.Another open question regarding mass balance methods are effects of the repositioning of stakes into flat areas with low debris cover which is forced by increasing rock fall activities. There also is evidence of wide spread melt at the base of the glacier which is so far unquantified.With rapidly shrinking areas, specific mass balance curves and total balance show larger differences, i.e. although specific mass balance increases, the areas shrink so rapidly that the total melt water runoff decreases. Equilibrium line is above summits for most of the mass balance glaciers in western Austria in most years of the last decade.So far, the Austrian glacier inventories did not split up glaciers in smaller entities, to allow to tackle the evolution of formerly larger glaciers without accounting for parent and child IDs. Now, for some glaciers the ice remnants are clearly not fulfilling the criteria for a glacier, as they consist only of a small part of the former glacier tongue, where the ice has been thicker and survived the former ablation area. Tackling glacier loss in a consistent way turns out to be tricky, as remote sensing data often does not allow to distinguish debris covered glaciers from cold rocky landforms as frozen base moraines. Aerial photography or LiDAR elevation models would be needed in shorter repeat periods as the decadal intervals used so far. During summer 2023, some smaller glaciers disappeared within weeks, and it is also the pace of this loss which is quite informative and relevant for local hydrology and hazard situation.
Investigating signals in summer seasonal forecasts over the North Atlantic/European region
Authors: Lockwood Julia , Dunstone Nick , Fröhlich Kristina , Fuentes Franco Ramón , Maidens Anna , Scaife Adam , Smith Doug , Thornton Hazel
Published: March 2024

The current generation of seasonal forecast models struggle to skilfully predict dynamical circulation over the North Atlantic and European region in boreal summer.  Using two different state-of-the-art seasonal prediction systems, we show that tropical rainfall anomalies drive a circulation signal in the North Atlantic/Europe via the propagation of Rossby waves.  The wave, however, is shifted eastwards compared to observations, so the signal does not contribute positively to model skill.  Reasons for the eastward shift of the Rossby wave are investigated, as well as other drivers of the signal in this region.  Despite the errors in the waves, the fact that seasonal forecast models do predict dynamical signals over the North Atlantic/Europe signifies seasonal predictability over this region beyond the climate change trend, and understaning the cause of the errors could lead to skilful predictions.
Closing in on Zero Emissions Commitment (ZEC) uncertainty
Authors: Hohn David , Monteiro Estela , Tran Giang , Mengis Nadine
Published: March 2024

A stabilisation of global temperature can be achieved by reducing anthropogenic CO2 emissions to zero. Delayed warming or cooling, called zero emissions commitment (ZEC), can still occur after emissions have stopped. The magnitude of ZEC has been estimated to be 0±0.3 degrees Celsius, based on multi-model means. The individual models, however, show a wide range of responses from the climate system to the cessation of emissions, furthering the uncertainties regarding future temperature developments.Therefore, it is crucial to improve our knowledge of the ZEC uncertainty range in multiple aspects. This study contributes to a better understanding of the leading drivers of uncertainty of ZEC by analyzing a perturbed parameter ensemble of key dynamics of ZEC in ambitious mitigation scenarios. Using an Earth system model of intermediate complexity (UVic ESCM), we quantify how model parameters affect ZEC estimates for zero emissions preceded either by idealised constant emissions (20 and 10 PgC/yr) or by net-negative emissions scenarios. Finally, we analyze how the efficiency of Earth system processes relevant to ZEC, like carbon burial and heat uptake, can vary over different timescales after cessation of emissions.
Paleostress reconstruction from fault slip data along the Purulia Shear Zone, Chotanagpur Gneissic Complex, India  
Authors: Kundu Subha , Mohanta Uddipta , Tiwari Sudheer Kumar
Published: March 2024

Paleostress analysis is commonly used to understand the brittle exhumation process of deeper crustal rocks to the surface. In this research, we have assessed different stress fields and associated tectonic events in the southern part of Chotanagpur Gneissic Complex (CGC) using fault slip data. The southern CGC comprises two significant crustal-scale shear zones: South Purulia Shear Zone (SPSZ) and the North Purulia Shear Zone (NPSZ), along and across which our fault slip data has been collected. These shear zones exhibit high-grade (amphibolite to granulite) facies Proterozoic rocks consisting mainly of felsic gneisses and migmatites in which low-grade metapelite of North Singhbhum Mobile Belt (NSMB), calc-silicate and mafic granulites of CGC occur as enclaves.

 There has not been any previous study to determine the major stress orientations during brittle exhumation acting upon the Proterozoic rocks in the study area. Thus, our main aim in this study is to understand the variation in stress regime along and across these shear zones and also try to reconstruct the paleostress orientation to determine the history of brittle exhumation of the lower crustal rocks during major orogenic stages of the Proterozoic period. Almost 1000 homogeneous fault slip data have been analyzed using Win-Tensor software. The primary fault data within both shear zones exhibits an approximate E-W orientation, whereas other sets range from NW-SE to NE-SW. Reconstructing stress fields using the age, overprinting relationship and sense of fault movements show that during the Neoproterozoic period (1.0-0.95 Ga), the direction of the compressional stress regime was in N-S orientation. This indicates an oblique-slip movement (thrusting and sinistral strike-slip fault) of the northern CGC block with respect to the NSMB resulting in crustal thickening. The evidence of E-W striking, orogen-parallel normal faults was produced from an N-S directed extensional stress and is primarily responsible for brittle exhumation of these widely distributed granulite facies rocks especially the CGC gneisses in the Purulia region through crustal extension and thinning at 0.95–0.85 Ga.
Risks of unavoidable impacts on forests at 1.5 with and without overshoot
Authors: Munday Gregory , Jones Chris , Steinert Norman , Mathison Camilla , Burke Eleanor , Smith Chris , Huntingford Chris , Varney Rebecca
Published: March 2024

Regional climate impacts studies are usually predicated on output from fully-coupled Earth system models, which, due to computational constraints, can only simulate a limited number of scenarios and ensemble members. Using the PRIME system, we can simulate spatially resolved impacts quickly - emulating the response of 34 CMIP6 models, and generating ensemble members that capture the IPCC assessed range of equilibrium climate sensitivity (ECS). We assess the tail risks associated with high ECS simulations on critical tropical and boreal forest ecosystems over the 21st century and beyond, using three policy-relevant strong-mitigation IPCC WG3 emissions scenarios with different relationships to 1.5°C global warming. We quantify the future resilience and risk of dieback across these ecosystems, focus on the reversibility of loss using a temperature overshoot-and-return scenario and delineate hazardous climatic space for the Amazon basin, with climate-boundaries consistent with the literature. We show that despite using emissions scenarios which achieve 1.5 and 2 degrees Paris Agreement targets, uncertainty in ECS exhibits unavoidable risk of Amazon forest health decline and dieback, further highlighting the requirement for urgent, focused, global mitigative actions.
Spatio-Temporal Dynamics of Extreme Precipitation and Dry Spells in Alpine Catchments under Changing Climatic Conditions
Authors: Milojevic Tatjana , Steger Christian R. , Lehning Michael
Published: March 2024

Heavy and extreme precipitation and drought events are expected to increase in frequency and intensity as a result of climate change. Investigating the projected evolution of these events in terms of their spatio-temporal dynamics is important for understanding if certain regions are more susceptible to negative impacts of the changes in extremes. The spatio-temporal dynamics of extremes in complex terrain, such as in the Swiss Alps, is of particular interest as the same event might impact nearby catchments in different ways. Using climate model data at a horizontal resolution of 2.2km, dynamically downscaled with the regional climate model COSMO for the emission scenario RCP8.5, we explore projected extreme precipitation and dry spells for the end of the 21st century (2090-2099) relative to present conditions. We apply connected component labelling (CCL) to define precipitation clusters and identify the spatio-temporal changes in extreme precipitation events in alpine catchments of the southern Swiss Alps. In addition, we investigate changes between present and possible future drought conditions. The main aim is to determine if certain watersheds in the southern Alps are expected to experience different vulnerabilities to climate change-driven extreme precipitation and drought events and if the propensity to a certain type of extreme varies between different catchments. Preliminary results indicate that, relative to present-day conditions, the total amount of precipitation tends to decrease in the future scenario with increasing temperature across multiple sites. Initial assessment of the CCL results indicates that a higher overall number of extreme precipitation clusters may be found in the future summer season relative to present conditions, with weaker differences for the remaining seasons. We also expect to find shifts in the spatial range and duration of the precipitation clusters and dry spells between the present and end of century conditions.
Projecting Impacts of Climate Warming on Methane Production and Emissions from Urban Ponds
Authors: Sepulveda-Jauregui Armando , Martinez-Cruz Karla , Peeters Frank , Gessner Mark O.
Published: March 2024

Urban ponds are significant emitters of methane (CH4) to the atmosphere. Methane cycling in these ecosystems is influenced by a multitude of factors, including redox conditions, organic carbon and nutrient supplies, pollutant loads, as well physical environmental factors such as temperature. However, the quantitative relationships between CH4 production and temperature remain insufficiently known. Our aim in the present study was to quantify the impacts of CH4 production in urban pond sediments as a critical prerequisite to projected impacts of global warming on CH4 emissions from freshwaters. We collected intact sediment cores from eight ponds located in the city of Berlin, Germany, and incubated them over a broad range of temperatures (2 to 44 °C) to determine the thermal dependencies of CH4 production. The selected ponds represent a variety of urban land-use types, including residential areas, industrial areas, protected forest areas, and recreational green spaces. Our results indicate a clear dependency of CH4 production on temperature, showing that methanogenesis was consistently driven by mesophilic microorganisms, with optimal temperatures ranging between 28 and 36 °C, despite sediment temperatures that are mostly much lower throughout the year. Our findings indicate that methanogenesis in sediments of urban ponds occurs through both the heterotrophic and hydrogenotrophic pathway, with the prevailing temperatures in these environments being conducive to producing the essential precursors needed for syntrophic hydrogen production. We also integrated these temperature relationships into global warming scenarios, specifically within the Representative Concentration Pathway (RCP) framework, to make projections for the year 2100. The results of the analysis spanning a range of scenarios, from the very stringent RCP 2.6 to the continually rising RCP 8.5 indicate that even with moderate global warming, CH4 production and thus emissions to the atmosphere from urban ponds will markedly increase in the future.
Relative contribution of high-resolution Sentinel-1 data assimilation and modeling choices to improve regional water budget estimates
Authors: De Lannoy Gabriëlle , Busschaert Louise , Modanesi Sara , Dunmire Devon , Brangers Isis , Lievens Hans , Heyvaert Zdenko , Massari Christian , Getirana Augusto , Bechtold Michel
Published: March 2024

Land surface models provide self-consistent estimates of the water stored in various components of the land system, i.e. in the soil, vegetation and snow, and of water fluxes. Assimilation of satellite-based data helps to update these estimates to some extent, but it has some limitations when human processes, such as irrigation, are missing in the modeling system. Furthermore, the simulated water distribution heavily depends on the choice of meteorological input and other model choices. In this study, we aim to quantify the relative contribution of (i) Sentinel-1 data assimilation for soil moisture and snow updating, (ii) meteorological input, and (iii) modeling irrigation over the Po river basin in Italy.The Po river network channels the discharge of snow melt water from the Alps and Apennines, combined with surface and deep subsurface runoff from the hillslopes and valley. During the summer, the river network supplies irrigation water to the large agricultural area in the Po river valley. The Po basin is thus a unique testbed to study various water budget components in an environment with pronounced seasonal water storage dynamics and human water management.More specifically, we assimilate 1-km Sentinel-1 data into the Noah-MP land surface model coupled to an irrigation module and the hydrological modeling and analysis platform (HyMAP) as runoff routing module. The Noah-MP simulations are forced with meteorological data from either the fifth generation ECMWF atmospheric reanalysis (ERA5) or the Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) for the years 2015-2023. Sentinel-1 snow depth retrievals are assimilated over the mountains in the winter, whereas Sentinel-1 backscatter are mainly assimilated in the valley during the spring, summer and fall. The state updates are applied to snow depth, snow water equivalent, and soil moisture. These updates subsequently trigger updates in estimates of irrigation, leaf area index, discharge and other variables, resulting in a self-consistent re-analysis of the entire water budget of the Po basin. The impact of the Sentinel-1 data assimilation relative to that of the activation of irrigation modeling is quantified using independent in situ and remotely sensed measurements of soil moisture, leaf area index, snow depth, evaporation, irrigation and discharge.
Remote sensing-based detection of resilience loss in the terrestrial water cycle
Authors: Lotcheris Romi , Wang-Erlandsson Lan , Rocha Juan
Published: March 2024

In the face of Anthropogenic change, ecosystems globally have shown evidence of resilience loss in the past several decades. By governing key processes in terrestrial ecosystems, the hydrological cycle is critical for Earth system stability. A resilient system is able to retain its function and structure in the face of external perturbations. Changes to driving hydrological variables, i.e., precipitation, evaporation, and soil moisture, are thought to be important drivers of terrestrial ecosystem resilience, and vice-versa through land-atmosphere feedbacks. Resilience has been estimated through time series analysis, where an increase in metrics of system recovery time can signal a loss of system resilience. To date, such methods of resilience analysis have not yet been applied to hydrological variables. As a result, there is limited quantification of the role of the water cycle in Earth system resilience.Here, using remotely sensed time series data, we employ both early warning signals of resilience loss and indicators of rate-based tipping to asses resilience loss in key hydrological variables at the global scale. In doing so, we present a spatially distributed assessment of global water resilience, highlight regions vulnerable to resilience loss, and provide insights into how water resilience affects terrestrial ecosystem resilience. Changes to hydrological variables can have wide-reaching impacts on ecological (e.g., affecting biodiversity, ecosystem structure and function), and social systems (e.g., affecting crop yields in breadbasket regions). Here, we present a new dimension to the characterisation of regions vulnerable to resilience loss.
Examining the Impact of Stream Permanence on Headwater Stream Carbon Emissions 
Authors: Conroy Hannah D. , Hotchkiss Erin R. , Cawley Kaelin M. , Goodman Keli , Jones Jeremy B. , Wollheim Wilfred M. , Butman David
Published: March 2024

Quantifying headwater stream carbon emissions is important for our understanding of the global carbon cycle because these emissions (an estimated 0.93-1.15 Pg C year) can be substantial compared to the terrestrial flux. Headwater stream networks can have high emissions due to their coupling with the terrestrial environment and high turbulence with some estimates predicting headwater stream networks can contribute 70% of the global riverine stream emissions. These carbon emissions are challenging to predict, especially with regards to headwater stream network spatiotemporal heterogeneity. The majority of headwater streams exhibit changes in stream network area on a seasonal basis, and these locations and extents are not often well documented because they are based on topographic maps with limited spatial accuracy. Research suggests 50-80% of river networks are comprised of non-perennial stream segments.  Physically based models are a potential solution to both mapping streamflow permanence and carbon dioxide emissions by accounting for the spatiotemporal heterogeneity that can occur in stream networks.In this study, we modeled stream permanence at three streams across the United States in different ecosystems using the Watershed Erosion Prediction Project (WEPP) hydrological model to simulate changes in stream network area over the year. We then used these results to inform a process-based stream network model to predict carbon emission from these networks throughout the year. We calibrated these network model with longitudinal data collected at the three sites during both low and high flow. Our results show the importance of considering stream permanence when predicting stream network carbon emissions, and how some ecosystems may emerge as hotspots for these emissions during high flow periods.
Trends in Aragonite Dissolution through the Phanerozoic
Authors: Nohl Theresa , Kocsis Adam , Balthasar Uwe
Published: March 2024

Different calcium carbonate polymorphs, such as aragonite and calcite, participate differentially in early marine diagenesis due to their different thermodynamic stability. The microbial decay of organic matter causes distinct redox zones during the early stages of burial. In these conditions aragonite is unstable and dissolves, while the dissolved calcium carbonate can then reprecipitate as calcite cement. This results in areas or layers of calcium carbonate export (i.e., marl) and areas or layers of calcium carbonate import (i.e., limestone). The implications for the interpretation of carbonate rock sequences are highly debated, and the potential influences of this redistribution of carbon and other elements on global geochemical cycles remains underexplored. The intensity of this early diagenetic carbon redistribution is largely driven by availability of aragonite in the original sediment. As the seawater Mg/Ca ratio and temperature strongly impact inorganic calcium carbonate mineralogy and skeletal mineralogy (at least before the Jurassic), we expect that the intensity of the redistribution varies throughout the Phanerozoic with seawater Mg/Ca and temperature, i.e. aragonite-calcite sea conditions. In this study we evaluate the intensity of early diagenetic overprint and aragonite dissolution through the Phanerozoic by comparing diagenetically inert Al/Ti ratios of limestone-marl alternations from published datasets in the context of available shelf area and palaeotemperature. We identify time intervals with higher or lower diagenetic overprint and discuss the implications for stratigraphy, palaeoenvironmental reconstructions and carbon cycling.
A new observational analysis of near surface air temperature change since the late 18th century developed for the GloSAT project
Authors: Morice Colin , Berry David , Cornes Richard , Cowtan Kevin , Cropper Thomas , Kennedy John , Kent Elizabeth , Rayner Nick , Steptoe Hamish , Osborn Timothy , Taylor Michael , Wallis Emily , Winn Jonathan
Published: March 2024

The GloSAT project is developing a new observational analysis of global air temperature change over land and ocean since the late 18th century.A new global analysis processing system has been developed that uses a computationally efficient spatial statistical method to estimate air temperature anomaly fields from historical observations. This will be the first presentation of this analysis approach. This method, based on Gaussian Markov Random Fields, jointly estimates temperature anomaly fields over land and ocean based on weather station and ship-based air temperature observations. The increased computational efficiency of the approach compared to conventional kriging-based estimates allows for increased spatial resolution in the analysis.Observational uncertainties are represented within the analysis framework to propagate uncertainty into the output ensemble data set. This accounts for errors arising from uncorrelated effects and structured errors such as residual biases in observations from an individual weather station or ship after correction. Observational error models have been co-developed with project partners providing the input land and marine data products.Initial results from the application of the analysis system to GloSAT air temperature observation data will be demonstrated.
Evaluation and modelling of the impact of drought on groundwater reserves in Wallonia in the context of climate change
Authors: Hutzemakers Julien , Orban Philippe , Vandelois Guillaume , Dassargues Alain , Goderniaux Pascal , Brouyère Serge
Published: March 2024

Climate change has started to impact water resources in many regions and countries. Extreme events have become more frequent, with, in particular, severe winter or summer droughts that may affect groundwater reservoirs which are essential for drinking water. The exceptionally arid winters of 2016 and 2017 in Wallonia (Belgium) opened discussions on the necessity to develop tools and indicators that allow quantifying such impacts and modelling the responses of aquifer systems to such events.In this context, the objective here is to describe the methodology that has been developed inWallonia (Belgium). The approach relies on numerical groundwater flow models used to obtain trends in piezometric levels and groundwater balances using different specific drought scenarios.Modelling results are used to compute spatial maps of maximal piezometric drawdowns and recovery times by comparing baseline and drought scenarios. Adopting a flow budget perspective, groundwater flow modelling results are also used to quantify indicators reflecting relative shifts in water transfers between aquifer recharge, rivers, adjacent aquifers and exploited groundwater water resources. The approach is illustrated using different strategic regional aquifers of Wallonia modelled using various numerical groundwater flow models able to compute groundwater budgets and simulate both the partially saturated and fully saturated zones of aquifers and the interactions with surface water courses. To assess the resilience of the groundwater bodies, three different scenarios were simulated: the first entailed a series of years with typical recharge levels, the second involved three consecutive years with the same recharge as in 2016-2017, followed by years with standard recharge rates, and the third replicated the second scenario but follows the three arid years with an exceptionally wet year.Collectively these methodologies yield a better comprehension of drought impacts at a regional scaleboth in terms of spatial variability and large-scale water transfers.
Exploration and reevaluation of a tailing storage facility from a high-sulfidation epithermal gold deposit
Authors: Gutzmer Petya , Bachmann Kai , Tolosana-Delgado Raimon , Tusa Laura , Contreras Cecilia , Büttner Philipp , Gutzmer Jens
Published: March 2024

Reevaluating tailings material originating from a high-sulfidation epithermal gold deposit has unveiled the potential for a holistic remining endeavour. The primary objective of this operation would be the mitigation of minerals containing penalty elements, specifically sulphur in pyrrhotite, a major contributor to acid mine water drainage, alongside the concentration of precious elements like gold. Furthermore, exploring the applicability of the silicate fraction for industries such as ceramics, glass, and geopolymer production has been considered.To accomplish these objectives, an initial drill core campaign featuring six drill holes was executed, accompanied by a thorough material characterization using automated mineralogy, geochemical assays, and hyperspectral analysis. The subsequent step involved a geometallurgical domaining process based on 64 geochemical assays, particle size measurements, and mineralogy assessments. A Mahalanobis distance hierarchical cluster analysis was employed to differentiate domains, and predictions for these domains were extended to all hyperspectral imaging samples.The outcome of this comprehensive approach revealed the delineation of four distinct domains, each characterized by variations in modal mineralogy and trace elemental contents. This strategic analysis provides valuable insights into the heterogeneity of the tailings material, laying the groundwork for targeted interventions to address environmental concerns and maximize the extraction of valuable resources.
Present and future evolution of the winter snow cover in the French Vosges massif with the help of the regional climate MAR model
Authors: Fettweis Xavier , Ambroise Bruno , David Pierre-Marie , Ghilain Nicolas , Paul Patrice
Published: March 2024

The current and future evolution of snow cover in the Vosges massif (N-E of France) was simulated at a resolution of 4 km with the regional climate model MAR (version 3.14) forced by the ERA5 reanalysis. Thanks to the adjustment of only few parameters, MAR (initially developed for the polar regions) was optimized and validated with respect to daily observations of temperature, precipitation and height of the snowpack. Over the 62 winters (DJF) 1960-2021, MAR suggests a statistically significant decrease of about a factor of two in the average snow depth due to the significant increase in temperatures (~+2°C/62 years). Although precipitation has slightly increased (+10-20%/62 years) due to a non-significant strengthening of the westerly circulation, it falls more and more in the form of rain, especially below 1000 m. Above 1000 m, it does not snow less than before but there is more melting reducing the snowpack between two snow events. By extrapolating current trends, an anomaly of +2.5°C (resp. +3.8°C) compared to the winters of 1960-90 would be sufficient to no longer have snowpack on average below 750m (resp. 1000m). This trend is fully confirmed by MAR forced by 5 global models (EC-EARTH3, IPSL-CM6A-LR, MIROC6, MPI-ESM1-HR, NorESM2) from the CMIP6 database using both SSP245 and SSP585 scenarios over 1980-2100. In 2050, the average winter snow cover at 1000m will be reduced by half and will become almost non-existent in 2100 following SSP585. While with SSP245, MAR suggests skiing conditions still possible until 2100 above 1000m.
Present and future of Extreme El Niño teleconnections over North America in CMIP6 models
Authors: Beniche Margot , Vialard Jérôme , Lengaigne Matthieu
Published: March 2024

Previous studies did suggest a diversity of the ENSO teleconnection pattern, with an eastward shifted pattern for El Niño relative to La Niña or for “eastern Pacific” (EP) relative to “central Pacific” (CP) El Niño events. Recently, Beniche et al. (in revision) demonstrated that extreme El Niño events (i.e. the strongest EP events, such as those in 1982/83, 1997/98, and 2015/16) were the only events leading to a clear eastward shift of the winter ENSO teleconnection pattern over North America. This specific teleconnection is also associated with reproducible wet (warm) anomalies over the western USA coast (northern USA and Canada). They did however demonstrate it based on the limited observational dataset, and a single AMIP CNRM-CM6.1 ensemble. The current study aims at evaluating the robustness of these results using the broader AMIP6 and CMIP6 datasets. The specificity of the Extreme El Niño North American winter teleconnection pattern, and its inter-event and inter-member reproducibility, are robust across 23 historical AMIP ensembles (1979-2014). These events are associated with 73% chances of warm conditions over the Northern USA and Canada and 68% chances of wet conditions over the Western US coast across the AMIP ensemble. The stronger reproducibility of the extreme El Niño teleconnections can be explained by a more favourable Signal to Noise (SNR) ratio (mainly due to stronger signal). We further evaluate the realism of these teleconnections patterns in presence of the systematic biases that are present in CMIP6. We only select CMIP6 models that reproduce Extreme El Niño events based on the precipitation-index of Cai et al. (2014). In agreement with previous studies using CMIP5 (e.g. Bayr et al., 2019), we find that models with stronger cold climatological SST bias are unable to simulate extreme Niño3 rainfall anomaly events. CMIP6 models that reproduce extreme El Niño tropical rainfall reasonably also reproduce the specific extreme El Niño 500 hPa geopotential height and surface temperature winter teleconnection pattern over North America. They however do not reproduce well the specific wet anomalies over the west American coast associated with those events, casting doubt on the CMIP6 ability to project precipitation changes over this region. We end by discussing the relevance of these results for understanding projected changes in ENSO teleconnections over North America in the context of different Shared Socioeconomic Pathways (SSPs) scenarii.
The global CML data collection initiative GCDCI: The solution for scaling up CML rainfall estimation in developing countries?
Authors: Chwala Christian , Uijlenhoet Remko , Overeem Aart , Winterrath Tanja , van de Giesen Nick
Published: March 2024

Rainfall estimation from commercial microwave link (CML) attenuation data has matured and is being implemented by several European meteorological services. Individual studies have also confirmed its applicability in developing countries. But data collection and data access remain cumbersome, requiring to start from scratch in each country and in each cooperation with a new mobile network operator (MNO). More often than not the precious CML attenuation data that is produced for monitoring purposes is not stored on a long-term basis and thus is lost forever if no cooperation with researchers or meteorological services incentivizes archiving.To avoid further loss of data and to allow to better scale up CML data acquisition and data collection across different countries, we propose to start the global CML data collection initiative (GCDCI). The GCDCI will provide containerized templates for the required IT systems for CML data collection, archiving and monitoring, as well as template documents for the required legal agreements. Each MNO will get a separate cloud-based compute and storage infrastructure which they can use to do long-term monitoring and analysis of their network, providing an incentive for them to transfer their data to the GCDCI platform. Potentially, access for third parties, based on trilateral agreements with GCDCI and individual MNOs, could be implemented, e.g. to allow the development of derived products by the private sector. A central compute infrastructure, only accessible by GCDCI staff, will access data from the individual instances of the MNOs and do a centralized CML data processing. Potentially the centralized processing can be combined with real-time satellite data to both enhance the CML data processing as well as the generation of rainfall products from satellite data.With our poster we want to spark a discussion about this approach and start forming a consortium to put it into operation as a not-for-profit organization with inspirations from initiatives like TAHMO and GPCC.
The ANR project “FirstMove”: first movements of divergence between future tectonic plates
Authors: Autin Julia , Mathey Roxane , Suire Harmony , Ballay Mélanie , Ulrich Marc , Manatschal Gianreto , Sauter Daniel , Petri Benoît , Schaming Marc , Somoza Losada Luis
Published: March 2024

As two tectonic plates drift away, the earlier movements, prior to oceanic crust formation, are ill-constrained. We are convinced that the kinematic models of plate movements could be significantly enhanced by focusing on the divergence before final lithospheric breakup. During this phase of transition several problems arise. Firstly, the classical interpretations of magnetic anomalies are not trustworthy (debated geometry and/or origin of anomalies). Secondly, the movements are more complex than in oceanic domain (polyphase deformation, obliquity, asymmetry). Those particularities occur especially if plate breakup happens in magma-poor conditions where mantle is exhumed at the surface (in about 50% of instances).We focus on two pairs of conjugate magma-poor rifted margins: the Bay of Biscay and the Australia-Antarctica margins. In these areas, magnetic anomalies are controversial and seafloor formation started with large domains of hyperextended continental crust and exhumed mantle. Thus, the location and age of the LaLOC (landward limit of the oceanic crust) are uncertain. We aim to better define these domains in space, divergence direction and time through geophysical data and localized petrological observations and dating. This project is in its starting phase, it includes 2 PhD thesis. This presentation focuses on the general framework of the project and the preliminary results.
How can we improve the correctness and plausibility of our hydrological models?
Authors: Hauffe Corina , Spieler Diana , Brandes Clara , Pahner Sofie , Schütze Niels
Published: March 2024

Using hydrological models is a common task for almost all hydrologists. Sometimes there is enough time to conduct a comparison study before selecting a model or we use the model we already know. But do we really know “our” model? Do we test all processes and approaches implemented prior to the model application? Usually we assume that the models are working correctly and by doing so we strongly rely on the developers willingness and capability to provide a mathematically and physically well tested hydrological model.We believe that more effort is needed to ensure the quality assurance of models. This topic is yet underdeveloped in hydrology. We argue that our models should pass a standardized quality test in which they proof physical robustness and hydrologic plausibility. The commonly used split-sample test (Klemes, 1986) for an area of interest during the model validation may not be the best option to test for model quality. Attempts to increase standardization, transparency, and model quality have already been made e.g. by introducing the good modelling practice (van Waveren et al., 1999) and the FAIR principles (Wilkinson et al., 2016).Nevertheless, there is still much potential to improve the quality assurance of models. We suggest a framework consisting of (1) the usage of synthetic input data and catchment properties, (2) a standardized test scheme, and (3) a set of diagnostics to evaluate the model results. The current study focuses on the development of the test scheme, which includes global behaviour tests, robustness tests, and additional tests.Applying these tests serves different purposes: (1) detecting model limitations, (2) finding unintended feedback processes, (3) wrong or hydrological implausible responses, and (4) hidden or fixed parameters of a model. This kind of functional validation already proofed to be useful. A case study for the model ArcEGMO revealed several findings, e.g. fixed parameters, undocumented process implementations for lake evaporation and an unintended model response in the calculation of the groundwater recharge. Therefore, we believe that standardized tests would improve our model understanding, model usage and the trust in the model results. Klemeš: Operational testing of hydrological simulation models, Hydrological Sciences Journal, 31, 13–24, https://doi.org/10.1080/02626668609491024, 1986.van Waveren et al.: Good Modelling Practice Handbook, Tech. report, Dutch Dept. of Public Works, Institute for Inland Water Management and Waste Water Treatment, https://www.researchgate.net/publication/233864541_Good_Modelling_Practice_Handbook, 1999.Wilkinson et al.: The FAIR Guiding Principles for scientific data management and stewardship, Scientific Data, https://doi.org/10.1038/sdata.2016.18, 2016.