bluuebunny/crossref_metadata_2025 huggingface dataset:
Do the early nineteenth century eruptions strengthen evidence for volcanically-induced Eurasian winter warming?
Authors: Osborn Timothy , Wallis Emily , Joshi Manoj , Taylor Michael , Hawkins Ed , Schurer Andrew , Morice Colin
Published: March 2024

It is well-established that explosive volcanic eruptions typically lead to cooler surface temperatures in summer, but the picture in Northern Hemisphere winter is much more uncertain. Recent large, low-latitude eruptions have been followed by warm anomalies across Eurasia in winter and cold anomalies near Greenland, hypothesized to be part of a dynamical response to the volcanic forcing that drives a positive North Atlantic Oscillation (NAO). But the evidence for a dynamical, winter warming response is inconclusive because internal variability is large, many climate models do not simulate a dynamical response like this, and there are few such eruptions to study.New datasets that allow additional eruptions from the early 19th century to be studied are therefore particularly valuable and we will present new analyses of the winters following four large eruptions in 1809, 1815, 1831 and 1835 (alongside four later eruptions in 1883, 1902, 1982 and 1991). This analysis is made possible by a new gridded instrumental dataset combining marine and land air temperatures from the 1780s onwards developed in the ongoing GloSAT project. It is supplemented by analysis of an ensemble of historically-forced simulations with UKESM1.1 initialised in 1750, also from the GloSAT project, and by two reanalyses (20CRv3 from 1806 and ModE-RA from 1421).For the instrumental and reanalysis datasets, warming in Europe was found in the first post-eruption winter following six out of the eight cases studied, and in the second post-eruption winter in five. Similar results were found for cold anomalies near Greenland and for a positive winter NAO index.  The anomaly magnitudes for individual cases were mostly within the range of internal variability but the consistency of the response across eruptions and datasets was significant in comparison with non-volcanic winters. The UKESM1.1 simulations showed a significant response (with Eurasian winter warming, Greenland cooling and positive NAO) for only the largest eruption (Tambora), suggesting a response may require a minimum forcing strength to occur.
Identifying sources of Ionospheric Variability: planning for EISCAT-3D operations
Authors: Kavanagh Andrew J. , Grocott Adrian , Walach Maria-Theresia , Reidy Jade , Clilverd Mark
Published: March 2024

The important question of how much of the variability in the high latitude ionosphere is driven by atmospheric processes as opposed to space weather impacts remains unanswered.  The EISCAT-3D radar provides a unique opportunity to probe this variability across multiple spatial and temporal scales. One of the key aims of the DRIIVE project (DRivers and Impacts of Ionospheric Variability with EISCAT-3D) is to determine the balance of energy input to the lower ionosphere and quantify the variability under different atmospheric and geomagnetic conditions.  Here we present a preliminary study of the variability using historic data from the EISCAT UHF radar taken over the course of several years in the winter months. We identify wave like signatures that occur simultaneously with Travelling Ionospheric Disturbances (TID) as seen in coherent radar data (SuperDARN), alongside enhancements due to energetic precipitation.  The magnitude of the variations are compared for different years and different driving conditions. This study will allow us to optimize the design of future experiments for EISCAT-3D to study the variability while developing effective analysis techniques to maximise utility of the new radar system.
A tale of a meteorite who was too magnetic - using comics to simplify complex ideas
Authors: Sanchez Sabrina , Vervelidou Foteini
Published: March 2024

Somewhere in the vast landscape of the Sahara desert, a man stumbles upon an unusual kind of rock. After being passed around from dealers to collectors, the rock finds itself in a research laboratory. The rock is confused and does not remember where it comes from. The researcher invites the rock to a space journey, leading it back to its origins, the planet Mars. This is the story of an unusual friendship between a scientist and a meteorite, brought alive in the pages of a comic book. The book itself was born through the friendship between two planetary scientists who share a passion for planetary magnetic fields and a desire to communicate their passion to the public and inspire the next generation of planetary scientists.Meteors and meteorites have always fascinated people, but a particular aspect of these space rocks remains enigmatic to the general public: their magnetic records. This comic book aims at communicating complex scientific concepts and laboratory protocols through illustrations infused with a touch of humor. Intended for teenagers and adults, the comic explores how planetary magnetic fields are generated, how rocks record them and how the magnetic record of rocks helps scientists decipher how planets form and evolve over time. Importantly, the comic also aims at spreading the following message: meteorites should not be exposed to magnets. Doing so comes at the risk of erasing billion years old of geological history. Though initially conceived for the web, the next stage of this project is to have the comic book printed and distributed at scientific outreach events, schools, and comics festivals. Ultimately, we hope that this comic book will find its place at the bookshelves of public libraries and teenage bedrooms.
Enhancing Bioremediation: Insights from a Numerical Modeling Approach
Authors: Eddaoui Noura , Soulaine Cyprien
Published: March 2024

Bio-remediation of soil contaminated by petroleum hydrocarbon is a highly complex process, requiring coupled interactions and synergistic effects between physical, chemical and biological phenomena. Monitoring and improving the bio-remediation of such system remains a formidable challenge. Our approach involves the development of a comprehensive mathematical and numerical model that couples two-phase flow, bio-reactive transport, and the dynamic of bacterial populations, with the aim of investigating the mechanisms governing pollutant and nutrient transport, bacterial activities and bio-degradation within porous media. Important processes including the effect of biofilm growth on the permeability of the porous media and the interaction between the biofilm matrix and the fluid system, are taken into account. Numerical simulations were carried out to evaluate the effect of biomass accumulation and nutrients availability on the bio-degradation rate, providing new insights into optimizing in-situ bio-remediation processes for effective cleanup. Additionally, key issues such as controlling contaminant mobility and estimating efficiency criteria will be addressed as well.
Spatio-temporal Nonlinear Quantile Regression for Heatwave Prediction and Understanding
Authors: Bassotto Deborah , Diaz Emiliano , Camps-Valls Gustau
Published: March 2024

In recent years, the intersection of machine learning (ML) and climate science has yielded profound insights into understanding and predicting extreme climate events, particularly heatwaves and droughts. Various approaches have been suggested to define and model extreme events, including extreme value theory (Sura, 2011), random forests (e.g., (Weirich-Benet et al., 2023) and, more recently, deep learning (e.g., (Jacques-Dumas et al., 2022)). Within this context, quantile regression (QR) is valuable for modelling the relationship between variables by estimating the conditional quantiles of the response variable. This provides insights into the entire distribution rather than just the mean but also aids in unravelling the complex relationships among climate variables (Barbosa et al., 2011; Franzke, 2015). QR has been extended in many ways to address critical issues such as nonlinear relations, nonstationary processes, compound events, and the complexities of handling spatio-temporal data. This study presents a novel approach for predicting and better understanding heatwaves. We introduce an interpretable, nonlinear, non-parametric, and structured Spatio-Temporal Quantile Regression (STQR) method that incorporates the QR check function, commonly known as pinball loss, into machine learning models. We focus on analysing how the importance of predictors changes as the quantile being modelled increases. This allows us to circumvent arbitrary definitions of what constitutes a heatwave and instead observe if a natural definition of a heatwave emerges in predictor space. By analysing European heatwaves over recent decades using reanalysis and weather data, we demonstrate the advantages of our methodology over traditional extreme event modelling methods.ReferencesBarbosa, S.M., Scotto, M.G., Alonso, A.M., 2011. Summarising changes in air temperature over Central Europe by quantile regression and clustering. Nat. Hazards Earth Syst. Sci. 11, 3227–3233. https://doi.org/10.5194/nhess-11-3227-2011Franzke, C.L.E., 2015. Local trend disparities of European minimum and maximum temperature extremes. Geophys. Res. Lett. 42, 6479–6484. https://doi.org/10.1002/2015GL065011Jacques-Dumas, V., Ragone, F., Borgnat, P., Abry, P., Bouchet, F., 2022. Deep Learning-based Extreme Heatwave Forecast. Front. Clim. 4, 789641. https://doi.org/10.3389/fclim.2022.789641Sura, P., 2011. A general perspective of extreme events in weather and climate. Atmospheric Res. 101, 1–21. https://doi.org/10.1016/j.atmosres.2011.01.012Weirich-Benet, E., Pyrina, M., Jiménez-Esteve, B., Fraenkel, E., Cohen, J., Domeisen, D.I.V., 2023. Subseasonal Prediction of Central European Summer Heatwaves with Linear and Random Forest Machine Learning Models. Artif. Intell. Earth Syst. 2. https://doi.org/10.1175/AIES-D-22-0038.
Assessing climate change impacts in the Tagus-Segura water transfer (Spain) through artificial intelligence
Authors: Lagos-Castro Ivan , Pulido-Velazquez Manuel , Macian-Sorribes Hector , Mason Simon , Aranda-Domingo Jose
Published: March 2024

Being the most extensive water infrastructure in Spain, the future of the Tagus-Segura interbasin transfer is contested by climate change and increasing controversy regarding its use. It is a crucial infrastructure for regional socioeconomic development since it significantly contributes to the sustainability of one of Europe's most important agricultural areas. Diverse stakeholders' interests have generated conflicts impacting its decision-making processes. Several regulations have established maximum transferable volumes in the last decades depending on water availability and demands in the involved basins. However, the volumes transferred do not only account for those limits but also include expert criteria and ad-hoc considerations, making it complex to predict them. Artificial intelligence emerges as an effective solution to address this challenge and to reconcile all the factors affecting its current operating rules.To this end, this contribution combines artificial intelligence (fuzzy logic) with climate change scenarios and hydrological and water resource management models to predict future water transfers from the upper Tagus (donor basin) to the Segura (receiver basin). Climate change scenarios refer to five CMIP6 (Coupled Model Intercomparison Project Phase 6) climate models and four scenarios: historical (1979-2014), SSP126, SSP370, and SSP585 (2015-2100). Using their meteorological projections, the eco-hydrological model TETIS is used to obtain future time series of streamflows in response to them. The current operation of the water transfer is inferred through fuzzy logic systems that take into account the hydrological discharge of the upper Tagus estimated by TETIS, the storage level of the upper Tagus reservoirs (Entrepeñas and Buendia), the storage levels of the rest of the Tagus and the Segura basins, the regulatory limits, and the month of the year. The results show how foreseen streamflows in the upper Tagus would affect the transfer, providing valuable information for water planning in both basins, particularly in the Segura, for its adaptation to any decrease in water received from the Tagus basin.AcknowledgmentsThis study has received funding from the European Union's Horizon 2020 research and innovation programme under the GoNEXUS project (grant agreement No 101003722); and from the SOS-WATER project under the European Union's Horizon Europe research and innovation programme under grant agreement No. 101059264.
Modelling and forecasting of water resources availability in mountainous Mediterranean springs
Authors: Gómez-Beas Raquel , Contreras Eva , Polo María José , Aguilar Cristina
Published: March 2024

The amount of water available for the production of natural mineral water is affected by the variability of the flow regime in the springs from which the water is extracted. This variability occurs at different time scales (seasonal and inter-annual), being more pronounced in mountainous Mediterranean areas. Since water quality remains constant in the aquifers throughout the hydrological year, the main uncertainty in the plant's production lies in the springs flow regime. In snow dominated areas it is necessary to analyse both the influence of snow dynamics on the springs flow regime, and to establish the response time between the rainfall events and the increase in the subsurface flow regime.A forecasting model has been developed for several springs within the Guadalfeo river basin (southern Spain), where a bottling plant is operated by an international company. The model combines two approaches: a conceptual model (MCAL); and a seasonal forecast model (MPEL).MCAL is based on linear adjustments between measured monthly mean flow data at the different locations of the springs, and measured series of rainfall and snowfall from two meteorological stations in the area, as well as adjustments with the mean monthly flow in the antecedent months. The best results were obtained between mean monthly flow and the mean monthly flow of antecedent months, with low relative errors (0,2%-10%) in all the locations for twelve months ahead.MPEL allows to forecast groundwater supplies six months ahead in the different locations, from two products generated by the European Centre for Medium-Range Weather Forecasts (ECMWF): Multi-model seasonal reforecasts of river discharge for Europe and Multi-model seasonal forecasts of river discharge for Europe from January 2021 to present. The hydrological model WiMMed (Watershed Integrated Model in Mediterranean Areas) has been implemented and calibrated, to generate historical simulations in periods when there are no flow measurements at the springs. Using the ECMWF products and performing a bias-adjustment, the forecasts of the groundwater supplies are obtained for several possible future scenarios.The results obtained showed the lowest mean relative error values with the MCAL forecasts from May to October (0.8%-8%), whereas the mean monthly flow from November to January was better predicted with the MPEL forecasts (1.3%-12%). The relative errors were similar with both models between February and April (3%-20%).
How grasslands are managed will determine their ability to adapt to increased water scarcity under climate change
Authors: Westermann Sven , Bumberger Jan , Schädler Martin , Thober Stephan , Hildebrandt Anke
Published: March 2024

Grasslands are highly dynamic ecosystems that adapt to environmental drivers such as climate, soil properties and anthropogenic management. However, the belowground response and adaptation of grassland communities to environmental drivers are poorly understood. Here, we investigate differences in the temporal dynamics of root water uptake, its depth pattern and the evolution of plant-available soil water storage between three different grassland management types and in two different climate treatments (control and future). The climate scenarios included treatments with and without a precipitation manipulation that partially shifts the precipitation from summer to spring and autumn. Soil moisture measurements were carried out at 6 depths up to 90 cm on three land use types (i) extensively and (ii) intensively managed grassland and (iii) extensive pasture at the Global Change Experimental Facility (GCEF) in Central Germany. Afterwards, root water uptake was estimated from diurnal variations in soil water content. We found that the grassland vegetation, in general, extracts water to depths of up to 90 cm during the growing season and can go even deeper. Extensively managed grasslands in the future climate scenario had increased root water uptake depths even in spring when water was not limiting indicating an adaptation to changing rainfall patterns. In contrast, more intensively managed grasslands could not compensate for greater water limitation with deeper root water uptake. Root water uptake depths during summer differed between the management types only in the future climate scenario, with drier conditions, along with the management intensity: The more intense, the shallower the uptake. This demonstrates that the ability to adapt to changing climate depends on management. Cumulative atmospheric water deficit was the main driver of root water uptake depth until the first mowing while ecosystem structure (vegetation height) and soil properties (plant available water at the beginning of the vegetation period) affect that relationship.
The selective boundary crossing in stochastic processes driven by white shot noise
Authors: Calvani Giulio , Perona Paolo
Published: March 2024

Many physical, chemical, financial, and ecological processes show the presence of a threshold, which may affect their dynamics. For instance, chemical reactions occur when the energy reaches the activation value; for insurance companies and banks, ruin may happen when the balance drops down a minimum amount; in fluvial hydraulics, sediment transport, and morphodynamic processes start when bed shear stresses (i.e., flow discharge) overcome a critical threshold. Other processes may show the presence of additional boundaries. For stochastic processes, whose dynamics depends on the frequency and magnitude of random fluctuations, it is interesting to know the average time the process takes to reach one of the critical boundaries starting from a known value. This quantity is known in the literature as Mean First Passage Times (MFPTs). The quantification of the MFPTs is usually performed by considering one threshold, only. When two or multiple thresholds are present, one may consider the MFPTs of reaching either one of the thresholds, without having passed the other ones. Such a selective condition is referred to in the literature as splitting probability. In this work, we consider stochastic processes governed by a typical Langevin equation with deterministic drift and random instantaneous jumps (white shot noise). We perform a statistical-trajectory-analysis starting from a point between two thresholds and derive exact relationships of the splitting probabilities and the MFPTs of crossing one threshold, only, based on process-dependent dimensionless parameters. Such formulations are then explicitly given for the cases of constant and linear drift functions and both positive and negative jumps. We test the derived formulations against data from MonteCarlo simulations, by varying the process parameters, the starting point, and the values of the thresholds. The comparison shows very good agreement and confirms the correctness of the derived relationships. Additionally, the analysis highlights the role played by the dimensionless parameters. Then, data from flow measurements in a river are considered and we successfully test the formulations against the duration of the raising limb of high-stage events. The derived formulations can be readily applied to calculate both the duration of the raising and the falling limbs of flow events, which are important quantities for engineering applications, as well as for modeling purposes in river eco-morphodynamics.
Neogene – Quaternary evolution of the northeastern Fram gateway, European Arctic – preliminary results
Authors: Martinez Orlando , Rydningen Tom Arne , Laberg Jan Sverre , Lasabuda Amando P.E , Plaza-Faverola Andreia , Winsborrow Monica
Published: March 2024

An important geological event in the Cenozoic evolution of the European Arctic was the onset of the Fram Strait’s opening through the separation of Eurasia and Greenland along the Molloy Fracture Zone. This event facilitated the inclusion of the Arctic Ocean in the global ocean circulation, resulting in an influx of warm water and the subsequent transport of heat and moisture to the north. To study the Neogene – Quaternary nature of this inflow of water into the Arctic Ocean and its paleoclimatic implications, we have developed a seismic stratigraphic framework by combining all available 2D multi-channel seismic surveys with the chronostratigraphy (
The diurnal cycle of gravity waves in GNSS-RO data
Authors: Lear Emily , Wright Corwin , Hindley Neil
Published: March 2024

Gravity wave sources such as convection are known to have a diurnal cycle, so it is expected that gravity waves should also follow a diurnal cycle. However, although this cycle can be simulated in models and observed in ground based data at fixed locations, it is difficult to observe in global satellite observations, due to their low time resolution, particularly since most gravity wave resolving instruments have sun-synchronous orbits and therefore always observe the same local solar time. In this study, GNSS radio occultation (GNSS-RO) data are used to investigate whether a diurnal cycle in gravity wave amplitudes can be seen in the stratosphere using these observations. Radio occultation uses GNSS signals received by a satellite that measures the bending angles and phase delay, due to these signals passing through the atmosphere. These measurements are randomly distributed in local solar time and have the high vertical resolution required to accurately resolve gravity waves. Specifically, in this work, GNSS-RO dry temperature data are used from multiple satellite missions, including COSMIC 1 and 2, Metop-A, -B and -C, and CHAMP. Wave amplitudes are found using the 1D S-Transform and the amplitudes are then binned in local solar time and averaged for each month, using all available data from the years 2001-2023. Consistent with theoretical observations, a diurnal cycle in gravity wave activity can be seen in the results and comparisons to convection data sets suggest this is strongly linked to convection. These results are also compared to wind data, which will affect the generation and filtering of the waves.
Late Cenozoic evolution of the Dent Blanche Tectonic Nappe in the Western Alps imaged by low-t thermochronology.
Authors: Gemignani Lorenzo , Hülscher Julian , Zucali Michele , Sobel Edward R. , Kuiper Klaudia , Albino Irene
Published: March 2024

The Cenozoic uplift evolution of the Western Alps has been examined from various perspectives. Several studies have suggested that a Late Miocene-Pliocene European slab break-off, coupled with increased erosion due to enhanced glaciation, serves as a driving factor controlling the Western Alps topography. Alternatively, strain partitioning resulting from Adriatic indentation and Oligocene clockwise rotation leads to contrasting kinematic regimes, segmenting the Western Alps into blocks with differential exhumation. Here, we analyze the evolution of the Dent Blanche Tectonic System (DBTS), an Austroalpine nappe in the Western Alps surrounded by oceanic units from the former Liguro-Piemontese ocean.We apply Low-T thermochronology (apatite and zircon (U-Th)/He) and high resolution mica 40Ar/39Ar dating from the DBTS. ZHe sample ages from the DBTS are ~30 Ma, with an extremely low eU sample from the lower elevation of the Valpelline Valley as young as ~7 Ma. AHe samples are younger, ranging from ~20 Ma to ~3 Ma. Reliable mica Ar ages range from the Paleocene to Oligocene. Most of the samples' age distributions have low radiogenic Ar yields (low 40Ar*), and part of the analyzed muscovite shows low K/Ca ratios, likely indicating chloritization.Inverse modelling of the cooling ages from selected samples from the core of the DBTS (Arolla Units) shows that the exhumation rate of the DBTS is one-fold lower than the exhumation rates derived in the units north of the nappe. These rates are comparable with slower exhumation rates south of the nappe.We propose that the DBTS system underwent its highest exhumation rates in the Oligocene to Late Miocene, predating the proposed Pliocene slab break-off as well as Pliocene increased glaciation. The identification of Pliocene-Pleistocene ages from one sample is interpreted to reflect glacial erosion localized in the Valpelline Valley; this is aligned with similar increased denudation rates since Pliocene observed in other Western Alps regions. However, this single cooling age does not provide conclusive evidence that glaciation drove the DBTS’s exhumation from ~3 Ma ago.
Numerical simulation of Landscape Evolution using Landlab: A case study of Dibang Basin, North-East India
Authors: Narayan M Uma , Sahu Surendra Kumar , Bharti Rishikesh , Nair Archana M
Published: March 2024

The continual modification of the topography due to varied processes results in diverse and dynamic terrain. Landscape evolution studies can link the effect of small-scale topographic quantities on long-term landscape evolution. In this study, the evolutionary pattern of the Dibang basin, located at the limb of the Eastern Himalayan Syntaxis stretch along the active tectonic region of northeast India is analysed using the stream power incision model (SPIM). SPIM is an empirical power law equation linking erosion with channel area and bed slope.  With constant tectonic forcing and homogeneous physical properties, river profiles deviate from linearity and exhibit convexity (indicating uplift) and concavity (indicating erosion) in their longitudinal profiles. These deviations indicate the transient responses of the river profile due to tectonics. Here, the landscape is modelled assuming that the Dibang River lying close to the mountain front shows bedrock properties. The evolved topography is seen to exhibit an erosion-dominated landscape with a rapid decrease in the mean elevation. The profile of the Dibang River exhibits a concave-convex-concave shape, indicating that the river channel is in a state of disequilibrium. The steepness index is observed to be varying across the Dibang basin with higher values in the middle and upper right parts of the basin. The χ plot also reveals the transient nature of the river profile.
Using large, automated, light and dark chamber systems to directly measure rates of ecosystem gross primary productivity (GPP) and respiration (Reco)
Authors: Larsen Klaus Steenberg , Pullens Johannes Wilhelmus Maria , Christiansen Jesper Riis , Tariq Azeem , Bruun Sander , Lærke Poul Erik , Larsen Poul , Jørgensen Preben
Published: March 2024

The biological processes of carbon (C) uptake via plant photosynthesis (gross primary productivity, GPP) and carbon loss by autotrophic and heterotrophic respiration (ecosystem respiration, Reco) each constitute a C flux of approx. 130 Gt C per year, equal to 1/7 of the atmospheric C pool. Still, because the biological processes driving GPP and Reco are both active during daytime, they are intrinsically difficult to measure directly. The eddy covariance technique, which is effectively the gold standard for measuring net ecosystem exchange (NEE), relies on partitioning models of NEE to estimate GPP and Reco, but these methods remain debated because other processes, such as inhibition of leaf-level respiration during daytime, are not accounted for.  In ecosystems with short-stature vegetation like grasslands, shrublands, tundra, and many agricultural systems, light and dark closed chamber measurements at the ecosystem scale enable direct daytime measurements of NEE (under light conditions) and Reco (under dark conditions) while GPP can be directly estimated as NEE - Reco. Long-term data series of automated light and dark chamber measurements are, however, very rare.Here, we present data of > 50,000 measurements over six years from a novel, automated light and dark gas exchange measurement chamber that was tested in heathland, wetland, and agricultural vegetation types. In the heathland, we applied standard eddy covariance gap-filling methods to estimate annual NEE across the six years of observations. The results show annual NEE rates ranging from -96 (net uptake) to 21 (net release) g C m-2y-1 over the different years. We further applied standard eddy covariance nighttime and daytime methods to partition the observed NEE measurements into GPP and Reco. Using the nighttime method, GPP ranged from 966 to 1355 g C m-2y-1 while Reco ranged from 867 to 1372 g C m-2y-1. On average, this was only 0-4% higher than observed rates from the chamber measurements. In comparison, the daytime method yielded GPP and Reco rates that were approximately 11-30% higher than observed rates. The slightly to moderately lower direct measurements with the automatic light and dark chamber could indicate that the chamber observations are able to account at least partially for the daytime leaf-level inhibition of respiration and thus may provide a sound method for measuring the actual rates of GPP and Reco. While potential biases cannot be ruled out and will be discussed, our results indicate that automated light and dark chambers may provide an additional and highly useful tool for estimating rates of GPP and Reco in short-stature vegetation and may further serve to help constrain methods for partitioning NEE fluxes observed with other techniques, such as the eddy covariance methodology.
Implementing and simulating the water isotopes (δ18O and δD) distribution in the Mediterranean Sea using a high-resolution oceanic model 
Authors: Ayache Mohamed , Dutay Jean-Claude , Mouchet Anne , Tachikawa Kazuyo , Risi Camille , Ramstein Gilles
Published: March 2024

Water isotopes are one of the most widely used proxies in ocean climate research. However, there are still gaps in our understanding of the processes that control their composition.  Compared to other large ocean basins, the Mediterranean is ideally suited to improve our understanding of the processes influencing and driving oxygen isotopic variability, and to refine the current modelling approach. For the first time in a high-resolution Mediterranean dynamical model (NEMO-MED12), stable water isotopes (δ18O and δD) were successfully implemented and simulated in the whole basin. The well-known east-west gradient of δ18O in Mediterranean water masses is successfully simulated by the model. Results also show good agreement between simulated and observed δD. δD shows a strong linear relationship with δ18O (r2 = 0.98) and salinity (r2 = 0.94) for the entire Mediterranean basin. Furthermore, the modelled δ18O/salinity relationships are in good agreement with observations, with a weaker gradient simulated in the eastern basins than in the western basins. We investigate the relationship of the isotopic signature of the CaCO3 shell (δ18Oc) with temperature and the influence of seasonality. Our results suggest a more quantitative use of δ18O records, combining reconstruction with modelling approaches. This opens up broad perspectives for paleoclimate-related applications.
Multivariate flood coincidence risk analysis in the UK
Authors: Stavrianaki Katerina
Published: March 2024

River flooding occurs when the volume of water in a river channel is too great to be contained and it overspills on to surrounding land, with both hydro- meteorological and riven basin conditions as contributing factors. The Severn river basin district, which covers over 21,000 km2 lies both in England and Wales. It extends from the Welsh uplands, through the rolling hills of the Midlands and south to the Severn Estuary. In total over 5 million people live and work in the region which includes urban areas such as Bristol, Coventry, Cardiff, the South Wales Valleys and parts of the West Midlands conurbation. It has a particularly rich diversity of wildlife and habitats, supporting many species of global and national importance.Flood risk in the Severn River Basin District (RBD) in England is widespread. According to the mapping of the Environment Agency, there are 193,729 people currently at risk of flooding from rivers and the sea, and 328,847 people at risk of flooding from surface water. The main sources of flooding affecting the RBD are fluvial, surface water and sewer. In many locations, multiple sources of flooding interact.In this study we analyse the flood coincidence risk, which is the risk that arises when large floods occur simultaneously in the mainstream and in its tributaries using multivariate copula functions. The risk is characterized in terms of flood magnitude and is calculated for the Severn RBD, UK. Exceedance probabilities are calculated for 5, 10 and 100 years return periods.
The Determination of Mercury's Libration with BepiColombo MORE Investigation using Optical Navigation
Authors: Togni Andrea , Bernacchia David , Gomez Casajus Luis , Zannoni Marco , Tortora Paolo , Iess Luciano
Published: March 2024

The ESA mission BepiColombo will reach Mercury in late 2025 to begin an extensive exploration of the planet. The Mercury Orbiter Radio-Science Experiment (MORE) is one of the 11 scientific instruments on board the Mercury Planetary Orbiter (MPO), which will enter a polar and eccentric orbit around the planet. The main aim of the MORE investigation is to study the gravitational field of the planet to obtain scientific findings in geophysics, geodesy, and improve current knowledge about Mercury’s internal composition and dynamics.Specifically, one of the objectives of MORE is to increase confidence on the state and size of Mercury’s core, which is expected to be at least partially molten and decoupled from the mantle. Such study can be performed by estimating the second-degree coefficients of the gravity field, Mercury’s 88-day libration amplitude, and the planet’s obliquity. The comprehensive estimation of these parameters requires synergy between classic radiometric tracking and optical navigation algorithms to obtain accurate joint information about the state of the orbiter and estimate the amplitude of the forced longitudinal libration of Mercury from differences in the position of surface features as MPO passes over the same region at different epochs.In this work, we present the results of our simulations of the MORE radio science experiment for the estimation of the libration amplitude of Mercury during the science phase of BepiColombo, using optical observables extracted from simulated images of Mercury.
Landscape evolution on early Mars: a look inside a martian fan system
Authors: Gupta Sanjeev , Stack Morgan Kathryn , Mangold Nicolas , Ives Elizabeth , Gwizd Samantha , Caravaca Gwénaël , Williams Rebecca , Barnes Robert , Randazzo Nicolas , Horgan Bryony , Siebach Kirsten , Tate Christian , Núñez Jorge , Sholes Steven , Kah Linda , Paar Gerhard , Maki Justin , Bell III Jim
Published: March 2024

The modern surface of Mars does not sustain liquid water, however relict landforms observed on orbital images provide strong evidence of past aqueous activity. Nevertheless on-the-ground analysis of sedimentary strata are required to robustly characterise the specific nature of early Mars palaeoenvironments. The Mars 2020 Perseverance rover is exploring a prominent sedimentary fan deposit at the western margin of Jezero crater – the Western fan – which has been interpreted to be an river delta that prograded into an ancient lake basin during the Late Noachian-Early Hesperian epochs on Mars (~3.6-3.8 Ga). Perseverance’s traverse across the fan in 2022-2023 provides a remarkable window into a fossilised sediment routing system on Mars with potential to understand how water and sediment were distributed across a Martian landscape under a markedly different climate to present day. Here we use the rover’s Mastcam-Z cameras to characterise sedimentary geometries in a distal to proximal transect across the western fan and reconstruct sediment dynamics on the Western fan and infer past environmental change. The distal reaches of the preserved fan show a sedimentary succession that records a transition from distal alluvial fan into lacustrine and subsequently foreset delta deposits. This succession records the initiation of a martian lake system and lake level rise, though the delta stratal geometries suggest deposition during episodes of lake level fall. In the medial sector of the upper exhumed portion of the fan, complex stratal geometries are observed with a variety of scenarios for palaeoenvironmental interactions possible. In particular, the presence of large-scale foreset units preserved in this ‘mid-fan’ sector possibly suggests complex deltaic interfingering with fluvial strata during lake level fluctuations. In more proximal and stratigraphically higher (and hence younger) sectors of the fan, we observe strata deposited by progradation of fluvial systems culminating in a sequence of rounded boulder-containing deposits that signal transition to a routing system characterised by high discharges. Misquoting Shakira “the sediments don’t lie”; they record a history of sustained water transport and habitability on early Mars.
Predicting seismic anisotropy in the upper mantle using supervised deep-learning
Authors: Tommasi Andrea , Cerpa Nestor , Carazo Fernando , Signorell Javier
Published: March 2024

Both elastic and viscoplastic behaviors of the Earth’s upper mantle are highly anisotropic, because olivine, which composes 60-80% of the mantle, has a strong intrinsic anisotropy and develops strong crystal preferred orientations (CPO). Predicting the evolution of anisotropy with strain is essential to: (1) probe indirectly the deformation in the mantle based on seismic measurements and (2) accounting for the deformation history when simulating the long-term dynamics of the Earth. However, traditional micro-mechanical approaches to model the evolution of CPO-induced elastic and viscous anisotropies are too memory-costly and time-consuming for coupling into geodynamical simulations. To speed up the prediction of seismic anisotropy in the mantle, we developed deep-learning (DL) surrogates trained on a synthetic database built with viscoplastic self-consistent simulations of texture evolution of olivine polycrystals in typical 2D geodynamical flows. A first challenge was the choice of memory-saving representations of the CPO. Training the DL models on the evolution of the elastic tensor components avoided the need of storing the CPOs. However, the major challenge has been to prevent error compounding in a recursive-prediction scheme – where a model prediction at a given time step becomes the input for the next one - to evaluate the anisotropy evolution along a flow line. We implemented multilayer feed-forward (FFNN), ensemble, and transformer neural networks, obtaining the best efficiency/accuracy ratio for the FFNN. The results highlight the importance of (1) the standardization of the outputs in the training stage to avoid overfitting in predictions, (2) the statistical characteristics of the strain histories in the training database, and (3) the influence of non-monotonic strain histories on error propagation. Predictions for complex unseen strain histories are accurate, much more time-efficient and memory-costly than the traditional micro-mechanical models. Our work opens thus new avenues for modeling the strain-controlled evolution of mechanical anisotropy in the Earth’s mantle. This work was supported by the European Research Council (ERC) under the European Union Horizon 2020 Research and Innovation programme [grant agreement No 882450 – ERC RhEoVOLUTION.
Large-scale atmospheric circulation changes in the northern Mediterranean realm during the Younger Dryas: new insights from Lago Grande di Monticchio (Italy)
Authors: Blanchet Cecile , Cormier Marc-André , Liang Zuobing , Zhao Xueru , Rik Tjallingii , Ramisch Arne , Wulf Sabine , Schwab Markus , Brauer Achim , Sachse Dirk
Published: March 2024

The Mediterranean region is recognized as a climate change hotspot, where temperatures increase faster than the global average. Modelling experiments suggest that such rapid and drastic changes will induce droughts and extreme rainfall events in this vulnerable region. Records of past climatic changes are useful to determine the speed and mode of regional responses and climatic sensitivities. We examine here the response of southern European hydroclimate to large-scale oceanic disturbances and rapid climatic changes during the Younger Dryas (YD) interval (e.g., 14-11 ka BP).We present new results from Lago Grande di Monticchio (Italy) that allow us to explore the dynamics of precipitation at high temporal resolution. By combining multiple tracers (hydrogen isotope ratios of leaf waxes, X-ray fluorescence scanning, microfacies analyses, tephrochronology), we were able to determine both rainfall dynamics and sedimentary and environmental responses. We identified a pronounced positive shift in hydrogen isotope ratios (expressed as δD values) during the YD cold period of ca. 20 ‰ between 12.6 and 11.5 ka BP. We interpret this to reflect to a decrease in the input of north Atlantic moisture (a significant contributor to annual rainfall at present) and lower overall precipitation amount. This coincides with an increase in the varve thickness and occurrence of organic-clastic microfacies. The presence of marker tephra layers in the record (esp. the Neapolitan Yellow Tuff and Pomici Principali) provides important temporal tie-points that enable us to compare local hydroclimatic responses across the wider region. In particular, the observed drying trend at Monticchio is in striking contrast to more humid conditions north of the Alps in western, central and eastern Europe, potentially reflecting the southward migration of synoptic climatic systems (westerlies) and the presence of sea-ice in the moisture source region.
Understanding Hydrological Model Performance through Variability Analysis of Observed Water Balance Components and Meteorological Forcings
Authors: Modiri Ehsan , Samaniego Luis , Schweppe Robert , Shrestha Pallav Kumar , Rakovec Oldrich , Kelbling Matthias , Kumar Rohini , Javier Leal Rojas Jeisson , Martínez-de La Torre Alberto , Robinson Emma L. , Chevuturi Amulya , Facer-Childs Katie , Blyth Eleanor , Sutanudjaja Edwin , Wanders Niko , Thober Stephan
Published: March 2024

Hydrological modelling forms a pivotal component in assessing water balance closure and providing valuable seasonal forecasts for essential climate variables such as soil moisture and streamflow. In the pursuit of enhancing forecasting capabilities, this study employs four land surface and hydrological models (HTESSEL, JULES, mHM, and PCR-GLOBWB) driven by four distinct meteorological forcings (ERA5LAND, EM-EARTH, MSWEP, and WE5E). The investigation spans the reference period from 1993 to 2019, focusing on a comprehensive evaluation of streamflow, latent heat, runoff flux, and terrestrial water storage as integral components of the water balance equation.The assessment begins by scrutinising the performance of observation datasets globally, aiming to discern areas of robust agreement and potential limitations. Subsequently, the simulations, generated by diverse meteorological forcings, are analysed to gauge the individual skill of each hydrological model and forcing combination.The study then delves into a variability analysis to determine the impact of forcings on hydrological model performance. Furthermore, exploring the elasticity of runoff and streamflow to changes in precipitation adds an additional layer to understanding system dynamics. This multi-faceted approach seeks to quantify the relative contributions of meteorological forcings and hydrological models, providing insights into the intricacies of their interactions and their collective influence on model performance.In conclusion, this research offers a  differentiated perspective on the global applicability and performance of these four hydrological models under four meteorological forcings. By systematically assessing the impacts of forcing variability and model structure, the study contributes valuable information for refining hydrological modelling practices and enhancing the accuracy of seasonal forecasts. Observational datasets are inconsistent in certain regions, where no single meteorological forcing stands out as the best performance. These areas are predominantly arid regions such as the Sahara, South Western Australia, and Eastern Brazil, in addition to mountainous regions like the Himalayas, where water balance closure poses a challenge.
Boron and strontium isotopic signature in rainwaters from Mt. Etna, Italy
Authors: Brugnone Filippo , Salvadori Matteo , Pennisi Maddalena , D'Alessandro Walter , Brusca Lorenzo , Parello Francesco , Calabrese Sergio
Published: March 2024

The isotopic compositions of boron (δ11B‰) and strontium (87Sr/86Sr) were measured, for the first time, in 10 rainwater samples from Mt. Etna, Italy. The samples were collected during the paroxysmal sequence of 2021-2022. The chemical composition was determined using an ICP-MS, while the isotopic ratios of B and Sr were measured using a mass spectrometer MC-ICP-MS (Neptune Plus™), after specific pre-concentration procedures in clean rooms (class 100 - 1000). In the analysed rainwater samples, the concentrations of B and Sr were between 4.6 µg L-1 and 42.2 µg L-1, and between 9.7 µg L-1 and 541 µg L-1, respectively. Overall, the isotopic composition of B ranging from +1.29‰ ± 0.30‰ to +42.9‰ ± 0.20‰, with a median value of +22.0‰ ± 0.19‰. The lowest δ11B‰ values were measured in the site closest to the main active craters (3.6 km), with a median value of +11.4‰ ± 0.21‰; the highest was measured in the site close to the Ionian Sea (Zafferana Etnea), with a median value of +38.1‰ ± 0.21‰. Strontium (87Sr/86Sr) ratios were between 0.703728 ± 0.000008 and 0.710363 ± 0.000006, with a median of 0.707328 ± 0.000007. The highest and the lowest 87Sr/86Sr ratios were measured in the sites most and less affected by the contribution of the volcanic emissions, with median values of 0.704339 ± 0.000007 and 0.709583 ± 0.000007, respectively. Although exists few data of isotopic ratios of boron and strontium on fluids in volcanic systems (δ11B‰ between -9.3 to 21.4‰), there are no studies on rainwater influenced by volcanic emissions. Nevertheless, the data available in the literature are sufficient to attribute Etna's volcanic source as the major contributor to B and Sr emissions in the atmospheres of this area. The rainwater chemistry of the Zafferana Etnea site was partly influenced by the volcanic source, but the measured isotopic ratios at this site showed a strong contribution from the marine source. The results provide the first comprehensive study of B and Sr isotopes in Mt. Etna rainwater. Two main sources of atmospheric emissions of B and Sr were recognised: sea-salt aerosols and volcanic gases. This research also adds to the potential for the use of B and Sr isotopes as volcanic emissions contribution tracers.