bluuebunny/crossref_metadata_2025 huggingface dataset:
ONFIRE Dataset: Harmonizing Decades of Wildland Fire Data
Authors: Gincheva Andrina ,   ONFIRE group
Published: March 2024

We present the ONFIRE Dataset (Gincheva et al., 2023), a gridded monthly burned area (BA) data product with national wildland data from several regions: Australia (since 1950), Canada (since 1959), Chile (since 1985), Europe (since 1980) and the United States (since 1984), covering up to the year 2021. This database is organised on a uniform 1° × 1° grid, providing a consistent spatial resolution for global analysis. Records from different sources and regions have been extracted and harmonised using open and reproducible methods. The data remapping and validation process ensures consistency and comparability between different regions. This dataset complements existing remotely sensed databases, offering users the opportunity to explore and analyse changes in fire regimes. The ONFIRE Dataset is accessible on Zenodo (https://zenodo.org/records/8289245; Gincheva  & Turco,  2023).ReferencesGincheva, A., Pausas, J. G., Edwards, A., Provenzale, A., Cerdà, A., Hanes, C., ... & Turco, M. (2023). A monthly gridded burned area database of national wildland fire data (ONFIRE).Gincheva, A., & Turco, M. (2023). ONFIRE dataset: Monthly Gridded Burned Area data (1.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.8289245AcknowledgementsA.G. thanks to the Ministerio de Ciencia, Innovación y Universidades of Spain for Ph.D. contract FPU19/06536. M.T. acknowledges funding by the Spanish Ministry of Science, Innovation, and Universities through the Ramón y Cajal Grant Reference RYC2019-027115-I and through the project ONFIRE, grant PID2021-123193OB-I00, funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”. S.J. acknowledges funding by the MCI/AEI Ramón y Cajal Grant Reference RYC2020-029993-I. M.B., A.P., and M.M. acknowledge the support of the European Union - NextGenerationEU in the framework of the National Biodiversity Future Center of Italy; A.P. and M.M. acknowledge the support of the EU project FireEUrisk, grant no. 101003890. M.E.G acknowledges research support provided by ANID/FONDECYT N° 1231573 and ANID/FONDAP 15110009; COD 1522A0001. R.L. was supported by FAPERJ (Grant E-26/200.329/2023) and CNPQ (Grant 311487/2021-1). M.M.B. acknowledges funding from the New South Wales Government (NSW Bushfire and Natural Hazards Research Centre) and the Australian Research Council (DP 220100795). F.M. and E.C. were supported by the European Space Agency FireCCI project. 
Phase-field modeling of texture evolution in magmatic rocks
Authors: Kundin Julia , Chakraborty Sumit
Published: March 2024

Texture formation in rocks is modeled using a quantitative phase-field model of eutectic growth with three thermodynamic phases (e.g. Diopside - Anorthite - Melt) in a quasi-binary magmatic system with unlimited quantity of crystals of different orientation and anisotropy. In nature, specific layering microstructures have been observed for which many possible explanations have been provided. Moreover, textural irregularities initially induced during nucleation, by fluctuation in crystal size or by other mechanisms continue to develop and sharpen over time. By phase-field modeling, we verify two models of igneous layering. The first mechanism is that, due to the formation of a layer with crystals of larger size, these crystals will grow faster at the expense of smaller crystals. The second mechanism is that a layer with an increasing fraction of the second phase is formed on top of the initial layer of the first phase to have crystallized. We have found that, in this case, without anisotropy of surface energies, no layering is produced. The boundary conditions and parameters of the models necessary for the formation of layers will be discussed.
The use of bioindicators to assess airborne microplastic deposition in remote peatlands of La Réunion
Authors: Margenart Henar , Hansson Sophia V. , Sonke Jeroen E. , Hagelskjaer Oskar , Yakovenko Nadiia , Ah-Peng Claudine , Beilman David W. , Clerc Philippe , Le Roux Gaël
Published: March 2024

Microplastic contamination spreads throughout all-natural environments, including the most remote. Although the microplastic cycle in nature is not fully understood, it is recognized that both terrestrial and marine environments contribute to microplastic emissions into the atmosphere. At the same time, atmospheric deposition is a significant source of distant microplastics to pristine environments. Still, our understanding of the origin, fate, and characteristics of airborne microplastics and the amount of these particles in natural compartments remains limited. Our study aims to quantify the atmospheric deposition of microplastics in remote locations of La Réunion island, a French overseas department situated in the Indian Ocean. La Réunion is one of the most affected regions by the beaching of (micro)plastics from the nearby garbage patch in the Indian Oceanic gyre. We hypothesize that the plastic-garbage patch of the Indian Oceanic gyre emits microplastics into the atmosphere that are transported to the terrestrial environments of La Réunion. Employing Raman spectroscopy, we have identified microplastics (>2 µm) deposited in bioindicators such as Sphagnum mosses and Usnea lichens. Sphagnum and Usnea were collected across seven sites selected according to different levels of human impact and atmospheric exposure. Our preliminary results indicate differences in microplastic concentrations in Sphagnum (5⋅106 -  1⋅107 MPs-1 dw) compared to Usnea (1⋅107 - 2⋅107 MPs g-1 dw), with polyethylene being the most abundant polymer in both bioindicators. The higher abundance of small microplastics (2-10 µm) suggests the ocean and long-range atmospheric transport are the main drivers of microplastic contamination to the remote areas of La Réunion. Our results will contribute to the comprehensive assessment of the global microplastic cycle by quantifying recent microplastic deposition in remote ombrotrophic peatlands.
A new fully erosive end-member to the strait depositional model: the importance of strong internal tides and shallow water settings, case of the Rion-Antirion Strait (Greece) 
Authors: Caterina Basile , Rubi Romain , Fakiris Elias , Christodolou Dimitris , Dimas Xenophon , Geraga Maria , Papatheodorou George , Ferrari Aurélia
Published: March 2024

Straits are crucial in terms of oceanic circulation between basins. Many modern straits are dominated by tidal currents that flow differently than in the connected basins. These tidal currents are shaping the seafloor into complex geometries, alongside sediment sources, tectonic activities and inherited lowstand features. The proposed common tidal strait depositional model comprises a strait centre zone in erosion bounded on both sides by depositional areas with 2D and 3D tidal dunes (known as dune-bedded strait zones). This model does not consider another type of hydrodynamic forcing that can be generated in strait, internal tidal waves. The aim of this study is to evidence the combined effect of tidal currents and internal tides on the morphosedimentary features of the strait seafloor.We focused here on the Rion-Antirion strait in Greece, connecting the Corinth Gulf with the Ionian Sea. Despite its location in the microtidal Mediterranean context, this 2 km wide and 70 m deep strait is strongly experiencing strong tidal currents. We utilized high-resolution multibeam bathymetry (MBES) covering a 21 km² area to reveal seafloor morphological structures. Swath bathymetric profiles were coupled with chirp sub-bottom and sparker reflection profiles imaging the internal sedimentary structures and with currents data from two ADCP campaigns. To comprehensively assess all the oceanographic parameters, we also incorporated satellite data and ROMS modelling. Consequently, we establish connections between oceanographic circulation, sea bottom dynamics within the strait and Gulf, and the observed sedimentary features.Typically, in tidal settings, sand deposition occurs when the tidal current velocity drops, usually before the currents change direction, and the existing strait tidal model shows sand dunes. The complex bathymetry features observed in the Rion tidal strait lack dunes but features erosional characteristics such as deep pools and crest morphology, with limited depositional features. In our settings, the numerical model demonstrates that the strait experience strong tidal currents alongside currents associated with the internal tide, which are predominantly out of phase, generating significant turbulences. As a result, there are no periods during which sand can settle. These factors underline the absence of deposition in this case and the need to revise the strait depositional model to incorporate this new end-member.
The role of paleogeography and CO2 on Eocene deep-sea temperatures: A model-proxy comparison study
Authors: Straume Eivind Olavson , Nummelin Aleksi , Taylor Victoria , Meckler Anna Nele , Zhang Zijian , Zhang Zhongshi
Published: March 2024

We present new analysis of climate model simulations for the Eocene (~56 – 34 Ma) and investigate the relative role of atmospheric pCO2 and changes in paleogeography on ocean circulation and deep-sea temperatures. The Early Eocene experienced warm greenhouse conditions, followed by cooling towards the Late Eocene, leading to the formation of land-based ice sheets near the Eocene–Oligocene Transition. The cooling was largely controlled by decreasing atmospheric pCO2 but was also likely influenced by changes in ocean circulation caused by paleogeographic changes, including the opening and closing of oceanic gateways. Changes in ocean circulation influence the distribution of heat in the surface ocean but also the storage of heat in the deep ocean and are crucial to account for in order to reproduce the Eocene climatology. Reconstructed deep-sea temperatures can thereby provide crucial benchmark constraints on ocean circulation simulated by climate models.In this study, we analyze a series of simulations using the Norwegian Earth System Model (NorESM-F), run with different paleogeographies, pCO2, and realistic oceanic gateway configurations. Our results show that changes in deep sea temperatures caused by CO2 perturbations are sensitive to oceanic gateway configurations and corresponding ocean circulation patterns. Specifically, reducing pCO2 in simulations where the paleogeography allow for an active AMOC yields less changes in mean deep-sea temperature than simulations without AMOC, which show significant mean deep-sea cooling. This is related to changes in ventilation and deep-water formation. The modelled changes vary on regional and basin scale, and we compare the model simulations to new clumped isotope temperature reconstructions from a variety of drill sites in the global ocean with the aim to understand the mechanisms causing the observed deep sea temperature changes.
Land-derived organic matter drives benthic carbon and nutrient cycling on the Siberian Arctic Ocean shelves
Authors: Wild Birgit , Sauerland Lewis , Ray Nicholas E. , Gangnus Ivan , Yakushev Evgeniy , Gustafsson Örjan , Dudarev Oleg , Semiletov Igor
Published: March 2024

The Arctic Ocean is currently changing at a high rate, and projections over the next decades include an increase in water temperature and retreat of sea ice, as well as increased input of freshwater and land-derived material released by permafrost thaw. These changes might substantially alter marine biogeochemical cycles and primary production, with repercussions for the Arctic Ocean greenhouse gas balance as well as ocean acidification. The large and shallow continental shelf seas north of Siberia are particularly affected by these changes as they receive land-derived material from strong coastal erosion and large rivers such as Ob, Yenisey and Lena. In recent studies, we have shown a transition from predominantly land- to marine-derived organic matter in sediments from the coast to the shelf break based on isotopes and biomarkers, an increased decomposition state of land-derived organic matter, as well as a decrease in sediment and water column nitrogen concentrations. We here combine this understanding with incubation experiments to assess the impact of these gradients on benthic CO2 production and nutrient remineralization. We found that fresh, land-derived organic matter typical for near-shore environments showed highest decomposability to CO2 in controlled, aerobic laboratory incubations, as indicated by correlations of CO2 production with concentrations of terrigenous biomarkers (lignin, high molecular weight n-alkanes), and biomarker proxies indicating the decomposition state of these compounds. Fresh, land-derived organic matter was also associated with highest ammonium and nitrite release to the water column, measured during on-board incubation of intact sediment cores. The opposite pattern was observed for phosphate and silicate fluxes that were highest in more marine-influenced settings. Our data suggest that increased input of land-derived organic matter to the Siberian Arctic Ocean shelves could promote benthic decomposition processes near the coast, including CO2 release that might contribute to the strong ocean acidification already observed in the region. Furthermore, the different controls on nutrient fluxes indicate a de-coupling of nitrogen, phosphorus and silicon remineralization, with implications for nutrient limitation and primary production in the Arctic Ocean.
Assessing the Impact of Surface Energy Inputs on Radiative Feedbacks in Tropical and Extra-tropical Regions: Strength, Evolution, and Timescales
Authors: Salvi Pietro , Gregory Jonathan , Ceppi Paulo
Published: March 2024

In recent years, radiative feedbacks in the earth system have been strongly tied to the spatial pattern of sea surface temperatures (SSTs). This “pattern effect” has been strongly tied to the strength of cloud radiative feedbacks driven by atmospheric stability changes. SST patch Green’s functions experiments have revealed that the ratio of warming in deep convective tropical regions, versus outside, drives significant changes in atmospheric stability. These Green’s functions can be used to reconstruct feedbacks from given warming patterns. However, it remains unclear how different warming patterns arise. Different Green’s functions, prescribing surface heat fluxes in atmosphere-ocean coupled models instead of temperature changes in fixed SST experiments, may answer this question by showing how energy inputs translate into temperature changes.Using a simplistic set of patches of applied surface heat fluxes in CESM2-CAM6 and HadCM3, we find that heat input into the tropics results in strongly negative radiative feedbacks from enhanced warm pool warming. This results in a small climate sensitivity to this tropical forcing. Conversely, heat fluxes input into the extratropics cause significantly less negative feedbacks that result in greater climate sensitivity to extratropical forcing.Furthermore, the response to tropical forcing occurs rapidly, with equilibrium roughly achieved within a few years both in slab ocean and fully coupled models. The response to extratropical forcing, by contrast, induces near-zero feedbacks in the first few years, followed by significantly weaker negative feedbacks than seen under tropical forcing, which leave this simulation far from equilibrium after 150 years in the fully coupled model.These outcomes of forcing, from within the tropics and outside, can be combined to explain the early changes in feedbacks in response to global uniform forcing, or near-uniform global forcings such as from CO2. Reconstruction of the uniform case by summing the tropical and extra-tropical cases gives a good fit, except for an apparent temperature dependence in CESM2, and shows that extra-tropical component of surface forcing is driving the long-term feedbacks in the uniform forcing scenario.Understanding the process of how the pattern of forcing results in different temperature change patterns may be key to comprehending future temperature changes, given that the pattern of future forcing evolves with the changing mix of anthropogenic forcing agents. Furthermore, exploring how models vary in their conversion of forcing into temperature change, even within the simple experimental design of this study, may highlight significant model feedback differences and contribute to narrowing the range in model predictions of future warming.
Pluvial Flooding Risk Mitigation: a machine learning approach for optimal management of an urban drainage system
Authors: Lanciotti Sabrina , Alfonso Leonardo , Ridolfi Elena , Russo Fabio , Napolitano Francesco
Published: March 2024

According to the Intergovernmental Panel on Climate Change (IPCC), the variability of extreme rainfall events is increasing in many locations. The continuous expansion of urban areas makes urban flooding more common, thus increasing the need for improved management of drainage systems in large cities. Urban pluvial flooding (UPF) occurs when surface runoff cannot be efficiently conveyed into the drainage system, due to intense rainfall events exceeding the capacity of stormwater drainage systems, or due to inlets' poor maintenance which are often either partially or fully blocked. Many drainage systems may not be efficient due to outdated design approaches that do not consider these aspects. Therefore, there is a need to improve the design of structures and to prioritize risk adaptation and mitigation strategies to build resilient cities against the effects of pluvial flooding. During extreme rainfall events generating pluvial flooding, discharges exceeding the sewer system capacity are diverted by sewer overflows. For this reason, the objective of this work consists of defining a methodology to determine the optimal management strategy to mitigate sewer overflows using machine learning techniques. Here we simulate pluvial flooding within a large urban area by using the freely available Storm Water Management Model EPA-SWMM, based on a detailed reproduction of the geometric characteristics of a branch of the drainage network in a large city. By simulating the different propagation effects of synthetic hyetographs in the pipelines and artefacts, the dynamic operating conditions of the actual network are performed using machine learning techniques, by applying Python to the SWMM data model (PySWMM). The project, which is ongoing, thus aims at the optimal management of the combined overflow devices of a sewer system through their real time control during a flood event to mitigate pluvial flooding risk in urban areas.
Continuous monitoring of dust impacts across the inner heliosphere by the Solar Orbiter RPW/TDS Maximum Amplitudes
Authors: Píša David , Souček Jan , Kočiščák Samuel , Kvammen Andreas , Vaverka Jakub , Formánek Tomáš , Santolík Ondřej , Morooka Michiko , Maksimovic Milan , Zaslavsky Arnaud
Published: March 2024

Hypervelocity (>1 km/s) dust grains orbiting in the inner heliosphere can collide with a spacecraft and create a plasma cloud that changes electrical conditions in the surrounding plasma. These changes can be detected by the onboard radio and plasma wave receivers acting as efficient dust impact detectors. Estimated dust impact rates depend on the observation time window and they are commonly extrapolated. Our study presents the RPW/TDS Maximum Amplitudes (MAMP) data that continuously monitors signals from up to four RPW antenna configurations (monopole or dipole, and HF Search Coil) onboard the Solar Orbiter satellite. The signal is sampled in the high cadence (2.091 Msps) and stored in a buffer as the absolute maximum amplitude. MAMP values are then provided with a cadence between 32 and 128 sps, giving us a time resolution between 8 and 31 ms. Individual dust impacts detected by the onboard algorithm evaluating 62ms-long waveform snapshots every second are compared with the MAMP observations and show a very good match. After corrections for the high amplitude plasma waves or non-standard operational modes, and together with the TDS Statistics, the MAMP observations are used for the individual dust impact identification and corrected impact rates during the entire Solar Orbiter mission.
Simulated influence of ice-shelf calving on the evolution of a potential West Antarctic Ice Sheet instability
Authors: Feldmann Johannes , Reese Ronja , Winkelmann Ricarda
Published: March 2024

The observed rapid thinning, speed-up and retreat of the ice in West Antarctica’s Amundsen Sea Embayment might indicate an early stage of a marine ice sheet instability (MISI), potentially leading to the disintegration of the West Antarctic Ice Sheet (WAIS). In general, the stability of a marine ice sheet is strongly linked to the dynamics of its buttressing ice shelves which act as a regulator of the ice discharge into the ocean. Existing numerical modeling studies usually simulated MISI-type WAIS retreat either under prescribed fixed present-day calving front positions (associated with very strong ice-shelf buttressing) or in the absence of ice shelves (neglecting ice-shelf buttressing). These approaches represent extreme cases of realizing ice-shelf buttressing in simulations of a WAIS retreat and comparison between the study results are difficult due to the use of different numerical models and experimental designs. Here we aim to investigate the influence of time-evolving calving fronts and associated buttressing changes in the course of an unfolding WAIS disintegration, based on simulations with the Parallel Ice Sheet Model (PISM). One focus will be on how ice-shelf calving affects MISI retreat rates and the extent of a potential WAIS collapse, i.e., the time evolution and magnitude of the associated sea-level contribution.
Sensitivity of coda correlation wavefields to spatio-temporal variations of microseism noise sources
Authors: Safarkhani Mahsa , Schippkus Sven , Hadziioannou Céline
Published: March 2024

Previous research suggests that continuous seismic noise records can effectively extract information about the properties of the Earth's subsurface. The coda of the correlation wavefield between station pairs shows sensitivity to crustal heterogeneity and has been described as a multiple scattering signal. These signals allow to monitor variations in dv/v to detect weak changes in the medium at depth. Oceanic regions, which are highly effective in generating microseisms, play a crucial role in the distribution of seismic energy sources. In Green's function estimates from cross correlations, highly asymmetric correlation wavefields are common due to non-homogeneous source distributions.This study focuses on the impact of oceanic noise sources on the coda of the correlation wavefield between station pairs. We utilized ambient seismic noise interferometry to retrieve the correlation wavefields between some master stations throughout Europe and the Gräfenberg array located in Germany, in the microseism frequency range. We then applied cross-correlation beamforming to these correlation wavefields. This identifies the source direction for correlation wavefields over a three-year period, allowing us to compare variations in source direction and seasonality with results from raw data beamforming. We find dominant source directions towards the north-northwest of Gräfenberg in winter (with slowness expected for surface waves) and towards the south in summer (with slowness expected for body waves) in the raw data and throughout the coda of the correlation wavefields up to lapse times of one hour. This is in contrast to the diffuse wavefield expected from classical seismic interferometry and demonstrates that higher-order correlations, which are computed during the correlation beamforming of correlation functions, do not improve the degree of scattering in the correlation wavefield coda when persistent, isolated noise sources are present. Additionally, the findings demonstrate notable correlation between the seasonal incidence of microseisms and the very late coda of the correlation wavefields, raising questions about the current understanding of the correlation wavefield coda.
Appraising and reducing riverine flood risk: a case study from Central Italy
Authors: Dottori Francesco , Darienzo Matteo , Fagugli Giacomo , Gabellani Simone , Ghizzoni Tatiana , Ottonelli Daria , Pignone Flavio , Trasforini Eva
Published: March 2024

On 15 September 2022 a catastrophic flood event hit the Misa river basin in Central Italy. The magnitude of the event (intensity of precipitation, water discharge, debris and sediment transport) and the subsequent impacts were far more severe and extended than previous flood events in the same area, thus calling for a radical change in current practices of flood risk management. In this framework, the present study aims at 1) providing a comprehensive assessment of flood risk for the Misa river basin, and 2) designing appropriate risk reduction measures at river basin scale. We reconstructed the September 2022 event by integrating in-field surveys, hydrological data, hydraulic models, observations of the event (e.g. flood extent maps) and historical data of past flood events, taking into account the incompleteness and uncertainty of both models and observations. Moreover, we modelled exposure and vulnerability of population and economic activities in the area, using detailed surveys of observed impacts to inform the model set-up. The outcomes of these activities allowed to review the risk analysis tools currently available in the Misa river basin, and to design updated risk scenarios for present and future climate conditions. Finally, the risk scenarios have been used to explore different alternatives for flood risk reduction, in agreement with local authorities and stakeholders. We evaluated a range of structural measures (strengthening of dike systems, detention areas, river diversions) and non-structural measures (land-use planning, relocation, flood-proofing measures), considering existing risk management plans and new analyses carried out in this study (e.g. cost effectiveness of measures).
Estimating bottomside ionosphere electron content using navigation augmentation observations from two CENTISPACETM LEO satellites
Authors: He Rong , Li Min , Li Wenwen , Zhang Qiang
Published: March 2024

The upcoming low earth orbit (LEO) constellations can bring new opportunities for ionospheric sounding below the LEO satellite altitude. The CENTISPACETM LEO satellites working with an altitude of 700 km broadcasting navigation augmentation signals to the ground stations. This study established a regional bottomside ionospheric map (RBIM) using navigation augmentation signals from two CENTISPACETM satellites on April 1, 2023, under moderate solar activity and quiet geomagnetic conditions. The RBIM accuracy was subsequently validated through comparison with multiple datasets, including Global and Regional Ionospheric Maps (GIMs and RIMs) constructed from ground-based GNSS observations, as well as the differential Slant Bottomside Electron Content (dSBEC) derived from LEO observations. To build the RBIM, the vertical bottomside electron content (VBEC) is fitted by two distinct methods, which are grid map and polynomial methods. The root mean square (RMS) values of the RBIM fitting residuals are 1.2 TECU and 0.7 TECU for the two methods, respectively. The RBIM precision evaluated by LEO dSBEC is better than 1.0 TECU. Comparing the VBEC from established RBIM to the GIM/RIM indicates that the RMS values mostly within 3-8 TECU, which can attribute to the limited modelling precision of the latter two models. What’s more, the RBIM facilitates the probe of the proportional variation of the VBEC over the total electron content using experimental data. The results derived from LEO observations indicate that the VBEC proportion is 83% at noon and 53% at night in the north mid-latitude region, presenting a reduction of 35.36%, which is more realistic than that calculated values from the empirical International Reference Ionosphere (IRI-2020) model (4.65%). Thus, the RBIM can not only benefit LEO navigation augmentation but also provide significant observations on the vertical distribution of ionospheric electron content.
Divergent temporal shifts in climate sensitivity of Norway spruce along an elevational and continentality gradient in the Carpathians
Authors: Popa Andrei , Jevšenak Jernej , Popa Ionel , Badea Ovidiu , Buras Allan
Published: March 2024

Climate change is affecting forest ecosystems all around the globe, through warming as well as increased drought frequency and intensity. Across much of Europe, climate change has caused a major dieback of Norway spruce (Picea abies L.), an economically important tree species. However, the southeasternmost fringe of this tree species – the Eastern Carpathians – has not yet suffered large-scale dieback. In recent decades, temporal shifts of climate sensitivity (TSCS) have been observed on a global scale. Thus, studying TSCS over time may elucidate the degree to which Norway spruce may be vulnerable to climate-change induced decline in upcoming decades.Under this framework, we analyzed a regional tree-ring network comprising more than 3,000 trees, with the aim of quantifying TSCS since 1950. We mathematically defined TSCS as the slope parameter of the regression of climate sensitivity (the correlation coefficient) over time. Given the often-observed contrasting shift of climate sensitivity at low versus high elevations, we were particularly interested in studying potentially divergent TSCS along elevational and spatial gradients. Our results revealed several indications of TSCS for Norway spruce in the Eastern Carpathians. First, at high elevations (>1,100 m a.s.l.), we found that the positive link between summer temperature and spruce growth decreased significantly over the study period. In turn, these trees, over time, featured an increasing positive relationship with late winter temperatures. At low elevations (
Intermittent supply of North Adriatic Dense Water to the deep South Adriatic Pit  through gravity currents: an observational study
Authors: Le Meur Julien , Wirth Achim , Paladini de Mendoza Francesco , Miserocchi Stefano , Cardin Vanessa
Published: March 2024

Severe winters in the northern Adriatic potentially generate gravity currents flowing along the eastern flank of the Adriatic, filling and ventilating the deepest layer of the southern Adriatic Pit with high-density water. The pulses of gravity current observed by data at the moorings in the Canyon of Bari (BB site) and the shelf-slope observation site (FF) are followed by strong fluctuations in the thermohaline properties in the pit observed at the E2M3A site in 2012, 2017, 2018 and 2022. While temperature was the main driver of gravity flow in 2012, salinity played an equal or greater role in the following extreme gravity current events. Thermohaline data from these three moorings show an arrival from mid-February to June and the relaxation phase of the high frequency oscillations (few tens of hours) lasts about two months. During this phase, the gravity current water displaces and mixes with the surrounding water masses. The gravity currents lead to a restratification of the water column, while local convection processes in winter time erode the stratification.The effects of gravity currents in the southern Adriatic have a profound impact on the Eastern Mediterranean circulation, influencing its thermohaline properties and facilitating the ventilation of deep waters. The Adriatic dense water formation adds to and competes with the convection in the Gulf of Lion, forming the dense waters in the Mediterranean which outflow through the Strait of Gibraltar into the northern Atlantic.The European Multidisciplinary Seafloor and water column Observatory (EMSO) South Adriatic Regional Facility (E2M3A in the pit, BB and FF at the edge of the pit) has been providing hourly data on temperature, salinity, oxygen and currents along the water column for about 15 years. This makes it possible to study these high-frequency small-scale processes and their interaction with the surroundings over an extended period of time and to assess their role in a changing climate.
Role of infiltration on land–atmosphere feedbacks in Central Europe: WRF-Hydro simulations evaluated with cosmic-ray neutron soil moisture
Authors: Arnault Joel , Fersch Benjamin , Schrön Martin , Bogena Heye Reemt , Hendricks-Franssen Harrie-Jan , Kunstmann Harald
Published: March 2024

The skill of climate models partly relies on their ability to represent land–atmosphere feedbacks in a realistic manner, through the coupling with a land surface model. However, these models often suffer from insufficient or erroneous information on soil hydraulic parameters. In this study, the land–atmosphere model WRF-Hydro driven with ERA5 reanalysis is employed to reproduce the regional climate over Central Europe with a horizontal resolution of 4 km, for the period 2017-2020 during which cosmic-ray neutron sensor (CRNS) soil moisture is available at three Terrestrial Environmental Observatories. The soil hydraulic parameter datasets referred to as SoilGrids and EU-SoilHydroGrids, together with Campbell and van Genuchten–Mualem retention curve equations, are used to assess the role of infiltration on modeled land–atmosphere feedbacks. After calibration of the percolation parameter to better capture observed discharge amounts in the observatories, it is found that WRF-Hydro with Campbell and SoilGrids gives the lowest mean temperature and mean precipitation differences compared to the E-OBS product from European Climate Assessment & Dataset, by reducing soil moisture in the rootzone, increasing temperature, and decreasing precipitation through a positive soil moisture–precipitation feedback process. WRF-Hydro with van Genuchten–Mualem and EU-SoilHydroGrids best reproduces CRNS soil moisture daily variations, despite enhanced positive biases that generate a larger proportion of convective precipitation favored over wet soils and spurious discharge peaks. The question remains open whether an infiltration modeling option that better captures CRNS soil moisture dynamics can also lead to a clear improvement of the simulated climate.
Global loss in global hydropower supply under droughts using a hybrid model
Authors: Shah Jignesh , Hu Jing , Edelenbosch Oreane , van Vliet Michelle
Published: March 2024

Hydropower is considered as an important source of renewable energy due to its flexibility and storage capabilities. However, hydropower faces significant challenges with climate change and especially the increasing risks of extreme weather events such as droughts.In this study, we analysed the impact of historical droughts on hydropower at a global scale by developing a hybrid model that combines a physically based hydropower model with a machine learning model. This integrated approach enables us to capture important features affecting hydropower generation beyond water availability, considering the details of local specific conditions at hydropower plant sites while it can be applied across the globe. A new open-source global dataset is developed that contains key information of the hydropower plant characteristics and their reservoir attributes by merging various plant sources with a global reservoir database. The hybrid model is trained against observed monthly hydropower generation data at the power plant level. By employing this approach, we aim not only to enhance the realism of simulating hydropower output compared to the simplistic physically based equation but also to leverage the flexibility of machine learning. Additionally, this method enables us to circumvent detailed power system modelling which requires significant computing power and extensive data.We found that the performance of our hybrid hydropower model surpasses the simple physics-based hydropower equation at most hydropower plant sites. Key findings highlight the significant losses of hydropower generation during major historical drought events across the globe.
Evidence of boiling in ore-forming process based on quartz textures and fluid inclusions studies, a case study in Mamouniyeh Cu deposit, Iran
Authors: Goudarzi Mohammad , Zamanian Hassan , Klötzli Urs , Ullah Matee
Published: March 2024

Boiling is one of the common processes that lead to the formation and enrichment of precious metal deposits. The investigation of the spatial relations between fluid boiling and deposition of precious metals is a valuable tool in exploration of epithermal deposits. Fluid boiling, isothermal mixing and surface dilution of fluids processes are important factors for the instability of chloride and sulphide complexes, which lead to the simultaneous deposition of Fe-Cu and then deposition of sulphide phases in the final stages of mineralization which are caused by a sudden decrease in pressure in the fractures. To investigate evidence of boiling and its role in mineralization we have studied fluid inclusions and quartz textures in the Mamouniyeh Cu deposite in the middle part of Urumieh-Dokhtar magmatic arc in Iran. Evidence for fluid boiling, such as different liquid-vapor ratios of fluid inclusions, the coexistence of fluid inclusions with different salinities and co-existing liquid single-phase fluid inclusions with vapor single-phase fluid inclusions and breccia, crustiform and colloform textures of quartz indicate that boiling process occurred during the formation and growth of minerals. The study of 138 fluid inclusions in ore-bearing silica veins shows the similar density values from 0.8 to 1 g/cm3 for quartz with pyrite + chalcopyrite, chalcopyrite and chalcopyrite + specularite ± pyrite ± chalcocite mineralization systems. Adjacency of multiphase fluids with vapor-rich fluid inclusions indicates that fluids are trapped at the boiling point, that is, in the state where the vapor is in equilibrium with the liquid. As a result of this boiling part of the Cu in the fluids was deposited as chalcopyrite. Evidence shows this process probably occurred at a depth of about 700 meters below the water table and lithostatic pressure of about 16 MPa. In the case study area, boiling, mixing of magmatic fluids with meteoric fluids and cooling process by oxide and sulphide complexes, that this mixing process has reduced the temperature and salinity in the system and caused oxide-sulphide mineralization include chalcopyrite, pyrite, bornite, specularite, and secondary ore minerals include chalcocite, covellite, azurite, malachite, chrysocolla, goethite, and limonite which related to granodiorite, monzonite and gabbro-diorite intrusive rocks.
Mapping Mediterranean temporary ponds in SW Portugal using remote sensing
Authors: Gennari Ginevra , Neves Maria C , Monteiro Jose P
Published: March 2024

Mediterranean temporary ponds on the Southwest Portuguese coast are areas of significant biodiversity and are recognized as priority habitats by the Habitat Directive (92/43/EEC). The fauna and flora species that inhabit these ponds are well adapted to the variability of the Mediterranean climate, exhibiting a high resistance to drought and the ability to survive without water for months. Among them, the Triops vicentinus species stands out for its uniqueness, considered a living fossil that has persisted since the time of the dinosaurs.These temporary ponds are situated in shallow depressions where rainwater accumulates for seasonal periods. They face increasing threats due to anthropogenic pressures, primarily arising from intensive farming techniques, real estate development linked to tourism, and a general lack of awareness among the population regarding the significant biological and ecological value of this habitat. The area was the focus of the LIFE + project titled 'Conservation of Temporary Ponds in the Southwest Portuguese Coast of Portugal' conducted between 2013 and 2018. During this initiative, georeferenced mapping of the ponds and associated biodiversity was produced. However, the geographical evolution of these ponds has not been monitored since then.This study aims to map the ponds and track their evolution between 2018 and the present. To map the water bodies, we use Sentinel-1 and 2 datasets along with the Sentinel application platform SNAP. The surface water extraction method relies on the Normalized Difference Water Index and a supervised classification algorithm. The applied methodology has proven to be efficient in detecting and interpreting the dynamics of water bodies. The results of this investigation enhance our understanding of the uncertainties associated with the applications of Sentinel-2 and Sentinel-1 for monitoring temporary ponds and contribute to our knowledge of the current status of this habitat.This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) –UIDB/50019/2020 (https://doi.org/10.54499/UIDB/50019/2020),UIDP/50019/2020 (https://doi.org/10.54499/UIDP/50019/2020) andLA/P/0068/2020(https://doi.org/10.54499/LA/P/0068/2020). 
Regional scale debris flow susceptibility mapping in Barla Mountains (NW Taurus), Türkiye
Authors: Karabacak Furkan , Görüm Tolga
Published: March 2024

As in many high mountainous regions of the world, Türkiye is also a country heavily affected by landslides. Considering that Turkey has the highest number of landslide-related deaths in Europe (14 per year), debris flows also have a devastating impact on the southern part of the country. On July 13, 1995, a debris flow killed 74 people and destroyed 180 houses in Senirkent District in Barla Mountain. Barla Mountain, where physical weathering is predominantly effective on widespread limestone, exhibits mainly arid/semi-arid climatic conditions. After the 1995 event, check dams were built within the scope of debris flow prevention. This study aims to perform susceptibility analyses of debris flow hazard using a spatially distributed empirical model (Flow-r) on the northern slopes of the Barla Mountain Belt.All sub-catchments along the Barla Mountain Belt where the model was applied were afforested to mitigate debris flows. The Flow-r model consists of two stages: identifying potential source areas and calculating areas that could be affected by debris flows using flow direction algorithms. Potential debris flow source points and a digital elevation model with a spatial resolution of 5 m were used as model inputs. Model results were calibrated in each basin through reports of previous debris flow events (for Senirkent), aerial photographs, and field observations. Regarding the study's results, 7°-15 m/s model output was determined as the worst-case scenario, and 6°-17 m/s model output was determined as the extreme scenario. Through the field observations, physical weathering and debris production continued at elevations higher than the timberline depending on lithology and climate, and we observed that the check dams were filled with debris. According to the validation results of the Flow-R model we performed at this site, the accuracy, precision, and positive predictive power are 87.78%, 46.45%, and 23.03%, respectively. As a result of the study, considering the complex structure of debris flows, regional-scale debris flow susceptibility maps were produced with minimum data requirements and short computation times, and a primary source was provided in pre-disaster risk management studies. In the Barla Mountain, our findings identified differential weathering variations of limestone lithologies attributes and substantial debris generation as factors contributing to areas with a discriminating likelihood of debris flows under worst-case scenarios. Furthermore, the results of the model supported by the field observations revealed that the check dams in the region have lost their functionality. Moreover, on hillslopes subjected to afforestation, our findings indicated that the model's predicted spread areas did not align with historical debris flow occurrences.
Simultaneous immobilization of several heavy metals in naturally contaminated soils using waste and recycled materials
Authors: Saito Takeshi , Kawabe Yoshishige , Watanabe Naoki
Published: March 2024

The water leachable amounts of heavy metals including arsenic (As), lead (Pb), and cadmium (Cd) can be found in relatively higher concentrations in surplus soils from construction activities. There is a potential risk to human health and negative impacts on the soil and water environment. One of the cost-effective and efficient strategies for remediation techniques is the immobilization of heavy metals based on natural and artificial materials. The objective of this study is therefore to use five waste and recycled materials such as fly ash and recycled concrete. It tries to achieve simultaneous immobilization of several heavy metals in naturally contaminated soils. Two representative natural soils containing relatively higher concentrations of water leachable As, Pb, and Cd were selected and tested for a simple batch immobilization experiment in the laboratory. The weight percent of each waste and recycled material added to each soil was 2.5%, 5%, and 10%. After 24 hours of curing at 20oC, 10 times the volume of ultrapure water was added and shaken for 6 hours. The supernatants were filtered through a 0.45 µm filter and the concentrations of heavy metals were measured by ICP-MS. Generally, the immobilization rate of As, Pb, and Cd increased with increasing additive weight of waste and recycled materials. Recycled concrete especially demonstrated simultaneous immobilization of these heavy metals above with its addition of 2.5% to 5%, suggesting a better immobilization performance compared to other waste and recycled materials.
Effects of wildfires on water quantity and quality in southern Chile
Authors: Stehr Alejandra , Vyhmeister Nicole , Saenger Vicente , Villegas Pablo , Duarte Efrain
Published: March 2024

Wildfires are a global and catastrophic phenomenon, generating major impacts on soil characteristics, erosion, water flow and water quality at the watershed scale, among others. Such effects depend on the severity of the fire, a metric that depends on the intensity of the fire and the nature of the vegetation that is burning. During the last 60 years the average annual area burned in Chile due to wildfires has been approximately 65,000 hectares per year. This figure has been greatly surpassed in the last 5 years, averaging approximately 155,000 hectares per year. Although worldwide, especially in the United States and Europe, there is evidence of impacts on the quantity and quality of water from wildfires, this is not the case in Chile. Given the above, the objective of this work is to analyze the effects on water quantity and quality in burned and unburned watersheds in the Andes and Coastal Cordillera in southern Chile. Two native forest basins and two exotic plantation basins were studied, one burned and one unburned in each class. The native forest basins correspond to the Allipén River and Quepe River basins, located in the Andes Mountain range, while the exotic plantation basins are found in the Carampangue River basin, located in the Coastal Mountain range. The results indicate differences in nutrients (phosphorus and nitrogen) present in the water between burned and unburned watersheds during the rainy season.