bluuebunny/crossref_metadata_2025 huggingface dataset:
Exposure to pollutants Risk model in the Aburrá Valley (Expor2)
Authors: Solórzano-Araque Valeria , Carmona-Estrada Sebastián , Osorio Pablo A , Isaza-Cadavid Santiago , Cruz-Ruiz Lisseth , Quintero Olga Lucía , Pinel Nicolás , Lopez-Restrepo Santiago
Published: March 2024

The study presents a framework for a human exposure model to pollution based on Chemical Transport Models (CTMs) for the urban area of Medellín in Colombia, including the metropolitan area in which is situated in the the city. The exposure model utilises pollutant concentration simulations obtained from the LOTOS-EUROS CTM drived by the WRF Numerical Weather Model (NWM) simulations conducted in January 2019 within the Aburrá Valley. The simulations provide spatial and temporal resolutions of 1 km x 1 km and 1 hour, correspondingly. This study applies the data from the 2017 Origin Destination Survey, which surveyed 16,340 households and 36,364 individuals living in urban and rural areas of the 10 municipalities of the Aburrá Valley. This data on demographic variables and weekday travel patterns helped to analyse human behaviour and intra-urban migration in order to develop a precise measure of daily pollution exposure for different geographic zones. The total mean exposure is calculated from the linear combination of  the exposure time and the mean concentration in every zone.The study examined the morphological composition of fine particulate matter PM2.5 and PM10, resulting in the identification of six distinct groups, including mineral, organic/biogenic, tire wear, metallic, paint with high titanium content, and salts. Cytogenotoxicity tests assess the survival rates of cells in eye, skin and lung tissues. The resulting data is extrapolated to determine an irrigation factor specific to the urban area. It is worth highlighting that the central and southern regions of the Aburrá Valley, designated by high population density and multiple sources of pollution, exhibit heightened pollution exposure. On the other hand, the assessment of high-risk regions in the central zone is influenced by the lack of information in other parts of the urban area.
Kinematic Insights from Optical Feature Tracking on Rock Glaciers in the Kazakh Tien Shan: Understanding Sub-Landform Scale Patterns of Rock Glacier Flow
Authors: Wood Ella , Bolch Tobias , Streeter Richard , Schrott Lothar , Bates Richard
Published: March 2024

Rock glaciers exhibit complex and heterogenous dynamics, which are expressed in their pattern of surface flow; these surface kinematics provide insights into the processes taking place within the rock glacier system. Remote sensing methods using optical and radar imagery to detect movement are well established and have been widely applied at different spatial and temporal scales. However, the sub-landform scale is often overlooked despite considerable flow heterogeneity observed within individual rock glaciers. Feature tracking methods are suited to investigating kinematic detail as they are able to measure vector direction as well as magnitude, allowing them to identify complex and non-linear patterns of flow. This compliments widely used SAR interferometric methods which accurately detect slow displacements but don’t account for flow direction.Here we show how optical imagery can be used to investigate rock glacier kinematics at the sub-landform scale. The study focuses on 18 rock glaciers in the Kazakh Tien Shan. This region hosts numerous large, complex rock glacier landforms, many of which are part of larger systems composed of small, retreating normal glaciers, moraines and downwasting debris zones. These rock glaciers are an important and interconnected component of the deglaciating environment and are likely to be hydrologically significant stores of ice in the Tien Shan region.Rock glacier velocities have been measured using an intensity based cross correlation algorithm implemented in Python, with adaptable pre and post processing steps that enable the best results to be achieved on different types of optical imagery. The results from Pleiades, Planet and Sentinel image pairs taken from 2016 onwards are compared to investigate how source image resolution and sensor type impact the spatial patterns detected. High resolution Pleiades imagery provides the most detailed results, however, lower resolution Sentinel and Planet imagery is also able to detect sub-landform scale variations in flow. Over a 7-year time interval Sentinel imagery identifies flow velocities comparable to those derived from high-resolution imagery across the 18 rock glaciers investigated. Planet imagery performed the worst of the three data sources, highlighting the importance of image quality as well as resolution for intensity-based image matching methods. There is considerable variability in the mean, maximum and range of velocities detected between the landforms investigated. Rock glacier flow is heterogenous at both intra and inter landform scales, this is related to local topography but is also likely to be dependent on rock glacier internal structure and the distribution of material input. 
How should we measure clay?
Authors: Ghosh Urmi , Afriyie Ernest , Abd Elmola Ahmed , Hillier Stephen , Robertson Jean , Baggaley Nikki
Published: March 2024

There is an international commitment to monitor soil, as reflected in the new EU soil monitoring law on 5th July 2023.  However, direct measurements of soil properties, such as water retention, cation exchange capacity, adsorption isotherms etc. are expensive and time-consuming. Pedotransfer functions (PTFs) utilize soil properties that are easy to measure and inexpensive as predictors of these critical soil parameters. Clay content plays a crucial role in the estimation of many PTFs.  However, it is often universally estimated by particle size, which fails to capture the diversity of clay mineral types which exhibit markedly different and diverse effects on the physico-chemical behaviors of soils1, 2.  Non-clay minerals often constitute a significant portion of the clay size fractions. Furthermore, clay minerals may not disperse and instead remain in larger size fractions, further complicating the understanding of the effects of clay. The crucial question arising is: “How should we quantify clay content”? We have devised a predictive modelling framework that combines soil spectroscopy analysis, which is more widely available in soil databases worldwide, with X-ray Powder Diffraction (XRPD). This approach serves as a method for predicting the clay 'mineral' content, providing a  much more useful predictor of soil properties. The 703 soil samples from the National Soil Inventory of Scotland 2007-2009 (NSIS2)3 with both high-quality XRPD and IR spectral data are used to develop a predictive model for quantifying clay mineral content from MIR spectroscopy by correlating the spectral data to the quantitative assessment of clay minerals from XRPD (reduced using powdR package in R) using Machine Learning (ML) techniques (e.g., Cubist, Random Forest). Our current study attempts to answer two key scientific questions: 1. Can spectra data in the MIR region, combined with ML algorithms, accurately predict mineral clay concentrations generated from XRPD? 2. Which machine learning proves most effective in developing a national-scale calibration model for prediction?  References:[1] Schmitz, R.M., Schroeder, C., Charlier, R., 2004. Chemo – mechanical interactions in clay : a correlation between clay mineralogy and Atterberg limits 26, 351–358. doi:10.1016/j.clay.2003.12.015[2] Six, J., Conant, R.T., Paul, E.A., Paustian, K., 2002. Stabilization mechanisms of soil organic matter: Implications for C-saturation of soils. Plant Soil 241, 155–176. doi:10.1023/A:1016125726789[3] Lilly A, Bell JS, Hudson G, Nolan AJ, Towers W. 2011. National Soil Inventoryof Scotland 2007-2009: Profile description and soil sampling protocols. (NSIS_2). TechnicalBulletin, James Hutton Institute. DOI: 10.5281/zenodo.7688040.
Study of extreme heatwave seasons in South Asia using rare event simulations
Authors: Le Priol Clément , Monteiro Joy M. , Bouchet Freddy
Published: March 2024

Extreme climate events have major impacts on human societies and ecosystems. The most detrimental events are often extremely rare, with return time of centuries or even millennia. Studying these events in the context of climate change is crucial to help adaptation efforts globally. Yet the study of these extremely rare events is extremely challenging due to the lack of data. Indeed, such events have likely not been observed in the instrumental period. An alternative is to use a global climate model to simulate these extremely rare events. However, this comes at a huge computational cost : gathering good statistics on centennial events would require to run a few thousand years of simulation. Rare event algorithms have recently been introduced in the field of climate science to tackle this difficulty [1]. By concentrating the computational effort on the trajectories most susceptible to lead to the extreme event of interest, they allow for the sampling of extremely rare events at a much lower computational cost than standard simulations. In this study, we run a rare event algorithm to sample extreme heatwave seasons in a heatwave hotspot of South Asia, using the intermediate complexity model Plasim. We compare the outcome of the algorithm against an extremely long – 8000 years – control run. This comparison allows us to demonstrate that the algorithm not only estimates return times with high precision (as shown in previous work), but also exhibits high precision in the estimation of composite statistics: composite maps conditioned on centennial heatwave seasons estimated from the algorithm, are in very good agreement with the ones from the 8000-year long control simulation. Our results suggest that extreme heatwave seasons in the studied region are associated with a quasi-stationary atmospheric wave-pattern stretching from the North Atlantic towards South Asia. We also show that the algorithm correctly estimates the intensity-duration-frequency statistics of subseasonal heatwaves occuring within centennial heatwave seasons. Thus rare event algorithms could, for instance, be combined with seasonal forecasts to provide information regarding expected number of heatwave days and the distribution of the duration and intensity in an extreme heatwave season, which could be useful for adaptation planning.  References[1] F. Ragone, J. Wouters, and F. Bouchet, “Computation of extreme heat waves in climate models using a large deviation algorithm,” Proc Natl Acad Sci USA, vol. 115, pp. 24–29, Jan. 2018. 
Weathering crust and cryoconite holes on the Hells Gate and Nansen Ice Shelves (East Antarctica)
Authors: Traversa Giacomo , Di Mauro Biagio
Published: March 2024

The penetration of shortwave radiation at the surface of an ice shelf has the potential to induce internal melting, resulting in the formation of a porous layer close to the surface commonly known as the weathering crust. This dynamic hydrological system is known to host light-absorbing impurities and microbes, forming a highly porous layer at the ice sheet's surface. The presence of the weathering crust significantly impacts the overall volume of generated meltwater by modulating the extent to which shortwave radiation is absorbed or reflected by the ice. Beyond external meteorological forcing, local conditions leading to weathering crust formation can be influenced by biological impurities on ice surfaces. This interplay between surface ice structures, cryoconite holes (CHs) and weathering crust contributes to the spatial and temporal variability of albedo and surface melt. In this study, we analysed uncrewed aerial vehicle (UAV) data and ground-based field spectroscopy data collected during the 2022/23 austral summer in Antarctica. The aim is to map CHs spatial distribution and to evaluate their radiative impact on blue ice fields at the Hells Gate Ice Shelf in Northern Victoria Land (East Antarctica). Furthermore, we documented the formation of the weathering crust and supraglacial ponds at Hells Gate and Nansen Ice Shelves across the summer solstice. By analysing Sentinel-2 satellite data, we were able to determine the spatial variability in surface albedo before and after the formation of the weathering crust. In detail, at the Hells Gate Ice Shelf, we estimated < 1% of area covered by CHs. Over frozen ponds and ice bands the area covered in CHs reached almost 10%. The corresponding spatially integrated-radiative forcing resulted to be about 1 Wm-2 in average, but locally it reached values of over 200 Wm-2, thus sustaining liquid water inside the CHs. As for the weathering crust, the delta albedo (Δα) was found to be about +0.10 and +0.40 respectively where weathering crust covered blue and marine ice. On the other hand, the supraglacial pond and stream formation provided an opposite Δα of about -0.30 over blue ice and -0.50 over areas previously characterised by snow cover. However, the fractional area interested by positive Δα resulted to be significantly higher than positive Δα areas over the two ice shelves.
Electrical conductivity in a Griggs apparatus: a new experimental geophysical tool to investigate geological processes
Authors: Ferrand Thomas P. , Précigout Jacques , Sifré David , Savoie Frédéric , Champallier Rémi , Gaillard Fabrice
Published: March 2024

Electrical conductivity measurements on well-characterized materials in the laboratory allow accurate interpretations of electrical anomalies within the lithosphere and asthenosphere. But so far, most measurements have been performed statically, and hence, the effect of deformation and/or differential stress on electrical conductivity remains largely unknown. Here we report the first successful deformation experiments performed in a new-generation Griggs-type apparatus adapted for electrical conductivity measurements. The experiments were conducted on samples of Åheim dunites at a confining pressure of 1 GPa and temperatures of 500, 650 and 800°C. In silicate polycrystals, electrical charges are known to preferentially travel through grain boundaries, which act as high-diffusivity pathways. Our results show that stress and strain can significantly impact the electrical conductivity of peridotites by changing the thickness and the number of grain boundaries, respectively. At fixed P-T conditions, the electrical conductivity varies within an order of magnitude during deformation. This motivates to reappraise interpretations of electrical anomalies in mantle rocks, at least in tectonically active regions. The design presented in this study is fully stable at 1 GPa (≈ 30 km depth) and should be stable up to 2 GPa at least, and to average temperatures as high as 1000°C. Further developments should soon enable similar measurements at pressures up to 4 GPa (120 km depth). These experimental achievements open a new research field, which will help to understand electrical anomalies and strain localization processes in rocks under stress at depth, notably within the lower crust, the upper mantle, and subducting slabs.
Interannual and regional variability in winter nutrient concentrations in Icelandic Waters
Authors: Olafsdottir Solveig , Benoit-Cattin Alice , Olafsson Jon
Published: March 2024

We present spatial and temporal patterns of nutrients concentrations from February observations from two hydrographically different regions in the high latitude North-Atlantic: The northern Irminger Sea and the Iceland Sea. Our observations are from two time-series stations located off the continental shelf and from stations on the shelf. The Irminger Sea, southwest of Iceland, is primarily in the realm of Atlantic Water derived from the North Atlantic Current. The Iceland Sea is north of the Greenland-Iceland-Faroe Ridge separating the Nordic Seas from the sub-arctic North Atlantic. Both regions undergo strong seasonal variations and winter mixing is induced by strong winds and loss of heat to the atmosphere. The winter mixed layer depth is found to be variable in the Irminger and Iceland Seas, but it reaches much deeper in the Atlantic Water of the Irminger Sea as a halocline limits the vertical convection in the Arctic Waters of the Iceland Sea. Consequently, the winter mixed layer depths in the two regions range from or 300-700 m and 150-250 m respectively. The nutrient concentrations in the surface layer that result from the winter vertical mixing vary interannually and there is a significant spatial difference between the two regions where the long term (1991-2020) average for the nitrate concentration is 14.4 µmol kg-1 in the Atlantic Water and 10.3 µmol kg-1 in the Arctic Waters. Higher spatial differences are in the silicate concentration, in the Atlantic Water the long-term average concentration is 6.8 µmol kg-1 and 4.0 µmol kg-1 in the Arctic Water. The interannual variations in the relative abundance of nitrate and silicate, the Si/N ratio, are likely to influence the productivity of silicious diatoms in the spring bloom. Nutrient concentrations at the end of winter on the shelf are also high, they reflect the state of the offshore waters. Our observations show hydrographic changes that have induced significant biogeochemical changes in these regions.
Linking volcanic tremor amplitude to drone records of lava lake level changes during the 2021 Geldingadalir eruption, Iceland
Authors: Joachim Alea , Eibl Eva P. S. , Müller Daniel , Walter Thomas R.
Published: March 2024

On March 19, 2021, an effusive eruption lasting for six months began in the Geldingadalir valley on the Reykjanes peninsula, in the southwest of Iceland. This eruption was characterised by episodic lava effusion from 2 May to 18 September and changing eruptive behaviour. Here, we analyse five of such effusion episodes of 8 June 2021 by using drone video data acquired over the active crater lake together with volcanic tremors that were recorded by a seismometer located at 5.5 km distance from the active vent. We are thus able to study each of the five episodes in terms of tremor amplitude evolution and its frequency spectrum, and compare it with the timing, height and dynamics of the lava lake, its bubbling and crater overflow. We observe a slow rise of the lava lake by 25.1 to 26.2 metres within 6.15 ± 2.35 minutes, followed by a rapid fall of the lava lake surface to its previous level within 1.6 ± 0.12 minutes. In contrast, the quiescence period in the tremor lasts ~ 10.12 ± 0.68 minutes followed by another 2.55 ± 0.2 minutes of tremor. Thus, the duration of tremor generation is shorter than the time required for the lava lake to reach its maximum height. Furthermore, the tremor amplitude reaches its maximum after the lava lake has started to sink. We discuss the volcanic tremor generation in relation to lava lake elevation and related processes.
Arctic Warm and Moist Air Intrusions in ICON Simulations
Authors: Landwehrs Jan , Tiedeck Sofie , Murto Sonja , Rinke Annette
Published: March 2024

Warm and moist air intrusions (WAI) contribute strongly to extreme warm events in the central Arctic and deliver a major part of the moisture transport into this region, with significant impacts on cloud formation and the surface energy balance. Within the PolarRES EU-project we use the ICON model to study such events both in case studies for the MOSAiC expedition and climate simulations.MOSAiC provided comprehensive observations of two WAIs in mid-April 2020 when near-surface air temperatures reached the melting point for the first time in this spring. We evaluate different ICON-LAM set-ups, including a pan-Arctic domain with 11km horizontal resolution, as well as more confined domains at convection-permitting 2.5km resolution with varying cloud microphysics settings. A better agreement with local observations is found on the smaller model domains at higher resolution. Additionally, the representation of liquid water is improved by using a more complex two-moment cloud microphysics scheme, where a scenario with higher CCN (cloud condensation nuclei) concentration is found to be more suitable for the aerosol-rich intrusion around April 16.In a climatological perspective we demonstrate the tracking of moisture intrusion events in decadal-scale climate simulations with ICON-LAM at 11km resolution in a pan-Arctic domain. We drive the regional model with ERA5 and selected CMIP6 GCMs to obtain vertically integrated water vapor transport at high spatial and temporal resolution. This is then used to identify, track and classify WAIs, to study their climatological characteristics, impacts and long-term trends under climate change.
Heavy-rain Forecasting with the Application of High-density Swarm Network of Optical Rain Sensors and Artificial Intelligence.
Authors: Shrestha Nibesh , Buddrick Alexander , Mewes Benjamin , Oppel Henning
Published: March 2024

Heavy rainfall, a prominent consequence of climate change, induces substantial pluvial flooding as the urban drainage systems fail to deal with the water surge. The risks intensify with the cloud-burst rain on a catchment area without any gauge. Especially in topographically complex watersheds, the limitations associated with conventional precipitation monitoring tend to exacerbate. These heavy-rain events, if undetected, pose severe threats, causing extensive damage to the settlements and industries without timely warning.With a motive to bridge this gap, we present the exemplary development of a cutting-edge AI-supported early warning system and cell detection (now-casting) of heavy rainfall events. Utilizing an IoT-based optical method, we record qualitative rainfall intensity data with a high-density swarm network of rainfall sensors spread across the target region. These data can be immediately used to forecast the path of the rain with the physical optical-flow method. Furthermore, these data are used to train the AI, generating heavy rain forecasts up to 60 minutes before the rain reaches points of interest. This lead time is crucial for citizens and rescue forces to reduce the chaos phase and prepare themselves on time even before the heavy rain cells reach their location and create havoc.The innovative optical rainfall sensors have been installed and tested in Liederbach am Taunus since the summer of 2022, demonstrating their efficacy and accuracy during the August 2023 heavy rainfall storm event. The system adeptly captured heavy rainfall data, showcasing great potential for early warnings when implemented at a full scale alongside AI applications.
The impact of storm surges on ocean tides: insights from numerical simulations
Authors: Muis Sanne , Hart-Davis Michael , Veenstra Jelmer , Verlaan Martin , Williams Joanne , Dettmering Denise
Published: March 2024

The interaction between tides and storm surges can significantly affect shallow water regions with large tidal ranges. In modelling studies, including the atmospheric forcing, which drives the storm surge estimations within the model, can result in changes to the amplitudes and phases of the major tidal constituents. In certain regions, this can have severe impacts on the tidal predictions.A standard product used to provide the atmospheric forcing is the ERA5 product developed at ECWMF. Previous studies have shown the presence of tidal constituents within the sea level pressure data provided by ERA5 used in various applications. For example, the commonly used Dynamic Atmospheric Correction derived from these data, which is used to correct satellite altimetry measurements for the atmospheric influence on the radar returns, has been shown to significantly impact the estimation of ocean tides from satellite altimetry. The Global Tide and Surge Model (GTSM), developed at Deltares, allows for the global estimation of ocean tides with and without atmospheric forcings. This presents the possibility of evaluating the influence of storm surges on the estimation of individual tidal constituents and the resultant prediction of tidal heights. In this poster, three model simulations are produced, which are as follows: an ocean tide-only version, a storm surge-only simulation and a tide plus storm surge version. The eight major tidal constituents are evaluated globally to assess the changes in their respective amplitudes and phases. Finally, several case studies are presented in regions with high influence on the individual constituents by evaluating the results of the tidal predictions with respect to in-situ measurements. 
Mapping Heat Risks in Delhi: A Geospatial Approach to Enhancing Urban Resilience
Authors: Pritipadmaja Pritipadmaja , Prabhu Shravan , Garg Rahul Dev
Published: March 2024

Rapid urbanisation and changing climate patterns have intensified heat stress in urban areas. Factors such as the Urban Heat Island (UHI) effect, population growth, land use changes, and inadequate green and blue infrastructure contribute to elevated temperatures. The objective of this study is to map heat risks in Delhi using geospatial indicators, showcasing the potential of open-source satellite imagery to enhance Heat Action Plans (HAPs).
 
Utilising Google Earth Engine (GEE) as a robust tool, our methodology integrates satellite imagery and various geospatial data to analyse the drivers and indicators of heat risk based on the IPCC AR5 framework considering Hazard, Exposure and Vulnerability. Comprehensive heat risk maps are generated for Delhi, a city of over 20 million residents experiencing extreme heat and escalating heatwaves. These maps identify areas with increased exposure and vulnerability, providing valuable insights for developing precise mitigation strategies.
 
The outcomes of this research contribute to enhancing Delhi's Heat Action Plan and offer a scalable methodology for assessing heat risks in other cities. The automated GEE script and framework can be readily applied, facilitating the integration of these assessments into HAPs. Moreover, the study emphasises future plans to collaborate with government authorities and disaster management agencies to incorporate on-ground socio-economic data, further refining the heat risk assessment process.
 
Keywords: Heat Risk, Urban Heat Island, Land Surface Temperature, Google Earth Engine
Protects and Heats
Authors: Tavecchio Walter
Published: March 2024

The project “Protects and Heats” aims to safeguard the environment, to reduce the carbon dioxide emissions and the risk of collapse of buildings affected by earthquakes.This is a new way to heat and cool buildings and at the same time mitigate the seismic vibrations. The logic of the project is to create a discontinuity (Moat) in the ground in front of the structures to be protected, similar to damping methods that are implemented to dampen the vibrations produced by mechanical machines and without compromising the stability of the buildings themselves.The project involves the construction of a double row of aligned micro piles and the insertion of HDPE and steel pipes inside the vertical drilling holes.Closed circuit geothermal probes will be positioned, inside some vertical holes, with a low enthalpy closed circuit geothermal system.The method of the project is achieved by combining two types of technologies:-   The first concerns the interposition, between the direction of the seismic waves and the buildings, of a damping barrier.The vertical barrier starting from the topographic surface will be positioned outside the buildings, generally orthogonal to the direction of the seismic waves.-  The second concerns the installation of geo-exchange pipes, in the holes.
Mercury fluxes from hydrothermal venting at mid-ocean ridges constrained by measurements
Authors: Heimbürger-Boavida Lars-Eric , Torres-Rodriguez Natalia , Yuan Jingjing , Petersen Sven , Dufour Aurélie , Gonzalez-Santana David , Chavagnac Valerie , Planquette Hélène , Horvat Milena , Amouroux David , Cathalot Cecile , Pelleter Ewan , Sun Ruoyu , Sonke Jeroen , Luther George
Published: March 2024

The UNEP Minamata Convention on Mercury aims to reduce human exposure to toxic mercury through the reduction of anthropogenic emissions. We are primarily exposed via the consumption of fish that bioaccumulate mercury from the ocean. The current paradigm is that anthropogenic mercury emissions (present-day 3,100 tons per year) have increased the global oceanic mercury reservoir by 21%. This estimate is flawed because we do not know how much natural mercury resided in the ocean before anthropogenic emissions started. We are similarly unable to quantify how anthropogenic emissions have affected fish mercury levels. Hydrothermal venting is the only direct source of natural mercury to the ocean. Previous studies, based on vent fluid measurements alone, suggested that hydrothermal mercury inputs could range from 20 and 2,000 tons per year. We use observations of vent fluids, plume, sea water and rock cores from the Trans-Atlantic Geotraverse (TAG) hydrothermal vent at the Mid-Atlantic ridge aquired during three dedicated oceanographic cruises. The combined observations suggest that the majority (67–95%) of the mercury enriched in the vent fluids (4,966 ± 497 picomoles per litre) is diluted into sea water  to reach background seawater levels (0.80 picomoles per litre) and a small fraction is scavenged locally (2.6–10%). An extrapolation of our results suggests that the global hydrothermal mercury flux from mid ocean ridges is small (1.5 - 65 tons per year) compared to anthropogenic mercury missions. While this suggests that most of the mercury present in the ocean is of anthropogenic origin, it also gives hope that the strict implementation emission reductions in the framework of the Minamata Convention could effectively reduce fish mercury levels and human exposure.
Torres-Rodriguez, N., Yuan, J., Petersen, S., Dufour, A., González-Santana, D., Chavagnac, V., Planquette, H., Horvat, M., Amouroux, D., Cathalot, C., Pelleter, E., Sun, R., Sonke, J. E., Luther, G. W., and Heimbürger-Boavida, L.E.: Mercury fluxes from hydrothermal venting at mid-ocean ridges constrained by measurements, Nat. Geosci., 1–7, https://doi.org/10.1038/s41561-023-01341-w, 2023.
 
ECMWF 6th generation ocean and sea-ice reanalysis system (ORAS6)
Authors: de Boisseson Eric , Zuo Hao , Chrust Marcin , Browne Philip , Balmaseda Magdalena , de Rosnay Patricia
Published: March 2024

Ocean and sea-ice reanalyses are reconstructions of historical ocean and sea-ice states by ingesting observations into simulated model states through data assimilation methods. Reanalysis provides invaluable information for climate monitoring and is an essential component in long-term prediction such as seasonal to decadal forecasts. The Ocean ReAnalysis System-6 (ORAS6) is the 6th generation of ocean and sea-ice reanalysis system developed at ECMWF. ORAS6 is forced by hourly ERA5 atmospheric fields and uses an ensemble variational ocean data assimilation (EDA) to produce an 11-member ensemble of ocean reanalyses. Both the new EDA system and the use of the latest reprocessed input datasets help making better use of ocean observations to provide ocean states with improved fit to observations both at the surface and the subsurface, a better representation of the daily cycle of the surface temperature and more accurate ocean transports. ORAS6 sea-ice states are produced using a new multi-category sea ice model assimilating sea-ice concentration observations and show improved fit to satellite observations. This increased complexity came with its lot of technical challenges but now opens the door for the future assimilation of new sea-ice variables such as sea-ice thickness and new diagnostics such as snow depth over sea-ice that will benefit from future satellite missions.Ocean and sea-ice states from ORAS6 will be used to initialise the ocean component of the ECMWF operational coupled ensemble forecasts and provide the lower boundary conditions for the upcoming ERA6 atmospheric reanalysis produced by the Copernicus Climate Change Service (C3S). This presentation will feature results from the first stream of production of ORAS6 covering the most recent decade as well as a preview of ORAS6 streams covering the rest of the satellite-observed decades as well as the pre-satellite period with a focus on performance evaluation against the current ECMWF operational system-5 (ORAS5).
Seepage Induced Morphodynamics of Alluvial Channels: Unraveling Dune Dynamics and Flow Characteristics
Authors: Behera Pradyumna Kumar , Pandey Abhishek , Deshpande Vishal , Kumar Bimlesh
Published: March 2024

Experimental studies were conducted to analyze the alterations in flow behavior and turbulent characteristics over dune-shaped bed features in the absence and presence of downward seepage. Experiments were designed in two categories to understand the flow characteristics: (1) over fixed (immobile) dunes, and (2) dunes made of sand (mobile). In both the categories of experiments, measurements were taken for no seepage condition and the results were then compared when downward seepage discharge of 10% and 15% of the no seepage discharge were allowed through the porous sand bed placed on the flume bed. Instantaneous velocities were collected using Acoustic Doppler velocimeter (ADV) for no seepage and seepage conditions. Significant enhancement in streamwise velocities, RSS, turbulent intensities, turbulent kinetic energy (TKE) values, and bed shear stress was observed at the initial sections on the stoss side and the lee side sections under the influence of downward seepage over both fixed bed as well as mobile bed conditions. The Anisotropic Invariant Map (AIM) illustrates the prevailing 1D anisotropy in the initial and lee side sections of the dune under downward seepage condition. Quadrant and octant analyses show increase in sweep and ejection events in the near bed zone of the initial and lee side section of the dune under downward seepage conditions. Similar patterns of turbulent parameters were observed for the dunes under mobile conditions. However, at the middle sections and crest portion of the fixed bed dune, the magnitudes of turbulent parameters have been found decreasing along the depth of flow. Contradicting the flow and turbulence patterns observed at the crest portion of the fixed dune, the magnitudes of turbulent parameters increase significantly under seepage conditions in the near-bed region of the crest portion. The increase in the magnitudes in the near-bed region of the crest portion for the mobile bed experiments is due to an increase in the scour depth on the lee side section of the dune, owing to higher amount of sediment movement from lee side section of the dune. The increase in scour depth on the lee side section of the mobile dune under the influence of seepage generates higher magnitude of turbulence eddies, which reach the crest portion, leading to a rise in flow velocity and turbulence parameters in the near bed region at the crest portion of the mobile bed dunes, resulting in increased celerity of the dunes under seepage conditions.Keywords: Two-dimensional dune; downward seepage; acoustic Doppler velocimeter; turbulence characteristics; anisotropy; bursting events; dune morphology.
Ice Borehole Thermometry: Paleo-Climate reconstruction using Bayesian modeling
Authors: Shaju Kshema , Laepple Thomas , Zaspel Peter
Published: March 2024

In the quest of understanding the past and present climate system, we aim to reconstruct paleo-climate using Bayesian inversion from Antarctic borehole temperature profiles. We aim to develop a refined process for reconstructing the temperature evolution of Antarctica over the last century and millennia. Initially, a forward heat transfer model is implemented that simulates borehole temperature profiles for time-dependent surface temperatures. The forward model provides an approximate notion of the borehole depth at which a signal from the past may be obtained. Using forward simulations, a greedy approach is employed for the optimal placement of temperature sensors in the borehole to record temperature effectively. We invert the forward model to reconstruct past surface temperature evolution from borehole temperature measurements. For this, we apply Bayesian inference to optimally account for the uncertainty in the various influencing quantities. We model known uncertainties as priors and obtain the reconstructed surface temperatures with connected uncertainty information.
Spline-based geomagnetic field  modeling revisited
Authors: Schanner Maximilian Arthus , Korte Monika , Holschneider Matthias
Published: March 2024

Many existing global geomagnetic field models for historical and longer timescales are based on spherical harmonics for the spatial part and low order basis splines for the temporal dynamics. The related modeling procedure is well established and implements a regularized non-linear least squares inversion. Early papers on the methodology already mention uncertainty estimation in this context. Even though they use a different language, this connects the regularized least squares approach to Bayesian statistics. However, most likely due to computational costs, the ideas from the early papers were lost in subsequent studies and most presented models rely on bootstrapping methods for uncertainty estimation or do not include uncertainties at all. In a statistical setting, this translates to presenting a point estimate (mean or mode) of the posterior distribution.We revised the established spline based modeling formalism in order to excavate the procedure for uncertainty estimation and complement the point estimate by covariance matrices. This way, uncertainty estimates can be provided for many existing models retrospectively. Using ensemble techniques, the estimated uncertainty can also be propagated to derived quantities like the PSV-index or geomagnetic shielding. Finally, the statistical view provides a new way of estimating the regularization parameters using marginal likelihood optimization. The presented method is applicable to satellite based models in principle, although it is less relevant there due to the large amount of data and uncertainties from other sources (e.g. external fields).
Conceptual proof, current application, and lab procedures to quantify crustal thickness variations with muon paleotopometry
Authors: Raab Gerald , Gosse John , Hidy Alan
Published: March 2024

Measuring the topographic relief evolution over hundreds of thousands to million-year timescales remains challenging. Current approaches use a mix of basin stratigraphy, numerical modelling of terrestrial cosmogenic nuclide (TCN) exposure ages on strath terraces, and exhumation histories based on thermochronology or drainage basin evolution. Yet, even a combined mix of these methods is incapable of quantifying the rate changes with precisions needed to differentiate climate from tectonic drivers over multiple glacial cycles and longer timescales.The recently conceived muon-paleotopometry (MPT) approach is tailored to close the methodological gap of determining relief generation. MPT exploits the dependence of cosmic ray muon flux on crustal shielding depth. The spatial concentration pattern of multiple muon-induced TCN measured along a near-horizontal transect under valleys and peaks relates directly to the history of changes (positive or negative) in crustal thickness. MPT allows paleotopometry measurements above the sample datum over an isotope-specific monitoring duration. By sampling at depths of hectametres, long-lived TCN (e.g., 10Be, 26Al) are not sensitive to minor short-term (150 m) and update on the progress for the current large-scale relief investigation of the European Alps.
Effect of Coral Reefs on Wave Height
Authors: Usoltseva Mariia , Passaro Marcello , Dettmering Denise
Published: March 2024

Coral reefs, among other benefits, provide natural protection from waves for coastal communities. In the context of climate change and its role in the degradation of coral reefs and the intensification of extreme weather events, there has been a growing interest in understanding the sheltering properties of coral reefs. Despite this interest, there remains a lack of comprehensive studies that systematically assess wave behaviour on coral reefs using remote sensing techniques.This study utilized along-track altimetry observations from the European Space Agency's Sea State Climate Change Initiative (CCI) v3 L3 dataset, complemented by ERA5 data, to examine the influence of coral reefs on wave height. Changes in significant wave height (SWH) on coral reefs, derived from the multi-mission altimetry dataset, are compared with those computed from ERA5 reanalysis in its gridded format and interpolated on satellite tracks. The assessment is conducted on a global and regional scale, considering different offshore sea states. Additionally, the study explores the influence of the structural complexity of coral reefs on their capacity to attenuate waves. This is achieved through a regional analysis of altimetry measurements in years with a high percentage of hard coral cover and years after destructive storms.The results demonstrate a high degree of agreement between SWH attenuation computed from the satellite altimetry dataset and ERA5 interpolated on the satellite tracks, yielding a correlation coefficient of 0.724. Additionally, this study contributes to the expanding body of knowledge regarding the influence of coral reefs on wave height. Despite the pronounced variability contingent upon the state of coral reefs and the local wave climate, about 80% of observations show a reduction in wave height as waves traverse coral reefs. Statistical evaluation reveals an increase in the reduction of wave height with an increase in offshore wave conditions, as evident in the analysis of all three datasets. Furthermore, case studies on extreme events show a regional decrease in wave attenuation on coral reefs with reduced hard coral cover. The study highlights the potential of satellite altimetry in the observation of wave height changes across coral reefs, as well as the ability of coral reefs to attenuate waves and mitigate the destructive potential of storms, thereby contributing to coastal protection and resilience.
Development of fold styles in the strongly arcuate Cuddapah fold-thrust belt, India: new insights from analogue models
Authors: Patsa Ayan , Mandal Nibir
Published: March 2024

Many arcuate orogenic belts display complex patterns of fold structures. However, the kinematics of their development is poorly understood. This study aims to explore the origin of complex fold structures in the Proterozoic mobile belt of Cuddapah in peninsular India. This is a N-S trending thin-skinned fold-thrust belt, showing a spectacular crescent shape with westward convexity. The tectonic reconstructions suggest that the Cuddapah fold-thrust belts (CFTB) evolved through westward indentation of the westerly convex Nellore-Khammam schist belts (NKSB) during the collision between the Indian shield and the Antarctic block, interpreted as a consequence of the Rodinia Supercontinental event in Neoproterozoic time. The westward convergence resulted in the development of highly deformed Nallamalai fold belt (NFB) in the eastern part of CFTB, consisting of orogen-scale overturned folds with arcuate trends as well as higher order west-verging F1 folds on a wide range of spatial scales. Inclined to recumbent F1 folds are coaxially refolded by orogen-parallel F2 folds in outcrop scale. However, the superposition of steeply inclined E-W trending cross-folds (F3) that produced culminations and depressions on F1 and F2 indicates that the belt underwent orogen-parallel shortening in the course of its evolution. We performed laboratory experiments on a scaled representative CFTB model to understand such spatiotemporal evolution of the strain field in the CFTB. Two sets of experiments were run with a constant (2 cm/yr) and a temporally varying (2 cm/yr in Stage I to 1 cm/yr in Stage II) convergence velocity. The experimental results show that the CFTB during the initial periods of shortening undergoes mainly flattening deformations with maximum horizontal instantaneous stretching axes (ISAHmax), describing an arcuate trajectory in the eastern part that conforms to the indentor shape. In the later periods of the experimental runs (albeit at different times in the two experiments), the arcuate shape of the fixed wall causes a SW and NE-directed upper crustal flows from the elevated NE and SW parts of the CFTB, respectively. The flow convergence causes the strain field in the central part of the CFTB to develop a horizontal constriction. This kinematic transition leads to superposition of cross-folds on orogen-parallel folds, manifested in culmination (domes) and depression (basins) structures.
Understanding spatio-temporal pattern of crop diversification for India
Authors: Kumari Chanda , Shukla Roopam , Gleixner Stephanie
Published: March 2024

Abstract: Agrobiodiversity, a key principle of agroecology, encompasses crop diversification, offering resilience to climate variability (Ronnie Vernooy, 2022). Increasing crop species diversity within a region could improve agricultural sustainability, but knowledge of the spatiotemporal variation of crop species diversity and how this is related to climatic conditions is limited (Sjulgård, H., et al., 2022). Higher crop diversity may alleviate the effects of heat stress (Degani et al., 2019, Marini et al., 2020) and drought (Bowles et al., 2020, Marini et al., 2020) on crop yields. Therefore, crop diversity will play a crucial role in the functioning of agroecosystems under climate change (Sjulgård, H., et al., 2022). Hence, this study aims to investigate the relation between the spatiotemporal pattern of crop diversity and changing climatic conditions at the district level in India by building relationship between crop diversification and climatic variables. Crop species diversity was estimated using the Shannon Index. Advanced statistical analysis was used to understand the relationship between climatic variables and crop diversity. The outcome will also help the policymaker, researchers, and field practitioners in designing climate-resilient agricultural practices following the principles of agroecology.Keywords: Crop diversification, Shannon Index, Climate variables, Risk map, Agrobiodiversity, Agroecology, India.Figure 1: Schematic representation of the proposed work
Millennial-scale changes in hydroclimate during the last glacial period in central Europe reconstructed from leaf wax δD
Authors: Zander Paul , Sirocko Frank , Du Xiaojing , Sun Chijun , Rubach Florian , Britzius Sarah , Haug Gerald , Martínez-García Alfredo
Published: March 2024

Millennial-scale climate events during the last glacial period, such as Dansgaard-Oeschger cycles and Heinrich events, are well-documented in ice cores and marine sediments. During Dansgaard-Oeschger cycles of the last glacial period, repeated rapid warming events of a similar magnitude to modern-day warming occurred over the North Atlantic region. However, the impacts of these fluctuations on hydroclimate in Europe remain poorly constrained, mainly due to a lack of high-resolution, well-dated paleoclimate records. Here, we use D/H ratios (δD) measured on n-alkanes derived from leaf waxes preserved in lacustrine sediments from Eifel maar crater basins to reconstruct changes in hydroclimate. Our record spans the past 60,000 years and is tied to the Greenland NGRIP ice core chronology using a high-resolution index of lake productivity. Initial results show that δDwax was more depleted during interstadial phases of the last glacial period. Multiple factors may influence δDwax; however, if an isotope “temperature effect” played a dominant role, the warmer interstadials would have been associated with more positive δDwax values, in contrast to the observations here.  Thus, we interpret low δD during interstadials as a signal of wetter, more humid conditions, possibly related to a shift towards more winter precipitation due to changes in the position of the westerlies. We compare our proxy measurements with an isotope-enabled transient climate simulation of the last deglaciation (iTRACE) to constrain the dynamical factors associated with changes in precipitation δD over stadial/interstadial changes. These results provide important constraints on past millennial-scale hydrological changes in Europe in response to changes in North Atlantic circulation.