bluuebunny/crossref_metadata_2025 huggingface dataset:
Preliminary insights on uranium-bearing Jurassic phosphorites of the Ionian zone, Albania, their distribution and genesis
Authors: Sinojmeri Agim , Fociro Ana , Della Porta Giovanna , Grieco Giovanni , Beqiraj Sajmir
Published: March 2024

Phosphorites are well-known, worldwide, for accommodating a significant amount of U relative to other sedimentary rocks, due to the crystal structure of apatite where U substitutes Ca. In Albania, uranium-bearing Lower Jurassic phosphorites form a distinctive horizon identified across the entire Ionian zone. Two different types of U-bearing phosphatic deposits are identified within the Lower Jurassic carbonate succession in Albania; one, stratigraphically younger, layered and parallel to carbonate strata and the other due to infiltration in older, brecciated carbonates. The first type consists of lenticular shape deposits of limited lateral extension intercalated in thin-shelled bivalve packstone/rudstone, possibly corresponding to the Toarcian Bositra-rich organic rich “Posidonia” shales of Austria and Germany. The phosphatic horizon is confined by dark gray J2 limestone on the top, while the bottom shows signs of an early erosion. Their extent varies from 5-10 m to 100-160 m, while their thickness varies from 0.3 to 6 m. The radioactivity measurements indicate that the intensity of gamma radiation varies from 0.6 to 1.66 µSv/h, while the uranium content varies from 50 to 230 ppm, the highest values corresponding to the P2O5 peak of 32.66%. The second type of phosphorite mineralization developed in a widespread horizon throughout the Ionian zone. Its extension varies from 1.5 to 8 km, composed of continuous zones up to 0.5-1 km with some small interruptions. Uranium-bearing phosphatic deposits occur as the infiltrated matrix of breccias (caused by hydraulic or tectonic stress, not of sedimentary origin) made of angular clasts of Pliensbachian inner carbonate platform facies of the J1 (peloidal and oncoidal packstone/grainstone with Siphovalvulina foraminifers and Palaeodasycladus mediterraneous dasyclad algae). The intensity of gamma radiation varies from 0.5 to 1.1 µSv/h, uranium content varies from 50 to 150 ppm and the P2O5 highest peak is 15%. In accordance to the first data achieved, the uranium-bearing phosphorites of Early Jurassic age in Albania formed in deep, oxygen-depleted marine conditions as suggested by the abundance of thin-shelled bivalves. The well-documented early Toarcian Oceanic Anoxic Event driven by an increase in nutrients linked to high volcanic emissions of CO2 may have favoured the formation of the phosphate deposits. The intensive tectonic events associated with the Alpine Tethys Ocean opening during the Early and Middle Jurassic should be the main factor causing the brecciation and controlling the formation of later infiltration mineralization.
Changing groundwater ecosystems and recharge – neither temperature nor nutrients or carbon are the main drivers
Authors: Schmidt Susanne I. , Svátková Miroslava , Kodeš Vít , Shabarova Tanja
Published: March 2024

Waterbodies across the world undergo changes. This influences the communities in the ecosystems. Groundwater is no exception. However, few studies focused so far on how the combined effects from environment, groundwater recharge, and a changing climate, impact the organisms living in the groundwater. In 2019-2021 in southwestern Czech Republic, we sampled fauna and microorganisms in 37 wells that had been monitored by CHMI for up to 40 years and that varied in the trends in chemical and physical characteristics. The wells tapped the shallow quaternary and deeper aquifers of seven major hydrogeological zones. Some of the wells represented recharge zones, others tapped artesian aquifers. Trends in temperature over the past decades were ambiguous. Carbon and nutrients did not show clear patterns, neither over time, nor predicting fauna and microorganisms. Fauna was, however, significantly more abundant in wells representing recharge zones. Most unexpected were the observations that silica increased significantly in all but one well, and that faunal numbers were lowest in the wells with the highest silica values, although there is no reason for fauna being harmed by silica, - on the contrary. The correlation is thus believed to show indirect effects, with the increase in silica probably being the (by)product from either climate change or land use change, or the combination of the two, and groundwater fauna being impacted by the underlying developments. This may have implications for ecosystem functions, and ultimately, the use of groundwater for drinking water production.
The Impact of Ocean Circulation Changes on the Glacial-Interglacial Difference between EASM and ISM Speleothem Records
Authors: Wang Jian , Cheng Hai , Zhang Haiwei , Cai Yanjun , Zhao Jingyao , Sha Lijuan
Published: March 2024

The Asian summer monsoon is a highly complex system that comprises two distinct subsystems: the Indian summer monsoon (ISM) and the East Asian summer monsoon (EASM). A thorough understanding of the intricate change processes and inherent differences between these two subsystems is crucial for deciphering the mechanisms driving climate change and, ultimately, predicting future climate patterns. The Indonesian Throughflow (ITF), a critical component of the global thermohaline circulation, serves as the sole low-latitude channel transporting warm seawater from the tropical Pacific to the Indian Ocean. This circulation directly impacts the mass and heat balance of the Indo-Pacific region.In this study, we utilized stalagmite samples from southwestern China and obtained high-resolution speleothem records dating back to ~18-9 ka BP. Through meticulous comparison and analysis of speleothem records from both the ISM and EASM regions, we observed significant disparities in the δ18O amplitude between glacial and interglacial, particularly around the Younger Dryas interval. Notably, the timing of this amplitude difference aligns with the flooding of the Karimata Strait, suggesting a potential linkage between the ocean circulation change and monsoon dynamics.This study delves deeper into the potential impact of the Karimata Strait's flooding on δ18O within ISM and EASM speleothem records. We propose that this flooding redirected freshwater runoff away from the South China Sea, leading to comparatively heavier δ18O of surface seawater in the SCS. Furthermore, it is likely inhibited the surface flow of the ITF, subsequently curtailing heat transfer from the Pacific to the Indian Ocean, combined with an intensified Agulhas leakage during the deglacial, these factors contributed to relative cooling of the Indian Ocean, in turn, magnified the ISM strength relative to that of the EASM. The position of the Walker circulation's ascending branch was also influenced by these oceanic changes. In the early Holocene, this branch shifted eastward, leading to a reduction in distant moisture sources in the EASM region.The above changes ultimately caused the δ18O of stalagmites in the EASM region to be relatively positive in comparison with that in the ISM region during interglacial, indicating the significance of ocean circulation changes for the evolution of climate system, and may help explaining the “missing” 100 ka signals in EASM speleothem records.
Indian Ocean variability changes in the Paleoclimate Modelling Intercomparison Project
Authors: Brierley Chris , Thirumalai Kaustubh , Grindrod Edward , Grosvenor Harry , Barnsley Jonathan , Williams Charles , Ford Heather
Published: March 2024

The Indian Ocean exhibits multiple modes of interannual climate variability, whose future behaviour is uncertain. Recent analysis of glacial climates has uncovered an additional El Niño-like equatorial mode in the Indian Ocean, which could also emerge in future warm states. Here we explore changes in the tropical Indian Ocean simulated by the Paleoclimate Model Intercomparison Project (PMIP4). These simulations are performed by an ensemble of models contributing to the Coupled Model Intercomparison Project 6 and over five coordinated experiments: four past periods (midHolocene, lgm, lig127k and midPliocene-eoi400) and an idealized forcing scenario to examine the impact of greenhouse forcing. The two interglacial experiments are used to characterize the role of orbital variations in the seasonal cycle, whilst the others are focused on responses to large changes in global temperature. The Indian Ocean Basin Mode (IOBM) is damped in both the mid-Holocene and last interglacial, with the amount related to the damping of the El Niño–Southern Oscillation in the Pacific. No coherent changes in the strength of the IOBM are seen with global temperature changes; neither are changes in the Indian Ocean Dipole (IOD) nor the Niño-like mode. Under orbital forcing, the IOD robustly weakens during the mid-Holocene experiment, with only minor reductions in amplitude during the last interglacial. Orbital changes do impact the SST pattern of the Indian Ocean Dipole, with the cold pole reaching up to the Equator and extending along it. Induced changes in the regional seasonality are hypothesized to be an important control on changes in the Indian Ocean variability.
Structure and numerical solution of a thermal problem with internal Dirichlet conditions
Authors: Zlotnik Sergio , Fernández Mariano Tomás , Díez Pedro
Published: March 2024

Inverse problems in geophysics seeking to understand the current state of planet Earth use data from multiple observables and involve a variety of physical principles. One of the key fields to determine is the temperature, affecting almost all the other physical quantities involved (e.g. densities, viscosities, wave propagation velocities, among others).The Lithosphere-Asthenosphere Boundary (LAB) is a boundary layer that affects most of the processes and properties in the Earth structure. Determining its location is one of the goals of inversions. It is usual within numerical studies to define the LAB as an isotherm. The need of determining the thermal field in accordance with a given LAB location leads to a mathematical problem with imposed interior Dirichlet conditions. In particular, the isotherm defining the LAB has to be located in the position tested by the inverse solver. Several approaches are sucessfully used to solve this kind of problem, but usually they lack of a sound physical model at least in some parts of the domain.Here we analyze the mathematical structure of a thermal problem with known interior conditions and then propose several numerical procedures to solve it. The proposed methods are tailored to the geophysical case and are based on the certainty of the different boundary conditions that are imposed in the model.Moreover, because this thermal solver is expected to be used many times within an inverse scheme, we want the numerical mesh to be fixed. The LAB, therefore, will not fit the mesh.
Application of ITRS 2020 realizations for the SLR-based POD of selected geodetic and Earth-observing satellites
Authors: Bloßfeld Mathis , Zeitlhöfler Julian , Rudenko Sergei , Seitz Manuela
Published: March 2024

Since 2023, three different solutions for the latest (2020) realization of the International Terrestrial Reference System (ITRS) are publicly available, namely the ITRF2020, the JTRF2020 and the DTRF2020. All solutions are based on the same input data but were derived using different combination approaches and data correction strategies. Since the ITRS realizations are used as a priori reference frames for precise orbit determination (POD) of Earth orbiting satellites, it is important to investigate the impact of the different frames on the POD results.In this study, we briefly introduce the different features of the ITRS realizations and elaborate how the data correction models (e.g., periodic variations vs. non-tidal loading corrections) of the different xTRF2020 solutions can be optimally applied for the POD of selected satellites tracked by Satellite Laser Ranging (SLR) stations. We conclude the study with results obtained for various orbital parameters, such as the scaling factor of the non-gravitational (non-conservative) accelerations as well as the estimated empirical accelerations. Finally, we summarize the optimal settings of each ITRS realization for the satellite PODs discussed in this paper (i.e., LAGEOS-1, LARES-2, Jason-1/2/3).
Paleomagnetic constraints on neotectonic deformation within the SouthernTian Shan piedmont and implications for the latest Miocene enhancedaridification in the Tarim Basin
Authors: Qiao Qingqing
Published: March 2024

The India-Eurasia collision reactivated the Tian Shan belt of Central Asia and led to crustal shortening which hasbeen accommodated by fold-and-thrust belts on both flanks of the orogen. Southward propagation into the TarimBasin has been accommodated by the Kuqa fold-and-thrust belts which record a range of well-preserved syntectoniccontinental sequences. Using existing magnetostratigraphic age constraints, we have conducted an indepthpaleomagnetic and rock magnetic investigation of this fold-and-thrust belt with the aim of linking theneotectonic deformation to the uplift of the Tian Shan orogen to the north. Anisotropy of magnetic susceptibility(AMS) shows “pencil structure” fabrics between levels dated 31.0 and 5.5 Ma. These are succeeded by incipientdeformation fabrics at ~5.3 Ma, which dates an abrupt decrease in shortening by synsedimentary strain. Thischange coincides with the timing of initial syntectonic growth strata in the foreland basin of the Southern TianShan and contemporaneous vertical-axis rotations in the Yaha section. Collectively this evidence implies that theSouthern Tian Shan piedmont underwent transpressional deformation with rotation accompanying strain partitioningduring a regional sinistral shear. The extreme aridification which has occurred in the Tarim Basin sincethe latest Miocene is interpreted in terms of the deflection of the ambient westerly airstream away from thisregion due to the growth of the Tian Shan and its final collision with the Pamir.
Archaeometry in geosciences: the study of ancient geomaterials for archaeological investigations.
Authors: Gambino Francesca , Appolonia Lorenzo , Borghi Alessandro , Cheney Sylvie , Cossio Roberto , De Bernardi Stefano Marco , Dino Giovanna Antonella , Ghignone Stefano , Sartorio Gabriele
Published: March 2024

The term "archaeometry" was first used in 1958 as the title of a special volume published by the Research Laboratory for Archaeology and Art History at Oxford University.  Archaeometry is a scientific discipline that employs various techniques primarily for the identification of sites, settlement patterns, archaeological stratigraphy, and the production and analysis of found artefacts.Ancient buildings, artifacts, and finds consist predominantly of natural and artificial resources obtained from geological sources. Geosciences techniques are optimal for obtaining information on the origin and technological properties of archaeological artefacts and materials used in cultural heritage from geological sources.This study conducted a petrographic and geochemical analysis of historical mortars from the Roman Theatre of Aosta and the Medieval Sarriod de la Tour Castel located in the Aosta Valley in North-West Italy. Mineralogical phase-specific distribution of elements in mortar samples was calculated using a semi-automated method of image analysis incorporating multivariate statistical analysis of X-ray spectral images. Based on SEM backscattering, a cluster image analysis was conducted to determine the ratio of aggregate, binder, and porosity. Additionally, simple algebraic operations were utilized to fully quantify the oxides in every EDS spectrum, and to compute the distribution of Hydraulicity Index (HI) within the examined domains.This study provided many answers about supply areas, variation of raw materials over time, network/transport systems, development and production processes. The petrographic analysis has enabled identification of both the binder and aggregate type. Specifically, it has afforded information on the type of raw material used to produce the lime, the ratio of binder to aggregate, the origin of the aggregate (sedimentary or crushed rock) and its composition.These investigations were conducted in close collaboration with archaeologists to reconstruct the exchanges between ancient civilizations and evaluate their technological progress.Ultimately, the progress of geosciences within the field of Cultural Heritage highlights how this type of study is essential for the dissemination and museology of what represents the culture of materials from  archaeological, historical and scientific point of view.
Numerical modeling of collapsed deep-seated gravitational slope deformations: insights from Velka Fatra Mts., Slovakia
Authors: Toločka Andrius , Kapustová Veronika
Published: March 2024

Large-scale deep-seated gravitational slope deformations (DSGSDs) are common but not highly investigated phenomena around the world. In the Carpathian Mountains, they played an important role during the Quaternary evolution of typical core mountain ridges formed by crystalline basement and surrounded by Mesozoic deposits. There is evidence that most of the biggest catastrophic rock slope failures (collapses) in the Carpathian Mountains appeared exactly in areas that are affected by DSGSDs. Two DSGSD-affected slopes (Brdo and Žlebiny) on the northeast side of the Velka Fatra Mountains (Western Carpathians, Slovakia) have been subjected to a detailed investigation involving geomorphic mapping, remote sensing analysis, structural data collection, and numerical modeling. To improve our understanding of these gravity-induced processes, we performed a back-analysis of collapsed DSGSDs through a 4-stage continuum-based finite-element model set up using the RS2 code (Rocscience). We used geomechanical rock data from fieldwork and previous laboratory tests, as well as interpretation in RSData software (Rocscience), to obtain the major rock mass parameters for the models. Results show that these DSGSDs are strongly predisposed by regional geological structures given by the intersection of bedding planes, joint sets, and thrust faults. The numerical modeling approach and performed back-analysis have enabled a better view of the development of these deep-seated slope failures in the Velka Fatra Mountains. It suggests a high diversity of mechanisms leading to the origin of these DSGSD cases. The main causal factors influencing their development have been bedrock structure, the lithological composition of dolomite and limestone layers, thrust faulting, and, finally, deep weathering of the rock mass. Both cases have deep basal shear zones and a few series of gravitational faults associated with complex joint sets. According to the numerical modeling results, Brdo DSGSD shows a typical scenario of a symmetrical sackung surrounded by shallow landslide areas, while Žlebiny DSGSD developed into a one-sided deep-seated slide with a few large-scale tilted rock blocks.
Stoichiometry of soil organic matter and microbial functional traits altered after 5 years of maize monoculture
Authors: Martín Roldán María , Vetterlein Doris , Tarkka Mika , Blagodatskaya Evgenia
Published: March 2024

The long-term transformation of organic matter in agroecosystems is modulated by soil properties and functional traits of plants and microorganisms, and is an indicator of soil quality. We studied how contrasting soil texture (loamy vs sandy) and two plant genotypes (a wild type, WT and a mutant deficient in root hairs, rth3) altered organic matter through microbial functioning in a field experiment after 5 years of maize monoculture. Our hypotheses were that (1) loamy rather than sandy soil will promote a larger OM storage; and (2) root-hairs, entailing a higher root-soil interface and water retention in the rhizosphere, boosting microbial processes and OM fluxes, will increase OM content not only in the rhizosphere but in the long-term, also in the bulk soil. To address these hypotheses, plots were filled with homogenized soil, being sandy soil a mix of 16.7 % loam with quartz sand, and the two maize genotypes. After 5 years of monoculture, soil was collected at the early maize growth stage of BBCH19, in the first 20 cm and the 20 to 40 cm depths. We determined stoichiometric ratios of total (TOC/TN) and labile (DOC/DON) fractions of soil organic matter, and microbial eco-physiological indexes related to OM transformation and sustainability, i.e. respiration-to-biomass ratio, qCO2, and microbial-to-total organic C ratio, Cmic:Corg.  The 5- and 7-times larger C supply in loamy vs sandy soil, for WT and rth3, respectively was explained by 40% more efficient C metabolism, i.e. less C losses through respiration per biomass unit, by 90% lower specific labile C content (DOC:Cmic ratio) and by 60% faster microbial turnover (µmax-1) in the former. As the TN content was only 3.1 and 4.2 times larger in loamy than sandy soil for WT and rth3 respectively, the resulting C:N ratio was 1.7- times greater for loamy than sandy soil, indicating more unbalanced stoichiometry in the former for both genotypes. Remarkably, the C and N content increased 20 and 36 %, respectively, after 5 years of maize monoculture, in the plots under root hair-deficient mutant than under wild type maize resulting in significantly larger C storage at rth3-plots in loamy soil. This may be explained by the reported higher exudates production by rth3 under the field conditions. Soil depth up to 40 cm did not show big differences in the capacity for C storage, likely due to similar root density in both depths. Concluding, loamy soil showed a higher capacity of C storage through microbial turnover and sandy soil demonstrated larger C losses through DOC compounds and respiration after 5 years of maize monoculture. Finally, carbon availability was not the limiting factor in sandy soil for microbial growth, but rather other factors such as soil water holding capacity, or OM fluxes from rhizosphere to bulk soil.
Frameworks for considering extreme weather risks in future climates given major uncertainties
Authors: Watson Peter
Published: March 2024

How can we best apply our science to predicting risks of extreme behaviour in a system as complex as the climate? It would be desirable to be able to represent all of our knowledge about the risks so that it can be applied to enable effective decision-making. Risk assessments often consider only the range of behaviour displayed by climate models, but a substantial part of the risk seems likely to be due to the possibility of the real world veering outside this range. It will be illustrated how implicitly ignoring this component would lead to risks being systematically underestimated, and how multi-model and initial condition large ensembles can be misleading. Recent work on storyline methods has illustrated potential ways to think beyond numerical model simulations, but downplays the quantification of event risks. But since we generally lack clear bounds on how intense extreme events can be, this seems to leave open the question of just how intense should the events be that are considered in analyses. It also does not seem to satisfy decision analyses that seek to quantitatively trade off protection against extremes against other benefits. This presentation considers how we can go beyond counting events in simulations, using tools such as climate models to inform our future projections without being constrained to ignore possible outcomes that they cannot simulate, whilst also retaining as much quantitative knowledge about event risks as possible and acknowledging when ambiguities become very large. Frameworks from philosophy and decision analysis will be surveyed and it will be discussed how these may help to show a way forward in our climate prediction predicament. It will be suggested that climate science should aim to be pluralistic in the knowledge frameworks it considers, to be of use to the broadest possible range of decision making.
Slope Stability Analysis and Mitigation of Mehla Landslide, District Chamba, Himachal Pradesh, India.
Authors: Banshtu Rajeshwar Singh , Versain Laxmi Devi , Singh Abhay Pratap
Published: March 2024

The Chamba Distirct is situated in the North Western part of the Himachal Pradesh State where presence of ancient monuments in the form of temples and holy lakes make this district a pilgrimage destination. Extensive damage to some of these monuments has been done due to occurrence of natural disasters. Himalayas represents a highly sensitive ecosystem vulnerable for natural disasters. Landslides are common phenomena in this geodynamically active terrain triggered by a wide variety of factors. The increased magnitude and frequency of Landslides is a cause of concern, since these interfere with human interest, causing immense loss to human life, infrastructure and natural resources. Extensive human activity in the region has further intensified erosion and triggered slope failures. The consequences are occurrence of large landslides, particularly in the zones of active faults and thrusts. The Chamba- Bharmaur highway has number of such active slide zones which causes obstruction for normal activities of the inhabitants. The area lies in seismically active region due to which occurrence of micro-earthquake at repeated intervals disturbs the already weathered rock mass. The initiation of Landslide near Mehla village on NH-153 can be attributed to the developmental activities ranging from farming on hill slopes to development of highways. Based upon geotechnical properties, numerical modeling of the landslide site using Geo5 software was conducted in order to calculate the factor of safety. The results of the numerical study can be used to ascertain the dependability of these slopes for future activities and suggesting mitigation measures to lower the frequency and severity of landslides in areas with similar geological conditions. This will further help in preserving the rich ancient heritage from occurrence of natural disasters in this region.Keywords: natural disaster, ancient monuments, earthquake, hill slopes.
The impact of extreme heat on lake warming in China
Authors: Wang Weijia , Shi Kun , Woolway Iestyn
Published: March 2024

Global lake ecosystems are subjected to an increased occurrence of heat extremes, yet their impact on lake warming remains poorly understood. In this study, we employed a hybrid physically-based/statistical model to assess the contribution of heat extremes to variations in surface water temperature of 2260 lakes in China from 1985 to 2022. Our study indicates that heat extremes are increasing at a rate of about 2.08 days/decade and an intensity of about 0.03 °C/ day·decade in China. The warming rate of lake surface water temperature decreases from 0.16 °C/decade to 0.13 °C/decade after removing heat extremes. Heat extremes exert a considerable influence on long-term lake surface temperature changes, contributing 36.5% of the warming trends within the studied lakes. Given the important influence of heat extremes on the mean warming of lake surface waters, it is imperative that they are adequately accounted for in climate impact studies.
Land-Atmosphere Interactions over North West Himalaya
Authors: Navale Ashish , Lanka Karthikeyan
Published: March 2024

Precipitation can originate from evaporated water over oceans and land in remote locations or from local terrestrial sources. The precipitation due to these local sources is called recycled precipitation. Recycled precipitation has been used extensively to study land-atmosphere interaction and has shown to be helpful when studying the relationship between atmospheric or terrestrial variables and precipitation. Mountainous areas such as the Himalaya, Tibetan Plateau, Alps, Andes, and the Rocky Mountains are a hotspot for high local recycling and land-atmosphere interaction. The North West Himalaya (NWH) has drawn attention recently to the issue of climate change due to the region's drastically reduced rainfall and rapidly rising temperature over the past century. Climate change also affects the large number of processes involved in land-atmosphere interaction. The complex topography and heterogeneous climate of NWH makes it challenging to understand the land-atmosphere interaction in this region. In this study, we use an Eulerian water tagging method implemented into the Weather Research and Forecasting (WRF) model to study land-atmosphere interaction in NWH. This method is considered one of the most accurate techniques to quantify recycled precipitation. We simulated summer (June, July, August, and September) and winter (December, January, February, and March) precipitation in the NWH for twenty years from 2001 to 2020.Results show that, due to availability of more thermal energy the summer experienced more recycling than winter. The western disturbances in winter and southwest monsoon during summer contributes to the locally evapotranspirated moisture and affects the recycling ratio of NWH. However, the irregular western disturbances lead to high variability in the winter recycling ratio. Our analysis shows a strong diurnal cycle of recycling ratio in NWH which peaks in the afternoon. The trend analysis from twenty years although did not show any significant trend in recycled precipitation, other variables affecting land-atmosphere interaction such as soil moisture, latent heat and 2-meter air temperature showed significant trends in NWH. We also studied land-atmosphere interaction over two contrasting regions: the foothills of Himalaya and the high-elevation region. The recycled precipitation was high in the lower elevations during summer and at higher elevations during winter. We also found higher land-atmosphere interaction during summer at higher elevations and during both summer and winter at foothills. However, due to continuous precipitation along the foothills of NWH, a brief shift in soil moisture to a wet regime is expected during monsoon which reduces the influence of soil moisture on the atmosphere leading to low land-atmosphere interaction. However, good land-atmosphere interaction exists throughout the summer in the higher Himalaya, where this change in regime is not apparent.
Unlocking the H2 potential in Saudi Arabia: Exploring serpentinites as a source for H2 production
Authors: Saidy Kebba , Fawad Manzar , Whattam Scott , Al-Shuhail Abdullatif , Alshuhail Abdullah , Alqubalee Abdullah , Mohammed Farooqui , Sulistyohariyanto Faris , Chattopadhyay Sabyasachi
Published: March 2024

The global transition to a low-carbon energy future has ignited interest in hydrogen as a clean and versatile energy carrier. Saudi Arabia contains, vast tracts of mantle-dominated Neoproterozoic ophiolites overlain by a sedimentary cover in the east. Our research explores the untapped potential of Saudi Arabia’s ophiolite serpentinites as a possible source of hydrogen generation through serpentinization and related processes. H2 is derived from serpentinization, which primarily involves the hydration of minerals rich in iron and magnesium, (e.g., olivine), resulting in the formation of serpentine and H2.  We have conducted a comprehensive assessment of serpentinites in the Arabian Shield employing the Geographic Information System (GIS) to locate, Arabian ophiolites with the largest ultramafic segments. Ophiolites studied include Jabal Ess, Jabal Wask, Bi’r Tululah, and Jabal Tharwah. Subsequent to ophiolite identification, we delineated fractures and measured fracture density to provide insight into the potential of serpentinite fractures on the amount of hydrogen seepage and the rate of hydrogen production. The results of our quantitative fracture density analysis and their relation to the volume and rate of hydrogen production will be discussed. A complimentary H2 anomaly survey will ground-truth the results of this study.
The behavior of Li and B isotopes in high-T and low-T eclogites enclosed by phengite schists
Authors: Wang Dan , Romer Rolf , Liu Fulai , Glodny Johannes
Published: March 2024

Subduction zones are critical sites for recycling of Li and B into the mantle. The way of redistribution of Li and B and their isotopes in subduction settings is debated, and there is a lack of detailed studies on Li and B partitioning between minerals of different types of eclogites and their host rocks. We present Li and B concentration data of minerals and Li and B whole-rock isotope data for low-T and high-T eclogites and their phengite schist host rocks from the Changning–Menglian suture zone, SW China. Omphacite controls the Li budget in both the low-T and high-T eclogites. Low-T eclogites have Li and δ7Li values (8.4–27.0 ppm, –5.5 to +3.2 ‰) similar to their phengite schist host rocks (8.7–27.0 ppm, –3.8 to +3.0 ‰), suggesting that Li was added to low-T eclogites from the phengite schists. In contrast, high-T eclogites have much lower δ7Li values (–13.2 to –5.8 ‰) than the phengite schists, reflecting prograde loss of Li or exchange with wall rocks characterized by low δ7Li values. Phengite and retrograde amphibole/muscovite are the major B hosts for low-T and high-T eclogites, respectively. The budgets and isotopic compositions of B in eclogites are affected by the infiltration of fluids derived from phengite schists, as indicated by eclogite δ11B values (–15.1 to –8.1 ‰) overlapping with the values of the phengite schists (–22.8 to –9.5 ‰). Lithium and B in eclogites are hosted in different mineral phases that may have formed at different stages of metamorphism, implying that the contents and isotopic compositions of Li and B may become decoupled during subduction-related fluid-mediated redistribution. We suggest a mineralogical control on the redistribution of Li and B in eclogites during subduction and the exchange of Li and B with the immediate wall rocks. The observed contrasting Li and B isotopic signatures in eclogites are likely caused by a fluid-mediated exchange with different types of wall rocks during both prograde metamorphism and exhumation.
Memory of the Sea: an art-science collaboration across generations in two Arab villages in Israel
Authors: Lazar Michael , Sher Daniel , Tenenbaum Tamar , Mawasi Jasmine , Ammash Kefayaa , Soussan Yara , Fawaz Nabaa
Published: March 2024

People who live by and off the sea have a collective memory of it and how it has changed over the generations. This memory is a vital part of the connection between them and their environment, and can provide important scientific insights on how the sea has changed over time (e.g. species and habitat abundances, pollution, etc.). It can help guide the community as it searches for ways to responsibly harness the sea while conserving it for future generations. In this project, we explored means of recording the memory of the sea in collaboration with teenagers living near the coast of Israel from the two Arab villages of Jisr-az-Zarqa and Fureidis. The project included several field trips to the coast, each focusing on a different geological and ecological aspect, after which the teenagers interviewed and recorded their elders (parents, grandparents and/or fishermen) describing their memories of the coastal environment. These included songs about the sea, the role of women and their connection to the sea, descriptions of fish and plants, and more. The interviews were accompanied by photographic portraits, and initial scientific measurements were carried out by the students to assess current pollution in a nearby river. More advanced measurements are planned for the near future. A major challenge in the project was overcoming the language barrier and cultural differences between the academic researchers and the teenagers. This was facilitated by having the project led by educators from the villages themselves and/or other Arab communities. Efforts to finalize the interviews and translate the recordings into English and Hebrew are ongoing, and the more advanced scientific data has not yet been collected, with the project running into complications due to the current war between Israel and Gaza. The final aim is to have the project stay in the local communities as a cultural archive by housing the Memory of the Sea at a local museum in Jisr-az-Zarqa and in other venues around Israel.
Towards integrated models of mantle convection, surface dynamics and climate evolution 
Authors: Werner Niklas , Verard Christian , Brunetti Maura , Tackley Paul , Gerya Taras
Published: March 2024

The long-term evolution of the biosphere on Earth is tightly coupled to changes in the geosphere and climate. Investigating the evolution of Earth’s climate over the course of the Phanerozoic and beyond requires extensive numerical modelling efforts. Classically, this has been done using Earth System Models of varying complexity. While these models are well-suited to simulate a majority of processes in the ocean, the atmosphere and on the land surface, they lack a key component of the Earth system ―  the interior. Processes in the mantle drive plate tectonics on Earth and by means of degassing are a key factor in determining the atmospheric CO2 concentration, influencing biological evolution. Both, the position of continents as dictated by plate tectonics as well as the concentration of greenhouse gases in the atmosphere are known to be crucial in shaping Earth’s climate. An important suite of mechanisms that influences both climate and mantle can be found in silicate weathering, the erosion of weathered material and its transport and sedimentation in subduction zones. The influx of sediments into subduction zones has been shown to alter the rheology of the subduction slab, influencing the speed of subduction and chemistry of the slab and thereby impacting mantle convection processes (e.g. Bello et al., 2015). Here, we present a framework for coupling the new PANALESIS paleogeographic reconstruction (Vérard, 2019) to an Earth System Model of Intermediate Complexity (EMIC) and the mantle convection model with plate tectonics based on StagYY code. This is done using climate output from the EMIC to force a landscape evolution model that is used to compute sediment influx into subduction zones. Degassing rates obtained from the mantle convection simulations are then used to assess atmospheric CO2 levels and create climate lookup tables for different degassing scenarios. These data can then be used to force a temporally continuous carbon cycle model to update previous pCO2 curves for the Phanerozoic and beyond. Given the new paleogeographic reconstruction and the more sophisticated modelling framework, this approach may give new insights into the long-term interactions between mantle and climate and the consequences for biological evolution.ReferencesBello, L., Coltice, N., Tackley, P. J., Müller, R. D., & Cannon, J. (2015). Assessing the role of slab rheology in coupled plate-mantle convection models. Earth and Planetary Science Letters, 430, 191-201.Vérard, C. (2019). PANALESIS: Towards global synthetic palaeogeographies using integration and coupling of manifold models. Geological Magazine, 156(2), 320-330.
Constraining ion transport in the diamagnetic cavity of comet 67P
Authors: Lewis Zoe , Beth Arnaud , Galand Marina , Henri Pierre , Rubin Martin , Stephenson Peter
Published: March 2024

Comets are small icy bodies originating from the outer solar system that produce an increasingly dense gas coma through sublimation as they approach perihelion. Photoionisation of this gas results in a cometary ionosphere, which interacts with the impinging solar wind, leading to large scale plasma structures. One such structure is the diamagnetic cavity: the magnetic field-free inner region that the solar wind cannot penetrate. This region was encountered many times by the ESA Rosetta mission, which escorted comet 67P/Churyumov-Gerasimenko for a two-year section of its orbit.Within the diamagnetic cavity, high ion bulk velocities have been observed by the Rosetta Plasma Consortium (RPC) instruments. The fast ions are thought to have been accelerated by an ambipolar electric field, but the nature and strength of this field are difficult to determine analytically. Our study therefore aims to model the impact of various electric field profiles on the ionospheric density profile and ion composition. The 1D numerical model we have developed includes three key ion species (H2O+, H3O+, and NH4+) in order to assess the sensitivity of each to the timescale of plasma loss through transport. NH4+ is of particular interest, as it has been previously shown to be the dominant ion species at low cometocentric distances near perihelion. It is only produced through the protonation of NH3, a minor component of the neutral gas, and we show that this makes it particularly sensitive to the electric field.We also compare the simulated electron density to RPC datasets, to find the electric field strength and profile which best recreate the plasma densities measured inside the diamagnetic cavity near perihelion. From this, we also constrain the radial bulk ion speed that is required to explain the observations with the model.
Global long-term hourly 9 km terrestrial water-energy-carbon fluxes with physics-informed machine learning
Authors: Han Qianqian , Zeng Yijian , Wang Yunfei , Alidoost Fakhereh (Sarah) , Nattino Francesco , Liu Yang , Su Bob
Published: March 2024

In this study, we generate a global, long-term, hourly terrestrial water-energy-carbon fluxes, using model simulations, in-situ measurements, and physics-informed machine learning. The soil-plant model, STEMMUS-SCOPE was deployed to simulate land surface fluxes over 170 Fluxnet sites (STEMMUS – Simultaneous Transfer of Energy, Mass, and Momentum in Unsaturated Soil; SCOPE - Soil Canopy Observation, Photochemistry and Energy fluxes radiative transfer model). The model input and output data were then used as training data-pairs to develop the STEMMUS-SCOPE emulator using multivariate random forests regression algorithm. Here, physics-informed machine learning refers to the fact that the emulator was trained and constrained by the physical consistency represented by the soil-plant model. We compared the physics-informed emulator (RF_S-S) with the one trained using only Fluxnet in-situ measurements (RF_in-situ), and found that the land surface fluxes predicted by RF_S-S are less scattered than that by RF_in-situ.We estimate six variables simultaneously: net radiation, latent heat flux, sensible heat flux, gross primary productivity, solar-induced fluorescence in 685 nm and 740 nm. Results show that RF_S-S can estimate fluxes with Pearson Correlation Coefficient score (r-score) higher than 0.97 for these six variables. The testing result using independent stations (not included for developing emulators) show a r-score higher than 0.94. The feature importance shows that incoming shortwave radiation, surface soil moisture, and leaf area index are top predictor variables that determine the prediction performance. We further explore the performance of RF_S-S in predicting soil heat flux, root zone soil moisture, and leaf water potential, which assist the understanding of ecosystems’ drought responses to climate change.
Improvements of Radiative Transfer Processes in CoLM-Lake based on applications in in-situ lake simulations
Authors: Cao Xueqi , Wei Nan , Wei Zhongwang , Lu Xingjie
Published: March 2024

Lakes play an important role in the context of climate change response, necessitating accurate simulation of their thermal states to address associated challenges. Despite the progress in lake modeling, the description of several processes within current models require improvement. Traditional 1-D models often neglect the extinction effect of lake ice and oversimplify the extinction coefficient of lake water with a parameterized schemes. Moreover, the radiative transfer scheme adheres to the conventional Beer law. This study aims to enhance the radiative transfer process within the CoLM-Lake (The Common Land Model – Lake scheme). Implementation steps involve integrating observed water extinction coefficients for individual lakes, introducing the ice extinction coefficient, distinguishing radiation calculations between the visible light and infrared band, and replacing the traditional Beer law with a two-stream approximation scheme. The research analyzes simulation results regarding to freeze-thaw cycles, latent heat flux, sensible heat flux, lake surface temperature, and vertical temperature profiles. Results indicate that the simulated European lake surface temperatures driven by ERA5-LAND outperforms those for American lakes by CoLM-Lake. Incorporating observed water extinction coefficients, adding ice extinction, and employing the two-stream approximation scheme results in slight changes to the freeze-thaw date, but significant variations in ice thickness. For lakes with greater depths, the simulated latent and sensible heat flux exhibit substantial improvements, with more consistency with observed data. Validation of vertical temperature profiles for Nam Co (92m) and Sparkling (18m), two representative lakes, reveals that the original CoLM-Lake scheme overestimates/underestimates the upper lake temperature of Nam Co during summer/winter, and underestimates the winter upper temperature and summer lower temperature of Lake Sparkling. However, considering ice extinction and implementing the two-stream approximation mitigates these simulation errors. The study further incorporates ice dynamic processes into CoLM-Lake, distinguishes lake ice ages, and differentiates ice between blue and white ice, with subsequent evaluation. In conclusion, adopting the proposed scheme enhances the physical processes within CoLM-Lake, resulting in improved simulation performance.
Destinations of Climate Monitoring information: State of the Climate reports
Authors: Blunden Jessica , Dunn Robert , Kennedy John
Published: March 2024

One of the goals of climate monitoring is to ensure that the ongoing changes in the Earth's climate system are placed in context against longer-term changes and are clearly and widely communicated.  There are a number of reports produced on an annual basis which collate and synthesise the outputs from climate monitoring products for a range of essential climate variables (ECVs) and extreme climate events.  Among the most highly regarded peer-reviewed global-scale publications, a provisional version of the World Meteorological Organisation (WMO) State of the Global Climate report feeds into the United Nations Framework Convention on Climate Change Conference of the Parties (UNFCCC COP) process each year, directly informing policy makers and stakeholders about the current state of several key climate metrics.  The more comprehensive BAMS State of the Climate report is an almanac of the major events of each year and an assessment of more than three-dozen ECVs that encompass Earth's land, oceans, cryosphere, and atmosphere, which provides a useful reference document for a wide range of stakeholders, from the general public to educators to private and public decision makers.  In this presentation we outline the process behind each report, the wide range of information they contain, and give pointers on how to get more involved.