bluuebunny/crossref_metadata_2025 huggingface dataset:
A comprehensive petrophysical databank of crystalline reservoirs for assessing deep geothermal exploration targets in Finland and abroad
Authors: Heap Michael , Bischoff Alan , Luoto Toni , Reuschlé Thierry , Vuoriainen Satu , Spitz Marion , Leon-Stackow Marianne
Published: March 2024

ContextAs part of the Deep-HEAT-Flows project (https://deep-heat-flows.voog.com), we have collected a comprehensive geological and petrophysical dataset of crystalline reservoirs formed within fault zones and at the contact of igneous intrusions across Finland, evaluating their potential as deep geothermal reservoirs. Our investigations involve a range of laboratory-based experiments encompassing measurements of rock density, elastic wave velocity, electric resistivity, porosity, and permeability under various confining pressures, and the thermal properties of 120+ samples collected from diverse crystalline rocks. Additionally, we apply mineral and pore space caracterization techniques including petrography, micro-XRF spectrometry, SEM-EDS, hyperspectral imaging, and CT scans to understand the processes that control crystalline reservoir formation.FindingsOur findings highlight a common trend among various petrophysiscal parameters: rock density, resistivity, elastic wave velocity, thermal conductivity, and heat capacity typically reduce as the porosity increases, a characteristic observed across many sedimentary and volcanic rocks. Reservoir quality is primarily determined by the morphology of the pore network, encompassing fractures and interconnected moldic, sieve, and interparticle pores. The most promising reservoir properties were observed in rocks intersected by regional shear zones and therefore affected by intense brecciation, cataclasis, and hydrothermal alteration, leading to a notable porosity of ~20% and permeability in the order of 10−12 m2 (1 darcy). Moreover, the contact margin of rapakivi intrusions also include fractured and hydrothermally altered rocks that have significantly high porosity and permeability. In detail, rocks dominated by fractures typically have little porosity (
Very long-period observations at Piton de la Fournaise volcano, La Réunion
Authors: Duputel Zacharie , Costes Lucile , Ferrazzini Valérie , Lengliné Olivier
Published: March 2024

Volcanoes often exhibit very long period (VLP) signals, with periods ranging from 2 to 100 seconds. Due to their very long wavelengths, these waveforms are not strongly affected by volcano structural heterogeneities and provide invaluable insights into dike and magma properties that are not easily accessible though other observations. Historically, only a few VLP events have been recorded at the Piton de la Fournaise, primarily associated with collapses in the summit caldera in 1986, 2002 and 2007. However, since 2010, the monitoring network has evolved significantly and it is now equipped with several broadband stations, allowing a wide range of signals to be recorded. In this study, we show that VLP events are quite common at Piton de la Fournaise. Specifically, we identify swarms of VLP events during eruptions and during magma injections preceding eruptions. Source analysis of VLP events during eruptions indicates the resonance of the dike during sudden decreases in magma flow. Pre-eruptive VLP waveforms exhibit significant differences from those observed during eruptions, pointing to a distinct source process as the dike propagates laterally toward the volcano flank.
Fully Differentiable Physics-informed Lagrangian Convolutional Neural Network for Precipitation Nowcasting
Authors: Pavlík Peter , Výboh Martin , Bou Ezzeddine Anna , Rozinajová Viera
Published: March 2024

The task of precipitation nowcasting is often perceived as a computer vision problem. It is analogous to next frame video prediction - i.e. processing consecutive radar precipitation map frames and predicting the future ones. This makes convolutional neural networks (CNNs) a great fit for this task. In the recent years, the CNNs have become the de-facto state-of-the-art model for precipitation nowcasts.However, a pure machine learning model has difficulties to capture accurately the underlying patterns in the data. Since the data behaves according to the known physical laws, we can incorporate this knowledge to train more accurate and trustworthy models.We present a double U-Net model, combining a continuity-constrained Lagrangian persistence U-Net with an advection-free U-Net dedicated to capturing the precipitation growth and decay. In contrast to previous works, the combined model is fully differentiable, allowing us to fine-tune these models together in a data-driven way. We examine the learned Lagrangian mappings, along with a thorough quantitative and qualitative evaluation. The results of the evaluation will be provided in the presentation.
Take a photo, post it, alert it!
Authors: Ristov Mite
Published: March 2024

Encouraged by the problem of constantly air pollution, especially in the winter mounts, a group of students from the Josip Broz – Tito High School from Bitola, North Macedonia, under the mentorship of the geography teacher and in cooperation with the NGO Geosfera, conducted a school project. The main objectives of the project were: raising awareness among pupils about the harmful effects of PM particles on human health, identifying the city's air polluters, measuring PM particles concentrations in different locations around the city and informing the public and preparing draft mitigation measures of air pollution.First, the students held an educative lecture in front of the rest of the pupils at the school about the harmful effects of PM particles on human health. Then, we started a campaign to involve students and all citizens of Bitola in identifying the city's air polluters. Through the social networks, instructions were given, such as through an online Аpp and the GPS signal from the smart phone, to take a picture from a suspicious air polluter and to post the image with the given geographic coordinates on our Facebook group. A working group of students, according to the given coordinates of the citizens, put the polluters on an interactive map of Google Maps. A link from the map was sent to the authorized environmental inspector in the municipality, with the goal of faster response and inspection to those polluters.The absence of multiple measuring stations created numerous speculations among the citizens, but also with the institutions in the city, where the enormous air pollution originated, whether from the Thermal Power Plant Bitola or from the city itself.Therefore, in cooperation with the NGO Geosfera, we decided to measure the current concentrations of PM10 particles in two periods of the day, between 14 and 15, and between 19 and 20 hours. The measurements were made with a mobile particle detector at 14 locations. After the measurements were made, using the Google Earth, two maps were created, showing the results of the measurements. The obtained results confirm the suspicions that the cause of enormous air pollution in Bitola is not TPP Bitola, but households that mostly warm their homes with firewood (over 60%, Source: State Statistical Office). Also, a large number of citizens of our Facebook group have commented that part of the problem are Forest enterprises, which usually supply wet firewood. According to the US EPA, wet wood produces three times more PM particles compare with dry wood.The students from the school, in cooperation with the NGO Geosfera and the geography teacher, developed and submitted to the Municipality measures for reduction of air pollution. All these proposed measures were placed on an interactive map on Google Maps, through which all the citizens of Bitola will be able to visualize them.The action received positive reviews from the public in the city and achieved the desired effect, which is raising awareness among young people and alerting the competent institutions to solving the accumulated problems.
Effect of Implementing Moho Depths on Gravity Interpolation at Large Data Gaps 
Authors: Abd-Elmotaal Hussein , Kühtreiber Norbert
Published: March 2024

The coverage of the gravity data plays an important role in the geoid determination process. Still some parts in the world have poor gravity data coverage, with sometimes, large data gaps, e.g., Africa. In this paper we study the effect of implementing Moho depths on the gravity interpolation at large data gaps. For this reason, and in order to qualify that effect, an artificial data gap has been made in the gravity data set of Austria (originally with perfect gravity data coverage). The outcome of the present study is essential for the IAG sub-commission on the gravity and geoid in Africa in order to determine the African geoid from the available data sets with the best possible precision. The gravity interpolation has been made at the original omitted data points at the data gap with and without the Moho information. The interpolated gravity has thus been compared to the original omitted data values for both cases to determine the effect of using Moho depths on gravity interpolation. The results are shown and comprehensively discussed.
Pacific Array: international collaboration for large-scale array experiment in the Pacific basin
Authors: Isse Takehi , Kawakatsu Hitoshi , Lee Sang-Mook , Kuo Bang-Yuan , Gaherty James B.
Published: March 2024

             Constructing a seismic network in the oceans has been one of the most difficult challenges in seismology. Almost 70 % of the Earth's surface is covered by the ocean, so such a network is necessary for investigating the Earth's interior. Because the Pacific Ocean is the largest ocean basin, it was considered impractical to establish a large-scale dense seismic array.              However, in 2014, Kawakatsu and colleagues proposed a new array concept (Kawakatsu et al., 2014). Deploying ~15+ BBOBS as an array unit for 1-2-year observation period, and repeating such observations in a leap-frog fashion for a decade or so, would enable us to cover a large portion of the Pacific Ocean. International collaboration was essential to successfully implement this strategy, and since 2015, the concept has been realized as "Pacific Array" via international collaboration between partners in Japan, U.S.A, EU, South Korea, Taiwan, and China.              Since then, many array units have been funded, providing broadband data from across the Pacific. Oldest-1 (Japan-S. Korea), Oldest-2 (Japan-Taiwan), Young- and Old-ORCA, and OHANA (U.S.A) have all been completed; Galapagos and SaLOON (U.S. A.) are currently deployed; and HEB (Japan-Germany), GTJ, and EPIC (U. S. A.) will be deployed in the near future. Although each of these observations have their own scientific goals, they contribute to the larger international Pacific Array structure. We summarize recent progress of the Pacific Array and some of scientific result in each array.
Silicone availability and NaCl water type enhances the phosphorus release from sediments in coastal forest catchments in Akita, Japan
Authors: Hayakawa Atsushi , Kuroe Yuka , Kawata Ayumi , Nishina Kazuya , Ishikawa Yuichi , Takahashi Tadashi
Published: March 2024

[Background] Phosphorus (P) availability in soils and sediments is a critical parameter influencing primary production in terrestrial and aquatic ecosystems, controlled by both P chemical fractions in solid phase and solution composition. A recent study using Arctic soils reported that the addition of Si to the soil released P bound to Fe(II) compounds, but reports on other soils and sediments are limited. In our previous study, we detected higher P concentrations in stream water and iron-bound P content in river sediments in the marine sedimentary rock catchments of the Akita coastal area compared to catchments in the adjacent igneous rock area. Furthermore, high-P stream waters were NaCl water type with relatively lower Ca2+ and higher SiO2 concentrations. In this study, we evaluated the effects of different solution compositions and amorphous Si addition on P solubilization in sediments using river sediments from marine sedimentary and igneous rock regions. [Method] We tested each five river sediments (
Petrography and mineralogy control the nm-μm-scale pore structure of  lacustrine carbonate-rich shales of  China
Authors: Gou Qiyang , Lu Yangbo
Published: March 2024

Carbonate-rich shale in salt lakes has become a potential target for petroleum exploration. A full understanding of storage space development characteristics is the basis for the efficient development of this kind of shale. In this study, the complex mineral composition and multiple pore structure of a typical carbonate-rich shale from the Paleogene Xin’gouzui Formation in the Jianghan Basin were systematically analyzed. The mixed shale and dolomitic shale were the main lithofacies types in the study area. Both of them were dominated by interparticle (interP) pores. However, their pore sizes are noticeably different. Pores with a size of <100 nm are the main compositions of the mixed shale, with an average volume proportion of 78.24%. Conversely, the dolomitic shale develops mainly micro-sized pores and micro-fractures, with a ratio of 70.46%. The difference in pore structure for different types of shales is closely associated with mineral composition. When particles of different sizes are mixed, most of the interP pores are prone to be filled by fine minerals (e.g., clay), resulting in relatively small pore sizes for the mixed shale. Homogeneous carbonate minerals are favorable for the residual of larger size interP pores. However, recrystallization and secondary enlargement of carbonate minerals can also lead to a significant decrease in pore diameter of interP pores. With these results, a storage space development model for different lithofacies shales was established. This work is crucial to further reveal the reservoir mechanisms and hydrocarbon scales of an argillaceous dolomite reservoir.
Role of sediment-derived melts in Mo cycling of subduction zone
Authors: Huang Feng , Li Jie , Xu Jifeng , Zeng Yunchuan
Published: March 2024

While heavy molybdenum (Mo) isotope compositions in arc-related rocks have been linked to slab-derived fluids, the origins of arc lavas with light isotopic Mo compositions remain enigmatic. The two potential sources for the origin of light Mo isotopes in arc rocks are (1) dehydrated oceanic crust 1, 2 and (2) subducting sediments 3, 4. Although the former has been extensively recognized, the latter still poses an enigma. We present the Mo-Sr-Nd-Hf isotope compositions and elemental data of a suite of Jiang Tso andesites to elucidate the chemical compositions of sediment-derived melts in the central Tibetan Plateau. The andesites from the Jiang Tso area show elevated Mg# values, along with trace element characteristics reminiscent of melts derived from sediments. Their Sr-Nd-Hf isotope compositions (87Sr/86Sri = 0.710260–0.710671, εNd(t) = –10.63 to –8.97, and εHf(t) = –9.38 to –8.02) closely resemble those of contemporaneous sediments in the central Tibetan Plateau. In addition, these andesites exhibit higher Ce/Mo ratios (396–587) and extremely lighter δ98/95Mo values (−1.62‰ to −0.69‰) compared to the depleted mantle (δ98/95Mo = –0.21‰ ± 0.02‰) 5, 6 and the majority of arc lavas (δ98/95Mo = –0.07‰ ± 0.04‰) 3, suggesting a more plausible explanation lies in the involvement of subducting sediments rather than dehydrated oceanic crust in the source. Our latest findings, integrated with previous studies, indicate that the arc-related rocks exhibiting light Mo isotopes may not solely originate from the rutile-breakdown oceanic crust source but could also result from sediment melting at various sub-arc depths. Consequently, sediment-derived melts play a crucial role in Mo isotope cycling and the formation of arc magmas in subduction zones. 1 Chen, S., et al., Nat. Comm. 10, 4773 (2019). 2 Freymuth, H., et al., EPSL 432, 176-186 (2015). 3 Huang, F., et al., GCA 341, 75-89 (2023). 4 König, S., et al., EPSL 447, 95-102 (2016). 5 McCoy-West, A.J., et al., Nat. Geos.12, 946-951 (2019). 6 Willbold, M. & Elliott T., CG 449, 253-268 (2017).
Statistical downscaling of extremes in seasonal predictions - a case study on spring frosts for the viticultural sector
Authors: Roncoroni Sebastiano , Athanasiadis Panos , Gualdi Silvio
Published: March 2024

Spring frost events occurring after budburst of grapevines can damage new shoots, disrupt plant growth and cause large economic losses to the viticultural sector. Frost protection practices encompass a variety of vineyard management actions across timescales, from seasonal to decadal and beyond. The cost-effectiveness of such measures depends on the availability of accurate predictions of the relevant climate hazards at the appropriate timescales.In this work, we present a statistical downscaling method which predicts variations in the frequency of occurrence of spring frost events in the important winemaking region of Catalunya at the seasonal timescale. The downscaling method exploits the seasonal predictability associated with the predictable components of the atmospheric variability over the Euro-Atlantic region, and produces local predictions of frost occurrence at a spatial scale relevant to vineyard management.The downscaling method is designed to address the specific needs highlighted by a representative stakeholder in the local viticultural sector, and is expected to deliver an actionable prototype climate service. The statistical procedure is developed in perfect prognosis mode: the method is trained with large-scale reanalysis data against a high-resolution gridded observational reference, and validated against multi-model seasonal hindcast predictions. Our work spotlights the potential benefits of transferring climate predictability across spatial scales for the design and provision of usable climate information, particularly regarding extremes.
Time-series analysis on multi-modal data for precisionviticulture to support adaptation to changing climate patternsin Franconia
Authors: Brandmeier Melanie , Heßdörfer Daniel , Meyer-Spelbrink Adrian , Siebenlist Philipp , Kraus Anja
Published: March 2024

The cultivation of vine is an important economic sector in agriculture as well as a cultural legacyin many regions. Lower Franconia is one of Germany’s largest wine-producing areas with morethan 6,000 ha of vineyards and a production of 450,000 hectolitres of wine. In the context of climatechange, strategies to adapt to changing precipitation and temperature patterns and to mitigate risksfrom drought and grape diseases is of utter importance for sustainable viticulture. Water deficitproduces diverse effects, such as reduced berry size or the failure of fruit maturation, depending on theplant’s growth stage [1]. Severe water stress triggers partial or complete stomatal closure, resulting in areduction of photosynthetic activity [3]. Thus, ideal soil moisture is key to sustainable viticulture andmonitoring plant development, soil moisture and climate variables is crucial for precision viticulture[2]. Due to the typical trellis systems, satellite remote sensing using deca-meter resolutions (suchas Landsat or Sentinel-2 series) is not well-suited for plant monitoring as pixel information at thisresolution consists of vines and ground information of the space between plant rows that might begrass, other plants or soil. Thus, we investigate time-series of very-high-resolution multispectraldata derived from a UAV-based system, hyperspectral data from in-situ measurements as well assensor data for soil moisture and evaluate results with respect to different irrigation patterns. Suchmulti-sensor and multi-temporal approaches contribute to a better understanding of the vineyardas a dynamic system and, thus, lead to better monitoring and management options and allow tobuild a GIS-based Digital Twin of the vineyard. We will present first results from daily to weeklymeasurements, evaluate different vegetation indices and highlight temporal patterns and reactiontimes between soil moisture data and spectral measurements.[1] WJ Hardie and JA Considine. “Response of grapes to water-deficit stress in particular stages ofdevelopment”. In: American Journal of Enology and Viticulture 27.2 (1976), pp. 55–61.[2] Margareth A Oliver. “An overview of geostatistics and precision agriculture”. In: Geostatisticalapplications for precision agriculture (2010), pp. 1–34.[3] Maria Romero et al. “Vineyard water status estimation using multispectral imagery from an UAVplatform and machine learning algorithms for irrigation scheduling management”. In: Computersand Electronics in Agriculture 147 (Apr. 2018), pp. 109–117. (Visited on 10/10/2023).
Estimation of coniferous shoot structures by high precision blue light 3D photogrammetry scanning
Authors: Pisek Jan , Borysenko Oleksandr , Kuusk Andres
Published: March 2024

Clumping describes the heterogeneity of forest structure - the spatial arrangement of foliage elements, such as leaves or needles, within a vegetation canopy. Clumping information is essential for assessing radiation transfer through canopies, photosynthesis, and hydrological processes. The challenge in conifer stands arises from the difficulty of measuring gaps between needles within a shoot using traditional optical instruments, or LiDAR. Previous methods for estimating needle-to-shoot-area ratio were often destructive and labor-intensive. In this study, we introduce a highly efficient technique—blue light 3D photogrammetry scanning—to comprehensively characterize the structure of conifer shoots and determine shoot-level clumping. This approach significantly reduces the labor intensity associated with previous methods. To validate our technique, we compared it to the established photographic/volume displacement method for quantifying shoot-level clumping. Here, we present 3D shoot models, shoot-level clumping values, and their seasonal variations for a wide range of European native conifer species.The demonstrated effectiveness and performance of the blue light 3D photogrammetry scanning method offer the potential for more frequent and accurate measurements of 3D shoot structures. This advancement opens doors to further improvements in measuring and upscaling optical properties for coniferous canopies. In future research, the enhanced understanding of needle shoots, a fundamental yet often overlooked aspect of foliage clumping in canopies, will significantly improve 3D radiative transfer modeling for coniferous forests.
Remote sensing-based frameworks to quantify city-level carbon fluxes in urban green infrastructures
Authors: Kira Oz , Bamah Julius , Muleta Alexander , Bushner Shirley
Published: March 2024

The urban population is experiencing rapid growth, and it is estimated that around 90% of people will be living in cities by the year 2100. Given that urban areas are significant sources of greenhouse gas and pollutant emissions, and with the expectation that these urban areas will become even more densely populated, achieving sustainable urban living requires careful and well-informed urban planning for infrastructures capable of effectively mitigating these emissions. One commonly proposed approach to address this challenge is the implementation of urban green infrastructures, which are often regarded as net sinks for CO2. However, due to the diverse and varied land use within urban areas, our ability to precisely isolate and quantify their overall impact on the city's carbon balance is limited.Our research aims to overcome this limitation by testing two distinct frameworks. The first integrates remote observations with local measurements to determine the carbon balance of green infrastructures at the city level, ultimately producing a detailed CO2 sequestration map of these infrastructures. The second utilizes satellite observations of solar-induced chlorophyll fluorescence, a signal emitted exclusively by vegetation, to estimate urban vegetation's city-wide carbon sequestration potential. Our findings demonstrate that these two frameworks provide valuable insights into the carbon sequestration capacity of green infrastructures.The frameworks developed in this study offer a significant advancement in understanding the contribution of green infrastructures to the carbon budget of cities. This improved understanding can inform the planning of low carbon-emitting cities and aid in identifying green areas with limited—or even negative—net carbon uptake. Additionally, the results of this research may be instrumental for policymakers and city planners in developing more sustainable urban environments.
Seismic Activity in the Zabargad Fracture Zone (Red Sea): Insights from an Amphibious Seismic Network
Authors: Shiddiqi Hasbi Ash , Parisi Laura , Cano Eduardo V. , Mai P. Martin , Augustin Nico , Jónsson Sigurjón
Published: March 2024

The Zabargad Fracture Zone (ZFZ), located between 23.5o N – 26o N is the largest rift-axis offset in the Red Sea. The ZFZ is a fundamental tectonic element of ~100 km rift-axis offset that marks the transition between the northern and central Red Sea. Due to data scarcity, our understanding of the seismic activity and the potential presence of transform faults or non-transform offsets in the ZFZ area is limited. Local seismological datasets so far have been restricted to the onshore recordings, thus hampering the ability to study the ZFZ's role in the Red Sea’s tectonic evolution and to assess its potential seismic hazard associated with transform faults accommodating the rift-axis offset in the Red Sea.To fill this data gap, we deployed 14 broadband Ocean Bottom Seismometers (OBS) and four land stations for 12 months within the ZFZ to collect continuous waveforms. The newly collected data span the period 11/2021 to 11/2022. First, we corrected recorded OBS-waveforms for clock drift using skew values measured at the time of the OBS recovery and time-shifts measured from ambient noise cross-correlations for stations whose skews could not be measured. Next, we applied a deep-learning-based algorithm to automatically detect earthquakes and pick P and S phases. We verified and, if necessary, manually corrected these phase picks; this approach identified more than 3500 local earthquakes.To obtain reliable hypocentral locations, we inverted for an optimum crustal 1-D seismic velocity model of the ZFZ and station delays simultaneously. Using as reference a nearby land station installed on Precambrian bedrock, we obtained positive OBS station delays of up to 2 seconds. These delays correspond to late phase arrivals, most likely due to thick sedimentary and salt deposits. Our local magnitude (ML) calculations show that OBS-station ML values are up to 1.5 units larger than for the land stations. We find that station delays and ML deviations are correlated, highlighting the importance to account for the variability of shallow geological and bathymetric properties for accurate earthquake location and magnitude estimation.Our seismicity analysis reveals two major distinct spatial clusters of earthquakes, in the southern (23.95 o N – 24.53 o N) and northern (24.68 o N – 25.43o N) parts of the ZFZ. Seismicity in the south higher seismicity rate and spatially concentrated than in the north. We also identified three seismic swarms in the south and one seismic swarm in the north lasted for one to three weeks each. Our preliminary analyses document the potential of this new dataset to address key questions on the seismotectonics and seismic activity of the ZFZ.
Spatiotemporal variations in damages to socio-economic system from meteorological disasters in mainland China during 1989–2022
Authors: airiken muhadaisi , Li ShuangCheng
Published: March 2024

Drought, flood, hail and low temperature frost (LTF) are the main agrometeorological disasters in China. However, a comprehensive and quantitative study on the long-term trend of farmland and economic damage across the country is still lacking and needs to be carried out urgently. Based on historical statistical data from yearbooks and bulletins, the overall characteristics of the impacts of provincial meteorological disasters on population, economy and farmland during 1989-2022 were analyzed by using Mann-Kendall trend test at yearly and provincial scales in China. The results showed that the proportion of direct economic losses caused by meteorological disasters to GDP showed a decreasing trend. The SGD13.1 index, based on the number of deaths and the value of disaster losses, shows that there are abrupt years on the time scale under the Mann-Kendall trend test. In the past 30 years, crop loss in China has increased first and then decreased under natural disasters, and drought is the most serious type of disaster that causes farmland loss. The Person correlation analysis combining disaster intensity index and multiple factors shows that agricultural economic output has a significant negative correlation with disaster intensity, SDG13.1 and total precipitation, and a positive correlation with average annual temperature. There was a significant positive correlation between SDG13.1 and disaster intensity index. The results of this study systematically reveal the damage characteristics of meteorological disasters to socio-economic system in China, which are critical and necessary for disaster risk reduction and adaptive strategy development.
The influence of carbonate assimilation and deformation regime on the multiphase rheology of a phonotephritic melt from Vesuvius
Authors: Giuliani Gabriele , Di Fiore Fabrizio , Mollo Silvio , Romano Claudia , Di Genova Danilo , Vona Alessandro
Published: March 2024

The emplacement of magma chambers within a carbonate basement promotes a sequence of thermochemical reactions that progressively evolve from the carbonate wall-rock towards the magma, altering the chemical composition of the overall system (crystal + melt). Recent petrological and experimental studies highlight that varying degrees of limestone/dolostone assimilation controls the liquid line of descent of magmas, promoting or hindering the crystallization onset of distinct mineral phases.In this study, we investigate how differing degrees of limestone/dolostone assimilation and deformation regimes impact the rheology of a leucite-bearing phonotephrite magma from Somma-Vesuvius (Italy). Using starting materials doped with 0, 10, or 20 wt.% of CaO and CaO+MgO, mimicking the effects of limestone/dolostone assimilation, we conducted two sets of crystallization experiments at 1180°C under static and dynamic conditions (shear strain rate of 1 and 5 s-1).    We observe distinct rheological behaviours among melts as a function of composition and applied shear rate, displaying significant differences in terms of crystallizing mineral phases (±clinopyroxene±melilite±leucite±nepheline in the CaO-doped samples and ±clinopyroxene±melilite±olivine±leucite±nepheline, in the CaO+MgO-doped ones) and final crystal contents. Increased alkaline earth content (both Ca and Ca+Mg) alongside higher shear rates foster crystallization, leading to heightened crystal fractions (up to 51%) and larger crystals. Consequently, in heavily doped samples and under high shear rates, viscosity increased of up to 1.5 Log Pa s due to crystallization, causing the rheological transition from coherent flow to shear localization, culminating in physical separation (i.e., viscous rupture).  This study underscores the significant influence of deformation on magma, affecting both mineralogical assemblages and crystallization efficiency. These effects compound the pivotal role played by changing magma composition due to carbonate assimilation, governing magma’s crystallization capability, transport properties, and flow behaviour during its ascent from depth to surface.
Comprehensive Analysis of Diurnal Wind Power Density Variations for Optimizing Wind Energy Integration in Coastal Regions of India
Authors: Yadav Siddhita , Sarkar Arnab , Singal Sunil K
Published: March 2024

The global shift towards sustainable energy underscores the increasing importance of wind power in the energy transition. However, there is a scarcity of studies focusing on diurnal variations in wind energy potential across different sites, leading to potential inaccuracies in energy generation estimates. This study addresses this gap by conducting a thorough investigation into the diurnal patterns of wind power density (WPD) at 30 m and 60 m hub heights for six coastal Indian sites spanning the period 1969-2007.Hourly wind speed data obtained from the Indian Meteorological Department (IMD) for these locations formed the basis for a detailed analysis using the Weibull distribution model. The study highlights the crucial need to account for diurnal fluctuations in wind speed, as overlooking them may result in overestimating night-time and underestimating daytime WPD.Key findings include the identification of Tuticorin as exhibiting the highest diurnal WPD, reaching a peak of 714.53 W/m2 in July at the 60 m hub height, while Mormugao experienced the lowest diurnal WPD during December. Substantial variations in WPD were observed between day and night, emphasizing the necessity of considering diurnal wind speed fluctuations for accurate energy generation predictions.The implications of this study extend beyond mere data analysis. The results have practical significance for designing and sizing energy storage systems to ensure uninterrupted energy supply throughout the day and night. Additionally, the findings can guide the installation of hybrid energy storage systems, contributing to reduced operational costs and environmental impacts.The study concludes with recommendations for further research, suggesting the implementation of energy storage systems and hybrid systems for selected locations studied. Energy storage systems are deemed essential for balancing intermittent wind energy generation, while the integration of wind and solar resources in hybrid systems could optimize overall renewable energy generation. The insights gained from this study provide a foundation for developing region-specific renewable energy systems tailored to unique wind characteristics, emphasizing the importance of energy storage and hybrid solutions for a reliable and uninterrupted power supply.In summary, this study contributes valuable insights into the diurnal variations of wind power density in coastal regions of India, offering a comprehensive understanding of the wind energy potential in these areas. These insights serve as a basis for the development of sustainable and efficient renewable energy systems, highlighting the critical role of energy storage and hybrid solutions in ensuring a consistent and reliable power supply. 
Numerical simulations of the mesospheric region for sprite inception in winter thunderstorms over the Eastern Mediterranean
Authors: Haspel Carynelisa , Yair Yoav
Published: March 2024

Winter thunderstorms often exhibit compact vertical dimensions and lower heights of the major charge centers and are often accompanied by strong wind shear, with a propensity for positive cloud-to-ground strokes that can produce mesospheric transient luminous events (e.g. sprites, haloes, elves and jets). There are many optical observations confirming this over the Sea of Japan and the Mediterranean Sea, which are known to be the most convectively active regions during Northern Hemisphere winter.We use a 3D quasi-electrostatic model (Haspel et al., 2022) with wintertime thunderstorm charge configurations to evaluate sprite inception regions in the mesosphere under various conditions typical of the Eastern Mediterranean. This is a is a relatively new, numerically robust model based on an analytical solution to Poisson’s equation that was developed specifically to handle non-symmetric charge configurations in a large 3D domain.  We address several key questions related to the onset of sprites in winter: (a) the minimum charge that enables sprite inception under the compact thunderstorm structures, (b) the effect of wind shear (lateral offsets of 3-5 km between the cloud charge centers) on the electric field and the location of the area of possible sprite inception, and (c) how the time difference between consecutive strokes in adjacent cumulonimbus clouds affects the size and location of the area of possible sprite inception. Additionally, we will present results of sensitivity studies on the discharge time and profile, showing how the area of possible sprite inception depends on this factor. ReferenceHaspel, C., G. Kurtser and Y. Yair (2022). The feasibility of a 3D time-dependent model for predicting the area of possible sprite inception in the mesosphere based on an analytical solution to Poisson's equation. Jour. Atmos. Sol. Terr. Phys.,230, 105853, doi:10.1016/j.jastp.2022.105853.
Microbially-catalyzed mineral formation – Enhanced carbonate precipitation rates determined by U/Th dating and calcium isotopes
Authors: Smrzka Daniel , Tseng Yiting , Zwicker Jennifer , Pape Thomas , Schröder-Ritzrau Andrea , Frank Norbert , Schmitt Anne-Désirée , Birgel Daniel , Peckmann Jörn , Lin Saulwood , Bohrmann Gerhard
Published: March 2024

Carbon is removed from Earth’s surface and may be stored within carbonate minerals over long periods of time. The formation of authigenic carbonate in marine sediments accounts for much of this sequestered carbon, whereby the rate of sequestration depends on mineral precipitation rates. Among the catalyzing agents of carbonate precipitation are biofilms and microbial mats, which are ubiquitous in Earth surface environments. Microbial carbonates are abundant at methane seeps where they form by the sulfate-driven anaerobic oxidation of methane (SD-AOM), mediated by anaerobic archaea and sulfate-reducing bacteria. We investigated a 5 m long core composed almost entirely of two microbially-derived carbonate cements from an active methane seep in the South China Sea, offshore Taiwan. Phase-specific U/Th dating, lipid biomarker analyses, and calcium isotope data suggest that one of these phases is a direct product of biofilm mineralization, typified by high precipitation rates. This study is the first to estimate the accretion rate of individual carbonate phases in microbial limestones, and provides first-order constraints on the catalytic effect of microbial activity on carbonate precipitation. This has implications on the rate of global carbon burial, which may be significantly increased by the influence of biofilms and microbial mats on carbonate precipitation.
A new framework for retrieving bare soil information using multi-temporal Sentinel-2 images across China
Authors: Xue Jie , Zhang Xianglin , Chen Songchao , Su Ye , Shi Zhou
Published: March 2024

Detailed soil spatial information is a worldwide need for monitoring soil quality, especially in agricultural region. Remote sensing technology has evolved as a powerful tool for characterizing spectral reflectance of bare soil, which is the perquisite for retrieving soil information. However, existing methodologies were mostly designed to extract bare soil information from single satellite image, which is prone to cloud contamination and phenological variation. Although some composite algorithms based upon multitemporal images were proposed for soil mapping, they were all designed for coarse-resolution satellite dataset; besides, their generalization ability over a large scale (e.g., national) remains poorly explored. To fill the knowledge gap, we proposed a new framework, namely Two-Dimensional Bare Soil Separation (TDBSS), for extracting continuous bare soil information at 10-m spatial resolution based on multi-temporal Sentinel-2 images for cropland across China. The TDBSS used Soil Adjusted Vegetation Index and Green-Red Vegetation Index as two-dimensional indicators. The optimal thresholds for these two indicators were further obtained across two dimensions based upon ecoregion-specific samples. These thresholds were further applied for nine primary agricultural zones in China and subsequently adapted for the entire country. We also compared the framework with three widely used bare soil detecting algorithms (i.e., Geospatial Soil Sensing System (GEOS3), soil composite processor (SCMaP), and Barest Pixel Composite (BPC)) using the spatial accuracy. The TDBSS performed the best with an overall accuracy (OA = 78.28%), while SCMaP showed the lowest OA of 29.25%. The results showed the TDBSS was an effective method for a large-area mapping of bare soil. The resultant bare soil composite map holds great significance for further retrieving soil properties for Chinese cropland. TDBSS is computationally efficient and readily applied for a broad spatial scale, which is practically crucial to the food security, land management, and precision agriculture policymaking.
Convergence Behavior of Lattice Boltzmann Method for Pore-scale Modeling
Authors: Liao Qinzhuo
Published: March 2024

The characterization of reservoir rocks depends on the absolute permeability as a crucial parameter. To estimate this property numerically, one can employ a combination of digital rocks and Stokes flow simulation through the Lattice Boltzmann Method (LBM). In previous studies, the LBM has typically been implemented as an iterative process, wherein iterations are repeated until the parameter estimates between consecutive iterations reach a certain threshold level. However, we argue that this termination criterion is unsuitable and may compromise the accuracy of simulation results.In this study, we investigate the convergence of the LBM through various tests, including the Poiseuille flow between parallel plates and different types of digital rocks (such as dune sand, sandstone, and carbonates). We find that the logarithm of the relative error, when compared to the estimate at infinite time (representing a stable state), demonstrates a linear relationship with the number of iterations. This linear relationship suggests an exponential rate of convergence. On the other hand, if we rely on the difference in errors between consecutive iterations as the termination condition, the simulation may not reach a stable state.Instead, we propose a more accurate termination criterion for the LBM simulation by analyzing the decay trend of the error difference. This criterion provides a practical and appropriate approach for the characterization of reservoir rocks. Additionally, we offer a theoretical explanation for the convergence rate, which is linked to the spectral radius of the iterative matrix in linear algebra.
Robust weakening of the Gulf Stream during the past four decades observed in the Florida Straits
Authors: Piecuch Christopher , Beal Lisa
Published: March 2024

The Gulf Stream is a vital limb of the North Atlantic circulation that influences regional climate, sea level, and hurricane activity. Given the Gulf Stream's relevance to weather and climate, many studies have attempted to estimate trends in its volumetric transport from various datasets, but results have been inconclusive, and no consensus has emerged whether it is weakening with climate change. Here we use Bayesian analysis to jointly assimilate multiple observational datasets from the Florida Straits to quantify uncertainty and change in Gulf Stream volume transport since 1982. We find with virtual certainty (probability P>99%) that Gulf Stream volume transport through the Florida Straits declined by 1.2 ± 1.0 Sv in the past 40 years (95% credible interval). This significant trend has emerged from the dataset only over the past ten years, the first unequivocal evidence for a recent multidecadal decline in this climate-relevant component of ocean circulation.
Biogenic particle formation over the southeastern Qinghai-Tibet Plateau is increasingly influenced by anthropogenic emissions
Authors: Liu Yuliang
Published: March 2024

Aerosols formed on the Qinghai-Tibet Plateau, also known as the world's third pole, are more likely to enter the free troposphere due to its high altitude. This has far-reaching effects on radiative forcing and global climate. The southeastern Qinghai-Tibet Plateau, adjacent to the Himalayas, is commonly regarded as a pristine area that can offer insight into aerosol formation under pre-industrial conditions, free from the influence of human activities. Here we present observations taken at a representative site in southeast Tibet, a region covered by alpine forests and grasslands. The average aerosol particle nucleation rate (J1.7) is 2.5 cm-3s-1, exceeding the kinetic limit of sulfuric acid (SA) nucleation in most cases due to the low SA concentrations (with a mean of 2.5×105 cm-3). The critical role of highly oxygenated organic molecules (HOMs) in in-situ aerosol production is then to be found. Ultra-low and extremely low volatile HOMs dominate particles' nucleation and initial growth, respectively. Furthermore, these organic vapors come from the atmospheric oxidation of biogenic precursors, mainly monoterpenes with some contributions from sesquiterpenes and diterpenes. Surprisingly, over half of the ultra- and extremely-low volatile HOMs are organic nitrates, mainly formed through RO2 + NO terminations or NO3-initiated oxidations. These findings suggest that anthropogenic emissions influence the chemistry that drives biogenic new particle formation in the southeastern Qinghai-Tibet Plateau. As human activity increases, this region is transitioning from a pre-industrial to a post-industrial environment. The potential impact of this process on aerosol production and climate should be given more consideration.
Mechanistic insights into the fluorite-fluocerite-bastnasite transformation
Authors: Terribili Luca , Rodriguez-Blanco Juan Diego
Published: March 2024

Fluocerite is a rare earth element (REE) fluoride mineral with chemical formula (REE)F3. It is found in nature as an accessory mineral in magmatic-hydrothermal REE ore deposits, including alkaline complexes and carbonatites, where is associated with REE fluorocarbonates (i.e. bastnasite, parisite, synchysite), REE-bearing fluorite, cerianite, monazite and xenotime. Due to its relatively scarcity in these deposits, fluocerite kinetics and mechanisms of crystallisation, its role in REE fractionation and as phase for the evolution of magmatic-hydrothermal REE mineralizing systems have not received a lot of attention in the past years. Recently instead, fluocerite is gaining interest as it was suggested to be a precursor phase of bastnasite. Bastnasite is one of the most important minerals for the extraction of REE, indispensable in modern world because of their wide range of hi-tech industry and in clean energy applications. For this reason, illuminating the mechanisms of fluocerite crystallization and its role in the evolution of REE deposits could significantly enhance our understanding of the genesis of REE fluorocarbonates. The present study has two main objectives: 1) To study the kinetics and mechanisms of the fluocerite formation at temperatures ranging from ambient to low hydrothermal (up to 200 °C) 2) To demonstrate in situ that fluocerite reacting in the presence of a CO3-rich solution can transform into REE fluorocarbonates in hydrothermal conditions. For the first purpose, fluocerite was synthesized by reacting pure fluorite (CaF2) powder with REE-bearing solutions at different temperatures. To achieve the second objective, synthetic fluocerite was reacted with Na2CO3 solutions at hydrothermal conditions up to 200 °C. Samples of solids were taken at specific time intervals to follow the ongoing of the crystallisation reactions. The nature of crystallising solids, their quantification and growth morphology were determined with a combination of powder X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive microscopy (SEM-EDS).Our results showed that the fluocerite crystallisation rate decreases proportionally with the REE atomic number and increases with increasing T. The activation energy of crystallisation is similar irrespective of the REE used in the synthesis (~75 KJ/mol) while the activation energy of nucleation increases with the REE atomic number (80 - 96 KJ/mol). All fluocerites reacted with the CO3-bearing solutions transformed into bastnasite at all temperature, also forming cerianite in the Ce-bearing experiments. 