bluuebunny/crossref_metadata_2025 huggingface dataset:
RocMLMs: Predicting Rock Properties through Machine Learning Models
Authors: Kerswell Buchanan , Cerpa Nestor , Tommasi Andréa , Godard Marguerite , Padrón-Navarta José Alberto
Published: March 2024

Predicting the physical properties of rock is critical for modeling mantle convection. Density changes are the main driving force for mantle convection, for example, while elasticity/seismic properties allow probing of mantle dynamics and structure. Pressure-temperature (PT) conditions predicted by numerical thermo-mechanical models are often mapped to pre-computed pseudosections calculated by Gibbs Free Energy Minimization (GFEM) programs (e.g., Perple_X; Connolly, 2009) to predict phase changes and the associated evolution of rock properties (e.g., density, seismic wave velocities, and fluid contents). In principle, GFEM programs could be coupled to numerical geodynamic simulations (at each point in space and for each timestep) to establish models where phase assemblages and rock properties evolve self-consistently. In practice, this is currently intractable because GFEM programs remain too slow (102–104 ms per node) to be coupled to high-resolution numerical geodynamic models. While parallelization of GFEM calculations can increase efficiency dramatically (e.g., MAGEMin; Riel et al., 2022), predicting rock properties recursively during a geodynamic simulation requires GFEM efficiency on the order of ≤ 100–10-1 ms to be feasible. As an alternative to the GFEM approach, this study demonstrates the efficiency of predicting target rock properties through pre-trained machine learning models (referred to as RocMLMs). In our initial test case, RocMLMs are trained to predict density, seismic wave velocity, and melt fraction for dry upper mantle rocks based on an array of 128 Perple_X pseudosections (with 128x128 PT resolution) derived from 3111 harzburgite and lherzolite samples retrieved from the Earthchem.org repository. The training dataset size was reduced from 12813 to 1283 PTX examples by transforming the 11 oxide components of X (bulk rock composition) into a single Fertility Index value representing the estimated degree of melt extraction from a primitive mantle source. We show that Decision Tree, K-Neighbors, and single-layer Neural Network algorithms can predict rock properties up to 103 times faster than commonly-used GFEM programs (with some performance trade-offs), attaining the required efficiency of 100–10-1 ms. Our results imply that implementing dynamic evolution of rock properties in geodynamic simulations is now possible with RocMLMs. Future generations of RocMLMs will include hydrated systems and a larger array of mantle compositions (e.g., dunites and pyroxenites).
Detection of the spatial clustering mechanisms of streamflow extremes in the USA and relevance to flood insurance data
Authors: Papoulakos Konstantinos , Iliopoulou Theano , Dimitriadis Panayiotis , Tsaknias Dimosthenis , Koutsoyiannis Demetris
Published: March 2024

During the last decades, scientific research in the field of flood risk management has provided new insights and strong computational tools towards the deeper understanding of the fundamental stochastic behaviour that characterizes such natural hazards. Flood hazards are controlled by hydrometeorological processes and their inherent uncertainties. Historically, a high percentage of flood disasters worldwide are investigated regarding the aggregated number of the affected people, economic losses, and generated flood insurance claims. In this respect, the recently published National Flood Insurance Program data by the Federal Emergency Management Agency may yield novel perspectives into flood impacts. The objective of this study is to conduct a spatial analysis on the daily flow series within the US-CAMELS dataset. Specifically, we seek to identify spatial clustering mechanisms of over-threshold streamflow extremes, considering them as proxies for collective risk, in order to examine their underlying stochastic structure. Furthermore, we explore their relevance to the actual insurance data and develop some additional stochastic modelling approaches.
Increased predictability of extreme El Niño from decadal interbasin interaction
Authors: Ma Xuan , Liang Rizhou , Chen Xiaosong , Xie Fei , Zuo Jinqing , Sun Cheng , Ding Ruiqiang
Published: March 2024

Predicting extreme El Niño–Southern Oscillation (ENSO) events remains a formidable task. Utilizing eigen microstates (EMs) of complex systems, we elucidate the interplay of two key sea surface temperature (SST) anomaly modes, the newly identified North Atlantic–west Pacific Mode (NAPAM) and discovered Victoria Mode (VM). Our findings demonstrate that a cold NAPAM phase coupled with a positive VM phase markedly elevates the probability of extreme El Niño events; NAPAM's decadal variability serves as a key modulator of extreme El Niño events' frequency. Our empirical model, capitalizing on these modes, achieves robust forecasts with a 6–8 month lead time and boasts a 0.73 correlation with the observed ENSO index in hindcasts. Notably, the model precisely forecasts the intensity of four landmark extreme El Niño episodes: 1982/1983, 1987/1988, 1997/1998, and 2015/2016. Our findings offer promising avenues for refining ENSO predictive frameworks and deepen our understanding of the key climatic drivers.
Synergizing vegetation restoration and wildlife conservation to enhance natural climate solutions
Authors: He Qiang
Published: March 2024

To help achieve carbon neutrality and mitigate climate change, vegetation restoration and wildlife conservation have recently been promoted as two key natural climate solutions. Although ecological studies have widely reported the profound top-down impacts of wildlife on the structure and function of vegetation, vegetation restoration and wildlife conservation are often viewed and implemented as two independent natural climate solutions. Combining field experiments in degraded coastal wetlands and meta-analyses of experimental studies from vegetated ecosystems globally, we explore the impacts of wildlife on vegetation restoration and related carbon cycling processes. In the field experiments, we find that vegetation restoration through planting alone failed to lead to vegetation recovery due to grazing by herbivores and did not increase plant and soil carbon stocks. In contrast, co-restoring threatened predators or simulating their consumptive or nonconsumptive effects facilitated the establishment of planted seedlings, led to successful recovery of vegetation, and increased plant and soil carbon stocks. These effects of herbivores and predators on vegetation restoration were generally supported in our global syntheses of experimental studies from all vegetated ecosystems, although these effects were context-dependent and often varied with biotic and climatic factors such as herbivore density, temperature, and precipitation. Taken together, these results suggest that vegetation restoration, if synergized with wildlife conservation, can be more promising for enhancing carbon sequestration in many ecosystems. We conclude by outlining possible ways to achieve synergies of vegetation restoration and wildlife conservation and by highlighting their policy implications.
Environmental Assessment of Microplastic Pollution Induced by Solid Waste Landﬁlls in the Akmola Region (North Kazakhstan)
Authors: Rodrigo-Ilarri Javier , Salikova Natalya S. , Rodrigo-Clavero María-Elena , Urazbayeva Saltanat E. , Askarova Aniza Zh. , Magzhanov Kuandyk M.
Published: March 2024

This work presents the outcomes derived from an environmental assessment of microplastic pollution resulting from solid waste landﬁlls in the Akmola Region, situated in North Kazakhstan. This research represents a pioneering investigation conducted on microplastics within this speciﬁc region. This study encompasses a comprehensive examination of plastic waste disposal sites across the Akmola region, with a particular emphasis on evaluating the status of the municipal solid waste management system.To characterize the plastic content within the waste present at the landﬁll sites, quantitative techniques were employed. Through experimental means, the composition and fractionation of plastics within the municipal solid waste (MSW) at the landﬁlls were determined. These data were subjected to a comparative analysis, aligning them with ofﬁcial statistics and previously published scientiﬁc data from both Kazakhstan and other regions globally. The methodologies employed focused on the “soft” removal of organic substances through the use of oxidants which do not damage plastics, and were tested using a water-bath therapeutic treatment. Furthermore, an analysis of soil samples taken from the landﬁlls unveiled the ultimate retention of microplastic particles, attributed to leachate and rainwater runoff. Extracts were obtained from the subsoil samples using a density-based separation process, involving a three-step extraction followed by subsequent ﬁltration of the resulting supernatants. In addition, the soil samples underwent examination through dry-phase particle fractional separation. The particles were meticulously enumerated and classiﬁed, and their dimensions were measured employing microscopic techniques coupled with photographic documentation. The outcomes stemming from these diverse tests will serve as fundamental input for the forthcoming numerical modeling endeavor, which aims to simulate the behavior of microplastics within both soil and water. 
A stochastic model for the turbulent ocean heat flux under Arctic sea ice 
Authors: Toppaladoddi Srikanth , Wells Andrew
Published: March 2024

The physics of planetary climate features a variety of complex systems that are challenging to model as they feature turbulent flows. A key example is the heat flux from the upper ocean to the underside of sea ice which provides a key contribution to the evolution of the Arctic sea ice cover. Here, we develop a model of the turbulent ice-ocean heat flux using coupled ordinary stochastic differential equations to model fluctuations in the vertical velocity and temperature in the Arctic mixed layer. All the parameters in the model are determined from observational data. A detailed comparison between the model results and measurements made during the Surface Heat Budget of the Arctic Ocean (SHEBA) project reveals that the model is able to capture the probability density functions (PDFs) of velocity, temperature and heat flux fluctuations. Furthermore, we show that the temperature in the upper layer of the Arctic ocean can be treated as a passive scalar during the whole year of SHEBA measurements. The stochastic model developed here provides a computationally inexpensive way to compute an observationally consistent PDF of this heat flux, and has implications for its parameterisation in regional and global climate models.
Response of the caprock's fluorescence parameters to the leakage of palaeo-oil zones
Authors: Liu Keshun , Qu Jiangxiu , Zha Ming , Ding Xiujian
Published: March 2024

Abstract: The northern part of the the Junggar Basin is the Siberian plate, and the western part is the Kazakhstan plate, which is an important part of the Central Asian orogenic belt. This study discusses how fluorescence parameters inside the mudstone caprocks of the Mobei Bugle and Mosuowan Bugle respond to the leakage of palaeo-oil zones. It is based on X-ray diffraction analysis, TOC testing, physical property testing, rock pyrolysis experiments, and image observation. First, using quantitative fluorescence technology, it was established that the appropriate particle size range for the study area mudstone is between 100 and 140 mesh by examining the QGF E intensity and sample loss rate of the control group. Then, the influence of retained primary hydrocarbons inside the mudstone on the test results of quantitative fluorescence technology is speculated to be relatively weak based on an analysis of the correlation between TOC value and total hydrocarbon value, TOC value and fluorescence parameters. The QGF index of the 5265-5302m reservoir in PD1 well ranges from 3.9 to 87.2, with an average of 16.18; the QGF index of the 7034-7195m reservoir in MS1 well ranges from 2.2 to 57.5, with an average of 11.6. The reservoirs of the PD1 and MS1 wells contain palaeo-oil zones, based on the QGF index classification criteria. Both image observation and micro resistivity imaging logging analysis demonstrate that the caprock's physical properties in the PD1 well are inferior to those in the MS1 well. The pore types of the PD1 well caprock are filled dissolution pores and residual intergranular pores, whereas the pore types of the MS1 well caprock are dissolution pores and microcracks. There is a discrepancy of approximately 9 times between the development density of fractures in the MS1 well caprock (0.989 pieces/m) and the PD1 well caprock (0.114 pieces/m). The palaeo-oil zone can be effectively sealed due to the poor physical properties of the PD1 well caprock. The oil testing conclusion of the reservoir is oil-water layer, with a daily oil production of 8.52t. Therefore, as the depth decreases, the QGF E intensity value decreases, and the QGF λmax and TSF R1 values reflect higher hydrocarbon maturity. The MS1 well caprock has good physical properties and cannot effectively seal the palaeo-oil zone. The oil testing conclusion of the reservoir is water layer, with a daily oil production of 4.4t. As the depth decreases, the QGF E intensity value increases, and the QGF λmax and TSF R1 values reflect lower hydrocarbon maturity. Comprehensive analysis suggests that the fluorescence parameters inside the caprock exhibit characteristics related to the degree and form of palaeo-oil zone leakage.Keywords: Quantitative fluorescence technology, Fluorescence parameters, Mudstone caprock, Palaeo-oil zones
A self-consistent model of radial transport in the magnetodisks of gas giants including interhemispheric asymmetries
Authors: Devinat Marie , André Nicolas , Blanc Michel
Published: March 2024

The magnetospheres of gas giants are characterised by their strong magnetic fields, the fast rotation of the planet and the presence of embedded active moons (Io at Jupiter, Enceladus at Saturn), releasing neutral gas and, from there, plasma in the innermost regions of the systems. Their dynamics is believed to be controlled by a balance between the centrifugal force acting on cororating plasmas trapped in the planetary magnetic field, plasma pressure gradients and magnetic forces. This balance determines the rate of outward transport of mass, angular momentum and energy and has a strong influence on the global configuration and dynamics of the magnetospheres. It results in the formation of a magnetodisk of plasma at the planetary equator, and a global outward transport of plasma from the innermost source regions to the outer magnetosphere where it is lost through magnetospheric boundaries or downtail.     Until now, description of this transport has followed two different approaches in the literature. “Corotation enforcement” models focus on the description of angular momentum transport in a disk exchanging momentum with the planetary thermosphere/ionosphere via electric current systems transferring magnetic torques. They assume mass and conservation but do not explicitly describe the transport processes through the magnetodisk. On the contrary, radial diffusion models do not explicitly take into account angular momentum transport nor exchanges between the planet and the magnetospheric plasma, but they describe radial transport of mass and energy assuming a certain state of turbulence in the magnetodisk.    We present a unifying approach of the radial transport of mass, angular momentum and energy, using turbulent diffusion and including sources and sinks of plasma of arbitrary radial distribution throughout the disk. Our set of coupled equations independently describes momentum exchange with the two conjugate ionospheres, thus allowing for the study of interhemispheric asymmetries, such as the ones revealed by Juno, in this coupling. We will present solutions of our coupled set of transport equations that explore the different possible causes and effects of interhemispheric asymmetries in magnetodisk/planet coupling, with emphasis on the cases of latitudinally thin and thick disks corresponding respectively to the cases of Jupiter and Saturn. We will compare the outputs of our models with recent observational constraints brought by the Juno and Cassini missions.
The value of hydrologic observatories for large sample hydrology and vice versa
Authors: Wagener Thorsten , Coxon Gemma , Bloomfield John P. , Buytaert Wouter , Fry Matthew , Hannah David M. , Old Gareth , Stein Lina
Published: March 2024

Hydrologic observatories have been a cornerstone of hydrologic science for many decades, advancing hydrologic process understanding with focused field observations and targeted experiments. Observatories present our key opportunity for achieving great depth of hydrologic investigation, most often at the headwater catchment scale. We address two main aspects concerning hydrologic observatories in this contribution: (1) While reviews of individual hydrologic observatories and observatory networks exist, no study has investigated the diversity of observatories to understand whether common aspects increase the likelihood of scientific success. We synthesise information from 80 hydrologic observatories and conduct 25 interviews with observatory leads to fill this gap. We find that scientific outcomes are most enhanced by involving scientific and stakeholder communities throughout observatory inception, design, and operation; by enabling infrastructure to be adjustable to changing ideas and conditions; and by facilitating widespread data use for analysis. (2) While observatories are key for advancing local hypotheses, the transferability of knowledge gained locally to other places or scales has often been difficult or even remained elusive. Headwater catchments in particular show a wide range of process controls often only understood if viewed in a wider regional context of climatic, topographic, or other gradients. We therefore must place observatories into the wider tapestry of hydrologic variability, for example through comparison with large samples of catchments, even though significantly less information is available to characterise these diverse systems. We provide some thoughts on how this connection could be improved through digital infrastructure, mobile observational infrastructure and a renewed focus on gradients and contrasts of controlling processes. We believe that there is a significant opportunity to enhance transferrable knowledge creation in hydrology.
SSP3-7.0 projections of Antarctic sub-ice-shelf melting with the Energy Exascale Earth System Model
Authors: Asay-Davis Xylar , Comeau Darin , Barthel Alice , Begeman Carolyn , Lin Wuyin , Petersen Mark , Price Stephen , Roberts Andrew , Vankova Irena , Veneziani Milena , Wolfe Jonathan , Zhang Shixuan
Published: March 2024

To date, few Earth System Models (ESMs) have the ability to simulate the flow in the ocean cavities below Antarctic ice shelves and its influence on basal melting.  Yet capturing both this flow and the resulting melt patterns is critical for representing local, regional, and global feedbacks between the climate and sub-ice-shelf melting.  Here, we present a small ensemble of historical simulations and SSP3-7.0 projections in an ESM that includes Antarctic ice-shelf cavities, the Energy Exascale Earth System Model (E3SM) v2.1.  The simulations have active ocean, sea-ice, atmosphere, land and river components.  The model domain has 12 km horizontal resolution around Antarctica, which is adequate for capturing dynamics in the larger ice-shelf cavities, melt fluxes aggregated across Antarctic regions, and water masses across most of the Antarctic continental shelf. The projections show significant warming and freshening of water masses on the Antarctic continental shelf, a deepening and poleward shift of the Amundsen Sea Low (ASL), and a significant increase in Antarctic melting through the 20th and 21st centuries.  We also see a significantly more modest drift in water-mass properties and melt rates in our control simulation with constant 1950 conditions from which the historical runs were branched.  In addition to providing an estimate of future melting and other changes in regional and global climate under SSP3-7.0, these simulations are also a steppingstone to coupled ice sheet-ocean simulations planned for the near future.  We briefly discuss these plans and the coupling strategy that we are developing.
Advancing Volcano Monitoring Capabilities: Deployment of Cost-Efficient GNSS Units in the Lesser Antilles on Mt. Scenery, Saba
Authors: Krietemeyer Andreas , de Zeeuw-van Dalfsen Elske
Published: March 2024

The evolution of cost-efficient Global Navigation Satellite System (GNSS) equipment sparked increasing scientific interest to use this technology for precise geophysical measurements. In this research, we investigate the use of cost-effective GNSS units for deformation monitoring on the island of Saba in the Caribbean Netherlands. Saba hosts Mt. Scenery, an active but quiescent stratovolcano in the Lesser Antilles Volcanic Arc. The most recent eruption of the 887 metres high volcano occurred around 1640.In February 2022, four cost-effective GNSS units were installed on the island to densify the existing Royal Netherlands Meteorological Institute (KNMI) GNSS network of four permanent GNSS stations. While the equipment costs of a permanent GNSS station quickly exceeds 10.000 Euro, the cost-efficient units come at a price of about 1000 Euro. The cost-effective unit’s design includes all necessities for independent operation: Solar charger, microcontroller, cellular data transmission, as well as remote connection via the cellular 4G connection. Compared to permanent GNSS stations, the cost-effective unit’s installation time in the field is significantly reduced.We present the GNSS unit’s design and first deformation monitoring results of the deployed stations. The data is validated by comparing data of a cost-effective unit with those from a permanent GNSS station next to it. The GNSS units are well suited to monitor ground deformation on Saba as their daily positioning precision is similar to those of permanent GNSS stations. The cost-efficient GNSS units can therefore be used i) to expand existing deformation monitoring networks, ii) in stand-alone areas where the installation of conventional GNSS is deemed too costly, or iii) in risk-prone areas where rapid installation of expendable equipment is necessary.
Offshore Solar Farm Assessment and Uncertainty Determination for the United Arab Emirates
Authors: Medina-Lopez Encarni , Lazic Jasmina , Yousef Latifa
Published: March 2024

Floating offshore solar farms (OSF) are an attractive option for solar energy generation, as they help avoid land competition with other uses. Planning the deployment of OSF requires assessments for site selection, which are primarily based on energy yields, in addition to other considerations. The yields are determined through evaluations using climate and oceanic variables. Uncertainty in these variables can propagate to further uncertainty in yield estimations, which ultimately can lead to significant consequences in the cost of energy. In this work, we propose the development of a novel method to assess the viability of OSF considering insolation uncertainty, with a focus on the United Arab Emirates (UAE) region. Open-source satellite data is utilized to conduct initial site assessments, and produce a set of viable locations based on parameters that include solar irradiance, ambient temperature, sea surface temperature, wind speed and precipitation. Validation of the viable locations will be done through the deployment of meteorological instrumentation, to collect in-situ measurements for a minimum of one year. Machine learning techniques are examined to quantify the uncertainty, followed by determination of impacts on levelized cost of electricity (LCOE) and savings based on uncertainty reduction.
Mapping the Tesserae Highlands of Venus – Insights into Tectonic Deformation and Plateau Genesis
Authors: Leung Chit Yan Eunice , Cheng Hui Ching Jupiter , Webb A. Alexander G. , Moore William B. , Michalski Joseph R. , Siu Yat Hei Jason
Published: March 2024

Tesserae terrains on Venus are characterized by intersecting sets of tectonic fabrics, signifying pervasive, complex, and multi-stage deformation. The locally stratigraphically oldest tesserae units, which cover around 8% of Venus’s surface, are primarily exposed within regions of high topography, flat-topped, quasi-circular crustal plateaus. This association suggests that the highly deformed tesserae units are intrinsic to the formation of crustal plateaus, and that the tesserae units encapsulate a significant record of Venus’ early geologic history.The origin of crustal plateaus remains debated. Various models have been put forward to explain their formation, each considering the complex deformation evidenced by the tesserae unit and the thickened crust, which is supported by data on small gravity anomalies and low gravity to topography ratios. These models include (1) mantle upwelling, (2) mantle downwelling, (3) pulsating continent with subduction, (4) heat-pipe volcanism, and (5) lava pond and bolide impact hypothesis. Testing these models involves identifying the boundary relationship of tesserae units and surrounding units, as well as the types and sequences of deformation in the tectonic lineaments.In this study, we present a focused examination of the following selected tesserae highlands, ranging from the well-studied and previously mapped Ishtar terra to Western Ovda Regio, Ovda Regio, Thetis Regio, Tellus Regio, and Alpha Regio. Magellan synthetic aperture radar (SAR) full-resolution map (FMAP) and digital elevation model (DEM) are used to map the interior deformation patterns, as well as the stratigraphic and tectonic relationships at the highland boundaries. Preliminary results mostly do not support a bolide impact model yet are unable to falsify the remaining models. The current spatial resolution of the dataset limits our ability to identify the structural type of tectonic lineaments. Our work aims to advance our understanding of Venusian tectonics and highlight the importance of the acquisition of higher-resolution data to unravel Venus’ geological evolution.
A unique structure of the ionospheric current over the Asian-Oceania region determined by the combination of the ground-based and space-borne magnetometers
Authors: Zhang Pengyu , Sun Yang-Yi
Published: March 2024

The ionosphere owns a complex electric current system mainly driven by the ionospheric electric field and thermospheric wind. Changes in current can generate geomagnetic signals that can be observed both on the ground and in space. In this study, we analyzed the ionospheric current in the Asia-Oceania region by utilizing geomagnetic data collected from magnetometers of ground-based observatories and SWARM satellites at ~450 km altitude. The results present the geomagnetic variations at the two distinct altitudes, encompassing longitudinal, latitudinal, and seasonal variations. Furthermore, the Ionosphere-Electrodynamics General Circulation Model (TIE-GCM) was employed to simulate the associated geomagnetic signals. This study is the first to combine dense geomagnetic data from multiple altitudes and simulations to understand the ionospheric current in the Asia-Oceania region. The differences between the observational geomagnetic signals at different altitudes, along with the simulations, reveal a unique current structure that has not been previously discovered. The findings provide a new understanding of the intricate evolution of the current systems, which contributes to our knowledge of the electric dynamics within Earth's ionosphere.
Insights into the role of the environmental setting versus microbial actors for soil carbon cycling
Authors: Wasner Daniel , Schnecker Joerg , Han Xingguo , Frossard Aline , Zagal Venegas Erick , Doetterl Sebastian
Published: March 2024

Soil microbes perform important functions in the soil organic carbon (SOC) cycle and soil microbial decomposition activity is a major determinant of the carbon budget of a soil. It is well-established that soil microbial physiology is directly affected by temperature and moisture. However, it is less clear to what extent the environmental setting (i.e. long-term climatic conditions, soil physicochemistry) vs. the microbial actors (i.e. soil bacterial and fungal community composition) control the cycling of SOC in the absence of strong direct physiological constraints such as temperature and moisture limitation.To address this knowledge gap, we used 35 grassland topsoils (0 – 10 cm) from 10 WRB major soil groups along a north-south transect in Chile, which ranged from arid steppe to tundra. We compiled climatic data and relevant physicochemical soil properties, together with an in depth characterization of OM quality. We then incubated the soils for 1 week in conditions favorable for microbial activity (20 °C, 50 % of water holding capacity). After incubation, we quantified soil microbial carbon and nitrogen, enzyme kinetics of three groups of relevant extracellular enzymes, basal heterotrophic respiration as well as microbial growth rates and carbon use efficiencies by incorporation of 18O into DNA. In addition, we characterized the microbial actors by DNA extraction and Illumina barcoding of a region of the 16S rRNA gene (bacteria) and a section of the ITS region (fungi). Finally, to investigate how strongly the measured microbial SOC functions were linked with the environmental setting vs. the microbial actors, we applied three different cross-validated regression approaches.The resulting data highlights the links between environment, microbial community composition and SOC cycle functions under conditions without direct temperature and moisture limitation. Our findings show that the environmental setting controlled the amount of microbial biomass, and in extension biomass dependent SOC cycle functions such as heterotrophic respiration. In  contrast, microbial community composition was a better predictor of SOC cycle functions that are independent of microbial biomass such as carbon use efficiency and relative microbial growth rates. These insights help to disentangle the roles of the environmental setting and the microbial actors in the context of microbial SOC cycle functions.
Mapping the Moho in the Bohemian Massif and the Western Carpathians with P-receiver functions
Authors: Kampfová Exnerová Hana , Plomerová Jaroslava , Vecsey Luděk , Working Groups and AdriaArray Seismology Group AlpArray, AlpArray-EASI, PACASE
Published: March 2024

We present the Moho depths in the Bohemian Massif and Western Carpathians derived from P-to-S receiver functions calculated from broad-band P-coda waveforms from teleseismic events recorded at temporary and permanent stations operated in a region within 10–23º E and 47.5–52º N during last two decades. By the Zhu and Kanamori method (2000) and the Ps time delays (Kvapil et al., 2021), we process data collected from running AdriaArray Seismic Network (since 2022), PACASE experiment (2019 – 2022), AlpArray Seismic Network (2015 – 2019) and its complementary experiment AlpArray-EASI (2014 – 2015), as well as from previous passive seismic experiments in the region – BOHEMA I-IV (2001 – 2014), PASSEQ (2006 – 2008) and EgerRift (2007 – 2013). By applying different methods, we aim at upgrading the current knowledge of the crust in the broader surroundings of the European Alps (Michailos et al., 2023), the Pannonian Basin (Kalmar et al., 2019), and the Carpathians. Locally, differences between Moho depth from individual methods could highly exceed 5 km, thus reflecting various sensitivities of individual methods to the local complex structure. An extended amount of data and regionally combined evaluation provide a homogeneous estimate of Moho depths, particularly for the usage in deep Earth studies, e.g., in applying crustal corrections in the upper mantle tomography of Central Europe.
Tracking the fate of meltwater from different Northern ice sheet sectors over Heinrich Stadial
Authors: Endres Laura , Ivanovic Ruza , Romé Yvan , Tindall Julia , Stoll Heather
Published: March 2024

The addition of meltwater from continental ice sheets to the North Atlantic is thought to have played a pivotal role in the reorganization of climate and ocean circulation over the last deglaciation as well as during Heinrich events. This is supported by recent analysis of PMIP and CMIP results, which shows that meltwater addition into the North Atlantic can largely alter global climate, and remains a key uncertainty for both reconstruction and climate projections. To date, most model studies of freshwater “hosing” assume a relatively uniform distribution and apply meltwater to a large portion of the North Atlantic basin. However, AMOC weakening is sensitive to the actual input position of the typically cold and non-saline meltwater perturbation, and, on a centennial-millennial timescale, the resulting temperature and salt anomaly will only partially disperse over the entire North Atlantic surface ocean. In contrast, most proxy data sensitive to meltwater record the signal at a specific location. It is unclear if spatial heterogeneity of the ocean’s distribution of the meltwater anomaly may contribute to disagreements between freshwater proxy records and model simulations with freshwater additions tuned to reproduce the record of past AMOC weakenings.To enhance understanding of the spatial distribution of meltwater anomalies during deglaciations, we present the results of a model sensitivity study using HadCM3 and artificial dye tracers to track the fate of meltwater originating from different Northern ice sheet sectors. We consider different meltwater scenarios consistent with Heinrich Stadial 1 ice sheet reconstructions and compare the results under different AMOC states. The results confirm that, on a centennial timescale, meltwater distribution is not uniform over the North Atlantic Ocean. The emerging patterns expose that the efficiency of a meltwater injection to produce a surface ocean anomaly (in, e.g., salinity or δ18Osw) at a given proxy location differs between different ice sheet sectors by orders of magnitudes. Further, besides the direct effect of meltwater, the sensitivity of climate indicators, such as temperature, to changes in AMOC strength also shows regional discrepancies. 
Clay mineralogy and organic matter of Upper Miocene to Pliocene mudstones of the Kampungbaru Formation, Lower Kutai Basin, Indonesia
Authors: Jamaluddin Jamaluddin , Wagreich Michael , Gier Susanne
Published: March 2024

The Kampungbaru Formation is considered a potential source rock for petroleum in the Lower Kutai Basin, Indonesia. An integrated approach of organic petrography, total organic carbon (TOC), Rock-Eval pyrolysis, XRD analysis, and clay mineralogy of fifteen outcrop samples obtained from the Upper Miocene – Pliocene Kampungbaru Formation was conducted. The sediment is characterized by heterolithic, laminated mudstone and interbedded sandstone. Sandstones form thin layers and lenses with predominant lenticular to flaser bedding. The mudstone samples of the Kampungbaru Formation generally have total organic carbon (TOC) content between 0.06 to 8.76 wt.%.  The organic matter consists mainly of vitrinite (71 - 79.6 vol.%; avg. 75.3 vol.%), liptinite (16.90 - 27.4 vol.%; avg. 22.15 vol.%), and inertinite (1.5 – 3.50 vol.%; avg. 2.55 vol.%). Tmax values of these Upper Miocene – Pliocene mudstones are below 435 °C and vitrinite reflectance ranges from 0.27 ± 0.05 %Rr to 0.33 ± 0.05%Rr, indicating an immature stage in the diagenesis of kerogen. The pyrolysis data (HI vs. Tmax) show that type III kerogen dominates organic matter with HI values of < 200 mg HC/g TOC and would be expected to generate gas.  All of the organic matter in the samples is inferred to derive from terrestrial plants. Semi-quantitative XRD results of the mudstone samples in the studied section include varying proportions of clay and non-clay minerals. The bulk mudstone samples in the section are dominated by clay minerals (33.4%–63.0%, avg. = 47%), quartz (23.8%–60.5-%, avg. = 37%), and pyrite (6.0%–32.4%, avg. = 16%). The < 2 μm clay fraction consists of kaolinite, illite, mixed layer illite/smectite (I/S), and chlorite. Kaolinite is the most abundant clay mineral encountered in the studied Kampungbaru Formation. Kaolinite content is influenced by the sedimentary lithology setting. Most sediment deposited in the Mahakam Delta likely originates from erosion by the antecedent part of the Mahakam River.
Evolution of a prograding shelf complex affected by salt tectonics, the case of the SW Valencia Trough
Authors: Ramos Adrià , de Ruig Menno J. , Pedrera Antonio , Alfaro Pedro , Martin-Rojas Iván
Published: March 2024

The Valencia Trough is a NE-SW trending sector of attenuated crust located between the Iberian Peninsula and the Balearic Islands in the western Mediterranean, bordered by the Catalan Coastal Ranges to the northwest, the Iberian Chain to the west, and the Balearic fold and thrust belt to the south. It includes several kilometers of Jurassic-Cretaceous rocks deposited over Upper Triassic salt associated with rifting in the western Tethyan margin. The Mesozoic deposits are deeply eroded as a result of basin inversion and uplift in Oligocene time, followed by extension in latest Oligocene-Early Miocene time. Overlying Middle-Late Miocene foreland basin sediments are associated with the subduction and rollback of the Tethyan oceanic lithosphere. During the Pliocene and Quaternary, a prograding shelf complex was established on the eastern margin of Iberia reaching 3000m in thickness and affected by extensional faulting.The inspection of the available surface (geological maps and structural data) and subsurface data (2D seismic profiles and exploratory wells) allowed us to document the major role of the Triassic evaporitic sequence on the tectonic style and the configuration of the Pliocene to present-day sedimentary infilling in the Valencia Trough. Our results indicate that large N-S trending extensional faults, which control the depocentres of the Plio-Quaternary prograding shelf complex and offset underlying Mesozoic-Cenozoic sequence, detach into the salt layer. Supra-salt extensional deformation appears to be decoupled from extension in the sub-salt basement.Sequential backstripping restorations also illustrate the evolution of the deformation and depositional space associated with the flexing down of diapiric structures, which are nucleated over inherited basement faults, parallel to the supra-salt ones. These diapirs were developed in the basin margin during the Mesozoic and Miocene times. The salt expulsion is mainly triggered by the overburden deposition of the prograding clinoforms wedges sourced from the rivers located to the west (e.g., Júcar, Túria and Serpis). Salt diapirs recording a Plio-Quaternary activity can be encountered in the surroundings of the basin, synchronously to the development of the withdrawal salt depocenters.Moreover, the determination of the two extensional faults systems, salt-detached versus basement-involved, has significant implications on evaluating the structures responsible for the instrumental and historical seismicity in the area.
Detailed 3D Surface Reconstruction of Asteroids by Integrating Stereo Photogrammetry and Stereo Photoclinometry
Authors: Li Hongliang , Wu Bo , Liu Yi
Published: March 2024

3D models of asteroids provide their physical properties, such as shape, size, and surface features, which are of great importance to asteroid exploration missions and scientific research. The stereo photoclinometry (SPC) technique retrieves detailed surface topography of asteroids based on the reflectance information embedded in the image intensity of each pixel, thus the assessment of its performance is essential before the launch of the mission spacecraft. This work presents a laboratory experiment to evaluate the high-resolution and high-precision 3D surface models of asteroids reconstructed through an integrated photogrammetric and photoclinometric approach using simulation images. The whole experiment involves 3 steps. Firstly, construct the scaled-down experimental fields to simulate real in-situ conditions of the space probe with 3D printed models of asteroids, which represent the target asteroids of future missions. Then, collect simulation data according to various scenarios that might be encountered in a real on-orbit mission. Finally, reconstruct detailed asteroid models through the SPC refinement approach on the basis of stereo photogrammetry (SPG) models. Our previous studies indicate that SPC performance is influenced by both the azimuth and the incidence angles of illumination, as well as the image's general intensity. The experiment takes all these factors into account, as a reference for improving the image-acquiring plan during the in-situ detailed survey phase. The integrated approach will be tested for pixel-wise surface reconstruction of 3D-printed asteroid models of different shapes, i.e., Itokawa and Bennu. According to initial experimental results, the developed approach demonstrates the capability to attain high geometric accuracies and capture fine small-scale topographic details, which fulfills the requirement of the asteroid exploration missions.
Advancing seasonal hurricane predictions using causal AI
Authors: Latos Beata , Moon Il-Ju , Kim Dong-Hoon
Published: March 2024

In recent decades, the Atlantic region has seen more frequent and intense hurricanes, with the 2023 season ranking as the fourth-most active on record. Despite progress in understanding hurricane dynamics and identifying precursors, challenges persist in seasonal predictions.Conventional correlation measures often fall short in capturing causal relationships. Therefore, in this study, we employed the causal AI discovery tool PCMCI+ — a combination of the PC (Peter and Clark) algorithm and the Momentary Conditional test. PCMCI+ excels at uncovering causal relationships in time series data by addressing issues like autocorrelation, indirect links and common drivers.PCMCI+ was applied to nearly 150 lagged atmospheric and oceanic monthly ERA-5 time series from January to May between 1980 and 2022. Precursor regions, identified based on their causal links to hurricane numbers, were determined. Linear regression models and random forests were then used to predict hurricane numbers for each season.Results indicate that adopting PCMCI+ to select causal precursor regions significantly improved the accuracy of seasonal hurricane predictions, achieving a correlation of over 0.9 between observed and predicted numbers. While this study contributes to improved forecast precision, its primary focus is on exploring and discussing identified causes. The selected precursor regions are explained in the context of atmosphere-ocean interactions, providing valuable insights into their role in hurricane formation.This work was funded by the Korea Meteorological Administration Research and Development Program under Grant (RS-2023-00237121).
Quantifying risk of a noise-induced AMOC collapse from northern and tropical Atlantic Ocean variability
Authors: Chapman Ruth , Ashwin Peter , Wood Richard , Baker Jonathan
Published: March 2024

The Atlantic Meridional Overturning Circulation (AMOC) exerts a major influence on global climate. There is much debate about whether the current strong AMOC may collapse as a result of anthropogenic forcing and/or natural variability. Here, we ask whether internal decadal variability could affect the likelihood of AMOC collapse. We examine natural variability of basin-scale salinities and temperatures in four CMIP6 pre-industrial runs. We fit the CMIP6 variability to several empirical, linear noise models, and to a nonlinear, process-based AMOC model. The variability is weak and its processes inconsistent among the CMIP6 models considered. Based on the CMIP6 variability levels we find that noise-induced AMOC collapse is unlikely in the pre-industrial climate, but plausible if external forcing has shifted the AMOC closer to a threshold, which can be identified for the non-linear model using bifurcation analysis. However the CMIP6 models may systematically underestimate current Atlantic Ocean variability, and we find that substantially stronger variability would increase the likelihood of noise-induced collapse.
Enhancing Maize Production in Irrigated Crop Systems: Optimizing Water and Nitrogen Application for Sustainable Agriculture in Zambia
Authors: Mwape Mumba , Said Ahmed Hami , Phiri Elijah , Dercon Gerd
Published: March 2024

Reduced rainfall has been identified as a highly probable consequence of climate change in certain regions of Zambia. This is particularly concerning for small-holder farmers, who heavily rely on rainfall and are the primary producers of the country’s staple food, such as maize. The resulting decrease in production significantly impacts national food security. Recognizing the potential of irrigated agriculture to improve food security and sustain production levels, the Zambian Agricultural Research Institute (ZARI) has been actively engaged in research since 2021. Their focus is on enhancing irrigation and soil fertility management under conditions of reduced water availability.To address these challenges, a research trial was initiated at the ZARI research station in 2021. This trial aims to identify the optimal and sustainable water and nitrogen application for achieving maximum maize production in irrigated crop systems. Access tubes were installed in each subplot to monitor soil moisture to a depth of 1 m before and after irrigation on a weekly basis.This paper assesses the stored water in the root zone (up to 1 m) with interplay between amount of nitrogen fertilizer  applied and water application level.In the 2021 season, the results indicate that significantly more water was retained averagely throughout the growing season  in treatments with higher nitrogen levels, especially under reduced irrigation water applications (50% and 75% ETc). A similar trend was observed in the 2022 season, albeit only for 50% ETc. The increased stover yield may have contributed to reduced evaporation, minimizing losses. As nitrogen application levels rise, the ability to store soil water in the profile appears to increase. However, further analyses of soil moisture depth and root systems are needed to determine whether excess water in deficit-irrigated treatments is obtained from lower depths or if (and how much) water is lost in optimally irrigated treatments.