bluuebunny/crossref_metadata_2025 huggingface dataset:
Change and attribution of frost days and frost-free periods in China
Authors: zhu luanxuan , yan xiaodong
Published: March 2024

Frost events are a climatic phenomenon of great severity, exerting profound impacts on agricultural production and human endeavours. From 1961 to 2017, China has experienced a reduction in FDs and elongation of FFPs across most regions. Many factors contribute to the variation of frost events, which highlights the urgent need to scrutinise the intrinsic factors driving these climatic frost events' inter-annual and interdecadal fluctuations. This work analysed the temporal and spatial attributes of FDs and FFPs, using statistical methods to dissect daily minimum temperature data collected from ground observation stations from 1961 to 2017. The results reveal a declining trajectory in annual FDs and an ascending trend in FFPs. However, the interannual and interdecadal variations do not consistently align with the climatological course.  The spatial distribution of the first four modes of EOF exhibits a persistent variation, north-south, monopole, and east-west pattern for FDs and FFPs. In comparison, the modes of FFPs exhibit many complexities and diversities. Moreover, this study considers geographical location, altitude, and proximity to the ocean, as well as atmospheric circulation factors, including circulation indices, ocean indices, and other relevant indices, to elucidate their influence on frost events. In conjunction with the role of greenhouse gases in propelling global warming, we elucidate that the intensity of the Atlantic-European polar vortex, the area of the Indian Ocean warm pool, and the spatial positioning and extent of the subtropical high emerge as preeminent internal oscillations instigating interdecadal shifts in frost events. This study provides valuable scientific insights into the formation mechanisms and evolving patterns of frost events.
Hypothesis-testing and assisted-history-matching applied to evaluate uncertainty of model selection and parameter values: a case study of the impact of thermo-osmosis
Authors: Kiszkurno Feliks , Buchwald Jörg , Kolditz Olaf , Nagel Thomas
Published: March 2024

Pore pressure evolution and hydraulic flow are two important physical features to consider in barrier integrity and radionuclide transport applications. Existing literature suggests a potentially non-negligible impact of thermo-osmosis on pore-pressure evolution due to thermal gradients in clay rocks without arriving at a consensus. Numerical experiments based on models are a widely used method in the geosciences to test the relevance of physical features under specified conditions. Mismatch between the observations and the simulation can be partially attributed to the assumptions and simplifications made when developing those models. Their impact on the results and conclusions drawn from the numerical experiments can be significant and thus needs to be explored. Such exploration can proceed by jointly investigating the uncertainty associated with modelling choices, process selection and calibration. This study applies a hypothesis-testing method based on an assisted-history-matching workflow to integrate uncertainty evaluation of model selection, process representation and parameter identification. Three models were compared, representing, respectively, the correct, approximate and wrong hypotheses with respect to a synthetic data set resembling the ATLAS experiment, an in-situ, full-scale heating experiment performed at the HADES underground laboratory in Mol, Belgium. We show that the approach can recover the correct modelling hypothesis in the presence of parameter uncertainty despite competing hypothesis with the same amount of parametric degrees of freedom.
Sphagnum peatlands of Reunion Island: potential and limitations as environmental archives for the Quaternary of the Indian Ocean.
Authors: Le Roux Gaël , Ah-Peng Claudine , Liu Rongqin , Hagelskjaer Oskar , Margenart Henar , Sonke Jeroen , Hansson Sophia V. , Piotrowska Natalia , Pautot Corinne , Van Beek Pieter , Zambardi Thomas , Souhault Marc , De Vleeschouwer François , Bremond Laurent , Arnaud Fabien , Gandois Laure , Strasberg Dominique , Beilman David
Published: March 2024

Contrary to temperate and boreal peatlands built after the glacial retreat, tropical peatlands are potentially recording environmental information pre-dating the Holocene. However on tropical volcanic islands, Sphagnum moss are scarce and/or rarely build peat.Within the framework of the several projects on the territory of Reunion Island, we sampled peat bogs and Sphagnum mats of Reunion Island in 2021 (Margenat and Le Roux, 2023). The objectives were originally to use them as microplastic traps and thus reveal the history of atmospheric contamination by microplastics in the Indian Ocean over the last fifty years. It turns out some peat cores are older than expected and can provide amazing archives for the Holocene and Last Glacial environmental history of the Indian Ocean and La Réunion Island itself including the last period of strong volcanic activities. For example, one site located in the heart of the National Park is 25 ky old.In this talk, we will present the diversity of the Sphagnum peatlands of La Réunion, the first results of peat characterization, and the first results of radiometric age dating covering the last glacial maximum, the Holocene, and the most recent periods. We will then discuss potential and limitations of La Réunion peat records in paleo-landscape, paleo-atmosphere and carbon cycle aspects. References:Margenat, H., Le Roux, G., 2023. POST EXPEDITION REPORT Field Expedition La Réunion Island, France ATMO-PLASTIC Project. Zenodo. https://doi.org/10.5281/zenodo.7643599 
Carbon Budget of Complex Terrain Forest
Authors: Song Yunkun , Yan Xiaodong
Published: March 2024

Forest ecosystems represent significant carbon sinks within terrestrial ecosystems. Simulating carbon budgets in forest ecosystems located within complex terrains forms the foundation for understanding global carbon cycle dynamics. In this study, employing the FORCCHN model and utilizing mountain climate data as forcing parameters, the impact of the terrain factors of the Changbai Mountain Nature Reserve on carbon budget change in 1998–2017 was studied. The dynamics and distribution patterns of carbon fluxes at different slope aspects and elevations were discussed. Findings demonstrated that between 1998 and 2017, the per unit area gross primary production (GPP), net primary production (NPP), and net ecosystem production (NEP) for the Changbai Mountain Reserve were 839.35 gC·m-2·yr-1, 462.03 gC·m-2·yr-1, and 192.72 gC·m-2·yr-1, respectively. The carbon fluxes varied significantly with elevation: the GPP of the north, south, and west and the NPP of the east, south, and west decreased, and the NEP of the south and west increased. The total amount in GPP and NPP of the Changbai Mountain Nature Reserve fluctuated slightly year by year, but the carbon sequestration capacity decreased from year to year. The reserve had an average annual total GPP, NPP, and NEP of 1.62 TgC·yr-1, 0.89 TgC·yr-1, and 0.37 TgC·yr-1, respectively. The north was the strongest carbon sink in the study area, contributing 35.98%, 35.88%, and 36.80% to the total amount of GPP, NPP, and NEP, respectively. This study emphasized the significance of precise mountain meteorological data to accurately quantify the carbon fluxes of mountain forest ecosystems.
The role of subtropical mode waters in the variability of meridional heat transport in the North Atlantic subtropical gyre
Authors: Smeed David A. , Johns William E. , Smith Ryan H. , Rayner Daren , Volkov Denis L. , Elipot Shane , Petit Tillys , Kajtar Jules B. , McDonagh Elaine L. , Moat Ben
Published: March 2024

The AMOC is usually defined as the maximum of the overturning streamfunction.    The time series produced by the RAPID-MOCHA-WBTS observing array uses a streamfunction calculated in depth space.     Using data from the RAPID-MOCHA-WBTS array along with additional data from the WBTS sections in the Florida Straits and other hydrographic data, we have made a time series of the overturning streamfunction calculated in density space.  The streamfunction in density space reveals the shallow overturning cell associated with subtropical mode waters (STMW) that is obscured in the depth-space streamfunction.    The time series of the data also reveal that inter-annual variability in the amount of STMW in the Florida Straits is linked to changes in meridional heat transport.
Re-location and integration into the ISC Bulletin of earthquakes recorded by hydro-acoustic MERMAID instruments freely floating in the South Pacific Ocean
Authors: Namjesnik Dalija , Sigloch Karin , Simon Joel D. , Garth Tom , Harris James , Storchak Dmitry , Simons Frederik. J. , Bonnieux Sébastien , Yu Yong , Obayashi Masayuki
Published: March 2024

We present the analysis of more than 9000 hydro-acoustic earthquake records, recorded by a network of 50 instruments called Mobile Earthquake Recording in Marine Areas by Independent Divers (MERMAIDs), which are freely floating in the South Pacific Ocean. This network is part of the collaborative South Pacific Plume Imaging and Modeling (SPPIM) project. Our analysis focuses on evaluating how the MERMAID stations complement the conventional worldwide network of stations reporting to the ISC, comprising records of globally distributed seismic stations. In the context of routine earthquake (re)location, we evaluate the improvement of results of earthquake location estimates, particularly focusing on the Tonga-Kermadec subduction zone, where current distribution of seismic land stations is extremely sparse. MERMAIDs are often the closest “station” to earthquakes occurring in the Tonga subduction zone, and frequently fill significant station azimuthal gaps.We matched the MERMAID records from June 2018 to December 2023 to more than 3000 earthquakes which are reported to the ISC by many international agencies worldwide, allowing us to construct the MERMAID catalogue, complimented with additional parametric data such as MERMAIDs locations, observed direct P-phase picks and travel time residuals with respect to ak135 model, as well as their corrections for bathymetry. These data were integrated into the existing ISC Bulletin, and relocated using the ISC hypocentre relocation algorithm ISCLoc. The results of this successful first integration of MERMAID data into ISC routines presents an important step towards routinely including MERMAID traveltime picks in ISC Bulletin.
Using an oceanic acoustic noise model to evaluate simulated atmospheric states
Authors: Letournel Pierre , Listowski Constantino , Bocquet Marc , Le Pichon Alexis , Farchi Alban
Published: March 2024

Due to the lack of observations, Numerical Weather Prediction (NWP) models are poorly constrained in the Middle Atmosphere (MA ~10-90km) and thus significantly biased [1]. Infrasounds of oceanic origin (microbaroms) propagate across thousands of kilometers and integrate information on the MA dynamical state and particularly on winds. Thus, we investigate how to assess the performance of NWP models in the MA through simulations and global and continuous observations of microbaroms. Infrasound observations are processed using an adaptation of the MCML [2] algorithm to obtain the azimuthal distribution of microbarom amplitudes at the International Monitoring System Norwegian infrasound station I37NO. These observations are compared to simulations where modelled distribution account for the antenna response relative to MCML processing.Simulations of microbaroms arrival are carried for the year 2021 by combining a microbarom source model [3] and two propagation methods: a semi-empirical law using a single atmospheric profile and Parabolic Equation (PE) range-dependent propagation simulation accounting for the 3D atmosphere. Yearly comparisons through an optimal transport metric using atmospheric specification from different atmospheric models highlight the limitations of the semi-empirical law for a NWP model performance evaluation.Atmospheric models are thus assessed building on the PE propagation simulations and first conclusions on models relative performances are derived over specific periods of interest, including a sudden stratospheric warming. While the current work focuses on the evaluation of NWP models, it will also allow to define a method relying on microbarom observations to improve these models through Data Assimilation. [1] Le Pichon, A., Assink, J. D., Heinrich, P., Blanc, E., Charlton-Perez, A., Lee, C. F., Keckhut, P., Hauchecorne, A., Rüfenacht, R., Kämpfer, N., et al. (2015), Comparison of co-located independent ground-based middle atmospheric wind and temperature measurements with numerical weather prediction models, J. Geophys. Res. Atmos., 120, 8318–8331, doi:10.1002/2015JD023273.[2] B Poste, M Charbit, A Le Pichon, C Listowski, F Roueff, J Vergoz, The multichannel maximum-likelihood (MCML) method: a new approach for infrasound detection and wave parameter estimation, Geophysical Journal International, Volume 232, Issue 2, February 2023, Pag-es 1099–1112, https://doi.org/10.1093/gji/ggac377[3] De Carlo, M., Accensi, M., Ardhuin, F., and Le Pichon, A.: ARROW (AtmospheRic InfRasound by Ocean Waves): a new real-time product for global ambient noise monitoring., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7564, https://doi.org/10.5194/egusphere-egu22-7564, 2022.
Density-driven flow propagating over a bottom large-scale roughness
Authors: Adduce Claudia , Maggi Maria Rita , Di Lollo Giovanni
Published: March 2024

The hydrostatic imbalance between two adjacent fluids, driven by density variations associated with temperature, salinity, or sediment concentration gradients, often initiates the formation of gravity currents. These phenomena play a crucial role in various geophysical and engineering applications, influencing atmospheric, terrestrial, and subaqueous environments. In recent years, there has been growing research interest in understanding the interaction of gravity currents with obstacles on the seafloor. These obstacles can be artificial structures like pipelines and gas pipelines situated in the oceanic environment. Therefore, it is essential to investigate the dynamics of gravity currents over complex topography and analyze their characteristics and behavior as the initial conditions vary. This study experimentally examines the evolution of bottom-propagating gravity currents in the presence of an array of submerged cylindrical obstacles. The laboratory experiments were conducted within a Perspex tank with dimensions of 3 m in length, 0.3 m in height, and 0.2 m in width, using the lock-release technique by filling the left and right volumes of the tank to the same water depth. The density difference was reproduced through a salinity gradient. Submerged roughness was introduced by arranging a series of rigid plastic cylinders at a specified location, covering the entire width of the channel. Two different diameters, 2 cm and 2.5 cm, were analyzed, and the initial current depths were varied. A total of 24 full-depth lock-exchange experiments were performed. We employ an innovative image analysis technique based on light reflection to evaluate the instantaneous density fields. To apply the light attenuation technique and visualize the dense fluid, a controlled quantity of dye was introduced into the saline water. A calibration method was used to establish the correlation between light intensity and dye concentration for each pixel in the captured images. The conducted study clearly illustrates that an adequate height of obstacles results in a substantial portion of denser fluid being impeded by the foremost obstacle in an array. Additionally, transitioning from densified to less-densified array geometries induces distinct changes in flow morphologies. Upon concluding the analysis of this study, it is evident that all the experiments are affected by the presence of substantial bottom roughness.
Spatial modelling of microbial interactions and carbon dynamics in soils
Authors: Raynaud Xavier , Nunan Naoise
Published: March 2024

Soil hosts a large diversity of microorganisms, that are responsible for the transformation, storage in the soil and release of carbon (C) to the atmosphere. These transformations of C are realized by individual cells that all belong to a metabolic interaction network, i.e. a network of interactions within which cells from different species compete for, transform and exchange resources. Soil C respiration, soil C storage and soil Carbon Use Efficiency are all outcomes of the functioning of this metabolic interaction network. Understand the functioning of metabolic interaction networks is thus essential to understand the cycling of C in soils.We present a spatially explicit, individual based, model of microbial interactions in which cells are able to take up some resources, transform them into other products, which are released into the environment. Each cell is assumed to have a spatially limited impact on their environment. In this contribution, using different model parametrizations, we explore the interplay between spatial distribution of cells, resource diversity and microbial diversity, and show how the spatial distribution of cells can be a strong modulator of the functioning of metabolic networks in soils.
Hazard Assessment of Earthquake-Submarine Landslide-Tsunami Cascading Events on the Slope Fault Zone of Northern SCS
Authors: Du Peng , Li Linlin , Wang Dawei
Published: March 2024

The consensus in earlier studies was that the tsunami threat along the coast of south China primarily comes from destructive earthquakes occurring in the Manila subduction zone. However, two seismogenic structures on the continental shelf of the Northern South China Sea, namely the Littoral Fault Zone and the Slope Fault Zone, have been overlooked in these assessments. Both fault zones have a history of destructive earthquakes accompanied by tsunamis. In particular, the Slope Fault Zone, located in the shelf-slope bending zone, is prone to triggering submarine landslides after earthquakes, which can result in devastating tsunamis. This study aims to assess the potential threats posed by earthquake-submarine landslide-tsunami cascading events in the Qiongdongnan segment of the Slope Fault Zone to the coastal regions of Southern China.To achieve this, we conducted a probabilistic seismic hazard analysis using the latest findings on the fault structure of the Qiongdongnan segment and the comprehensive regional seismic catalog. This analysis provides important information about the likelihood of earthquakes in the region. Based on the seismic hazard analysis results, we assessed the stability of gentle slope areas (submarine landslide gap) using high-resolution bathymetric data, multi-channel seismic profiles, and gravity core samples of seafloor sediments. Finally, we established a model for potential submarine landslide sources in these areas and evaluated the tsunami hazard resulting from earthquake-triggered landslides.By comprehensively evaluating earthquake-submarine landslide-tsunami cascading events on the continental shelf fault zone of the Northern South China Sea, this study aims to provide a new perspective and understanding for earthquake and tsunami disaster prevention. Additionally, it seeks to establish the scientific foundations for the development of effective tsunami warning and risk management strategies.
Application of the GeoXO ACX NO2 Algorithm to GEMS and TEMPO and Intercomparisons with TROPOMI
Authors: Yang Kai , Kondragunta Shobha , Wei Zigang
Published: March 2024

The atmospheric composition instrument (ACX) on NOAA's GeoXO mission will enhance NOAA's air quality monitoring capabilities by providing hourly high-resolution observations of air pollutants over North America, like its predecessor, NASA's TEMPO mission. We are developing and implementing an advanced algorithm for accurate NO2 retrieval from GeoXO ACX. Applying this algorithm to GEMS and TEMPO, we demonstrate in this presentation the success of rapid production of high-quality NO2 data soon after the mission starts to collect Earthview measurements. We describe the technique for instrument characterization and identification of instrument artifacts for improving retrieval precisions, and the soft calibration approach for removing systematic biases in NO2 retrieval. Using TROPOMI as a transfer standard, we show consistent NO2 slant columns are retrieved from GEMS and TEMPO using the GeoXO ACX NO2 algorithm.
Multi-Offset Radio-Echo Sounding for Estimation of Englacial and Subglacial Thermal Conditions and Material Properties
Authors: May Daniel , Schroeder Dustin , Summers Paul , Teisberg Thomas , Broome Anna , Bienert Nicole
Published: March 2024

Radio-echo sounding (RES) is a widely used tool in the field of glaciology with which critical information about englacial and subglacial conditions can be derived. However, RES observations have historically been limited to zero-offset or small-offset surveys, typically employing one transmitting and one receiving antenna. The poor spatial and azimuthal coverage of the subsurface associated with these sparse geometries limits the ability to robustly constrain key englacial and subglacial properties including ice temperature, bed material composition, water content, ice fabric, and firn density. Furthermore, using radar only in zero- or small-offset configurations limits its potential to provide high resolution imaging of bed geometry. The maximum achievable offset in ground-based radar surveys is typically limited by the relatively high-loss coaxial cable which connects the radar transmitter and receiver. To overcome this limitation, two multi-offset ground-based radar systems, both built around an autonomous phase-sensitive radio-echo sounder (ApRES) as a transmitter, have been developed and deployed by the Radio Glaciology Group at Stanford. The first system forgoes cabled connection between a transmitting ApRES unit and a software-defined radio (SDR) based receiver, instead relying on a post-acquisition processing flow to ensure coherent summation of repeated measurements to achieve sufficient signal-to-noise ratios. The second system replaces the standard high-loss coaxial cable with low-loss fiber optic cable in order to extend the maximum achievable offset between transmitter and receiver. This requires outfitting the ApRES radar system with hardware to convert radio-frequency signals into optical signals that can be transmitted over fiber optic cable (RFoF). Both systems were deployed during the 2023-24 Antarctic field season as part of the Thwaites Interdisciplinary Margin Evolution project in order to collect multi-offset RES data on both floating and grounded ice. These surveys are aimed at detecting englacial temperature anomalies and the estimation of dielectric properties of englacial and subglacial materials through amplitude-versus-offset analysis of radar data. The dense multi-offset coverage in surveys described here was built up by frequent repositioning of only four SDR-based and one ApRES-based receiver; however, future surveys with these systems could have 10s or 100s of radar receivers simultaneously recording, allowing for survey geometries commonly employed in active source seismic imaging to be applied to radar imaging. 
Measured distributions of velocity and concentration for intense transport of bimodal lightweight sediment in tilting flume
Authors: Matousek Vaclav , Krupicka Jan , Picek Tomas , Svoboda Lukas
Published: March 2024

The laboratory experiments on the intense transport of bimodal sediment were conducted in a tilted, glass-sided flume with a variable longitudinal slope. Two fractions of lightweight solids were used, primarily differing in particle size, and each had a distinct color. The observed solid-liquid flow exhibited characteristics of being steady, uniform, turbulent, and supercritical. The bimodal sediment was transported as a combined load, with the finer fraction primarily supported by carrier turbulence, and the coarser fraction supported by interparticle contacts in the transport layer above a plane surface of the bimodal stationary bed. Distributions of solids velocity and concentration were measured for each of the two fractions across the transport layer above the bed using optical methods employing high-speed cameras. Additionally, the distribution of carrier velocity was measured across the flow depth. The measurements revealed a non-uniform distribution of solids for both fractions, with the maximum concentrations at the top of the bed for the coarser fraction and within the transport layer for the finer fraction at the highest bed shear. The results of the measurements allowed for the identification of the degree of stratification in the high-concentration sediment-laden flow and facilitated the evaluation of the interaction between particles of different fractions in the transport layer at various elevations above the bed. Furthermore, they enabled the quantification of the proportion of particles of the two fractions in the total discharge of solids through the channel.
An Underground Hydrogen Storage Site Selection Ranking Matrix: Insight into the Friulian Plain, Italy
Authors: Borghini Lorenzo , Corradetti Amerigo , Franceschi Marco , Del Ben Anna , Bonini Lorenzo
Published: March 2024

Net-zero emission targets for 2050 are pushing governments, energy industries, and the scientific community to explore the use of alternative energetic vectors. Among them, hydrogen has risen as a potentially extremely relevant technology, as testified by the establishment of several “hydrogen valleys” in the EU. One of the key aspects in the use of hydrogen as energy vector is its underground storage. The majority of studies focus on physical experiments and numerical simulations, whereas little attention has been so far directed on potential sites selection. This study presents a site selection and feasibility study considering the Cavanella Formation (lower Miocene, Northeast Italy) as potential reservoir for hydrogen storage. This unit comprises medium to fine glauconitic sandstones. The presence of the Cavanella Formation in the subsurface of the Friuli Plain is widely documented and the unit is easily identified in seismic lines. A preliminary petrophysical characterization of the Cavanella Formation was carried out on sampling collected from outcrops. The site selection study was based on interpretation of publicly accessible seismic lines, well logs, thin sections, and literature data. Each potential site was evaluated, attributing a storage feasibility index through a designed scoring matrix developed by us and based on literature reservoir characteristics needed for hydrogen storage. Results suggest that the Cavanella Formation could have good petrophysical characteristics for hydrogen storage and that potential storage sites could exist. The scoring matrix has already been tested on underground hydrogen storage sites currently in use worldwide and has proven reliable. The identification of possible sites for hydrogen storage and their petrophysical characterization can have significant impact on the deployment of this new technology, therefore helping the energy transition to renewable sources.
Effect of Local Dispersion on Mixing Enhancement when Applying an Engineered Injection and Extraction System: Laboratory and Model-based Evidence
Authors: Ziliotto Francesca , Basilio Hazas Mónica , Muhr Markus , Rolle Massimo , Chiogna Gabriele
Published: March 2024

Engineered Injection and Extraction (EIE) systems represent a promising groundwater remediation technique. This technology generates transient groundwater flow fields by periodically operating a system of pumping wells, with the goal of enhancing contaminant degradation through mixing with a treatment solution. The objective of this work is to provide experimental evidence of the effect of an EIE system on plume mixing and to investigate the effect of local dispersion on mixing enhancement. We perform laboratory experiments in a quasi-two-dimensional setup representing a vertical cross-section of an unconfined homogeneous aquifer. The setup is equipped with four wells, connected to a peristaltic pump, which are activated one at a time following an injection-extraction sequence. The wells operation establishes transient flows within the setup and introduces fluctuations in the groundwater table. A conservative tracer is injected in the middle of the area delimited by the wells, and a high-resolution image analysis technique is applied to track the evolution of the tracer concentration. We perform the experiments considering two different grain sizes and investigate the effect of the application of the EIE system on the plume mixing and spreading in contrast to two benchmark experiments where the wells are not operating and, therefore, only diffusion affects the tracer plume. Additionally, for one porous material, we permute the injection-extraction sequence to study the effect of different transient flow conditions and groundwater table fluctuations on plume deformation and mixing. We also provide a model-based interpretation of the experimental results using Richards equation and the conservative advection-dispersion equation to describe flow and transport processes, respectively. Plume spreading is quantified by computing the second central spatial moments, while the degree of mixing is estimated by calculating the plume area. We use the Okubo-Weiss metric computed over the plume area to link the mixing enhancement to the change in the flow topology. Our results show that EIE effectively enhances mixing and spreading at the laboratory scale, especially when the flow field leads to high values of the Okubo-Weiss metric. Moreover, local dispersion is shown to be a key factor for mixing enhancement in engineered injection and extraction systems.
The circumsolar solar energetic particle event on 2022 January 2022, particle spread within and outside a magnetic cloud
Authors: Rodríguez-García Laura , Gómez-Herrero Raúl , Dresing Nina , Balmaceda Laura A. , Palmerio Erika , Espinosa Lara Francisco , Kouloumvakos Athanasios , Jebarah Immanuel , Palmroos Christian , Laitinen Timo , Lee Christina , Cohen Christina , Fedeli Annamaria , Cernuda Ignacio , Roco Mario , Malandraki Olga , Rodríguez-Pacheco Javier
Published: March 2024

On 2022 January 20, the Energetic Particle Detector on board Solar Orbiter detected a solar energetic particle (SEP) event showing unusual sunward-directed fluxes. Near-Earth spacecraft separated by 17° in longitude from Solar Orbiter measured classic antisunward-directed fluxes. Parker Solar Probe and MAVEN, separated by 130° and 216° respectively from Solar Orbiter, observed the particle event as well, suggesting a widespread event of nearly 360° in the heliosphere. The SEP event was associated with an M5-class X-ray flare and a CME with a speed of 1400 km/s. The energetic particles reached 3 MeV and 100 MeV energies for electrons and protons, respectively.The aim of this study is to disentangle how the particles are able to spread throughout the heliosphere and how the local heliospheric conditions affect the acceleration and transport of the particles at different spacecraft locations. This work presents the observations and analyses that lead to a scenario in which the solar source injected energetic particles into the solar wind and within a preceding interplanetary coronal mass ejection (ICME) that was already present in the heliosphere at the time of the SEP event onset. In particular, Solar Orbiter measured the particles injected along the longest leg of an ICME still connected to the Sun at the time of the particle release.
Enhancing satellite orbit accuracy for sea level monitoring through Earth radiation pressure modeling
Authors: Nocet-Binois Maya
Published: March 2024

The accurate determination of sea surface height begins with the precise characterization of the orbit of altimetric satellites with respect to the Earth’s center of mass. To produce precise estimates of the orbital height of such altimetric satellites, Precision Orbit Determination (POD) combines satellite-tracking information with force models, including gravity, atmospheric drag, radiation, and others, which govern the motion of these satellites.However, it’s important to note that uncertainties arising from the modeling of non-gravitational forces, stemming from the interaction between photons, molecules, atoms, and satellite surfaces, constitute a significant source of error.With the goal of achieving radial orbit errors below 0.1 mm/year at regional and decadal time scales, an update in the modeling of non-gravitational forces, specifically addressing Earth radiation pressure, was performed. Indeed, the traditional model used in CNES' ZOOM orbit determination software was based on an average approach (Knocke et al., 1988) accounting for latitude and time dependent reflected/emitted radiations which did not consider the spatial and temporal complexity of reflection phenomena, such as cloud dynamics.To address this issue, an approach involving the use of observations from Earth radiation fluxes, such as CERES (NASA) and ERA5 (ECMWF), was adopted and tested during the lifetime of the Sentinel-6A and CryoSat-2 satellites. These efforts led to substantial improvements in the dynamic modeling of satellite orbits. Comparisons were made between the resulting satellite orbits and those based on the legacy model, with the aim of assessing their impact on sea level measurements. Although a slight discrepancy was observed between the two derived orbits, this difference was attributed to the introduction of empirical forces, typically employed to correct dynamic modeling errors. Consequently, an analysis of these empirical forces confirmed their relevance and underscored the value of the new force model
Geodetic observations of simultaneous rift-scale magma inflow in multiple sills in the Central Afar rift
Authors: La Rosa Alessandro , Pagli Carolina , Wang Hua , Sigmundsson Freysteinn , Pinel Virginie , Keir Derek
Published: March 2024

During plate spreading, large volumes of magma can be extracted from the upper mantle and intrude the crust. Geophysical and geochemical studies at active magmatic rifts and passive margins show that crustal intrusions mainly occur in the form of transient sill-like bodies. The sills pond at various crustal levels, potentially feeding shallower plumbing systems, dike intrusions and surface eruptions. Trans-crustal magma migration and intrusion thus have a key role in controlling extension, strain localization and subsidence during rifting. However, a clear understanding of the mechanisms of sill intrusion, their connection to upper mantle processes, as well as the spatial and temporal response of the sills to a new arrival of magma is still limited by the paucity of direct observations. In this study, we provide one of the few direct InSAR observation of rift-scale deformation caused by magma inflow from the upper mantle to multiple crustal sills in the Central Afar (CA) rift.We used InSAR time-series from 255 ESA Sentinel-1 interferograms during 2014-2021 and combined them with available GNSS measurement to retrieve the 3D velocity field and the temporal evolution of surface deformation in CA. We observed four uplift patterns with rates of ~5 mm/yr, that we inverted using four inflating Okada tensile dislocation sources (sills). Our best-fit model shows four sills elongated in a NW-SE direction, similar to the rift trend, and opening rates ranging between 16 and 44 mm/yr. The sills are located at various crustal depths but mainly in the mid-to-lower crust, following the thinning of the crust imaged seismically in CA. Cross-correlation of time-series also show that the uplift above the four sills starts simultaneously in December 2016 and continue until March 2021.We interpreted the simultaneous inflation of four distant sills as the result of a shared pressurization event caused by an episodic magma inflow from a common source in the upper mantle. Our results show that magma supply from the mantle beneath continental rifts is episodic, and occurs across large spatial scales but short temporal scales over which deep crustal magma ponding takes place. Such process could explain how the thick intruded crust common at magma-rich rifted margins is created and could help in understanding the long-term dynamics of rifting episodes and volcanism.
Investigation of the Vertical Geometry of Low Level Clouds in the Namib Desert
Authors: Malik Deepanshu , Andersen Hendrik , Cermak Jan
Published: March 2024

This study comprehensively investigates the vertical geometry of low-level clouds in the Namib desert. Using ceilometer measurements and meteorological station observations, a precise determination of cloud-base height and the separation of low-level stratus and fog is performed.The Namib Desert, known for hyper-arid conditions and frequent cloudiness, presents an intriguing environment for the study of low-level clouds and their vertical geometry. Fog (ground-touching low-level clouds), a common atmospheric phenomenon in the Namib Desert, is influenced by the interplay of coastal upwelling and spatial temperature differences. Differentiation of fog from other low-level clouds and understanding cloud dynamics are crucial, as fog impacts the water balance in this arid region. Here, ceilometer measurements of cloud base altitude are analyzed and combined with local station measurements with the aim of developing a statistical model to robustly predict cloud base altitude.Initial results suggest a robust correlation between the cloud base height and surface relative humidity, as well as other meteorological variables. This finding proves beneficial for utilizing meteorological parameters such as the lifted condensation level as a surrogate for cloud-base height. The outcomes of this study hold significance for modeling of satellite-based fog probability product and ecological studies.
Morocco’s Earthquake Risk Management: A Multi-Criteria Decision-Making Approach and Implications for the Recent Japan Earthquake
Authors: Bouramdane Ayat-Allah
Published: March 2024

Effective management and communication of earthquake risks is crucial for enhancing societal preparedness and resilience. This study investigates earthquake management strategies using Multi-Criteria Decision-Making (MCDM), specifically the Analytic Hierarchy Process (AHP). The focal earthquake event driving this investigation occurred on September 8, 2023, at 11:11 PM local time. With a magnitude of 6.8, the seismic incident had its epicenter approximately 72 km southwest of Marrakech within the Al Haouz province.A comprehensive assessment is conducted on ten distinct earthquake management strategies in Morocco. These encompass building codes and construction standards (S1), early warning systems (S2), public education and awareness (S3), land use planning (S4), emergency response plans (S5), international cooperation (S6), research and monitoring (S7), infrastructure resilience (S8), community preparedness (S9), and insurance and financial preparedness (S10). The evaluation involves a thorough examination against a set of criteria encompassing aspects such as effectiveness in risk reduction (C1), cost-effectiveness (C2), inclusivity and social equity (C3), adaptability and flexibility (C4), environmental impact (C5), compliance with standards and insurance uptake (C6), interagency collaboration (C7), and data utilization (C8).The resulting criteria weights underscore their relative importance, with C1 deemed highly significant (30%), C2 and C3 moderately important (20% and 15%, respectively), and C4, C5, C6, C7, and C8 holding lesser significance (ranging from 10% to 5%).Performance scores are assigned to rank the earthquake management strategies, revealing that A2 attains the highest score (0.45), followed by A4 (0.43), A10 (0.42), A9 (0.41), A3 (0.4), A8 (0.39), A7 (0.38), A6 (0.37), and A5 (0.35). A1 achieves a moderate score (0.32), providing valuable insights for decision-making in earthquake risk reduction.This research underscores the pivotal role of early warning systems in earthquake management, emphasizing the significance of timely alerts, community engagement, and financial preparedness within Morocco's comprehensive risk reduction strategy. The study advocates for data-driven decision-making to enhance preparedness, response capabilities, and mitigation measures. Moreover, this research holds implications for recent seismic events, such as the magnitude 7.6 earthquake in Japan on January 1, 2024.
Reconstructing oceanic plateau sequences and kinmatic analysis during the accretion process:insight from the Nuomuhongguole early Paleozoic accretionary complex in East Kunlun orogenic belt
Authors: Zang Rutao , Dong Yunpeng , He Dengfeng , Sun Shengsi
Published: March 2024

The oceanic plateau is an area characterized by abnormal thickness of ocean crust formed by a mantle plume. It not only constitutes a distinct section of the oceanic crust but also plays a crucial role in reconstructing the stratigraphy of ancient orogenic belts. The Nuomuhongguole area, situated in the southern part of the East Kunlun orogenic belt, contains rich records of early Paleozoic accretionary complexes. It is distinguished by extensive outcrops of pillow basalt and interbedded limestone, likely remnants of a seamount or oceanic plateau. To ascertain its tectonic setting, reconstruct the oceanic plate stratigraphy, and elucidate the subduction and accretion processes of Proto-Tethys in this region, comprehensive field geological work, along with studies in petrology, geochemistry, and geochronology, were conducted. A relatively well-preserved remnant of an oceanic plateau was identified. Moving from north to south, distinct rock units, such as the pillow lava-limestone unit, the pillow lava-breccia-limestone unit, and the sandstone-siltstone-chert unit, represent the top, slope, and foothill facies of the oceanic plateau, respectively. The majority of the pillow lavas are basaltic, displaying flat chondrite-normalized rare earth element (REE) patterns similar to those observed in the Java oceanic plateau. Zircons extracted from the pillow lava and dacite-porphyry yielded a U-Pb age of 430±3.4Ma and 427.5±3.0Ma, indicating that the oceanic plateau formed approximately 427-430 million years ago. Melanges with a "block-in-matrix" structure are preserved on both the north and south sides of the oceanic plateau. Detrital zircon ages from sandstones in these melanges suggest a provenance from the Central Kunlun Arc. Consequently, we propose that there was a northward subduction-accretion process of the oceanic plateau in Proto-Tethys along the Central Kunlun Arc belt during the Early Paleozoic.
TerraVirtuale: a ERC AdG funded project to model planetary magnetospheres with full electron physics. 
Authors: Lapenta Giovanni
Published: March 2024

The goal is to develop a model of the space environment around a planet based on a particle description of both ions and electrons. At present, models rely on a fluid description of the electrons due to algorithmic and computational challenges. We plan to use the particle in cell (PIC) model where both ions and electrons retain their nature as particles. This PIC model will allow us to investigate the critical role of energetic electrons participating in the energy and matter transfer from the solar wind to the planet inner space. The question about how solar storms impact the planet atmosphere and how planets’ atmospheres respond to the solar wind has both fundamental scientific importance and great social impacts for protecting our infrastructure from the most powerful solar storms.        What makes this goal now possible is the Energy Conserving semi implicit method (ECsim), developed by the author. The ECsim conserves energy exactly, a critical element in the investigation of energy flow from the solar wind. In addition, the energy conservation leads to enhanced numerical stability, which in turn greatly augment ECsim’s capability to simulate very large systems such as planet atmospheres while treating electrons as particles rather than fluid. TERRAVIRTUALE will start from this new development and introduce two critical innovations. First, we will implement the variable spatial and temporal resolution adaptation algorithm to ECsim for finer resolution closer to the planet and in selected areas of interest and coarser elsewhere. Second, we will implement CPU-GPU heterogenous algorithm to utilise new heterogeneous supercomputers developed by HPCEuropa. These new achievements will enhance ECsim capability to conduct PIC model by more than an order of magnitude to simulate the entire Earth’s atmosphere in their interaction with powerful solar winds.        TERRAVIRTUALE, if successful, will be the first PIC model to describe a planetary space environment where the correct particle nature of the electrons is considered with all its implication for the energy and matter transport. The challenge is to successfully augment energy conserving ECsim’s capability to model a region as big as the Earth space environment with the computers available within the next 3-5 years.
Climate Change Impact Assessment on Hydrological response of Tawa Basin for Sustainable Water Management 
Authors: Badika Pragya , Raghuvanshi Akash Singh , Agarwal Ankit
Published: March 2024

Sustainable water resources planning and management is critical in fulfilling the demands of present and future generation in limiting environment. River basins plays a crucial role in balanced and responsible management strategies, as they frequently serve vital role in freshwater supply, irrigation, hydropower generation, industrialization and to support a balance ecosystem. In the era of climate change and adverse environmental impacts, it is required to prioritize assessment for sustainable development and management of river basins to ensure a resilient water system. In this study, the Tawa Basin has been selected which is one of the important tributary of Narmada Basin and has a paramount importance in irrigation and hydropower generation. From a hydrological standpoint, basin response to climate change is critical for analysing hydrological extremes and developing long-term plans and strategies for water-related activities and policies. The basin experiences significant rainfall fluctuation throughout the year, particularly during the monsoon season (June to September) which adversely influence the runoff generation in the basin and consequently, the likelihood of catastrophic occurrences. However, the hydrological response of Tawa basin to climate change has been rarely investigated under socio-economic pathways. Present work sought to evaluate the hydrological response of Tawa basin under changing climate using Coupled Model Inter-comparison Project (CMIP6) scenarios. In this study, a comparative assessment has been done with the application of two conceptual lumped hydrological model to ensure the robustness of the Hydrological model. For this, the MIKE 11 NAM and GR4J model has been set up for period of 2009 to 2021. The model is calibrated at the downstream of the Tawa reservoir using the water balance at reservoir scale. For climate change assessment, the latest CMIP6 outputs has been incorporated for two shared socio-economic pathways; SSP2-45 and SSP5-85 for near (2040-2060) and far (2070-2100) future. In addition, evaluation was performed using the individual and ensemble output of climate models to ensure the uncertainty in hydrological responses. The findings of this study are critical for understanding how climate change will alter the hydrology of the Tawa River Basin. This research might lead to the adoption of a strategic strategy for sustainable water resources and improved societal resilience to climate change in the Tawa River Basin.