bluuebunny/crossref_metadata_2025 huggingface dataset:
The Martian Recurring Slope Lineae: Granular Flows Linked with Wind and Dust 
Authors: Leseigneur Yann , Vincendon Mathieu , Zhang Qing
Published: March 2024

Recurring Slope Lineae (hereinafter RSL) are seasonal dark flows observed on steep slopes (≳ 25°) of Mars that are overall dark (slope albedo < 0.2) (McEwen et al., 2011). These movements of up to a few hundred meters long appear and grow downwards (more or less incrementally), fade (partially or totally) more or less progressively, and recur almost every year. After considering it as liquid water or brine flows, the RSLs are now widely considered as granular flows of dark sand or dust, both involving dust at different levels. Mechanisms that may drive these movements are however not precisely understood. One of the main common features between RSL and dust is seasonality: major RSL formations are for example observed during the dust storm season, and RSL formation is enhanced after global dust storms. Here, we aim to better understand the role of dust and winds in these movements. We have first concentrated our study on Hale crater (323.48°E, 35.68°S), a well-studied RSL site located within an area of higher dust storm detections in the OMEGA/Mars Express dataset. Images taken by the HiRISE camera onboard Mars Reconnaissance Orbiter (during Martian Years 31, 32 and 33) have been used to characterise the RSL annual activities. We defined 3 intensity levels to classify formations and disappearances. Then, we compared these RSL activities to atmospheric dust optical depth measurements and Mars Climate Database (MCD) predictions of dust deposition and winds. Finally, we computed the effective reflectance values of several consecutive HiRISE images, taking into account the local slope of the surface, to quantify darkening and brightening. We observed that RSL formation and disappearance are correlated with the atmospheric dust optical depth variations. We also noticed that the prediction of dust deposition rate reaches two maxima during the dust storm season that occur simultaneously with intermediate and high RSL disappearance levels. Reflectance variations showed that RSL can disappear both by brightening and darkening, with relative variations from a few per cent to 40%, suggesting that RSL can also disappear by widespread dust removal all over the RSL slope. We also identified some correlations between RSL activities and wind predictions: the maximum of surface wind stress is reached during the first period (of the year) of high RSL formation level, and the convective winds reach high values during the dust storm season (Ls ~ 180-360°), corresponding to intermediate and high RSL formation levels. Overall, these results suggest that dust deposition/removal and winds are involved in the RSL disappearance and formation mechanisms at Hale crater.
The Geophysical Model Generator: a tool to unify and interpret geophysical datasets
Authors: Thielmann Marcel , Kaus Boris J.P. , Spang Arne , Schuler Christian , Aellig Pascal
Published: March 2024

Geophysical datasets and their interpretations form the basis of geodynamic simulations of the Earth’s mantle and lithosphere. Yet, creating geodynamic models from these datasets is often non-trivial, particularly in complex regions such as active orogens. Creating self-consistent three-dimensional models from these datasets poses a challenge due to technical issues such as different data set formats and different spatial resolutions, but also due to discrepancies in the data itself. At the same time, the different datasets obtained through initiatives such as AlpArray contain a wealth of data that can help to constrain subsurface models to an unprecedented extent. Yet interpreting these different data still involves subjective steps and ideally different datasets are combined in the process.To facilitate the joint interpretation of these datasets and the generation of geodynamic model setups, we therefore developed an open-source package - the Geophysical Model Generator (GMG) - to assist with unifying these datasets in a common data format that can then be further used to visualize, compare and interpret data. Within this package, we provide a set of routines to import different datasets, convert them to a common data format and to process them further (e.g., to create vote maps from different tomographies). These unified datasets can then be exported as vtk-files for further 3D visualization (e.g., Paraview). Moreover, with the Geophysical Model Generator it is also possible to create model setups for numerical models (such as the 3D geodynamic code LaMEM). This package thus covers the entire workflow from data import to numerical model generation. Key features of the Geophysical Model Generator include 1) the creation of 3D volumes from seismic tomography models, 2) the import of 2D data (e.g., surface or Moho topography or screenshots from published papers) and 3) the incorporation of point data such as earthquake locations or GPS measurements. Both scalar and vector data can be handled. With these tools, one can then create a consistent overview of the entire data available for a given region.The package is written in Julia and hosted as a public open-source repository on GitHub (https://github.com/JuliaGeodynamics/GeophysicalModelGenerator.jl). To assist the joint interpretation of different geophysical datasets, we furthermore provide a graphical user interface that allows to view and compare them (https://github.com/JuliaGeodynamics/GeoDataPicker.jl). The GUI provides an interactive interface, allows loading different datasets and facilitates the manual interpretation of different structures (such as subducting slabs) along profiles and visualize them in 3D while taking different data into account. 
Mid-20th Century Atlantic Circulation informed by Modern Observations and Models 
Authors: Hug Guillaume , McCarthy Gerard , Moat Ben , Worthington Emma
Published: March 2024

The Atlantic Meridional Overturning Circulation (AMOC) is a driving force in the redistribution of heat on our planet and has a particularly large impact on the climate of the Northern Hemisphere and Europe. Reliability of coupled model projections has been questioned due to a body of evidence that the multi-model mean of climate models disagree with observational proxies for the AMOC, in particular in the mid-20th century. In turn, the reliability of these observational proxies has been questioned as they are not direct observations of the AMOC.In order to study the variations of AMOC during the 20th century, we have developed layered models based on a limited number of time series: Ekman transport and the Florida Strait, as well as the density time series of the Thermocline, Antarctic Intermediate Waters (AAIW), Upper North Atlantic and Lower North Atlantic Deep Waters (UNADW, LNADW). These models, using the deep AMOC branches, are trained with modern RAPID measurements at 26N and compared to each other.We use these models to predict, from hydrographic profiles, an estimate of the strength of the AMOC during the (mid) 20th century. Locations where EN4 profiles may be relevant to the reconstruction are identified using ocean model data that correlate temperature and salinity with the location of the RAPID measurement. The linear contribution of wind stress is also removed from the density time series using simple linear regression. Our aim is to provide, in the light of modern direct observations, an answer on the reliability of AMOC reconstructions and historical climate simulations during the mid-20th century.
Assessing the relationship between forest structural diversity and resilience in a warming climate
Authors: Pickering Mark , Elia Agata , Girardello Marco , Oton Gonzalo , Capobianco Samuele , Piccardo Matteo , Ceccherini Guido , Forzieri Giovanni , Migliavacca Mirco , Cescatti Alessandro
Published: March 2024

Ecosystem resilience represents the capacity of an ecosystem to withstand and recover from external perturbations, an increasingly important property for ecosystem function in an era of escalating climate extremes and anthropogenic pressures. Whilst recent studies have related forest resilience to natural factors such as climate and biomass, the link between forest diversity and resilience is not yet understood. This study quantifies the sensitivity of ecosystem resilience on forest diversity in Europe over the period 2003-2021. Two commonly used resilience indicators are considered based on MODIS kNDVI (kernel Normalized Difference Vegetation Index) data acquired at high spatial and temporal resolution: the 1-lag temporal autocorrelation, relating to the ecosystem memory, and the standard deviation, relating to the ecosystem stability. Forest diversity is expressed in terms of horizontal and vertical structural heterogeneity metrics derived from GEDI (LiDAR) (Light Detection and Ranging) acquisitions. A Random Forest (RF) model is leveraged to isolate the interplay between forest resilience and diversity metrics by disentangling possible confounding environmental variables such as climate. The RF model is then applied to retrieve local sensitivities in terms of Individual Conditional Expectations. The work first finds that European forests with a higher level of vertical and horizontal structural diversity are systematically associated with higher resilience levels. The relationship is coherent across bio-geographical regions in Europe. Importantly, the emerging relation between forest resilience and forest diversity is consistent under increasing temperature patterns. This suggests that forest management targeted to higher levels of forest heterogeneity has the potential to offset the decline in forest resilience associated with the projected climate warming scenarios and the consequent increasing disturbance regimes.
Global bias-corrected seasonal forecasts: Towards efficient and near real-time solutions
Authors: Weber Jan Niklas , Lorenz Christof , Schober Tanja , Wiegels Rebecca , Kunstmann Harald
Published: March 2024

Droughts, prolonged heat-waves, heavy precipitation events and large-scale flooding - the last years have demonstrated that global climate change is already hitting hard in many places of the Earth. This, inevitably, leads to increased water stress that requires a more sustainable and timely water management across scales. In particular, for optimized use of water resources for irrigation or hydropower generation, it is essential to know their expected availability in the coming months all over the world. This sub-seasonal to seasonal temporal domain, from weeks to months ahead, is addressed by seasonal forecasting systems such as SEAS5, developed by the European Centre for Medium-Range Weather Forecasts (ECMWF). These systems have the potential to provide essential data for enhancing water management practices. Without a bias correction though, the data exhibit a notable deficiency in skill. We have shown for several regions of the world that the “Bias Correction and Spatial Disaggregation” method (BCSD) can improve the forecasting skill substantially. Our next step is now to expand our efforts from the regional to the global scale, i.e., to provide the BCSD-forecasts for the entire globe. Here, the challenge lies in significantly reducing the computational demand for the bias correction: Presently, the BCSD requires several days to execute on a global scale. However, if such forecasts should be used as decision support, a timely provision is crucial.We therefore present a method to achieve this task: The utilization of fixed Cumulative Distribution Functions (CDFs) rather than their recalculation for each pixel has the potential to enhance the computational efficiency of the bias correction. This approach not only significantly reduces the required data volume but also improves accessibility. To further achieve transferability of the system, we also demonstrate the performance of this system in a containerized environment. Our goal is to achieve a globally corrected SEAS5 forecasts within a time frame of ideally less than one day. With the provision of these bias-corrected data in near-real time, better estimations become available for direct utilization by water managers or as input for subsequent modeling processes.
Quantifying precipitation intermittency for Bergen, Norway, from measurements and models across a wide range of time scales
Authors: Bækkelund Ingrid O. , Steinslid Mari B. , Sodemann Harald
Published: March 2024

Intermittency of rainfall is an important property, for example in the context of urban flooding. There is currently a lack of information about the ability of numerical weather prediction models to represent precipitation intermittency for different weather situations, in particular at high resolution in space and time. Here we present a new way to quantify rainfall intermittency based on a near-continuous, high-resolution precipitation dataset from Bergen, Norway, one of the rainiest cities in Europe. 

We quantify precipitation intermittency from a precipitation dataset acquired at the Geophysical Institute, Bergen, spanning the period 2019-2022 at a 1 min time resolution. Precipitation rates were obtained from a Total Precipitation Sensor TPS-3100 (Yankee Environmental Systems Inc., USA) and a Parsivel2 disdrometer (OTT Hydromet GmbH, Germany). In addition, we use precipitation output at 1 min resolution from the regional high-resolution weather forecasts model HARMONIE-AROME for selected events. Precipitation intermittency is then identified for a range of minimum inter-event times (MIT) from 1 min to 24 h, and precipitation event durations from 1 min to 33 days. Next, the precipitation events for different intermittencies are related to average meteorological characteristics during the events with respect to air temperature, pressure, wind speed, rain rate and amount, and corresponding weather regimes.  

We compile the intermittency information into a 2-dimensional heat map that can be considered as a characteristic fingerprint for precipitation in Bergen. Particular frequency maxima and minima appear to be related to different precipitation processes and weather regimes. A scale gap between 30 min and 2 h event duration for MIT larger than 12 h indicates that separate factors control precipitation processes at these time scales. Weather regimes show a clear influence on the precipitation characteristics, with a markedly higher probability for long-duration rain events in the zonal flow regime for longer event durations at high MITs compared to the Scandinavian trough regime. A comparison between precipitation intermittency simulated by HARMONIE-AROME shows reasonable agreement with observed event characteristics for events lasting more than 1h, while events with durations of 30 min and less are poorly represented. 
Hypoxia exposure of short-term residents in the Qinghai-Tibet Plateau
Authors: Huo Wenyixin , Shi Peijun
Published: March 2024

The unique habitat and plateau hypoxia in the Qinghai-Tibet Plateau have always troubled tourists. The study of plateau hypoxia is of great significance to improve tourists' well-being and formulate related policies. In this paper, based on the data of oxygen content and blood oxygen saturation of short-term residents in the Qinghai-Tibet Plateau, Qinghai Province was divided into severe hypoxia region, hypoxia region and non-hypoxia region according to the established relationship between blood oxygen saturation and oxygen content. Combined with the results of the spatialization of short-lived population, the exposure numbers of short-lived population under different hypoxic zones in summer and winter were calculated. The results show that: 1) The distribution of tourist population in Qinghai Province presents a distribution rule of "one center gathering", and the population is mainly concentrated in the eastern region. The population density is high in the main urban areas with dense POI, and very low in woodland, remote mountain and other areas. 2) With the decrease of oxygen content, blood oxygen saturation decreased exponentially. 3) Compared with winter, short-term residents is more suitable to travel to the plateau in summer.
High energy proton and Helium spectra from SOHOs Electron Proton Helium Instrument
Authors: Hörlöck Malte , Jensen Stefan , Heber Bernd , Kühl Patrick , Sierks Holger
Published: March 2024

High energy protons and Helium in the heliosphere originate from multiple sources. Solar Energetic Particle events (SEPs), Anomalous Cosmic Rays (ACRs) and Galactic Cosmic Rays (GCRs) are prominent examples. Their energy spectra provide insights into acceleration and transportation processes.The SOlar and Heliospheric Observatory (SOHO) was launched December 1995 with the Electron Proton Helium INstrument (EPHIN) measuring protons and Helium from 4 MeV/nuc to 52 MeV/nuc with an additional open ended integral channel. However, its measuring capability was reduced due to the loss of two detectors in 1997 and 2017, respectively. Using Pulse Height Analysis (PHA) data in the integral channel, we present methods to derive energy spectra for protons up to more than 100 MeV and Helium spectra up to some 250 MeV/nuc. First results and comparisons to other instruments will be presented.The SOHO/EPHIN project is supported under Grant 50 OC 2102 by the German Bundesministerium für Wirtschaft through the Deutsches Zentrum für Luft- und Raumfahrt (DLR). This study has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 101004159 (SERPENTINE).
A Central Asian pro-glacial discharge database for improving hydrological models
Authors: Pohl Eric , uulu Esenaman Mukhammed , Halimov Ardamehr , Amschwand Dominik , Saks Tomas , Huang Jingheng
Published: March 2024

Central Asia’s mountain rivers are to a large degree fed by snow and ice melt and are a crucial contributor of fresh water downstream for millions of people. The attribution of how these meltwater sources will change their contribution to stream flow in a warmer future are, however, very uncertain. A major reason for this is an extremely sparse hydrometeorological monitoring network. This affects the calibration and validation of large-scale cryo-hydrological models that could be used for the task, or the validation and bias correction of reanalysis and remote sensing data needed to run such models. In combination with uncertainties about the glacier mass balances in the region, hydrological models are facing a pronounced equifinality problem. In order to improve this, and to understand better the glacier response to the current meteorological forcing in different climate zones of Central Asia, we instrumented 8 pro-glacial streams in Kyrgyzstan and Tajikistan with automated runoff gauges running at hourly resolution to also capture diurnal variability. These measurements complement the already (re-)established glaciological monitoring network at most of these sites and allow tackling the equifinality problem by constraining many variables. Here, we present first results from this database that shall serve to improve hydrological model calibration and parameterization, and understand relationships between meteorological forcing, annual glacier mass balance and meltwater generation. We also discuss instrumenting strategies and problems, and uncertainties related to gauge calibration.
SBAS-InSAR Analysis and Assessment of Landslide deformation in the Loess Plateau, China
Authors: Yang Yan , Motagh Mahdi , Haghshenas Haghighi Mahmud , Piter Andreas
Published: March 2024

Landslide is a geological disaster with extremely destructive effects, resulting in huge casualties and economic losses in China. The Loess Plateau is widely covered by several to tens of meters of loess, and the underlying bedrock with good water barrier properties. Due to the frequent rains, the soil body is easy to flow or slide along weak structural surfaces. There are lots of typical loess landslides in the Loess Plateau and they seriously affect the lives of residents, so studying landslide deformation in Loess Plateau is of great significance for both society and geological expert. Interferometric Synthetic aperture radar (InSAR), with the advantages of wide monitoring range, high density, high accuracy, and not affected by weather conditions, has become the most effective technical means for regional surface deformation monitoring and landslide identification. In this paper we perform landslide deformation survey based on the small baseline Subset InSAR (SBAS-InSAR) method in Tianshui, which is located on the Loess Plateau, using 594 interferograms from the Sentinel-1 satellite ranging from January, 2017 to December, 2022. SBAS-InSAR time series analysis connects independent SAR images based on certain spatial baseline and time baseline thresholds, and finally gets time series and velocity of the Loess Plateau. The locations of landslides from National Geological Disaster Survey Database provided by China Geological Survey are compared with our results to verify the applicability of SBAS-InSAR technology in the Loess Plateau. The comparison results show that SBAS-InSAR technique using sentinel-1 dataset can effectively identify landslides in most areas except for the areas covered by forest. The results of velocity map and landslide maps can be used for landslide identify and assessment in the Loess Plateau.
First detection of Lithium in Mercury's exosphere
Authors: Schmid Daniel , Lammer Helmut , Volwerk Martin , Weichbold Fabian , Scherf Manuel , Varsani Ali , Roberts Owen Wyn , Simon-Wedlund Cyril , Plaschke Ferdinand
Published: March 2024

Mercury has an extended exosphere that consists of various species. Based on theoretical considerations, the existence of Lithium (Li) in the exosphere around Mercury is predicted to be less than 5x107 cm-2. Because these density values are well below the detection limits of remote observation instruments on board past missions, Li has never been directly observed. Here we show the first on-site determined altitude-density profile of atomic Li7, derived from in-situ magnetic field observations by the MESSENGER spacecraft. The results suggest that the source of Li at Mercury is most likely meteoritic ablation. The findings will help to interpret the remote observations of Mercury's exosphere that will be realized in the near future by the BepiColombo mission.
Impact of Bedrock Fracturing on River Erosion: An Experimental Approach
Authors: Fournereau Marion , Guerit Laure , Steer Philippe , Kermarrec Jean-Jacques , Leroy Paul , Lague Dimitri
Published: March 2024

River erosion, via abrasion and plucking, plays a crucial role in the dynamics of continental landscapes. Indeed, fluvial erosion is thought to give the pace to hillslope erosion and to lead to the rapid export of produced sediments. Erosion rates and mechanisms are influenced by several factors. Among them, fractures in bedrock rivers are assumed to exert a strong control over erosion and thus, on landscape evolution. However, there is to date no systematic study of the impact of fracture geometry and density on bedrock river erosion.  

In this study, we investigate the impact of fracturing on erosion modes and rates of bedrock rivers using an experimental approach. The setup is an erosion mill designed to simulate the erosion of a fractured bedrock in a river. Fractured substrates are built with 3D-printed plastic (PVA) artificial fracture networks placed in concrete disks (diameter of 17 cm). To simulate erosion in a river, water and gravels covering two-thirds of the disk surface are added on the top of the disk.  Water and gravels are entrained by a motor-driven propeller, inducing erosion of the disk by abrasion and plucking.  We use a set of 4 cameras to monitor the disk’s topography every 2 minutes by Structure from Motion photogrammetry, allowing us to record erosion dynamics at high resolution. The impact of fracture geometry and density is explored through 36 experiments with varied fracture spacings, dips, and azimuths.   

Our results reveal that fracture network density influences erosion processes and the distribution of plucking and abrasion occurrence. Abrasions dominates in experiments with a a low fracture density, while experiments with a high fracture density facilitate the occurrence of plucking episodes. 

Fracture dip can also influence erosion processes at the scale of one disk, by generating an asymmetric network with respect to the flow direction. This tends to favour plucking on one side and abrasion on the other side of the disk. In addition, we sometimes observe spatial and temporal clustering of plucking episodes aligned with the flow direction. Finally, at the scale of the whole disk, the experimental results indicate that abrasion leads to a constant average erosion rate through time, whereas plucking induces significant spatial and temporal variations. These findings emphasize the effect of fracturing on erosion rates and modes and highlight the importance of incorporating this parameter into riverbed erosion models.  
Earthquake data analysis in the Racha region, Georgia: Implication for 3D structural model active faults
Authors: Kvavadze Nino , Alania Victor , Enukidze Onise
Published: March 2024

The Caucasus region, which is one of the good examples of collision-driven far-field deformations, is located in the northernmost part of the Arabia/Eurasia collision zone and is classified with moderate seismic activity. Racha region, a part of Greater Caucasus orogen, in particular is characterized with the highest activity. In recent year several moderate earthquakes were observed in the region, notably 2009 September 7 (Mw = 6.0), 2011 August 18 (Mw = 4.8), and also 2024 January, 2 (Mb = 4.4), with depths varying from 10 to 15 km. The strongest event during the instrumental period recorded in Racha was observed in 1991 April 29, with magnitude Mw=7.0 and Depth = 17.2 km. Which was the largest earthquake recorded in the region, causing casualties. This event caused a number of fore- and aftershocks. Following the Racha 1991 earthquake temporary, dense seismic network was installed around the area to study aftershock activity, around 2000 aftershocks of different magnitudes were recorded by this network in total. This data was analyzed in several papers (for example Triep, et al., 1995, Fuenzalida, et al., 1997), including hypocenters and focal mechanisms. Depths of the aftershocks were observed ranging from 0 to 15 km. The mechanism of Racha 1991 main shock was shown to be reverse faulting on a gently sloping (35°) plane. Also, strong earthquake mechanisms show reverse faulting with strike-slip components. This work was oriented to analyze existing earthquake data and see its correlation to a 2-3D structural model created for the area.Acknowledgments. This work was funded by Shota Rustaveli National Science Foundation (SRNSF) (grant# FR-21-26377).
Which data are available to evaluate the representation of human activities in hydrological models in France?
Authors: Sarrazin Fanny , Santos Léonard , Delaigue Olivier , Thirel Guillaume , Andréassian Vazken , Perrin Charles
Published: March 2024

Human activities perturb the large-scale water cycle by withdrawing large amounts of freshwater for agriculture, manufacturing, energy production and drinking water supply, and by operating dams/reservoirs. The risk that human water demand exceeds freshwater availability widely threatens human water security and ecosystem health, in particular in the face of climate change. Therefore, national-scale hydrological models need to integrate representations of human activities to anticipate and address water scarcity and to support the design of adaptation strategies beyond the local scale. However, the lack of detailed observational datasets of human influence at a national scale hinders the development and evaluation of integrated modelling approaches.This study focuses on processing a national observational dataset of human influence for hydrological modelling at the catchment scale in France, where climate change is expected to reduce water resources and increase water demand notably in the sector of irrigation. We collect data of water withdrawal, water release, reservoir operations from a large range of sources. These include national-scale datasets that are typically available at a coarse (annual) temporal resolution only and that are known to have large uncertainties, such as the French national database of quantitative water withdrawals. Covering a large spatial domain and attempting to account for uncertainties, our resulting dataset is a first step toward the development of robust integrated human-water system models at a national scale. 
Performance assessment of GNSS radio occultation measurements from five missions over China 
Authors: Mo Zhixiang , Lou Yidong , Zhang Weixing , Zhou Yaozong , Wu Peida , Zhang Zhenyi
Published: March 2024

Global Navigation Satellite System (GNSS) radio occultation (RO) is one of the most crucial observations in atmospheric and climate science. GNSS RO globally produces accurate and long-term stable vertical profiles for essential climate variables such as refractivity and temperature at high vertical resolution in all weather conditions. Currently, various RO satellite constellation programs have been developed by nations and companies, and the growing quantity of RO observations can contribute not only globally but also has the potential to benefit specific regions, such as China. To investigate the potential of RO observation in China, the performance of five operational RO measurements from COSMIC-2, MetOp-B/C, FY-3D/E, Spire and PlanetiQ on data coverage capabilities and quality are assessed by comparing with ERA5 and radiosonde over China. The results of data coverage showed that all RO missions can acquire extensive coverage over China with effective low-altitude penetration capability, whereas MetOp-B/C exhibits some gaps in local time coverage. The results of data quality confirmed that commercial Spire and PlanetiQ are comparable to those of national-led COSMIC-2, MetOp-B/C and FY3D/E, even though Spire exhibited a lower signal-to-noise ratio (SNR). The mean bending angle and refractivity relative differences of all RO measurements are within ±2.9% and ±1.5/0.9% (with respect to ERA5/radiosonde) in the altitude range of 5 to 35 km, respectively, and the corresponding relative standard deviations (SD) are less than 6% and 1.8/2.2%, respectively. Mean temperature and specific humidity differences of all RO measurements are within ±0.8/1.0 K and ± 0.7/1.0 g/kg, respectively, from the near surface to 15 km, with SD of less than 2.1/2.0 K and 1.8/1.7 g/kg. These results can help users further understand the strengths and weaknesses of these RO observations and indicate the significant application potential of numerous high-quality RO profiles from various RO measurements, which is anticipated to enhance numerical weather predictions for China.
The Influence of Burial History on the In-situ Petrophysical and Mechanical Characteristics of Pliensbachian Shale
Authors: Burchartz Raphael , Jalali Mohammadreza , Grohmann Sebastian , Winhausen Lisa , Gaus Garri , Seemann Timo , Erbacher Jochen , Littke Ralf , Amann Florian
Published: March 2024

Characterizing the host rocks for high-level radioactive waste disposal requires considering various rock parameters such as petrophysical (e.g., porosity, permeability and storativity) as well as mechanical (e.g., Young’s modulus) properties. The burial history and thermal maturity of rock formations, particularly shale, significantly affect these properties. Understanding the relationship between the thermal maturity and the referred properties is essential for transferring data among various test sites.Pliensbachian shales (Lower Saxony Basin, Hils area) are characterized by a notably homogenous mineral composition. Previous studies on this formation suggest a highly variable burial history over a lateral distance of about 50 km, reaching maximum burial depths between 1300 m in the southeast to 3600 m in the northwest of this region (Gaus et al., 2022; Littke et al., 1987, 1991). In the context of the MATURITY project, eight boreholes were drilled at five different locations with varying thermal maturity along this axis. Geophysical well logging was carried out in all boreholes to investigate mineralogical (clay mineral content), petrophysical (porosity), and rock mechanical properties (e.g., dynamic Poisson's ratio). First results revealed a homogeneous clay mineralogy in all boreholes. However, significant differences were observed in both the dynamic-elastic behavior and porosity of the investigated shale formation at different locations. The obtained data can be used to establish correlations between burial history and various shale rock properties, contributing to a site-independent characterization of shale formations for long-term disposal of high-level nuclear waste.  ReferencesGaus, G., Hoyer, E.M., Seemann, T., Fink, R., Amann, F., Littke, R. (2022). Laboratory investigation of permeability, pore space and unconfined compressive strength of uplifted Jurassic mudstones: The role of burial depth and thermal maturation. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften, 173 (3), 469-489
Littke, R., Baker, D. R., & Leythaeuser, D. (1988). Microscopic and sedimentologic evidence for the generation and migration of hydrocarbons in Toarcian source rocks of different maturities. Advances in Organic Geochemistry, Vol.13(Nos 1-3), 549–559.
Littke, R., Leythaeuser, D., Rullkötter, J., & Baker, D. R. (1991). Keys to the depositional history of the Posidonia Shale (Toarcian) in the Hils Syncline, northern Germany. Geological Society, London, Special Publications, 58(1), 311–333.
Determination of temperature dependent rate coefficients of the reaction of hydroxyl radicals with volatile organic compounds using a new OH reactivity instrument 
Authors: Novelli Anna , Berg Florian , Dubus René , Wahner Andreas , Fuchs Hendrik
Published: March 2024

Accurate knowledge of the rate coefficient of the reaction of volatile organic compounds (VOCs) with the hydroxyl radical (OH) is fundamental for understanding atmospheric chemical processes and for predictions of air quality forecasting models. Nevertheless, the temperature dependence of reaction rates of many organic compounds is not well investigated as measurements are challenging.In this work, we present absolute measurements of reactions rates with the OH radical for a series of VOCs for different temperatures. An OH reactivity instrument previously used for field and chamber measurements was further developed to enable these accurate measurements of reaction rates. The OH reactivity (kOH) is the inverse lifetime of the OH radical expressed by the product of the OH reactant concentrations and its reaction coefficient with OH. In this instrument, OH reactivity is measured by the direct observation of the decay rate of OH that is produced in a flow tube by ozone laser flash photolysis at 266 nm. The decay of OH radicals is measured at a high time resolution of 1 ms. If a known concentration of an organic compound is added to the bath gas (humidified synthetic air) the decay time directly gives the rate coefficient. As the air temperature can be controlled, the Arrhenius expression of the rate coefficient can be determined.VOC mixtures in synthetic air were prepared in canisters. The concentration was determined by the total organic carbon method, in which all carbon atoms are combusted to CO2 on heated catalysts and the CO2 concentration is measured by a commercial cavity ring-down instrument.The method was validated with several alkanes for which reaction rates are well-known. Excellent agreement within a few percent with recommendations by IUPAC and NASA-JPL demonstrates the high accuracy of the new method. The Arrhenius expression of OH reaction rates was determined for several monoterpenes and aromatic hydrocarbons. 
First assessment of the impact of pH equilibrated Ocean Alkanlinity Enhancement technology on marine biota in the Gulf of La Spezia (north-west Italy)
Authors: Calvi Davide , Groppelli Sara , Campo Francesco , Comazzi Federico , Basso Daniela , Cappello Stefano
Published: March 2024

Throughout the past decades, the rise of atmospheric carbon dioxide (CO2) levels has been one of the most important global issues. Higher CO2 concentrations contribute to a strengthened greenhouse effect, resulting in elevated temperatures and a severe acidification of the oceans.Recently, the Intergovernmental Panel on Climate Change (IPCC) highlighted the need to develop CO2 removal approaches, as an essential support to mitigate the ongoing climate change. To this purpose, Negative Emission Technologies (NETs) are capable of extracting CO2 from the atmosphere, keeping it stored in geological reservoirs for long periods.Among NETs, Limenet s.r.l. is proposing a pH equilibrated Ocean Alkalinity Enhancement (OAE) process which involves the permanent storage of carbon dioxide in seawater in the form of bicarbonates using calcium hydroxide and releasing a carbon enriched solution at the same pH of natural seawater. The life cycle assessment conducted on this process demonstrated that the advantages of CO2 capture and storage outweigh the greenhouse gas emissions produced by the entire process.Although this technology is economically promising and the chemical analysis has shown that CO2 stored in the form of bicarbonates in the seawater is quite stable, it’s necessary to assess any possible impact of the pH equilibrated OAE on marine organisms. In light of this, the aims of this project are:1) To assess the short-term response of the biota after the treatment.2) To study the effects of a prolonged exposure to the treated water on planktonic and benthic communities through mesocosms experimentation.All experiments are conducted in the Gulf of La Spezia (North-West Italy).
Relationships between geodynamics of Northern Sicily (Italy) and volcanic activity at Vulcano Island (Aeolian Islands, Sicily, Italy) from GNSS and seismic data
Authors: Messina Danilo , Barberi Graziella , Bruno Valentina , Mattia Mario , Patanè Domenico , Pepe Fabrizio , Rossi Massimo , Scarfì Luciano
Published: March 2024

We present an analysis of Global Navigation Satellite System (GNSS) and seismic data collected in the last decade in northeastern Sicily and the Aeolian Islands (Italy). During this period, La Fossa Caldera at Vulcano showed a significant phase of unrest since September 2021. Based on the analysis of GNSS time series and velocity fields, we found evidence of changes in the deformation pattern of the Peloritani area, which is located about 40 km south of Vulcano Island in northeastern Sicily. These changes occurred about seven months before the Vulcano unrest and were accompanied by an increase in seismic strain, which was released at increasingly shallower depths. This suggests a temporal correlation between the deformations detected in the Peloritani area and the volcanic activity of Vulcano Island, which was further investigated by analyzing another phase characterized by an increase in the areal variation measured at La Fossa Caldera in 2018.   This study presents a new perspective for understanding the geodynamic, volcanic, and seismic phenomena in the investigated area, with particular attention to the Vulcan unrest between September and November 2021.
Travel distance prediction for rock avalanche based on machine learning
Authors: Lin Ruoshen
Published: March 2024

Rock avalanches are one of the most destructive geological phenomena in mountainous regions. Understanding the dynamics and characteristics of rock avalanche movement plays a crucial role in assessing the potential hazards. However, the prediction for rock avalanche propagation is still challenging. Our study used an inventory of rock avalanches from Central Asia containing 412 historical cases from 6 countries provided by A. Strom. Considering several input parameters, the machine learning-based approach of extreme gradient boosting with grid search optimization was proposed. Input parameters including confinement type, headscarp height, mean slope angle of headscrap, length and width of the headscarp base, source volume, and maximal height drop (Hmax) are analyzed and discussed. Our proposed model can multi-output the distance of propagation L and the total impacted area, which outperformed by comparison with other machine learning models. Eleven rock avalanche events in Uzbekistan were introduced to demonstrate that the proposed model can be applied to prediction for limited parameters. For future work, we intend to propose a Convolutional Neural Network (CNN) architecture that combines spatial inputs and metadata as input in machine learning. Spatial inputs including elevation, slope, aspect, curvature, and lithology were used for our proposed model. Additionally, the CNN-based deep learning approach might be possible to predict rock avalanches which are characterized by complex terrain with multiple source areas and diverging paths. 
The impacts of northern hemisphere high-latitude climate on northeastern Australian summer monsoon evolution during the Holocene
Authors: Shi Ge , Yan Hong , Zhang Wenchao , Dodson John , Heijnis Henk , Burrows Mark
Published: March 2024

Influenced by the northern hemisphere high-latitudes, many of the millennial-centennial scale climate changes originating in the North Atlantic have been detected even in southern hemisphere. However, the linkage between hemispheres on orbital-suborbital time scales has not been firmly examined due to the absence of records from the Southern Hemisphere. Here we present such a record from Bromfield Swamp in tropical northeastern Australia. The Australian Summer Monsoon index (AuSMI) of the last 13.5 ka was reconstructed basd on the principal component analysis (PCA) of five proxies, the Rb/Sr, Ti/Ca, Al/Ca, mean grain size and organic content. The results reflected a weak AuSM influence during the Bolling-Allerod event and with a somewhat stronger influence during the YD event. During the Holocene, there was a decreasing AuSM before ~7.8 cal kyr BP, and then it enhanced from middle to late Holocene. The AuSM change was out of phase/ in phase with the East Asian summer monsoon/ East Asian winter monsoon during the Holocene, and all of them changed parallel with the northern-southern hemisphere temperature gradient. This implied the dominance of interhemispheric thermal contrast to the highly coupled East Asian-Australian monsoon changes, by modulating the Intertropical Convergence Zone migration, which was influenced by the retreat of northern hemisphere ice sheet from early to middle Holocene and the local summer insolation changes during the late Holocene. The study highlights the likelihood that high latitude northern hemisphere played a major role in the evolution of the northeastern Australian summer monsoon.
Finding reconnection lines and flux rope axes via local coordinates in global ion-kinetic magnetospheric simulations
Authors: Alho Markku , Cozzani Giulia , Zaitsev Ivan , Kebede Fasil Tesema , Ganse Urs , Battarbee Markus , Bussov Maarja , Dubart Maxime , Hoilijoki Sanni , Kotipalo Leo , Papadakis Konstantinos , Pfau-Kempf Yann , Suni Jonas , Tarvus Vertti , Workayehu Abiyot , Zhou Hongyang , Palmroth Minna
Published: March 2024

Magnetic reconnection is a crucially important process for energy transfer in plasma physics, the substorm cycle of Earth's magnetosphere and solar flares being prime examples. While 2D models have been widely applied to study reconnection, investigating reconnection in 3D is still in many aspects an open problem. Finding sites of magnetic reconnection in a 3D setting is not a trivial task, with several approaches from topological skeletons to Lorentz transformations proposed to tackle the issue. This work presents a complementary method by noting that the magnetic field structures near reconnection lines exhibit two-dimensional features that can be identified in a suitably chosen local coordinate system. We present applications of this method, with two approaches, to a hybrid-Vlasov Vlasiator simulation of the Earth's magnetosphere, showing the complex magnetic topologies created by reconnection. We also overview the dimensionalities of magnetic field structures in the simulation to support the use of such coordinate systems.
Spatiotemporal assessment and evaluation of aromatic VOC emissions: a case study for Spain
Authors: Oliveira Kevin , Guevara Marc , Jorba Oriol , Petetin Hervé , Bowdalo Dene , Tena Medina Carles , Montane Pinto Gilbert , López Franco , Pérez García-Pando Carlos
Published: March 2024

Volatile organic compounds (VOCs) significantly contribute to air pollution, pose serious health hazards to humans, and influence ozone formation and secondary organic aerosol production. Anthropogenic sources include various human-driven activities, such as solvent use, traffic and fuel evaporation, industrial emissions, and biomass burning. Despite their importance, the uncertainties associated with representing VOCs in atmospheric emission inventories are considerably higher than other reported air pollutants. This work presents a spatiotemporal assessment and evaluation of benzene, toluene, and xylene (BTX) emissions and concentrations in Spain. We run the High-Elective Resolution Modelling Emission System (HERMESv3) model to produce gridded bottom-up emissions of BTX and use it as input in the Multiscale Online Nonhydrostatic AtmospheRe CHemistry model (MONARCH) chemical transport model to simulate surface concentrations across Spain. The modelling results were then evaluated against official ground-based observation data for the year 2019. The intercomparison between modelled and officially reported observed levels allows for identifying sources of uncertainty in the anthropogenic emission inputs, which we further explored through specific sensitivity test runs. The largest levels of observed benzene and xylene were found in industrial sites near coke ovens, refineries and car manufacturing facilities, where the air quality modelling results show large underestimations. Official emissions reported for these facilities were replaced by alternative estimates, allowing heterogeneous improvement of the model's performance and highlighting that uncertainties representing industrial emission processes remain. For toluene, consistent overestimations in background stations were mainly related to uncertainties in the spatial disaggregation of emissions from industrial use solvent activities, mainly from wood paint applications. Observed benzene levels in Barcelona's urban traffic areas were five times larger than the ones observed in Madrid. MONARCH failed to reproduce the observed gradient between the two cities due to uncertainties in estimating emissions from motorcycles and mopeds. Our results are constrained by the spatial and temporal coverage of available BTX observations, posing a key challenge in evaluating the spatial distribution of modelled levels and associated emissions.