bluuebunny/crossref_metadata_2025 huggingface dataset:
Connecting the dots: groundwater temperature data as a key element in Climate Change conversation
Authors: Egidio Elena , De Luca Domentico Antonio , Lasagna Manuela
Published: March 2024

As our planet faces the complex challenges of global climate change, understanding and effectively communicating critical environmental indicators becomes critical. This study explores the importance of monitoring and reporting variation of groundwater temperature as a key component in understanding the broader implications of climate change.Groundwater, a key reservoir of the Earth's freshwater, plays a crucial role in moderating surface temperature and sustaining ecosystems. However, its temperature dynamics remain poorly studied despite its fundamental influence on groundwater dependent ecosystems and geothermal processes.This research synthesises groundwater temperature data from 15 different monitoring wells located in the unconfined shallow aquifer, consisting of gravel and sand, of Piedmont Po plain (NW Italy).Daily groundwater temperature data, available from 2010 onwards, were analysed and statistical elaboration performed evaluating the trend and the temperature anomalies.The regional distribution of mean monthly groundwater temperatures varied 7.7 and 14.0 ◦C and showed a general increase of the value up to 2.1 °C/10 years.Because the findings underline the urgent need for improved data communication strategies to disseminate valuable information to policy makers, researchers and the society, a proposal of dissemination approach is proposed in the paper.By illustrating and communicating the intricate interplay between groundwater temperature and climate change, this research aims to facilitate informed decision-making and promote a proactive approach towards climate resilience. The study not only contributes to the expansion of knowledge on climate science and groundwater impacts, but also underlines the imperative of easy and accessible reporting of data in addressing the multiple challenges posed by a rapidly changing global climate.
Dike-like structures control the unrest in Campi Flegrei
Authors: Tramelli Anna , Calò Marco
Published: March 2024

The occurrence of seismicity in active calderas causes great concern as it is one of the main precursors for the volcanic eruptions.Campi Flegrei is one of the largest known active calderas and its historical unrests are characterized by a high number of low to moderate magnitude earthquakes usually associated with soil uplifts reaching several centimeters or even meters within each cycle.The last unrest started in 2006 and is currently accompanied by a large sequence of events localized beneath the Soflatara-Piscarelli system, together with the increment of gas emission in Piscarelli and strong variations of several geochemical and geophysical parameters.Here we show two classes of seismic models generated using passive methods that employed both Earthquakes and Ambient Noise recorded from 2005 till March 2022.These models enabled us to demonstrate, for the first time, the existence of vertically elongated high P-wave velocity bodies beneath Pisciarelli, Pozzuoli, and a resurgent formation situated offshore. The most evident dike-like structures are positioned at the border of the resurgence dome involved in the uplift, indicating that the peripheral structures regulate the upward fluid migration, contributing to the ongoing unrest.   
Mapping Urban Heat Islands Using Calibrated ENVI-met Model : Application to Sense-City Data
Authors: Sellila Nacer , Waeytens Julien , Hendel Martin , Ulanowski Yan , Castellanos Alejandra
Published: March 2024

Urban heat islands (UHI) occur in urban areas with higher temperatures than in surrounding zones, exhibiting an average increase of 2°C. During summer heatwaves, this difference can even reach up to even 12°C. This intense heat phenomenon in urban areas leads to thermal stress, potentially causing health issues such as increased risks of dehydration, heat strokes, and other heat-related health problems. To evaluate the impact of thermal variations on health in urban environments, ENVI-met is used. This work focuses on two main points: sensitivity analysis and parameter calibration.Numerical sensitivity analysis allows to study the influence of urban area model parameters on quantities of interest (e.g. thermal confort indices). These parameters include notably surface albedo and emissivity. Hence, it gives information of their impact on heat islands. This step prioritizes the influence of each parameter, providing crucial insights for the subsequent stages of the study.To better understand these urban phenomena and design efficient mitigation solutions, the calibration of the ENVI-met model stands as a promising approach. It aims to establish a digital twin based on experimental data. This calibrated model will enable a detailed mapping of urban temperature and other environmental parameters, thereby enhancing our understanding of the mechanisms behind urban heat islands.This approach will facilitate an evaluation and comparison between the outcomes of the numerical model and the experimental data collected in Sense-City urban area. Sense-City is a climate chamber that can cover two $400m^{2}$ areas. These urban areas can be studied in natural conditions or in controlled climatic conditions. This comparison will strengthen the credibility and trust in the accuracy of the established digital twin. Thanks to simulations and experimental observations, we will have the opportunity to deepen our knowledge about the formation and the evolution of urban heat islands in this specific environment and to select efficient cooling strategies at the block-scale.
Leveraging remotely sensed evapotranspiration and soil moisture data for enhanced watershed modelling with the SWAT model
Authors: Taia Soufiane , Scozzari Andrea , Erraioui Lamia , Chao Jamal , El Mansouri Bouabid
Published: March 2024

In data-scarce watersheds, hydrological models are often calibrated by using only streamflow observations. This approach may overlook crucial landscape characteristics, which, instead, may significantly affect the runoff. This study explores the integration of parameters derived from remotely sensed data, focusing on evapotranspiration, soil moisture, and runoff, to enhance the overall accuracy of the Soil and Water Assessment Tool (SWAT) model. Four calibration scenarios were implemented: S1 (streamflow only), S2 (streamflow and evapotranspiration), S3 (streamflow and soil moisture), and S4 (all variables). Results showed that S2 achieved high scores for streamflow, outperforming S1, with slight improvements observed in some cases. However, scenarios incorporating root zone soil moisture (S3 and S4) negatively impacted the streamflow estimates. Nevertheless, S2 exhibited slightly better evapotranspiration simulation, while S3 and S4 improved soil moisture representation. Hydrograph comparisons highlighted satisfactory streamflow simulations in S1 and S2, while S3 and S4 overestimated flow peaks. The results of this investigation show that embedding remotely sensed data in the SWAT model, particularly evapotranspiration and soil moisture, may not necessarily improve runoff estimations, thus a careful analysis is required to determine the role of these parameters. In fact,  these parameters play a pivotal role in enabling hydrological models to achieve a more comprehensive and accurate representation of the water balance within a watershed.
Bioaccumulation of mercury in muscle tissue and hepatopancreas in red crayfish (Procambarus clarkii) in a transect of the Valdeazogues river and tributaries, Almadén Hg mining district, south central Spain. 
Authors: Higueras Pablo , Barquero José Ignacio , Bakale Feliciano , Esbrí José María , García Ordiales Efrén
Published: March 2024

The Almadén mercury mining district, located in South-central Spain, has been the most important producer of this element worldwide, until the cessation of exploitations in year 2003. The environmental consequence of this activity affects an area of some 250 km2, coincident both with a geological structure (the Almadén syncline) and a river basin (the Valdeazogues river and tributaries). The old cinnabar (HgS) mines and mineral showings are scattered in the syncline and in the basin, favouring a wide distribution of the elements in the soils and sediments, as reported by previous publications from this research group and partners.Crayfish (Procambarus clarkii) is an exotic river crab, with has replaced the autochthonous one  (Austropotamobius pallipes) due to its voracity. It is very common all along the Valdeazogues river and tributaries, and it is captured and consumed by local population in summertime, when it is easily captured in the ‘tablas’, water accumulated in river pods during the cessation of water running due the stational drought. Preliminary data on the Hg contents in this species, obtained in year 2005 reach up to 9,060 ng g-1 (in muscle) and 26,150 ng g-1 (in hepatopancreas), according to some previous publications of this research group.In this communication we present new data on this issue, obtained during the year 2022 along the Valdeazogues river and in some of its tributaries. In this research, 330 crayfish (sizes between 7 and 12 mm) were captured from upstream of the El Entredicho open pit mine to downstream of the confluence with the Guadalmez river (about 36.3 km), as well as the Los Álamos stream, and the Azogado stream, both tributaries of the Valdeazogues. All specimens were analysed by Zeeman effect atomic absorption spectrometry.The overall results showed maximum values of 3,567 ng g-1 of total Hg in muscle tissue, with a mean value for the district of 1,617 ± 920 ng g-1. In hepatopancreas which is an organ of the digestive tract with functions of absorption and storage of nutrients, as well as synthesis of digestive enzymes, the maximum value is very similar: a maximum of 3,590 ng g-1, while the mean is slightly lower, 1,025 ± 1,028 ng g-1. For the whole population, the relationship of Hg content in muscle tissue and hepatopancreas with size is not appreciable, probably because they are organisms of fast grown, and there is no general relationship between age and size. On the other hand, there is a relationship between Hg in hepatopancreas and salts contents and total Hg concentration in the nearby sediments.
High spatial resolution aerosol and surface reflectance retrieval and validation using Sentinel-2
Authors: Mantri Supriya , Remedios John , Yin Feng , Vande Hey Joshua , Carboni Elisa
Published: March 2024

Aerosols may vary spatially quite rapidly in an urban environment, but present aerosol products fail to detect them due to limitations in coarse spatial resolution. Aerosol dispersal can be mapped at local scales using Sentinel-2 with relatively high spatial (10, 20, and 60 m) and temporal (5 days) resolutions. A new high-resolution (60 m) coupled aerosol-surface reflectance retrieval algorithm Modified Sensor Invariant Atmospheric Correction (MSAIC) has been developed to address the urban air pollution problem from Sentinel-2. Sentinel-2 retrieved AOD products validated against Aerosol Robotic Network (AERONET) (R2= 0.830, and RMSE= 0.156) and MODIS (R2= 0.655, and RMSE= 0.240) AOD products. For light to medium aerosol loading (AOD < 0.2), it was largely successful in extracting AOD with uncertainties
Sedimentology and Geochemistry of Evaporites in Bâlâ-Karakeçili Basin (SE Ankara, Central Anatolia)
Authors: Karakuş Erhan , Tekin Erdoğan
Published: March 2024

Evaporitic precipitates exposed in the research area consist of gypsum. Seven gypsum lithofacies which massive gypsum (F1), bedded gypsum (F2), laminated gypsum (F3), nodular gypsum (F4), selenitic gypsum (F5), gypsum domes (F6) and satin-spar gypsum (F7) are recognized which are precipitated both shallow water and deep water environments in a restricted basin. Alabastrine, balatino, granoblastic and detritic textures are observed in petrographic studies. SEM/EDS analysis showed that celestite accompanied the gypsum precipitation. The strontium content of gypsum ranges between 197-22970 ppm which indicates the precipitation occured under marine conditions. Low barium content (2-129.4 ppm) indicates that there is no hydrothermal activity during gypsum precipitation, and arsenic, molybdenum and wolfram values lower than 1 ppm show that precipitation occurred under non-reductant conditions. Isotope values of δ34SSO4 range between 20.76‰ to 23.42‰ and δ18OSO4 ranges between 10‰ to 14.49‰ compatible with sulphur and oxygen values of Paleogene (Eocene-Oligocene) seawater. Furthermore, 87/86Sr values range from 0.707747‰  to 0.708558‰. These values correspond with late Eocene – early Oligocene seawater.All data indicate that the precipitation of evaporite in the study area occurred under marine environmental conditions during the late Eocene - early Oligocene time interval, in the last phase of the regression processes of the remnant Eocene sea, as a result of the horizontal movements of the Eocene period seen almost everywhere in the Anatolian microcontinent.
WRFChem Simulation of Aerosol perturbation on Outgoing Longwave Radiation over West Africa's Heterogeneous Landscapes
Authors: Oluleye Ayodeji , Akinyoola Julius , Imole Gbode Ezekiel , Mertens Mariano
Published: March 2024

Outgoing Longwave Radiation (OLR) across West Africa is characterized by significant variability as a consequence of the region's diverse landscape or landuse/landcover and the influence of various climatic drivers. This study revealed spatiotemporal patterns of OLR over West Africa, aiming to enhance our understanding through the assessment of the WRF-Chem model's ability to accurately capture these dynamic processes. CAMS reanalysis dataset was used to scrutinizing the model's performance on a regional scale. Two experiments were also conducted to investigate non-aerosol and aerosol perturbation on OLR variability in the region. Our findings revealed a distinctive spatial heterogeneity in OLR across West Africa, particularly during different seasons. Notably, during the June-July-August (JJA) period, the Guinea coast exhibited lower OLR values (160 – 195 W/m²) attributable to dense cloud cover, increased precipitation, and elevated water vapor content. In contrast, the Sahel and Sahara Desert regions displayed an average OLR value of 225 W/m², associated with lower humidity and precipitation levels. The December-January-February (DJF) and March-April-May (MAM) seasons revealed higher OLR values (255 W/m²) in the Sahel and Sahara Desert, attributed to clear skies and reduced humidity. The evaluation of the WRF-Chem model demonstrated its competency in reproducing observed data, evidenced by a positive correlation and relatively low Root Mean Square Error (RMSE). Variations in model performance across different data points and seasonal periods were indicated by the Standard Deviation. Trend analyses also indicated an increasing trend and variability in OLR values from February to August in the Guinea Coast and Sahara Desert, contrasting with a decreasing trend in the Sahel region. In a pristine atmosphere devoid of aerosol perturbation, OLR exhibited less variability and greater consistency from the Guinea coast to the Sahara Desert, with occasional extreme values noted in the latter. Conversely, periods of aerosol perturbation revealed a wider range of OLR values, signifying increased variability influenced by aerosol-induced alterations to the atmosphere's radiative balance and energy exchange.The study concludes that the influence of aerosol perturbations emerges as a key factor, introducing heightened variability in OLR values, which holds implications for our understanding of radiative processes in this region.
Climatic drivers of elevation-dependent warming (EDW): A concerted field and modeling assessment for an alpine national park
Authors: Zitzmann Simon , Fersch Benjamin , Kunstmann Harald
Published: March 2024

Mountain regions, such as the Alps, play a crucial role in providing ecosystem services, e.g., by acting as ‘water towers’ and substantially contributing to the discharge of the main European rivers. However, global warming is causing significant changes to the cryosphere, biodiversity and ecosystems in these regions. Hence, understanding the microclimatic changes in mountainous areas is essential, particularly the phenomenon of elevation-dependent warming (EDW), describing an amplified warming trend predominantly at higher elevations compared to adjacent lowlands. In the scientific community multiple drivers of EDW are being discussed, among them snow-albedo feedback, changes in cloud properties, and aerosols. The contribution of the individual drivers varies regionally and the role of surface energy balance components, especially ground heat flux, is rarely examined.Therefore, this study focuses on investigating the elevation-dependency of temperature trends and surface energy balance components, as well as its driving mechanisms in the Berchtesgaden National Park, Germany. This area in the northern limestone Alps is characterized by a highly variable topography, diverse landscapes and numerous ecosystems. Preliminary results from this ongoing study are presented, emphasizing the methodological approach and initial insights gained:Extensive data from the meteorological measuring station network, covering elevations from 600 to 2700 m.a.s.l., is analyzed to identify EDW patterns in the national park and its surroundings.Additionally, from fall 2023 to 2025, a transect of three meteorological stations is established at different elevations (600 to 2000 m.a.s.l.) for a detailed investigation of land surface energy balance. Besides measuring the radiative components in highly variable terrain, the field observations focus especially on ground heat flux, obtained at multiple positions within each station site to capture the small-scale variance and aspect dependency of ground heat flux. Additionally, at one of the stations the turbulent heat fluxes are assessed, using the Modified Bowen Ratio Method.To gain a holistic picture of the processes within the national park, the land surface model Noah-MP is employed to simulate the surface energy exchange processes at a high spatial resolution of 100 m. To improve the understanding of the development over time, model runs covering several decades in the past and a run during the measurement period (2023–2025) are performed, with results validated against the observational data.
Characterization of contaminated site using electrical resistivity and induced polarization methods
Authors: Meng Jian , Xia Teng , Ma Xinmin , Zhao Ruijue , Mao Deqiang
Published: March 2024

Soil and groundwater contamination has been widely concerned because of its impact on industrial, agricultural production, and even human health. Accurate delineation of contaminant distribution is the basis for successful remediation strategies. Traditional drilling based methods are costly and less efficient. Geophysical methods, particularly electrical resistivity (ERT) and induced polarization (IP), are sensitive to soil and groundwater contamination and have been proven very effective. However, there were still some pressing issues to be resolved, such as IP mechanism of contaminant, data acquisition, inversion strategies and monitoring system. In this study, we proposed the conceptual model of IP response for LNAPLs in-situ remediation process based on laboratory columns and sandboxes IP measurements, and quantified the effect of contaminant removal on IP parameters. In addition, the IP data acquisition method were improved for contaminated site surveys, doubling the detection depth and significantly increasing the IP data quality. Moreover, we propose a refined structure-constrained method that updates the smooth weights of all eight elements surrounding a boundary element using three different magnitudes. Combined with the joint interpretation of multisource data, detection accuracy was improved and the number of boreholes was reduced. We have applied ERT and IP techniques to more than 30 contaminated sites and proved their effectiveness.
Creeping sections on continental strike slip faults as the signature of deep fluid upwelling
Authors: Jolivet Romain , Garagash Dmitry , Pierre Dublanchet , Jara Jorge
Published: March 2024

Aseismic slip has been recognized over the last 50 years as one of the modes of elastic stress accommodation by large tectonic faults. Long strike slip faults have been imaged with InSAR and scrutinized with GNSS networks and creepmeters, revealing the strikingly ubiquitous occurrence of aseismic slip globally. From the 600-km-long creeping section of the Chaman to the 70 km-long Ismetpasa creeping section along the North Anatolian Fault, geodetic imaging illustrates the rich behavior of such aseismic slip, from mm-scale transient episodes of slip to seemingly continuously sliding fault segments.Most models explaining the occurrence of aseismic slip along continental faults rely entirely on an ad hoc parameterization of the frictional rheology of the fault. While the friction law governing slip along faults has been determined from laboratory experiments, the inference of the constitutive parameters of such friction law entirely derives from reproducing geodetic data in most cases. In particular, most creeping sections are interpreted as the signature of rate-strengthening material, diffusing stress through stable sliding. However, most rocks at seismogenic depths exhibit a rate-weakening behavior and some even show transient episodes of slip incompatible with purely strengthening properties. In addition, other mechanisms, including complex geometric configuration of faults or fluid circulation may offer the conditions for slow slip. Therefore, the direct inference of constitutive properties of a fault zone from kinematic observations may not be simple.We propose here a model in which upwelling of fluids sourced in the upper mantle through a vertical fault zone leads to the conditions for slow slip, irrespective of the fault constitutive properties. We map aseismic slip along three different fault zones, including the North Anatolian Fault (Turkiye), the San Andreas Fault (USA) and the Leyte fault (Philippines) and find a systematic relationship between the effective locking depth and the occurrence of aseismic slip. Our model explains this modulation of locking depth along strike and the subsequent modulation of surface shear stressing rate with the along strike variation in the mantle fluid source. This model applied to fault segments with relatively high mantle fluid source leads to low effective normal stress, large nucleation size of a frictional instability, and predicts occurrences of shallow aseismic slip. We perform numerical modeling to show that the critical parameter is the flux of upwelling fluid through the fault zone, which increase leads to the widening of the near-surface region of aseismic slip and transition to full-fault aseismic slip at large enough flux. We finally discuss the potential sources of fluids explaining such behavior.
Alternative ways to supply Rare Earth Elements: extractive waste recovery.
Authors: Casale Marco , Zhao Xinyuan , Khelifi Faten , Cavallo Alessandro , Padoan Elio , Yang Ke , Dino Giovanna Antonella
Published: March 2024

Rare Earth Elements (REE) are considered to be highly "critical" by the European Commission because the concentration of global supply and their use in a wide range of emerging technologies (e.g. smart phones, electric cars and wind turbines) and this at a time of increasing geopolitical tensions. According to the European Commission’s assessment, the demand for rare earth elements is expected to increase more than fivefold by 2030. Today, Europe is dependent on imports of these minerals, where China completely dominates the market, a factor which increases the vulnerability of European industry. Alternative sources of REE in Europe, such as recovery of quarrying and processing waste, are being considered.This research, part of an italian project NODES, wich has received funding (PNRR) from the EU, about circular economy and recovery of mineral waste, focuses on the possibility to recover REE from extractive waste. The investigated area cover Piedmont Region in northern Italy. Waste materials from gneisses and granites (ranging from blocks up to residual sludge) used as dimension stones were characterized for volume, chemistry, mineralogy, and texture.Based on the first analyses carried out, the most interesting contexts are those related to gneisses in Luserna Stone and Verbano Cusio Ossola quarrying area and to quartzites of Monte Bracco quarrying area.Thanks to a proper treatment activity (grinding, screening and magnetic separation), these materials, present in past extractive waste facilities and in extractive waste coming from exploitation and working activities, could be used to recovery of REE. After the first phase, connected to “waste” characterisation, the following activities will be linked to processing of the richest samples to exploit (at Laboratory level) REE, and to economic issues.An additional step will include leaching extraction tests (always at laboratory scale) to identify the best and most sustainable technique to extract and separate REE from the sampled extractive waste. Key words: Rare Earth Elements, Critical Raw Materials, Supply-chain, extractive waste, mining waste, leaching, magnetic separation.
Linking deep learning-based forest cover maps to treeline spatio-temporal patterns
Authors: Nguyen Thiên-Anh , Rußwurm Marc , Lenczner Gaston , Tuia Devis
Published: March 2024

Over the last decades, the position of the upper treeline in the Swiss Alps has been highly affected by drivers such as climate change and land use change interacting at various spatial and temporal scales. To better understand these interactions, it is necessary to quantify treeline dynamics over large areas at high spatial resolution and over long time scales. This can be decomposed into three tasks: mapping forest cover, delineating the treeline, and comparing the treeline position through time.We leverage archives of optical aerial imagery acquired over the Swiss Alps to map forest cover. These images constitute a large dataset of time series of 12 to 20 ortho-rectified aerial images at 1 m spatial resolution acquired throughout the time period 1946-2020. We have developed a deep learning-based method to automatically extract multi-temporal forest masks from these aerial images (under review).We then explore how treeline dynamics can be characterized using these forest cover maps. More specifically, we look at designing a spatio-temporal processing pipeline that implements widely used definitions of the treeline and treeline displacement, while being robust to potential errors in our deep learning-generated maps, such as noise caused by differing sensors and imaging conditions. We find that through a series of pixel-based processing steps, based solely on the generated forest cover maps and a Digital Elevation Model, we manage to 1. delineate the treeline at a chosen spatial scale and 2. measure the elevational treeline shift between two dates. The flexible choice of the spatial scale enables multi-scale analysis and comparison with existing treeline shift measurements derived from different data sources and methods.We hope that this automatic and flexible spatial analysis pipeline can link deep learning-based forest cover maps to ecologically relevant variables in a way that can foster the understanding of treeline dynamics.
Measurements and experimental budget analysis of OH, HO2 and RO2 radicals in a remote tropical marine location
Authors: Seldon Samuel , Whalley Lisa , Boustead Graham , Lade Rachel , Heard Dwayne , Read Katie , Callaghan Anna , Punjabi Shalini , Lee James , Carpenter Lucy , Neves Luis
Published: March 2024

The OH radical is the dominant daytime tropospheric oxidising agent, reacting with almost all Volatile Organic Compounds (VOCs). The majority of global methane is removed in the tropical troposphere by OH. The oxidation of VOCs by OH forms peroxy radicals, HO2 and RO2, with formaldehyde (HCHO) often formed as a product. In remote marine environments, ozone (O3) is destroyed during the day by reaction with OH or HO2, or photolysis.Ground-based measurements of OH, HO2, RO2, OH reactivity and HCHO, together with a comprehensive suite of supporting measurements, were made at the Cape Verde Atmospheric Observatory (CVAO), situated on the island of São Vicente located in the Tropical North Atlantic Ocean, during February 2023 as part of the NERC-funded PEROXY project. With no nearby emissions and prevailing winds from over the ocean, the clean marine air sampled was representative of the open ocean.In this work, time series and diurnal variations of the measured species are presented, and production and destruction rates of OH, HO2 and RO2 have been calculated. Reactions of the halogen oxides, IO and BrO, are shown to be important for understanding the chemistry of OH, HO2 and RO2. The CH3O2 reactions with halogen oxides are an important sink for RO2 and a possible source of HO2 that likely enhances O3 destruction in remote marine environments. Heterogeneous losses are also shown to be important for HO2. The OH budget analysis shows a possible minor missing source of OH while net HO2 production is observed, indicating either an overestimation of HO2 sources or an underestimation of HO2 sinks. Net RO2 production is observed, with the reactions of CH3O2 with halogen oxides and heterogeneous losses of CH3O2 to aerosols and the ocean surface needed to close the RO2 budget, but the magnitude of these loss processes is currently highly uncertain.
Multi-parameter Receiver Function Modeling: Application to the Subduction Zones of Cascadia and the Central Andes
Authors: Bloch Wasja , Schurr Bernd , Faccenna Claudio , Tilmann Frederik , Audet Pascal , Bostock Michael
Published: March 2024

Receiver functions are a powerful tool to image lithospheric stratigraphy. For flat lying structures, receiver functions can be stacked azimuthally to achieve high signal-to-noise ratios and h-κ-stacks allow to estimate the depth of interfaces (h) and P-to-S wave velocity ratio of the hanging layers (κ). For dipping layers, characteristic for the slab structure in a subduction zone forearc, these methods fail, because the moveout of phases arriving from different azimuths violates the basic assumptions of these methods.We here present a simple routine to simultaneously search for the depth of the top of slab and of the oceanic Moho, for strike and dip of the downgoing slab, as well as for the S-wave velocities and the P‑to-S wave velocity ratios of multiple layers of the overriding and downgoing plates in subduction zone forearcs. Our approach is based on the recent Python port PyRaysum of Frederiksen and Bostock's classic (2000) code for modeling ray-theoretical plane body-wave propagation in dipping anisotropic media, and on SciPy's simulated annealing global parameter search.We applied the routine to hundreds of azimuthally-dependent receiver function sections from the subduction zones of Cascadia (North America) and the central Andes (South America) and retrieved laterally coherent station measurements of the depth and orientation of the top of the subducting slab and the subducting Moho, with only weakly constrained seismic velocities. In Cascadia, we interpolated a regional slab model through fitting of regularized spline surfaces. Small scale structures that are not present in previous slab models can be resolved, e.g. under Olympic Peninsula (Cascadia) and Mejillones Peninsula (northern Chile). Where the receiver functions are more complex than can be accounted for by our model, the labeling of the modeled receiver function phases and comparison to the observed receiver functions allows us to confidently interpret the additional subsurface complexities and reconcile them with our interpretations.
Estimation and evaluation of carbon sink of terraces measures in Loess Plateau : A Case Study of Wuqi County
Authors: Yu Kaiyang , Zhang Xiaoping , Cheng Hui , Sun Weinan , Geng Wenliang , Wang Haojia , Liu Xuanhao , He Liang , Zhang Yujie , An Zefeng , Wang Yichen
Published: March 2024

Estimation and evaluation of carbon sink of terraces measures in Loess Plateau : A Case Study of Wuqi CountyKaiyang Yu1, Xiaoping Zhang1, Hui Cheng2, Weinan Sun1, Wenliang Geng1, Haojia Wang1, Xuanhao Liu1, Liang He1, Yujie Zhang1, Zefeng An1, Yichen Wang11Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China2Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, ChinaAbstract: Extensive terracing to cultivate land or plant trees and grasses, will affect biogeochemical processes in terrestrial ecosystem especially in areas with severe erosion. In order to clarify the carbon sequestration function and capacity of terrace in Loess Plateau, terraced fields with different planting types and years were selected to compare with corresponding slope land within Wuqi County (3,791 km2) of Loess Plateau to investigate the distribution characteristics of SOC on soil profile in 100 cm and searching for the influencing factors in the area. The results showed that：(1) Level terrace has significant carbon sink function in Loess Plateau. After the construction of terraced fields, SOC of six soil layers has the same variation trend with the construction years. The total SOC in the profile undergoes a rapid accumulation in the early 5-10 years of terracing construction, then exceeded the control group, and reaching a stable level after 20 years. (2) SOC in terrace dramatically decreases from surface layer to bottom layer, which exhibits surface aggregation effects. The content of SOC in 0-10 cm is significantly higher than that in deep soil layers, and the difference in SOC in deep soil is not significant. (3) The contents and accumulation rate of SOC in terrace are different with the planting types and years. Terraces with forest land generally has higher accumulating rate than other planting types. (4) There is significant correlation between total SOC and organic carbon content of large soil aggregates. Soil aggregates with particle size greater than 0.25mm determined the amount and trend of SOC content in the soil.  These results can provide an essential basis for improving the soil fertility and evaluating the benefit of terrace in carbon conservation on the Loess Plateau.Key words: Terrace; Soil organic carbon; Soil aggregate; Loess Plateau
On the radio wave polarization of Saturn lightning
Authors: Fischer Georg , Taubenschuss Ulrich , Pisa David , Imai Masafumi
Published: March 2024

The radio waves with Saturn lightning origin have been studied since the first detection by Voyager 1, but their wave polarization has rarely been explored. Fischer et al. (2007, JGR 112, A12308) examined lightning from a storm located at 35° south latitude and found its radio emissions below 2 MHz to be highly polarized (80%) in a right-handed circular sense with respect to the wave propagation direction. They explained this by absorption of the extraordinary mode in Saturn's ionosphere and the dominance of the ordinary mode emission, as the radio waves are propagating against a direction of the magnetic field when coming from a source in the southern hemisphere. A limited examination of Saturn lightning from the so-called Great White Spot at 35° north latitude by Fischer et al. (2011, Nature 475, 75-77) revealed radio wave polarization in the left-handed sense. In this presentation we will show the radio wave polarization of lightning from various other storms in Saturn's atmosphere, which have not been examined until today. In this way we want to corroborate the hypothesis that the sense of the circular radio wave polarization of Saturn lightning depends on the hemispherical location of the storm.
Building a hybrid drought monitor model based on U.S. Drought Monitor
Authors: Xu Haiting , Wei Jianhui , Pan Ying
Published: March 2024

Drought is one of the costliest natural disasters, capable of causing significant losses in agriculture, economy, and ecosystems. Different definitions of drought from multiple perspectives made drought research complicate. Exploring droughts from a comprehensive perspective improves our understanding of the evolution and drivers of drought, while there are few such comprehensive studies. The establishment of the United States Drought Monitor (USDM) marks a significant milestone in the development of composite drought indices, amalgamating objective inputs with subjective evaluations from local experts. Its uniqueness lies in integrating subjective assessments from climate and water resource experts across the United States. However, due to the human subjectivity involved in creating USDM maps, its algorithms are challenging to apply beyond the United States. In this study, a Hybrid Drought Monitor Model (HDMM)  was built using the random forest algorithm to predict drought categories based on USDM drought categories, input drought indices, and 10 static variables. The results indicate that during the testing phase, the overall accuracy of the 0.04° resolution HDMM reached 95%, surpassing the 91% overall accuracy at 1° resolution. Among the categories, D-1 (Normal or wet conditions) drought accuracy was the highest, while D0 (Abnormally Dry) drought accuracy was the lowest. During the validation phase, the HDMM exhibited good overall prediction of drought levels, yet spatial discrepancies existed across the continent. It performed poorly in the southwestern and northern regions, with overestimation of drought severity in many areas. Case studies of the 2017 Northern Plains Drought and the 2021 Southwestern Drought demonstrate that HDMM provided reliable drought classification and possessed good predictive capability. The HDMM can be adapted to other regions worldwide, offering a promising tool for land managers and local governments to prepare for and mitigate the impacts of drought.
Mobilisation and transport dynamics of potential toxic elements during high flow events in a small river catchment
Authors: Kittlaus Steffen , Milačič Radmila , Marković Katarina , Weber Nikolaus , Zessner Matthias , Zoboli Ottavia
Published: March 2024

Export of potential toxic elements and other particle bound pollutants from catchments is highly dependent on the flow regime. The main driver is the higher mobilisation and transport capacity for suspended particulate matter (SPM) during high flow events.  But are there further dynamics in the concentrations which are not purely driven by the SPM transport?To answer this question, we investigated the dynamics of the concentrations of potential toxic elements, several other elements and total suspended solids during high flow events by automated sampling and subsequent analysis of dissolved and total concentrations by ICP-MS after microwave assisted acid digestion. At 3 river monitoring sites 3 high flow events were sampled with 3-6 samples per event and site, covering different parts of the flow and turbidity peaks, which were recorded by online-measurements. To complement the river monitoring with data about potential sediment sources, landuse-stratified soil sampling in the catchment and river bed sediment sampling were conducted.Our case study was the Wulka river in eastern Austria with a catchment area of 384 km2 and two if its tributaries, one with a very high share of treated waste water and the other with no permanent input of waste water. With a mean annual precipitation of 695 mm and a mean elevation of 256 m a.s.l. the river can be classified as a low land river. The landuse is dominated by agriculture including significant share of viniculture.A first explorative principal component analysis showed, that several elements are strongly related with each other and the suspended sediment concentration. As this was expected, we used the SPM concentration to normalize the elemental concentrations and therefore taking out the variability caused by the suspended solids dynamics for further analysis. The remaining variability will be investigated regarding temporal and spatial patterns and correlation with the sediment and soil concentrations which can give indications about the emission pathways and sources.To characterize the sampled high flow events, a hysteresis index was calculated from the discharge and turbidity signal which revealed different types of hysteresis, some clockwise hysteresis, several complex hysteresis patterns with different directions of the hysteresis during different times of the event and one small event with anticlockwise hysteresis. Different types of hysteresis can give indications about the distance of the sediment source to the observation location, further contributing to the exploration of SPM sources.
Spatio-temporal distribution of subsurface urban heat islands – Insights from shallow groundwater temperature monitoring in Vienna
Authors: Kaminsky Eva , Laaha Gregor , Steiner Cornelia , Nyéki Eszter , Englisch Constanze , Griebler Christian , Stumpp Christine
Published: March 2024

In numerous cities worldwide, a rise in surface temperatures had been observed, contributing to the so-called "urban heat island effect". This effect leads to extended and hotter periods of warm weather within urban areas not only above but also below ground. The heat in the subsurface can be used for shallow geothermal energy, but it requires knowledge of spatial and temporal variations in groundwater temperature for efficient and environmentally friendly utilization of groundwater for heating and cooling. In the course of the 'Heat below the City' project, we have compiled spatial high-resolution data and developed groundwater temperature maps for the city of Vienna targeting the coldest and warmest annual conditions. Borehole temperature profiles were recorded in October 2021 and April 2022. This enabled the identification of distinct urban heat islands. Additionally, available long-term data (2001-2020) was used to conduct annual temperature trend analyses and extreme value assessments to evaluate temperature changes over time. In Vienna, an average annual temperature increase, considering all significant trends, of 0.9 ± 0.1 K/decade was observed for air, soil and shallow groundwater between 2001 and 2021. However, the increase is non-linear and, over the last decade, the change has accelerated with an increase of 1.4 ±0.2 K/decade (only significant trends taken into account). The current annual mean temperature is 14.1 °C (2021/ 2022) with individual warmer urban heat islands and locally heated locations of up to 30.6°C. Trends in extreme temperatures (represented by the lower/upper 10th percentile air, soil and groundwater temperature in quantile regression) generally show the strongest increase in the lower 10th percentile temperatures for all air and soil temperatures. But this varies site-specifically in shallow groundwater, where urban infrastructure and the interaction between surface and groundwater, in addition to climate change, influence groundwater warming. Potentially, those urban heat islands with increasing trends in groundwater temperatures have great potential for heat utilization, but should not be used for extraction of cold. These findings emphasize the importance of spatial and temporal high-resolution data and highlight the necessity for site-specific aquifer characterization for a sustainable use of shallow geothermal energy for heating and cooling.
Diversity at a Small Geoscience Conference
Authors: Lefebvre Alice , Bernhard Renée
Published: March 2024

Conferences are places where intellectual and communication standards are shown. Ultimately, they can contribute to create a sense of belonging or inadequateness. However, several analyses of specific diversity measures have demonstrated that large conferences often lack diversity in terms of gender, geographic location or race. The present contribution presents an analysis of the gender, country of affiliation and student status of the participants and presenters during four instances of a small European geoscience conference, as well as the length of presentation and number and tone of questions of the latest instance of this conference. We found that women make up about one-third of participants, session chairs, invited keynote speakers, and presenters (oral and poster) on average, but percentages vary greatly from one year to the next. Students represent around 30% of participants, but over 40% of poster presenters and 28% of long presentations. In total, only half of the participants asked a question, and most of the questions were asked by senior men. Around 25% of the questions were asked with a friendly tone; the remainder were neutrally asked. Friendly questions were asked more frequently after keynote lectures and long presentations than following short talks. We suggest concrete actions that can be taken to promote the development of an inclusive and supportive environment at small conferences.
Global scale gravity wave observations and analysis with the ESA Earth Explorer 11 candidate CAIRT
Authors: Rhode Sebastian , Ern Manfred , Preusse Peter , Ungermann Jörn , Polichtchouk Inna , Sato Kaoru , Watanabe Shingo , Woiwode Wolfgang , Riese Martin
Published: March 2024

The ESA Earth Explorer 11 Candidate CAIRT is a prime candidate for reliably observing gravity wave (GW) activity throughout the middle atmosphere up to the MLT region from about 15 km to 90 km altitude. A horizontally panning spectrometer with limb viewing geometry allows for the measurement of 3-dimensional temperature fields with high vertical resolution that can be used to quantify the global GW distributions and spectra as well as individual GW events. The detected horizontal spectrum of GWs would cover scales of about 100 km and above. Here, we show how the temperature retrieved by CAIRT can be utilized for characterizing GW parameters such as wave vector, amplitude, and phase. This wave-based approach allows for a precise estimation of the GW momentum flux (GWMF) and its development and distribution in the middle atmosphere, e.g., during an SSW event. The vertical resolution of the data is high enough for estimating the GW drag, shedding light on the role of GWs during global-scale dynamic phenomena. In addition, we show the applicability of using ray tracing the estimated GWs along the orbit tracks, which provides a means for increased horizontal coverage and better representation of GW drag due to accounting for horizontal propagation of the GWs.