bluuebunny/crossref_metadata_2025 huggingface dataset:
Forecast Verification Analysis of the CombiPrecip Ensemble
Authors: Ntoumos Athanasios , Sideris Ioannis , Gabella Marco , Germann Urs , Berne Alexis
Published: March 2024

CombiPrecip is a real-time application developed by MeteoSwiss since 2012, which combines point raingauge measurements with radar-derived spatial estimations of precipitation over a vast 710x640km2 domain, extending beyond the Swiss borders. It relies on the geostatistics-based kriging with external drift as an interpolation technique. This method is probabilistic by nature, yielding both a mean value and an associated variance for every estimation. The purpose of our study is two-fold: (i) validate that the variance provided by the underlying geostatistical method of CombiPrecip does properly represent the uncertainty of the CombiPrecip product and (ii) devise a numerical method to build an ensemble of realistic-looking members based on this geostatistical variance. For this, we employ widely used probabilistic verification measures (reliability diagrams, rank histograms, ROC curves) for a large set of cross – validation results over the period 2016 – 2022. In addition, based on established methods developed within the nowcasting community, we produce ensembles of N realistic precipitation members that not only mimic the spatial autocorrelation of the mean-value CombiPrecip but also replicate its pixel-scale variance. Overall, our results indicate that observations fall reasonably well in the uncertainty range provided by the CombiPrecip ensemble. 
Measurement of deep-ultraviolet cross-sections of strongly absorbing atmospheric species and their potential for trace gas detection
Authors: Wang Meng , C. Connolly Sean , S. Venables Dean
Published: March 2024

Absorption in the deep-UV region often excites strong electronic bands. In cases where vibronic structure is evident, these strong absorptions could be exploited for sensitive and selective quantification of trace gases, as is done in long-path DOAS systems to monitor ammonia emissions. Accurate and appropriate resolution absorption cross sections are essential for this purpose, but literature cross sections of adequate quality are not always available. In this study, we report new cross section for major inorganic species (NO and SO2), as well as important biogenic and anthropogenic volatile organic compounds (BVOC and AVOC). A spectrometer using a xenon arc flashlamp was used to measure absorption spectra in the wavelength range of 197 to 225 nm. Absorption cross section measurements using a flow cell were validated against SO2 absorption cross-sections, for which there is excellent agreement in the literature. We report a new absorption cross section of nitric oxide (NO) using the flow cell. Despite being a key nitrogen oxide species in the atmosphere, there are few NO absorption cross-sections between 190 and 230 nm and little agreement among the spectra. VOCs measurements were made in a static cell and validated against the isoprene absorption cross-section. New absorption cross sections are reported for important AVOCS (benzene, toluene, ethylbenzene, xylene) and key BVOCS (α-pinene, β-pinene, limonene, 3-carene, and myrcene). The measured absorption cross-sections are compared and discussed.We discuss the potential and challenges of using deep-UV measurements and the sensitivities that would be needed to be useful for trace gas detection in a range of contexts.
Advancing estimates of groundwater recharge by integrating multi-sensor observations across the vadose zone in a drying climate
Authors: Gelsinari Simone , Bourke Sarah , McCallum James , Thompson Sally
Published: March 2024

Understanding the impact of climate change on groundwater recharge is crucial for the sustainable management of groundwater systems, especially when regulatory agencies are managing aquifers already fully allocated. Recharge emerges as the outcome of Critical Zone (CZ) processes such as interception, runoff, or plant water uptake that use or store water from rainfall as it traverses the soil-plant-atmosphere continuum. Consequently, recharge is best understood and observed through multiple observations that can characterise storage, potentials and transport of water both in the soil and in the groundwater. Understanding how these CZ processes respond to a variable climate is essential for informing groundwater allocation management and decision-making.We present the results of field observations and a meta-analysis of recharge studies spanning the last 50 years in the Mediterranean climate area around Perth (Australia). This period coincides with a 15% reduction in winter rainfall, with the impacts on recharge partly revealed by the meta-analysis, but confounded by varying observation methods and sites. Seven field observation sites with consistent, multi-sensor instrumentation were therefore established to reveal recharge dynamics and estimate recharge fluxes. Electromagnetic soil moisture sensors provide vertical information across the soil profile (up to 10 meters below ground), complemented with soil water potential sensing at the surface and capillary fringe. ERT observations and manual soil moisture measurements in ancillary access tubes extend this information laterally (i.e. from 1D to 2D).  Groundwater depth, meteorological and remotely sensed information enables contextualisation of the observations. Historical data analysis shows that rainfall reductions lead to nonlinear (3 to 4 times higher), decreases in recharge. The installed monitoring stations reveal how the dynamics of wetting fronts are influenced not only by the climatic variables but also by the types of vegetation and their response to a drying climate. This suggests the presence of distinct local recharge mechanisms operating within the transient systems of the area. The insights obtained from these monitoring sites can be benchmarked against broader observations, such as data provided by remote sensing or borewell measurements, to generate databases of recharge estimates useful for models.
Willows root distribution on riverbanks through a descriptive approach
Authors: Leblois Solange , Piton Guillaume , Evette André
Published: March 2024

The use of Nature-based solutions for riverbank stabilization purposes in Western Europe is mainly based on willows implemented on engineered structures stabilizing riverbanks as they grow. Willows are ubiquitous and pioneer species capable of survival in submerged conditions when drowned a part of the year, therefore particularly well suited for soil and water bioengineering techniques. In the context of bend scour or of bed incision, bank toe bellow the line of brush growth is a weak point to control. This weaker zone presenting a low vegetation surface cover is in fact strongly subject to erosion leading to undermining and bank failure. This situation raised up the question: what is the effect on the soil stability of willows root reinforcement in this weak zone, knowing that their root system is allegdly able to develop in this part time drowned soil?  In order to understand the stabilizing function of these species bellow the brush line, willows root system implemented on riverbanks from two different alpine watersheds in France have been surveyed in autumn 2023. The root development is studied in regard of the ground water level and soil texture. Nine soil profiles with willows root systems are described in the study and the respective root area ratios have been estimated manually. Soil profiles were dug up to the last visible root and never exceeded 80 cm, corresponding to the ground water level of the low flows that were running during the measurements. The study describe three different species root system aged from 2 to 20 years: Salix purpurea, S. daphnoides and S. eleagnos.
Advancing Open Data Portals: Learnings from the EPOS Open-Source Solution
Authors: Vinciarelli Valerio , Paciello Rossana , Bailo Daniele , Goffi Claudio , Warren Daniel , Lavrnja-Czapski Janusz , Card Christopher , Atkinson Philip , Shelley Wayne , Roquencourt Jean-Baptiste , Retout Yann , Glaves Helen , Giuliacci Kety , Michalek Jan , Molander Jakob , Nedrebø Harald , Lange Otto , Freda Carmela , Saleh-Contell Kauzar , Sbarra Manuela
Published: March 2024

The European Plate Observing System (EPOS), established as a European Research Infrastructure Consortium (ERIC) in 2018, stands as a significant milestone in pan-European research infrastructures, focusing on solid Earth science. The EPOS Data Portal, officially launched in April 2023, is the place where FAIR principles and practices are implemented thanks to the adoption of a co-development approach and  harmonization of actions across communities of scientists, developers, data providers, and users. The EPOS Data Portal currently provides access to data and products from 10 different disciplines: Seismology, Near-Fault Observatories, GNSS Data and Products, Volcano Observations, Satellite Data, Geomagnetic Observations, Anthropogenic Hazards, Geological Information and Modeling, Multi-Scale Laboratories, and Tsunami.The EPOS Data Portal is based on a user-friendly user interface which provides intuitive visualization methods and interaction modes that significantly simplifies and facilitates the discovery and the access to the geoscientific community assets. Through the portal, users can: i) Perform data searches by combining a set of criteria; ii) Navigate and visualize the retrieved search results in different ways; iii) Fine-tune results using facets and advanced filters; iv) Download selected results or store them in a favorites list.The underlying system of the Data Portal has been crafted using a blend of open-source technologies, including Java, RabbitMQ, Python, and others. We implemented a modular architecture based on the microservices paradigm, facilitating seamless integration of new data and services through dedicated software interfaces. The source code, collaboratively developed by scientists and IT experts, is now available under a GPL license (https://epos-eu.github.io/epos-open-source/) along with a comprehensive developer’s guide. In this contribution, we demonstrate the potential impact of our open-source solution in advancing visualizations, interfaces, and best practices within the context of multidisciplinary research. Furthermore, we present how other research infrastructures, projects and initiatives can benefit from the shared knowledge and expertise, accelerating the development of robust and advanced Earth science data portals.
Inferring Surface NO2 over Western Europe: A Machine Learning Approach with Uncertainty Quantification
Authors: Sun Wenfu , Tack Frederik , Clarisse Lieven , Schneider Rochelle , Stavrakou Trissevgeni , Van Roozendael Michel
Published: March 2024

Nitrogen oxides (NOx = NO + NO2) are of great concern due to their impact on human health and the environment. Machine learning (ML) techniques are increasingly employed for surface NO2 estimation following fast-paced developments in artificial intelligence, computational power, and big data management. However, the uncertainties inherent in these retrievals are critical but are rarely studied in the rapid expansion of ML applications in atmospheric research.In this study, we have developed a novel ML framework enhanced with uncertainty quantification techniques, named Boosting Ensemble Conformal Quantile Estimator (BEnCQE), to estimate surface NO2 and assess the corresponding uncertainty arising from data. Quantifying such data-induced uncertainty is essential for ML applications as the ML models are data-driven. We apply the BEnCQE model with multi-source data to infer surface NO2 concentrations over Western Europe at the daily scale and 1 km spatial resolution, from May 2018 to December 2021. The space-based cross-validation with in-situ station measurements shows that our model achieves accurate point estimates (r = 0.8, R2 = 0.64, root mean square error = 8.08 ug/m3) and reliable prediction intervals (coverage probability, PI-66%: 66.4%, PI-90%: 90.4%). The model result is also in good agreement with the Copernicus Atmosphere Monitoring Service (CAMS) model output. Furthermore, the quantile estimation strategy used in our model enables us to understand the variations in the predictors’ importance for different NO2 level estimates. Additionally, integrating uncertainty information can uncover potential exceedances of the World Health Organization (WHO) 2021 NO2 limits in some locations, an exceedance risk that point estimates alone may fail to fully capture. Meanwhile, uncertainty quantification, by providing information on the uncertainty of each estimate, allows us to assess the robustness of the model outside of existing in-situ station measurements. The variations in uncertainty suggest that the model's robustness is related to conflicts between seasonal and spatial NO2 patterns influenced by multi-source data. It also reveals challenges in urban and mountainous areas where NO2 is highly variable and heterogeneously distributed.
Tracking CO2 mobility during magma-limestone interaction: insights from spectroscopic analysis of experiments
Authors: Deegan Frances , Capriolo Manfredo , Weis Franz , Callegaro Sara , Troll Valentin , Freda Carmela , Misiti Valeria , Aradi Lázló , Skogby Henrik , Darmawan Herlan , Geiger Harri
Published: March 2024

Magma-limestone interaction is thought to be an important source of carbon in volcanic arc emissions (1). To better understand the production of volatiles and their behaviour in silicate melts during magma-limestone interaction, we performed Raman and FTIR spectroscopic analysis of bubbles and glasses in the products of a time-series of high pressure-temperature experiments (2). The experiments were designed to simulate entrainment and assimilation of limestone (CaCO3) xenoliths in mafic magma using starting materials from an iconic example of a limestone-hosted arc volcano (Mt. Merapi, Sunda arc, Indonesia) (3). The experimental conditions were T = 1200 °C and P = 0.5 GPa, with run-times ranging from t = 0 s to t = 300 s. Our shortest run-time experiment (t = 0 s) reveals formation of CO2-rich bubbles (± C, CO, N2, H2, H2O, CH4) in and around the magma-limestone reaction site and fast diffusion of CO32- and CO2 molecules throughout the host melt (qualitatively faster than Ca diffusion). Longer run-time experiments (up to t = 300 s) show that bubbles evolved to become larger and richer in CO2 close to the reaction site and that they grew by extracting CO2 from the surrounding melt. Magma-limestone interaction thus rapidly mobilizes CO32- andCO2 and promotes formation of compositionally evolving CO2-rich fluids, which could migrate along fractures, faults, or other fluid escape pathways to contribute to atmospheric fluxes of CO2 at volcanic arcs. References(1) Mason E., Edmonds M., Turchyn AV (2017) Remobilization of crustal carbon may dominate volcanic arc emissions. Science 357, 290-294, doi: 10.1126/science.aan5049(2) Deegan FM, Troll VR, Freda C, Misiti V, Chadwick JP, McLeod CL, Davidson JP (2010) Magma-carbonate interaction processes and associated CO2 release at Merapi volcano, Indonesia: Insights from experimental petrology. Journal of Petrology 51, 1027-1051, doi:10.1093/petrology/egq010(3) Deegan FM, Troll VR, Gertisser R, Freda C (2023) Magma-carbonate interaction at Merapi volcano. In: Gertisser R., Troll VR, Walter T, Agung Nandaka IGM, Ratdomopurbo A (Eds.) Merapi volcano: Geology, eruptive activity, and monitoring of a high-risk volcano (Volcanoes of the World Book Series). Springer Verlag, Berlin, Heidelberg, New York. Chapter 10, 291-321, doi:10.1007/978-3-031-15040-1_
The sedimentary environment and models of mixed rocks in saline lake basins: a case study on Upper Shahejie Formation ( 4th Member) of Luojia area in Zhanhua depression, Bohai Bay Basin, China
Authors: Ma Yuan , Qiu Longwei , Yang Yongqiang , Tong Zebin
Published: March 2024

Mixed rocks refer to the rocks formed by the mixture of terrigenous clasts and carbonate sediments. In recent years, the development characteristics and sedimentary patterns of mixed rocks in saline lake basin in Upper Shahejie Formation (4th Member) of Luojia area in Zhanhua depression Bohai Bay Basin have yet to be solved, which brings certain limitation to the exploration of oil and gas in this area and some other places with the same environment. This study used detailed core description, sequence stratigraphy analysis, sedimentary analysis, and thin section observation to study the mixed rocks characteristics and sedimentary patterns of Upper Shahejie Formation (4th Member) in Luojia area, systematically. The research shows that the 4th Member of Upper Shahejie Formation in Luojia area is divided into a whole three-level sequence, including lowstand systems tract (LST), transgressive system tracts (TST), highstand systems tract (HST). Mixed rocks mainly develop in highstand systems tract, with a small amount developing in lacustrine transgressive system tracts. The lacustrine transgressive system tract has strong provenance supply, resulting in water dilution and a narrowly mixed phase zone. At highstand systems tract, the water in the lacustrine basin shrinks, and water salinization occurs. The decrease of water leads to the increase of terrigenous clast supply, forming mixed rocks and mixed strata with carbonate rocks.During the highstand systems tract, mixed rocks and mixed strata mainly distribute in the front of fan delta and the near-fan shallow lake area. The mixed rocks in the front of fan delta are mainly affected by provenance supply. The migration of fan delta lobes caused the enhancement or weakening of provenance supply, mainly forming mixed rocks composed of rich terrigenous clasts. Lacustrine wave transformation carried the terrigenous debris from the fan delta into the shallow lake area far away from the fan delta. Frequent lake level fluctuations control the occurrence of mixing, resulting in the superposition of multiple mixing tidal flats, mainly forming mixed rocks with terrigenous clasts and carbonate rocks.
Improving streamflow prediction across China by hydrological modelling together with machine learning
Authors: jiao wang , yongqiang zhang
Published: March 2024

Predicting streamflow is key for water resource planning, flood and drought risk assessment, and pollution mitigation at regional, national, and global scales. There is a long-standing history of developing physically or conceptually catchment rainfall-runoff models that have been continuously refined over time to include more physical processes and enhance their spatial resolution. On the other hand, machine learning methods, particularly neural networks, have demonstrated exceptional accuracy and extrapolation capabilities in time-series prediction. Both approaches exhibit their strengths and limitations. This leads to a research question: how to effectively balance model complexity and physical interpretability while maintaining a certain level of predictive accuracy. This study aims to effectively combine a conceptual hydrological model, HBV, with machine learning (Transformer, Long Short-Term Memory (LSTM)) using a differentiable modeling framework strategy, tailored to predicting streamflow under diverse climatic and geographical conditions across China. Utilizing the Transformer to optimize and replace certain parameterization processes in the HBV model, a deep integration of neural networks and the HBV model is achieved. This integration not only captures the non-linear relationships that traditional hydrological models struggle to express, but also maintains the physical interpretability of the model. Preliminary application results show that the proposed framework outperforms traditional HBV model and pure LSTM model in streamflow prediction across 68 catchments in China. Based on the test results from different catchments, we have adjusted and optimized the model structure or parameters to better adapt to the unique hydrological processes of each catchment. The application of self-attention mechanisms and a differentiable programming framework significantly enhances the model's ability to capture spatiotemporal dynamics. It is likely that the proposed framework can be widely used for streamflow prediction somewhere else.
Development of Rice Paddy Model Based on Noah LSM: Consistent Parameterization of Subcanopy Resistance from the Ponded Water to Dense Rice Canopy 
Authors: Lim Hee-Jeong , Lee Young-Hee
Published: March 2024

We developed a rice paddy model based on the Noah LSM considering the standing water layer during the irrigation period. In the model, we adopted a consistent subcanopy process from thin to thick canopy conditions and considered small scalar roughness length of water surface in rice paddy field. We evaluated the model’s performance against observations from three rice paddy sites with different leaf area index (LAI) and water depths during the growing season. Two simulations were performed in an offline mode: the fixed irrigation simulation of Noah LSM with saturation moisture in the top two soil layers during the irrigation period (IRRI) and the developed model simulation (RICE). The evaluation results showed that RICE outperformed IRRI in the simulating ground, sensible (H) and latent heat (LH) fluxes and topsoil temperature (Tsoil) on hourly and diurnal time scales. Two sensitivity tests of RICE were performed in relation to the subcanopy resistance and standing water layer: RICE without consideration of small roughness length of water surface during the irritation period (BARE) and RICE with a constant standing water depth (FIX). The sensitivity tests showed that BARE calculated very low subcanopy resistance values when the sum of LAI and stem area index was less than 2 m2 m-2, which resulted in cold biases in the daily mean Tg and Tsoil and also led to overestimation of daily mean LH. There was no significant difference in RICE and FIX with hourly and seasonal time scale statistics, suggesting that H, LH,  Tg and Tsoil of the developed model are not sensitive to changes in water depth. The structure of the developed model was also discussed.
Integrated model-data observations of water flow dynamics across bedrock and vegetation variations of a mountainous hillslope
Authors: Uhlemann Sebastian , Peruzzo Luca , Chou Chunwei , Williams Kenneth , Wielandt Stijn , Wang Chen , Falco Nicola , Wu Yuxin , Carr Brad , Meldrum Philip , Chambers Jonathan , Dafflon Baptiste
Published: March 2024

Hydrological processes in mountainous watersheds, and how soil, bedrock, and plants interact are still poorly understood. Through a dense network of soil moisture and temperature sensors, high resolution electrical resistivity tomography monitoring, and weather data we assess the above and below-ground processes driving the hydrological response of a hillslope during snowmelt and summer monsoon. The monitoring transect covers different bedrock and vegetation types, with a steep upper part characterized by shallow bedrock and covered by pine trees, and a gentle lower part underlain by colluvium and covered mostly by grass and veratrum. Coupling the monitoring data with a simplified hydrological model, we observe several important hydrological processes that show how variations in bedrock and vegetation type change subsurface flow patterns, allowing us to answer how subsurface flow pathways differ between shallow and deep bedrock units, and to assess the interactions between vegetation, bedrock types and subsurface flow dynamics. While on the steep section, characterized by thin soil and shallow bedrock, we observe mostly shallow and rapid lateral flow, on the gentle slope underlain by colluvium vertical flow is prevailing. Timelapse resistivity patterns indicate that for shallow bedrock, fractures and tree roots may provide preferential flow pathways into deeper bedrock units during snowmelt, which may provide means to mitigate summer drought conditions. Shading of the trees seems to further mitigate drought conditions by limiting evaporation of summer monsoon rainfall, leading to less drying of the shallow soil layer. In the lower, gentle part of the profile snowmelt is contributing to vertical flow recharging the aquifer, while in the summer upwelling groundwater is providing moisture to sustain plant growth. These observations show that variations in bedrock and vegetation pose a strong control on hillslope hydrology, creating spatially complex flow patterns. These results highlight the spatial heterogeneity of hydrological processes in mountainous watersheds, which need to be understood to predict how watersheds respond to disturbances.
VNIR Spectral comparison between S-Type asteroids and brachinites and ungrouped brachinites-like, in support of the HERA mission
Authors: Migliorini Alessandra , Carli Cristian , Bruschini Enrico , Cuppone Tiberio , Stefani Stefania , Pratesi Giovanni , Stephan Alice , La Forgia Fiorangela , Lazzarin Monica
Published: March 2024

The Didymos-Dimorphos binary system, target of the DART mission that successfully impacted the small moon Dimorphos in September 2022, is classified as an S-type asteroid. It shows spectral properties that well fit with the regions that are closer to high olivine abundances in the Band Area Ratio (B.A.R.) versus Band Center at 1 μm (BCI) plane. Further investigation of the Didymos-Dimorphos system will be performed with the HERA mission, to be launched in October 2024. S-type asteroids are characterized by spectral properties that span from low-Ca pyroxene, up to high-Ca pyroxene and olivine content, with possible different abundances of those phases. Different potential types of meteorites can overlap this region as suggested in different works. High interest is generally attributed to those objects with spectral properties that are in between pyroxene and olivine composition to better understand the potential detection limit of olivine and so clarify the olivine-paradox. Here, we investigate the spectral properties of 12 brachinites and ungrouped achondrites brachinite-like (UBAs), that have olivine abundance between 57% and 94% (and fayalite, Fa, between 17.5% and 34%) with some minor variation in mineral association, abundance, and composition. We study the Visible to Near Infrared (VNIR) reflectance properties to evidence how they change in a spectral range suitable to investigate S-types and compare with Didymos spectral properties. In the VNIR spectral range these samples clearly show a systematic trend between the BCI and the B.A.R. that correlate with the olivine abundance and slightly with iron content on olivine. In fact, meteorites with high olivine amounts but a very low Fa content (i.e. low iron) have positions of the absorptions coherent with the associated pyroxene. Clearly the samples investigated in this work moved from the portion of S (III) type with higher BCI up to the region defined by the S (I) type as defined by Gaffey et al. (1993), with VNIR mainly dominated by olivine. We can notice how Didymos nicely fit within this domain defined by brachinites-UBAs and it is slightly out from the OC boot defined by the S (IV) type.This research was supported by ASI-INAF n.2018-16-HH.0 (Ol-BODIES project) and by ASI (agreement n. 2022-8-HH.0) for ESA’s Hera mission.
Comparison of Exospheric Mg Distributions Observed by BepiColombo/PHEBUS During the 2nd and 3rd Mercury Swing-bys
Authors: Suzuki Yudai , Quémerais Eric , Robidel Rozenn , Chaufray Jean-Yves , Murakami Go , Leblanc François , Yoshioka Kazuo , Yoshikawa Ichiro
Published: March 2024

Mercury’s exospheric atoms are mainly ejected from the surface through several processes such as thermal input, UV irradiation, solar wind particle sputtering, and micro-meteoroid impact. Observations by the MESSENGER spacecraft have shown that Mercury magnesium (Mg) exosphere is related to its surface abundance. Additionally, Mg is an interesting species as its surface abundance reflects the non-uniformity of magma compositions. However, spatial distribution (especially in the latitude direction) and seasonal variability of Mg exosphere is not well understood due to its dark brightness and the geometry of observations.BepiColombo, the Mercury orbiting mission led by ESA and JAXA, is on its way to the planet. The 2nd and 3rd Mercury swing-bys were conducted on 22/06/2022 and 19/06/2023 (UTC), respectively, and many instruments observed the Mercury environments then. In this study, we analyzed Mg exosphere data from PHEBUS, the UV spectrometer onboard BepiColombo, to deduce temperature and production rate of Mg exosphere during each swing-by.As a result, similar signals were obtained through both swing-bys. Season, local time, and longitude of Mercury during both observations were similar, but boresights of PHEBUS were different (2nd: northward, 3rd: southward). These results show that Mg production rates have little year-to-year variability, which is consistent with the fact that Mg is mainly ejected by micro-meteoroid impact. Besides, these results mean that dust impact flux has little north-south asymmetry.In this presentation, we introduce the results obtained by observations of the spectrometer onboard BepiColombo, PHEBUS, during the 2nd and 3rd swing-bys. 
Clumped isotopes in carbonates: state of the art and open questions 
Authors: Bernasconi Stefano , Looser Nathan , Kueter Nico , Rosskopf Ricarda , Hemingway Jordon
Published: March 2024

Since its establishment almost 20 years ago, carbonate clumped isotope thermometry (Δ47, Δ48) has grown to the most widely applied branch of the rapidly evolving field of clumped isotope geochemistry. An increasing number of laboratories worldwide is implementing this technique and applying it to solve a broad range of Earth science questions. The introduction of carbonate-based standardisation (Bernasconi et al. 2021), together with recent efforts to improve temperature calibrations (e.g. Anderson et al. 2021), has solved inter-laboratory differences and greatly improved the confidence in temperature reconstructions based on Δ47. Discrepancies in absolute temperatures using different calibrations are now on the order of 1-2°C only. The next frontier in carbonate clumped isotopes is Δ48 which is even more analytically challenging than Δ47 but has the potential to solve long standing questions of equilibrium/disequilibrium precipitation of carbonates and better understand processes of biomineralization. An important remaining field that requires further research is related to the preservation of the original clumped isotope temperatures in deep time samples and the kinetics of C-O bond reordering. In this contribution, we will review the state-of-the-art analytical methods and calibrations and discuss open challenges in interpreting clumped isotope signatures of biogenic and inorganic carbonates with bond reordering models.Bernasconi et al. (2021) InterCarb: A Community Effort to Improve Interlaboratory Standardization of the Carbonate Clumped Isotope Thermometer Using Carbonate Standards. Geochemistry, Geophysics, Geosystems, 22(5),e2020GC009588..Anderson et al. (2021) A unified clumped isotope thermometer calibration (0.5–1100°C) using carbonate‐based standardization. Geophysical Research Letters, 48, e2020GL092069.
Amplitudes of medium scale gravity waves (GWs) in the ionosphere
Authors: Rusz Jan , Chum Jaroslav , Baše Jiří
Published: March 2024

The amplitude of GWs increases with height due to the decrease in the density of the atmosphere, but at the same time the attenuation of the waves also increases with height due to the dissipation of energy through friction.In this study, the propagation of GWs in the ionosphere is observed remotely, using multi-point, multi-frequency continuous HF Doppler sounding system situated in the western Czechia. The configuration of the system allows to determine not only the amplitude, but also the speed and direction of GWs propagation at different heights. An ionosonde located not far away from the Doppler sounding system is used to assign the reflection heights to individual measurements.The amplitudes of medium-scale atmospheric gravity waves propagating in the ionosphere are measured and statistically processed to investigate the daily and annual variations, and their relation to the speed of the neutral winds and the measurement height. Results from periods of solar maximum and minimum are compared.
Space-time variability of vegetation and their multi-faceted drought impacts in the tropical and subtropical regions
Authors: Ha Van Tuyen , Uereyen Soner , Kuenzer Claudia
Published: March 2024

Drought is a climate-related slow-onset hazard event and has a significant impact on agricultural production and ecosystem health. Mainland Southeast Asia is a tropical and subtropical region of major cropland and vegetation ecosystems, and this region is increasingly vulnerable to drought-related hazards. This study assessed space-time variability of vegetation dynamics and their drought impacts using satellite-based vegetation condition time series and multi-temporal drought indices from 2000 to 2022 over the MSEA region. Specifically, we examined the vegetation dynamics and their responses to multi-temporal (short-term and long-term) drought indices in consideration of different land cover types, land-use transitions, and elevation characteristics. We also used an explanable machine learning method to quantify the impacts of multi-faceted droughts on natural and undisturbed vegetation ecosystems. Our results revealed that vegetation in the MSEA region suffered from multi-year drought-induced stress, but overally nearly 70% of the region experienced a greening trend over the study period. Most declining vegetation areas are observed in forest and rainfed croplands in Cambodia and southern Laos whereas Vietnam witnessed a greening trend. Vegetation-drought analysis indicated that recent land-use transitions and lower altitude areas had higher responses of vegetation to droughts. In natural and undisturbed ecosystems, short-term drought disturbances had the largest impact on vegetation, accounting for nearly 93% of observed variations. The largest influential factors among the examined drought indices was identified as the SPEI-3 and TCI, accounting for around 35% and 20% of the observed changes in vegetation, respectively. Notably, the SPEI-3 highlights that favorable wet conditions can result in an enhancement of vegetation condition by up to 15%, while severe drought occurrences can lead to a significant reduction of up to 20% in vegetation condition.
Impact of Hunga Tonga Hunga Ha’apai eruption on the global stratospheric aerosol layer in comparison with other eruptions and extreme fire events of the past decade 
Authors: Kloss Corinna , Berthet Gwenaël , Sellitto Pasquale , Legras Bernard , Vernier Jean-Paul , Renard Jean-Baptiste , Jégou Fabrice , Konopka Paul , Plöger Felix
Published: March 2024

Using a combination of satellite, ground-based and in-situ observations, we quantify and compare the impact of the most recent moderate volcanic eruptions and extreme fire events (volcanic eruptions: Ambae, Vanuatu in July 2018; Raikoke, Russia and Ulawun, New Guinea in June 2019; extreme fire events: Canadian fires 2017 and Australian fires 2019/2020) on the global stratospheric aerosol layer and climate.A particular focus is set on the Hunga Tonga Hunga Ha’apai (Tonga islands) eruption of January 2022, which was exceptional especially in terms of water injection into the stratosphere. However, even the observed peak global average stratospheric aerosol optical depth exceeded that of the strongest stratospheric aerosol events of the last decade by a factor of more than 2.Since the eruption, we performed multiple measurement campaigns with Optical Particle Counters (POPS and LOAC) to study the aerosol optical properties of the freshly injected plume and its long-term evolution in terms of microphysical properties. The fresh plume consisted mostly of small (
Measuring evaporation-condensation charging of individual aerosol particles
Authors: Stoellner Andrea , Lenton Isaac Christopher David , Muller Caroline , Waitukaitis Scott Russell
Published: March 2024

Although cloud electrification has been studied for hundreds of years, it is still not fully understood [1]. The most promising charging mechanism – ice crystal-graupel collision charging – answers some of our questions, but leaves us with others. Why do ice crystals and graupel charge on collision in the first place? And why do they reverse their charging behavior below a certain temperature? To get some insights we take a step back and look at the charging behavior of individual aerosol particles in a humid environment. Shavlov et al. [2] suggest that the hydroxide and hydronium ions formed by the autodissociation of water are sufficient to cause charging during evaporation and condensation of water droplets or surface-adsorbed water on solid particles. This small amount of charge could be a precursor to bigger charge exchange during collision.            We aim to test this hypothesis by levitating individual aerosol particles in an optical trap and measuring their charge while varying humidity. Our setup allows for trapping of different types of solid and liquid particles in the micrometer size range, like water droplets and silica microspheres. In the future we also hope to study ice crystals. Figure 1 shows an illustration of the measurement principle. The particle’s charge is measured by applying a sinusoidal electric field and observing the resulting particle motion. The Mie scattering pattern of the particle furthermore gives information about the particle’s size and refractive index, both at equilibrium and during evaporation/condensation. The experiment allows us to control the relative humidity, pressure and air ion concentration around as well as air flow across the particle.Ultimately we hope to contribute to a better understanding of the microphysical processes involved in thundercloud electrification and adjacent electrical phenomena in the atmosphere. FIGURE 1. Optical tweezers (wavelength λ = 532 nm) holding a solid or liquid aerosol particle. A sinusoidal electric field is applied between the two electrodes and the resulting particle motion as well as the particle’s Mie scattering pattern are recorded.AcknowledgmentsThis project has received funding from the European Research Council (ERC) under the European Union’s Starting Grant (A. Stoellner, I.C.D. Lenton & S.R. Waitukaitis received funding from ERC No. 949120, C. Muller received funding from ERC No. 805041). ReferencesBerdeklis, P. and List, R. (2001) J Aerosol Sci. 58(18) 2751–2770.
Shavlov A. et al. (2018) J Aerosol Sci. 123 17-26.
Results from WINES: Wind turbIne Noise assEsSment in the Italian site candidate for “Einstein Telescope”, the third-generation gravitational wave detector.
Authors: Diaferia Giovanni , Giunchi Carlo , Molinari Irene , Olivieri Marco , Di Felice Fabio , Contu Andrea , D'Urso Domenico , Naticchioni Luca , Rozza Davide
Published: March 2024

The area in the municipalities of Lula, Bitti, and Onanì in Sardinia (Italy) is a candidate for hosting the “Einstein Telescope” (ET, the third-generation gravitational wave detector), given the extremely low level of natural and anthropogenic seismic noise at this site. For the same unique characteristics of this area, the multi-disciplinary geophysical far-field observatory “Faber” (PNRR-Meet project) will be set up.However, the strength and persistence of wind make this area exceptionally favorable for the exploitation of wind energy, as testified by the nearby Buddusò wind park that, consisting of 69 turbines and about 130 MW of total installed power, is the largest in Italy.It is well known that wind turbines are an important source of seismic noise between 1 and 10 Hz, posing a relevant concern for noise contamination of ET as it will operate in the same frequency range.In the context of the seismic characterization of such a candidate site, the WINES experiment (Wind turbIne Noise assEsSment in the Italian site candidate for the Einstein Telescope) provided a two-month-long passive seismic recording of nine broad-band stations placed at increasing distances from the Buddusò wind park. The aim of the experiment was the evaluation of the noise generated by the wind park in terms of amplitude, spectral content, and decay with distance, in relation to the wind park operation.Analyzing the frequency spectra at all stations, the spectral imprint of the wind park manifests through sharp, well-defined spectral peaks at 3.4, 5.0, 6.8, and 9.4 Hz, even in conditions of absent or moderate wind speed (0-3 m/s). With stronger winds (>20 m/s), all spectra increase their amplitude by an order of magnitude, and the sharpest and most persistent peaks are found at 3.5, 5.2, and 6.8 Hz. In both wind conditions, the amplitude of such peaks decreases with distance, being clearly distinguishable up to 5-6 km from the wind park. We use these spectral peaks to derive an empirical relationship for their amplitude vs. distance, highlighting a well-behaved exponential decay that translates into a two-orders-of-magnitude decrease within 10 km distance.Lastly, considering the assumption that the generated seismic noise propagates as Rayleigh waves, the continuous recordings along the array have been used for the estimation of the direction of noise arrival at each station. Signal coherence allows the recovery of this information for stations within 5 km from the wind park, showing a dominant back-azimuth of the incoming signal that is fully compatible with the position of the wind park with respect to each station.
Methane emissions at buried abandoned wells in Northern Germany: sampling strategies, pitfalls, and silver linings
Authors: Jordan Sebastian F. A. , Schlömer Stefan , Krüger Martin , Blumenberg Martin
Published: March 2024

As we are risking to exceed the 1.5-degree target in the next decade, effective measures to cut back greenhouse gas emission are necessary. With this in mind, the global community expressed the necessity to shift away from fossil fuels at COP 28 for the first time in its history. During this transition process, millions of oil and gas wells will be abandoned. However, recent studies found substantial methane emissions from old abandoned wells for example in the USA and Canada. Hence, the establishment of a proper abandonment procedure is necessary. To achieve this, further research of the current situation of abandoned wells in different countries, reasons for well integrity failure and best abandonment practices are inevitable. So far, only about a dozen countries have measured data on methane emissions and even less include it in their yearly greenhouse gas inventory. Germany has about 20,000 abandoned wells, which are generally plugged and buried, however, it is unclear, whether they are emitting methane or not.Here, we present an overview of two years of closed-chamber methane emission measurements at 59 onshore oil and gas wells in Northern Germany, covering both abandoned exploration and production wells. As the majority of well sites showed no methane leakage, we focus on two oil fields (“Steimbke Nord” and “Nienhagen (-Elwerath)”) with sample sites that showed minor methane emissions of up to ~540 nmol m-2 s-1. Based on a combination of soil gas hydrocarbon concentrations (methane, ethane, and propane) and isotopic methane compositions, we were able to link the methane emissions at three well sites at “Steimbke-Nord” to regionally occurring natural methanogenesis in the overburden (peat). One well at “Nienhagen (-Elwerath)”, however, was characterized by high δ13C-CH4 and a composition of higher hydrocarbons, typical for oil-associated gases and/or biodegraded oil. We will discuss two possible emission sources: (1) well integrity failure and (2) microbial degradation of oil residues from an old oil spill or a drilling mud pit. Furthermore, we will examine the mitigation potential of microbial methane oxidation for methane emissions to the atmosphere. In summary, our data demonstrates the complexity of emission studies on buried abandoned wells and underlines the necessity for a combination of soil gas sampling and flux measurements.
How do we perceive green spaces? Trait-based citizen science to support the monitoring and management of nature-based solutions
Authors: Scheuer Sebastian , Basnou Corina , Sumfleth Luca , Haase Dagmar
Published: March 2024

Idea and objectives: Urban citizens are key beneficiaries of benefits delivered by urban green-blue infrastructure as nature-based solutions. However, the delivery as well as the utilization of ecosystem services is tied to local context and therefore, depending, e.g., on the types of locally relevant societal or environmental issues, urban morphology, socio-demographic characteristics of potential beneficiaries and resulting demands for ecosystem services, or conditions of urban nature inclusive of the state of health of green elements. In this regard, citizens may not only act as beneficiaries of benefits provided by nature, but also as knowledge holders regarding local conditions in the broadest sense. Tapping into this body of knowledge, e.g., through citizen science and/or participatory mapping approaches, is considered crucial for achieving resilient, sustainable, and locally relevant as well as more widely accepted nature-based solutions that promote human health and well-being. From a set of diverse cases, the application of a trait-based framework showcases how citizen science and participatory mapping may support urban planning and the promotion, management and/or monitoring of urban green-blue infrastructure as nature-based solutions at the local level.Background: Traits are understood as aggregate features of individual elements of the green-blue infrastructure, including, e.g., spatial, structural, functional, sensory, institutional or contextual qualities. In line with the social-ecological traits concept, these characteristics are seen to shape human experiences, knowledge and affordances, thus linking qualities of urban nature with ecosystem services and therefore, potential (co-)benefits. However, traits may also help to uncover local social-environmental issues including potentials and concerns, thus challenging urban policy-making. The implemented citizen science framework that is being presented adopts social-ecological traits as research theme-related boundary objects, e.g., to explore citizens’ awareness, perceptions and ideas of locally-specific traits. In so-doing, first, potential feedback loops that may shape compatibility of urban green-blue infrastructure elements for specific purposes, uses, and/or users may be uncovered. Second, potential pathways for local action may be identified to support a more holistic and more inclusive management and planning of nature-based solutions.