bluuebunny/crossref_metadata_2025 huggingface dataset:
Oceanographic processes influence the high primary productivity in the Visayan Sea, Philippines  
Authors: del Rosario Aiko Love , Gallentes Adonis , Bilgera Princess Hope , Villanoy Cesar
Published: March 2024

The mechanisms behind the high productivity of the Visayan Sea (Philippines) need to be understood for better fisheries management. However, current global ocean models are limited to spatial resolution of 1/8° to 1/12° which is around 8-14 km in grid size. Due to the presence of islands, shallow depths and narrow straits surrounding the Visayan Sea, global models cannot resolve and explain the Visayan Sea surface currents. In this paper, we explore the possible reasons for the high productivity in the region through analysis of satellite-derived chl-a and high resolution hydrodynamic models of the Visayan Sea in DELFT3D-Flow and SURF-NEMO.Tide analysis suggests that the dominant constituents in the Visayan Sea are both semi-diurnal - M2 (principal lunar) and S2 (principal solar). In the larger Philippine Internal Seas which include the Visayan Sea, notably higher M2 and S2 amplitudes are observed in the latter. This can be attributed to the possible resonance of wave-wave interaction by tides coming from surrounding basins. Being a relatively shallow body of water (30-90 m) surrounded by deeper waters (100-1,700 m) and an area where maximum tidal amplitudes are found, stronger vertical mixing and nutrient exchange are ensued, thereby reinforcing productivity. Satellite-observed chlorophyll-a concentrations from 2002 to 2022 in the Visayan Sea and adjacent seas are consistently high, regardless of monsoon reversal. Empirical orthogonal function (EOF) analysis of chlorophyll data was also conducted to determine the dominant patterns of chl-a variance. The first 10 modes contribute 65.2 % of the total variance. Mode 1 (18.8 %) is attributed to the seasonal variability (i.e., monsoons). Mode 2 (11.1 %) pattern can be associated with the Nino3.4 ENSO Index, suggesting that primary productivity in the Visayan Sea could be well affected by the changing climate. Lastly, this study presents a recommendation of areas that need protection and focused management for better implementation of fishing seasonal closure in the Visayan Sea.
Agulhas Plateau large igneous province emplacement and carbonation constrained by in-situ U-Pb dating, Sr isotope geochemistry and clumped isotope thermometry of calcite veins in basaltic basement at IODP Site U1582
Authors: Gürer Derya , Jones Matthew M. , Bohaty Steve M. , Bernasconi Stefano M. , Nana Yobo Lucien , Roberts Andrew P.
Published: March 2024

Continental breakup leads to formation of new oceanic gateways, evolution of ocean bathymetry, and, in many cases, emplacement of large igneous provinces (LIPs). Changes in ocean circulation, volcanic CO2 emissions, and alteration of freshly emplaced ocean crust associated with these events were likely drivers of global-scale Cretaceous climate change. Yet, the precise timing and nature of Cretaceous continental rifting and submarine LIP eruptions remain largely unconstrained. The Agulhas Plateau (AP), along with Maud Rise (MR) and Northeast Georgia Rise (NEGR), are thought to constitute a once contiguous submarine LIP that was emplaced in the gateway between the incipient South Atlantic, Southern Ocean, and Indian Ocean basins during the breakup of Africa and East Antarctica. International Ocean Discovery Program (IODP) Expedition 392 recovered sedimentary and igneous rocks from the Agulhas Plateau, southwest Indian Ocean, including basaltic pillow lavas at IODP Site U1582, located on the northernmost edge of the plateau. Calcite veins and infills hosted in pillow lavas can provide insights into the timing and chemical environment of post-magmatic fracturing, fluid circulation, submarine weathering and carbonation of the LIP. We present in-situ U/Pb ages (n=12) of the calcite veins determined via laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), clumped isotope (Δ47) compositions (n=6) and 87Sr/86Sr ratios to investigate the timing and temperature of calcite precipitation. U/Pb geochronologic dates for vein calcite and infill are reproducible and yield Cenomanian to Turonian ages, consistent with shipboard nannofossil biostratigraphic age constraints for sediments intercalated between the pillows. Reproducible clumped isotopic paleotemperatures range from ~19 to 26°C, with a calculated δ18O value for precipitating fluids of ~-2 to +1‰ Vienna Standard Mean Ocean Water (VSMOW). The ranges of both these values are consistent with ambient mid-Cretaceous marine waters and, when combined with the age constraints for the basalt and sediments, support rapid weathering and carbonation of the submarine LIP following post-eruptive cooling. U/Pb geochronology of calcites at IODP Site U1582, refined by Sr isotope stratigraphy, provide a minimum age for the Agulhas Plateau. These data constrain the timing of the formation of a paleobathymetric restriction at the gateway between several incipient Cretaceous ocean basins, and have implications for geochemical interactions between mafic igneous rocks and seawater through the life cycle of a Cretaceous LIP.
Understanding spatio-temporal variability of aerosol composition based on MISR aerosol product over the Indian Subcontinent
Authors: Srivastava Shreya , Dey Sagnik
Published: March 2024

Understanding the spatio-temporal heterogeneity of aerosol composition is critical in improving climate projection and health impact assessment of air pollution. Systematic data on aerosol composition is lacking over the Indian subcontinent. In this work, we processed 22 years (2001 to 2022) of Level 2 version 23 Multi-angle Imaging Spectro-Radiometer (MISR) aerosol products to derive information about aerosol composition over the Indian Subcontinent.We broadly categorized aerosols into four types: Secondary Inorganic Aerosol (SIA), Absorbing (BC, OC), Sea- Salt and Dust. MISR aerosol retrieval algorithm assumes 74 aerosol mixtures considering 8 aerosol models based on size, shape and absorbing properties. We calculated the % retrieval frequency of all 74 aerosol mixtures over 22 years, month-wise, in a grid of 0.05 x 0.05. Utilizing this, we then mapped the monthly climatology of aerosol retrieval frequency of four broad types calculated summing over the frequency of a particular mixture multiplied by the fraction of aerosol models assumed in that mixture. We also investigated aerosol optical properties such as size and shape-segregated AODs, Angstrom exponent and SSA. The result shows a very high retrieval frequency for SIA (>50%), while a very low value (50% during monsoon months. Dust aerosol’s retrieval frequency is very high (>50%) during the pre-monsoon and monsoon months over the oceans surrounding Southern India, while the value is much lower over the land. SIA retrieval frequency is >60% over the land and nearby oceanic regions in the winter season, which decreases to 40%-50% in the pre-monsoon season, increasing dust fractions from
Segmentation and Tracking of Solar Eruptive Phenomena with Convolutional Neural Networks (CNN)
Authors: Stepanyuk Oleg , Kozarev Kamen
Published: March 2024

Solar eruptive events are complex phenomena, which most often include coronal mass ejections (CME), flares, compressive/shock waves, and filament eruptions. CMEs are large eruptions of magnetized plasma from the Sun’s outer atmosphere or corona, that propagate outward into the interplanetary space. Solar Energetic Particles (SEP) are produced through particle acceleration in flares or CME-driven shocks. Exact mechanisms behind SEP production are yet to be understood, but it is thought that most of their acceleration occurs in shocks starting in the low corona. Over the last several decades a large amount of remote solar eruption observations have become available from ground-based and space-borne instruments. This has required the development of software approaches for automated characterization of eruptive features. Most solar feature detection and tracking algorithms currently in use have restricted applicability and complicated processing chains, while the complexities in engineering machine learning (ML) training sets limit the use of data-driven approaches for tracking or solar eruptive related phenomena. Recently, we introduced a hybrid algorithmic—data driven approach for characterization and tracking of solar eruptive features with the improved wavelet-based, multi-instrument Wavetrack package (Stepanyuk et.al, J. Space Weather Space Clim. (2024)), which was used to produce training datasets for data driven image segmentation with convolutional neural networks (CNN). Its perfomance was shown on a limited set of SDO AIA 193A instrument data perfoming segmentation of EUV and shock waves. Here we extend this approach and present an ensemble of more general CNN models for data-driven segmentation of various eruptive phenomena for the set of ground-based and remote instruments data. We discuss our approach to engineering training sets and data augmentation, CNN topology and training techniques. 
Development of half-grabens along the northwestern end of Gediz-Alaşehir Graben: Inferences from morphometric and kinematic analysis
Authors: Tekin Taner , Dönmezoğulları Tamer , Sançar Taylan , Rojay Bora
Published: March 2024

Aegean Extensional Province under which evolution was primarily influenced by the interaction of the northward subducting African plate beneath along “Mediterranean Ridge” and the extrusion of the Anatolian continental fragment caused by relative motion along two major continental transform faults, dextral North Anatolian Fault and sinistral East Anatolian Fault. The resultant interaction led to a crustal extension in NW-SE trending direction in Western Anatolia known as the Gediz-Alaşehir Graben (GAG).The study of dynamic morphology along the graben displayed by mountain front morphology (mountain front sinuosity and symmetry of mountain ridges) is studied. To understand the dynamic effects, a series of profiles was taken from Spildağ Mountain in the west to Gölmarmara Lake in the east.Secondly, kinematic data are collected from fault planes from NW-SE trending, NE facing four faults developed between Manisa fault to Gölmarmara fault. The Angelier Inversion method was applied to the Win-Tensor program (Delvaux and Sperner, 2003) and used in the analysis of the fault slip data. The result is an NE-SW extensional regime that is overprinted onto NE-SW dextral and sinistral oblique-slip motion.Mountain front sinuosity (Smf) and sudden changes of slope along topographic profiles (kinks) indicate the activity of the faults but different rates of deformations. Moreover, indicators manifest a series of NE-facing half grabens that exist within the Gediz-Alaşehir graben. The ages from the dating of the calcite samples from either fault scarps and trenches are going to assist in better comprehension of the active tectonics of Gediz-Alaşehir graben.To sum up, the Gediz-Alaşehir graben which was constructed on four half-grabens developed under the NE-SW extensional regime during the post-Late Miocene manifests the current configuration of the topography.Keywords: Aegean Extensional Province, Gediz-Alaşehir Graben, morphometric analysis, kinematic analysis.
The opportunities and challenges of near-term climate prediction
Authors: Thornton Hazel
Published: March 2024

Accurate forecasts of the climate of the coming season and years are highly desired by many sectors of society. The skill of near-term climate prediction in winter in the North Atlantic and European region has improved over the last decade associated with larger ensembles, improving models and boosting of the prediction signal using intelligent post processing. International collaboration has improved the availability of forecasts and promoted the uptake of forecasts by different sectors. However, significant challenges remain, including summer prediction, understanding the risk of extremes within a season, multi-seasonal extremes and how best to post process the forecasts to aid decision making. This talk will summarise recent near-term climate prediction research activities at the UK Met Office and will detail our experience of providing such forecasts to the energy and water sectors.  
Vulcano International training Summer School of Geochemistry 
Authors: Pecoraino Giovannella , Tassi Franco , Calabrese Sergio , Cabassi Jacopo , Vaselli Orlando , Rouwet Dmitri , Tamburello Giancarlo , Capecchiacci Francesco , Venturi Stefania
Published: March 2024

Vulcano Island, an active closed conduit volcano in south Sicily, hosts from 2018 the Vulcano International Training Summer School of Geochemistry. The basic idea is to share scientific knowledge and experiences in a multi-aspect geochemical community, using local resources with a low-cost organization in order to allow as many students as possible access to the school. The Vulcano International Training Summer School of Geochemistry is addressed to students, graduate students, senior graduate students and  fellows, coming not only from Italy but also from European and non-European countries, aiming to bring together the next generation of researchers active in studies concerning the geochemistry and the budget of volcanic gases. The main aim of the school is to bring the next generation of researchers, active in studies concerning geochemistry in volcanic environments, and to introduce them with innovative direct sampling and remote sensing techniques. Furthermore, it gives young scientists an opportunity to experiment and evaluate new protocols and techniques to be used on volcanic fluid emissions, covering a broad variety of methods. The teaching approach includes practical demonstrations and field applications, conducted by teachers of international level. Students therefore have the opportunity to learn by practicing sampling techniques. Practical exercises include: direct sampling of high-temperature fumaroles and plume measurement techniques in the fumarolic crater field; direct sampling of low-temperature gas emissions and submarine emissions; measurement of diffuse soil gas fluxes of endogenous gases at Levante Bay Beach; sampling of groundwater and dissolved gases, and measurements of physical-chemical parameters by using multiparametric probes, in thermal waters in the Vulcano village. Also this year the school will take place from 17 to 21 June 2024.
Post-processing for an on-demand extremes digital twin – a multi-model approach for wind and solar energy production
Authors: Schicker Irene , Papazek Petrina , Gfäller Pascal , Odak Plenkovic Iris , Vujec Ivan , Kann Alexander , Horvath Kristian
Published: March 2024

 The amount of wind and solar energy fed into the European power grid increases rapidly and with the transition to a fossil fuel-free energy production, relying heavily on renewable energy sources, more accurate predictions for both high-resolution temporal and spatial scales are needed to ensure, most of all, grid stability. This is even more the case with extreme events, both extremes in weather across the nowcasting to weeks ahead time scale and combined and non-necessarily extreme weather, events such as Dunkelflaute or longer lasting solar/wind droughts. Accurate, frequently updated and especially on-demand available predictions of the expected power production are needed. Post-processing methods enable targeted forecasts of meteorological parameters both at site-location and regional level, which can server for a conversion to power production, particularly a direct conversion of NWP predictions and observations to power production.For an on-demand extreme digital twin forecasting system, fast and transferable post-processing methods, able to account for the upper/lower bounds of the respective distributions are needed. Furthermore, they need to be able to either generate on-the-fly (semi-)synthetic power production data or a reduced set of both observation and NWP input data. The latter is essential when moving towards hyper-resolution NWP simulations with only a limited set of training data available.Within the on-demand extreme digital twin initiative, several post-processing methods, statistical and (deep) machine learning, were implemented and applied to selected use cases for on/offshore wind and solar production extreme events. Here, we demonstrate (i) the capability of the Kalman filter, the analogs method, IrradPhyDNet, a sequence-2-sequence LSTM, Random Forest, and other machine learning/statistical methods in extreme event prediction, (ii) evaluate the methods skills by using heterogeneous (multiple NWP models, observations, climatologies, etc.) and varying length input data and real/(semi-)synthetic power data as target, and (iii) present a workflow for an on-demand prediction for wind and solar energy production including user-interaction.
Measuring nanoplastics in the atmosphere and other environmental compartments by TD-PTR-MS
Authors: Materić Dušan
Published: March 2024

Plastic pollution has been recognised to be a global problem, as particles of various sizes have been detected in water, soil and air, from urban to remote areas. Nanoplastics have been suspected to be a significant environmental and health problem; however, until recently, no quantitative method was available to measure the nanoplastics in environmental samples. Thermal Desorption – Proton Transfer Reaction – Mass Spectrometry (TD-PTR-MS) offers a good sensitivity, which makes the technique capable of measuring nanoplastics in environmental samples in the sub-nanogram range – opening new venues for plastics-related research. So far, we have successfully measured and reported nanoplastics deposited on the snow surface in the Alps [1], remote field sites in the French Pyrenees [2], rural surface water in Sweden and Siberia [3], in the Dutch Wadden Sea [4], urban air [5], and Greenland ice core and Antarctica sea ice [6]. Here, we will discuss nanoplastic loads for these different environmental compartments and their connection to the atmospheric transport of nanoplastics. We will discuss the methodological challenges and research gaps associated with measuring ultrafine micro- and nanoplastics. [1] D. Materić, E. Ludewig, D. Brunner, T. Röckmann, and R. Holzinger, “Nanoplastics transport to the remote, high-altitude Alps,” Environ. Pollut., p. 117697, Jul. 2021, doi: 10.1016/j.envpol.2021.117697.[2] S. Allen et al., “An early comparison of nano to microplastic mass in a remote catchment’s atmospheric deposition,” J. Hazard. Mater. Adv., vol. 7, p. 100104, Aug. 2022, doi: 10.1016/j.hazadv.2022.100104.[3] D. Materić et al., “Presence of nanoplastics in rural and remote surface waters,” Environ. Res. Lett., vol. 17, no. 5, p. 054036, May 2022, doi: 10.1088/1748-9326/ac68f7.[4] D. Materić, R. Holzinger, and H. Niemann, “Nanoplastics and ultrafine microplastic in the Dutch Wadden Sea – The hidden plastics debris?,” Sci. Total Environ., vol. 846, p. 157371, Nov. 2022, doi: 10.1016/j.scitotenv.2022.157371.[5] B. Kirchsteiger, D. Materić, F. Happenhofer, R. Holzinger, and A. Kasper-Giebl, “Fine micro- and nanoplastics particles (PM2.5) in urban air and their relation to polycyclic aromatic hydrocarbons,” Atmos. Environ., vol. 301, p. 119670, May 2023, doi: 10.1016/j.atmosenv.2023.119670.[6] D. Materić, H. A. Kjær, P. Vallelonga, J.-L. Tison, T. Röckmann, and R. Holzinger, “Nanoplastics measurements in Northern and Southern polar ice,” Environ. Res., vol. 208, p. 112741, May 2022, doi: 10.1016/j.envres.2022.112741. 
The evolution of crack transmissivity under normal and shear stress before and after slip
Authors: Yang Lining , Mecklenburgh Julian , Rutter Ernest
Published: March 2024

Understanding the flow of fluids in the subsurface is of vital importance to geo-energy exploitation and disposal of waste fluids. In most situations, individual cracks can be more effective for fluid transport than fluids flowing through the porous matrix of the rock. The enhancement of a single crack in a low permeable rock can be over 1000 times. However, for both porous matrix flow and crack flow, the bulk permeability and crack transmissivity are all affected by the stress state in the lithosphere.This study aims to investigate the influence of the Terzaghi effective normal and shear stress on the transmissivity of cleavage cracks under upper crustal conditions. Penrhyn slate was selected as samples for the experimental study because of its low porosity (
Melting and Remelting in a Crystallizing Magma Ocean
Authors: Manjon Cabeza Cordoba Antonio , Ballmer Maxim D. , Shorttle Oliver
Published: March 2024

Geodynamic modelling is increasingly dependent on the initial conditions. Non-steady-state planetary evolution models are complex enough that several solutions can be achieved with small variations in the initial temperature, composition, etc. Models of magma ocean evolution predict an overturn of a layer enriched in iron and incompatible elements. The absence of this layer in any tomographic inversion of the Earth suggests that our models of magma ocean evolution are missing key phenomena. Since these models are the basis for the initial conditions of Earth-applied geodynamic planetary models, there is an urgency to find the origin of the discrepancies between our idea of magma ocean crystallization and the current state of the Earth.To advance our understanding of the consequences of magma ocean crystallization, we carry out high resolution models of mantle flow coupled with (1D) magma ocean evolution (including melting and crystallization processes). We allow two different forms of topography to arise with a sticky air (sticky magma ocean) approximation: dynamic topography and thermodynamic topography. We explore how different equilibration times affect melt segregation and magma ocean composition, as well as how crystal settling influences solid state convection and differentiation. We calculate, as well, chemical exchange between the solid and liquid parts of our model by expanding on previous work, studying different equilibrium constants and allowing the system to self-regulate.Preliminary results suggest a competition effect between the two forms of topography mentioned above. This competition implies that the equilibrium constant of chemical exchange, as well as melting segregation speed and crystal growth and settling, will have an essential role in the equilibration between the solid mantle and the liquid magma ocean. This and other results have implications for Earth, but also for other discovered magma oceans such as those on the Moon, Mars or even exoplanets.
Optimization of ML-based regression models applying metaheuristic algorithms to determine the landslide susceptibility
Authors: Ajin Rajendran Shobha , Segoni Samuele , Fanti Riccardo
Published: March 2024

A landslide susceptibility modelling has been carried out by applying two machine learning regression algorithms (SVR and CatBoost), and later two population-based optimization algorithms (metaheuristics) such as PSO and GWO were integrated to assess whether the integration improved the performance of the two regression algorithms. A total of 18 predisposing factors were selected for the study. After the multicollinearity assessment and feature selection applying the information gain (IG) method, four predisposing factors (three factors with collinearity issues and one irrelevant factor) were excluded. Hence, 14 predisposing factors were selected for the modelling. The landslide susceptibility maps were thus created by applying the CatBoost, CatBoost-PSO, CatBoost-GWO, SVR, SVR-PSO, and SVR-GWO models. The validation employing different techniques (MAE, MSE, RMSE, and R2) confirmed that the CatBoost model (MAE = 0.065 and 0.071, MSE = 0.027 and 0.032, RMSE = 0.165 and 0.180, and R2 = 0.890 and 0.869) is better than the SVR model (MAE = 0.179 and 0.181, MSE = 0.063 and 0.063, RMSE = 0.251 and 0.252, and R2 = 0.746 and 0.745). The integration of optimization algorithms improved the performance of these two regression models, and the GWO has the best performance when compared to the PSO algorithm. Also, CatBoost-GWO (AUC = 0.910) has the best performance, followed by CatBoost-PSO (AUC = 0.909), CatBoost (AUC = 0.899), SVR-GWO (AUC = 0.868), SVR-PSO (AUC = 0.858), and SVR (AUC = 0.840). The Friedman and Wilcoxon-signed rank tests confirmed that the models are significant. The feature importance assessment using the CatBoost confirmed elevation, slope, geomorphology, road, and soil bulk density as the top five important predisposing factors.
Near-Earth Objects’ Forecast of Collisional Events (NEOForCE). Impact monitoring system
Authors: Vavilov Dmitrii , Hestroffer Daniel
Published: March 2024

Estimating the probability of a collision of asteroids with the Earth is an important task for planetary defense. There are systems that compute impact probabilities of near-Earth asteroids with the Earth on a regular basis: Sentry (Nasa, Jet Propulsion Laboratory) and CLOMON-2 (originally University of Pisa, now ESA). Here we present NEOForCE (Near-Earth Objects Forecast for Collisional Events) a new monitoring system developed at Institut de mécanique céleste et de calcul des éphémérides (IMCCE, Paris Observatory). This system is original and independent. As ephemeris of major planets and the Moon we use INPOP [1]. The asteroids’ orbits and covariance matrices are taken from DynAstVO database [2]. For computing the impact probability we use the Line Of Variation (LOV) sampling method [3] but with significant modifications. The longest axis of the confidence ellipsoid is chosen to be sampled obtaining virtual asteroids. Each virtual asteroid’s orbit is propagated from the time of discovery 100 years ahead with variational equations. Each virtual asteroid is a representative of its small vicinity and we apply the Partial Banana Mapping method (PBM) [5] for each of this vicinity to look for possible collisions. Then the results are combined and the procedure to find explicitly the initial conditions of the collisional trajectory is launched.The main differences with the existing monitoring systems are: usage of INPOP ephemeris of major planets instead of DE, having our own orbit fitting and propagation procedure of asteroids from DynAstVO, and implementation of Partial Banana Mapping method. Hence the system provides an independent assessment of the impact probability, which in case of risks is crucial. [1] Fienga, A., et al. (2020) INPOP new release: INPOP19a. Astrometry, Earth Rotation, and Reference Systems in the GAIA era. p. 293-297.[2] Desmars J., et al. (2017) DynAstVO: a Europlanet database of NEA orbits. European Planetary Science Congress. 2017. p. EPSC2017-324.[3] Milani A., et al. (2005) Nonlinear impact monitoring: line of variation searches for impactors. ICARUS, V. 173, p. 362-384.[4] Vavilov D.E. (2020) The partial banana mapping: a robust linear method for impact probability estimation. MNRAS, V. 492, p. 4546–4552.
Artificial Intelligence Reconstructs Historical Climate Extremes
Authors: Plésiat Étienne , Dunn Robert , Donat Markus , Ludwig Thomas , Kadow Christopher
Published: March 2024

The year 2023 represents a significant milestone in climate history: it was indeed confirmed by the Copernicus Climate Change Service (C3S) as the warmest calendar year in global temperature data records since 1850. With a deviation of 1.48ºC from the 1850-1900 pre-industrial level, 2023 largely surpasses 2016, 2019, 2020, previously identified as the warmest years on record. As expected, this sustained warmth leads to an increase in frequency and intensity of Extreme Events (EE) with dramatic environmental and societal consequences.To assess the evolution of these EE and establish adaptation and mitigation strategies, it is crucial to evaluate the trends of extreme indices (EI). However, the observational climate data that are commonly used for the calculation of these indices frequently contains missing values, resulting in partial and inaccurate EI. As we delve deeper into the past, this issue becomes more pronounced due to the scarcity of historical measurements.To circumvent the lack of information, we are using a deep learning technique based on a U-Net made of partial convolutional layers [1]. Models are trained with Earth system model data from CMIP6 and has the capability to reconstruct large and irregular regions of missing data using minimal computational resources. This approach has shown its ability to outperform traditional statistical methods such as Kriging by learning intricate patterns in climate data [2].In this study, we have applied our technique to the reconstruction of gridded land surface EI from an intermediate product of the HadEX3 dataset [3]. This intermediate product is obtained by combining station measurements without interpolation, resulting in numerous missing values that varies in both space and time. These missing values affect significantly the calculation of the long-term linear trend (1901-2018), especially if we consider solely the grid boxes containing values for the whole time period. The trend calculated for the TX90p index that measures the monthly (or annual) frequency of warm days (defined as a percentage of days where daily maximum temperature is above the 90th percentile) is presented for the European continent on the left panel of the figure. It illustrates the resulting amount of missing values indicated by the gray pixels. With our AI method, we have been able to reconstruct the TX90p values for all the time steps and calculate the long-term trend shown on the right panel of the figure. The reconstructed dataset is being prepared for the community in the framework of the H2020 CLINT project [4] for further detection and attribution studies.[1] Liu G. et al., Lecture Notes in Computer Science, 11215, 19-35 (2018)[2] Kadow C. et al., Nat. Geosci., 13, 408-413 (2020)[3] Dunn R. J. H. et al., J. Geophys. Res. Atmos., 125, 1 (2020)[4] https://climateintelligence.eu/
Source localization by backward atmospheric transport modelling for radioxenon detections at Mount Schauinsland with six hours sampling duration
Authors: Ross J. Ole , Brander Sofia
Published: March 2024

Part of the International Monitoring System (IMS) for the Comprehensive Nuclear-Test-Ban Treaty (CTBT) is  a network of highly sensitive radionuclide stations sniffing for tiny traces of fission and activation products in the atmosphere.  All IMS radionuclide stations have a high volume sampler for the detection of particulate radionuclides, some are equipped with noble gas systems for the measurement of radioxenon. The specific radioactive xenon isotopes are more likely to escape from underground nuclear explosions and have less complex features in atmospheric transport. There are also radioxenon background emissions from legitimate nuclear facilities. Isotopic ratio analysis allows to a certain extend for source characterization and timing. Atmospheric Transport Modelling (ATM) in backward and forward mode is applied to connect the measurements in space and time with potential releases.  Noble gas systems at IMS radionuclide stations used to operate with 24 or 12 hours sampling time. The next generation noble gas systems utilize shorter sampling periods. At station RN33 on Mount Schauinsland, Germany, a SPALAX system with 24 hours sampling is operated by BfS. In the phase II testing a  “Xenon International” system with six hours sampling time and better sensitivity to Xe-135, Xe-133m and Xe-131m was installed in parallel from July 2021 to April 2022. The main contributing emitter to elevated xenon activity concentrations at RN33 is the medical isotope production facility at Fleurus, Belgium.We investigated how the increase in time resolution in sampling and ATM changes the location capability of backward ATM. For that, the Lagrangian Particle Dispersion model HYSPLIT (NOAA-ARL) is applied driven by GFS meteorological data for all samples of the test phase. Calculation of expected Xe-133 contributions from Fleurus derived by ATM backward sensitivities and emission data show generally good agreement. As the Xenon International system also allows for additional detections particularly of Xe-135 and isomers Xe-133m and Xe-131m, the sensitivity to unknown additional sources is potentially improved and analysed. A coincidence analysis of repeating or in respect to isotopic composition remarkable detections which could not be well explained by emissions from Fleurus show several other potential source regions pointing to several  Nuclear Power Plants and research reactors.
Persistence of Rumours and Hate Speech Over the Years: the Manchester Arena Bombing 
Authors: Vicari Rosa , Elroy Or , Komendantova Nadejda , Yosipof Abraham
Published: March 2024

Following the 2017 Manchester Arena bombing, the ensuing discussions in the media and on social platforms highlighted the potential of terrorism to deepen societal divisions. This study investigates the dynamics of rumors on social media and in the press after the attack, as well as the subsequent discourse on migration policies. We compiled a dataset comprising 3,184 press articles and 89,148 tweets pertaining to the Manchester Arena bombing. The research aims to identify prevalent rumors, assess their short- and long-term effects on user engagement, analyze the sentiment in tweets related to each rumor, and scrutinize perceptions of terrorism threats and migration policies among both the press and Twitter users.The findings reveal that Twitter acted as an echo chamber for misinformation, amplifying specific rumors related to the attack, while the press demonstrated fact-checking practices and offered nuanced perspectives. Notably, one rumor suggesting the attacker was a refugee gained traction over time, reflecting a surge in anti-immigrant sentiments. Emotional responses on Twitter varied from a neutral tone to heightened distress and anger, underscoring the significant impact of social media narratives on public sentiment. The research highlights the polarization of views on social media, influenced by the concise format of tweets and the rapid production cycle, with Twitter users predominantly expressing very negative attitudes toward immigration. This study emphasizes the crucial role of the media in dispelling misinformation and cultivating a nuanced public understanding in complex socio-political contexts.
NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP-CMIP6)
Authors: Thrasher Bridget , Wang Weile , Michaelis Andrew , Brosnan Ian , Khajehei Sepideh
Published: March 2024

The NASA Earth Exchange Global Daily Downscaled Projections CMIP6 archive (NEX-GDDP-CMIP6) contains daily climate projections of nine variables derived from thirty-five CMIP6 GCMs and four SSP scenarios (SSP2-4.5, SSP5-8.5, SSP1-2.6 and SSP3-7.0) for the period 2015-2100. Each of these climate projections was downscaled to a spatial resolution of 0.25 degrees x 0.25 degrees using the daily version of the BCSD statistical downscaling method. The purpose of this archive is to provide a set of global, high-resolution, bias-corrected climate change projections that can be used to evaluate climate change impacts on processes that are sensitive to finer-scale climate gradients and the effects of local topography on climate conditions. In this session, we will provide an overview of the methodology, as well as the details of its execution on the NASA Advanced Supercomputing (NAS) facility. In addition, we will discuss the various considerations, assumptions, and limitations of the downscaled data. Lastly, we will illustrate the various modes of accessing the archive, including examples using the NASA Regional Climate Model Evaluation System (RCMES) and cloud computing resources.
Evaluation of remote sensing actual evapotranspiration products for hydrological modeling applications
Authors: Orság Matěj , Fischer Milan , García-García Almudena , Peng Jian , Samaniego Luis , Trnka Miroslav
Published: March 2024

Evapotranspiration (ET) is one of the main environmental variables for the study of land-atmosphere interactions due to its interconnection with the energy and water balance at the land surface. Despite the dedicated effort of the remote sensing community to estimate the magnitude of ET at global scales, the uncertainties and differences between products are still very large, especially when comparing ET products with different spatial resolutions. Here, we designed a round-robin experiment to determine the product or products most suitable for future integration in hydrological modeling. The evaluation is performed using eddy covariance measurements as reference and point-scale downscaling (PSD) benchmarking criteria to identify the added value of the high-resolution products. The eddy covariance measurements of latent and sensible heat fluxes are known to not close the surface energy budget. Therefore, the use of eddy covariance measurements as a reference could have important consequences for the later use of ET products in assimilation approaches. Therefore, two main strategies to deal with the energy balance closure problem are considered here. Firstly, we considered three energy balance closure scenarios – (i) assigning the energy balance residuum to sensible heat flux; (ii) distributing the residuum to both turbulent energy fluxes by preserving their ratio, i.e. Bowen ratio; (iii) assigning the entire residuum to latent heat flux. While the first case has no impact on ET, the two remaining ones lead to an increase in ET. Secondly, the use of the triple collocation method, which does not require a reference dataset, will be explored to complement these results. Despite these efforts to identify the best ET product for the integration of satellite ET products in hydrological models, we cannot conclude that the products reaching the best metrics in this evaluation will be the products adding more value to the assimilation approach. Therefore, further experiments should be designed to test if the products selected in the round-robin exercise are indeed improving the performance of hydrological models or on the contrary other ET products are more suitable for assimilation approaches. We acknowledge support from AdAgriF - Advanced methods of greenhouse gases emission reduction and sequestration in agriculture and forest landscape for climate change mitigation (CZ.02.01.01/00/22_008/0004635).
MSL TLS-SAM measurements consistent with localized methane containment and transport by 3-D atmospheric circulation in Gale crater
Authors: Pla-Garcia Jorge , C.R. Rafkin Scot , Ruíz-Pérez María , Atreya Sushil
Published: March 2024

The Curiosity rover has traversed more than 30 km from the landing site at the very bottom of Gale crater and has climbed more than ∼750 m into the Mt. Sharp foothills over more than five Martian years. Modeling and observations strongly suggest that the rover has ascended to elevations above a cold pool of air at the bottom of the crater [Ruíz-Pérez et al. 2024 in preparation]. During nighttime, downslope winds originating from both Mt. Sharp and crater rims would prevent the nighttime accumulation of methane released along the slopes above the cold pool and facilitate the convergence and accumulation of methane in the bottom of the crater. As a result, any methane released along the slopes at night is quickly transported downslope. After sunrise, the crater circulation transitions to an upslope regime. The reversal of the circulation should transport the methane accumulated in the bottom of the crater upslope as shown in MRAMS model tracer fields, that also indicate a substantial horizontal mixing that rapidly dilutes the methane-enriched air mass. Any methane released along the slopes is transported horizontally and vented out of the crater. MRAMS model predicts a methane front of peak values to pass higher elevations at increasingly later times after sunrise, moreover later in the morning (~10:00 LMST), but usually with highly and increasingly diluted with time methane values. At mid-morning, upslope circulation along surface rims is fully developed and there is a clear horizontal divergence at bottom of crater where methane is highly diluted due to 3-D atmospheric mixing and increasingly advected upslope out of crater. At dusk, downslope winds starts to develop through sloped surfaces of Mt. Sharp, as well as the cold pool of air at the bottom of the crater, which begins to trap methane released from the ground to start the cycle again. Consistent with [Pla-García et al. 2019] and [Moores et al. 2019] the 3-D crater circulation supplemented by the growth and collapse of the PBL is necessary to explain the TLS-SAM methane observations.
Changes in ocean tides by the end of the 21st century in response to stronger stratification
Authors: MacPherson Leigh , Opel Lana , Schindelegger Michael , Arns Arne , Vafeidis Athanasios
Published: March 2024

Recent model results in combination with observations have provided a first coherent picture of secular changes in ocean tides since 1993. Strengthening of ocean stratification has been identified as an important driver of the observed secular trends, where the barotropic tide is primarily affected through enhanced tidal conversion at topography. These changes are responsible for open-ocean trends in the order of 0.1 mm yr-1 for the barotropic M2 tide, increasing to magnitudes comparable to the tidal response to sea level change (0.2—0.4 mm yr-1) in several coastal regions. This has ramifications for global projections of future extreme sea levels, which either neglect changes in tides or consider them solely as a function of sea level rise. In this study, we employ a global high-resolution (1/12°) internal-tide permitting numerical ocean model to quantify future changes in ocean tides until 2100 as a result of upper-ocean warming and the concomitant increase in stratification. We simulate the evolution of leading tidal constituents in 5-year average time slices and use EC-Earth3P HighResMIP density data to constrain the model’s background stratification. As the Representative Concentration Pathway (RCP) in the EC-Earth3P simulation is a high greenhouse gas emission scenario (RCP8.5), we also consider data from a CM2.6 coupled global climate model, which is more closely aligned with a medium stabilisation scenario (RCP6.0).
Modelling the 10th century Eldgjá eruption in Iceland and revisiting evidence of its climatic and environmental impacts
Authors: Fuglestvedt Herman , Gabriel Imogen , Sigl Michael , Þórðarson Þorvaldur , Krüger Kirstin
Published: March 2024

The episodic eruption of Eldgjá in the 10th century stands as the largest basaltic flood lava eruption on Earth during the Common Era. The eruption released an estimated 200 Tg of sulphur dioxide into the atmosphere, a substantial emission that likely had severe impacts on the climate and environment. Various sources, including observations of haze over Europe, a minimum in tree ring temperature reconstructions, and suppressed flow of the Nile, suggest that the eruption had both regional and global effects.Petrological evidence from Iceland quantifies the sulphur and halogen emissions from the eruption site, and subsequent deposition is recorded in high-resolution Greenland ice cores. Additionally, recent analyses of Greenland cryptotephra have shed light on the eruption’s date and duration (Hutchison et al., JGR under revision).In combination, these constraints provide valuable information about the nature of the eruption, but they do not directly quantify its climate forcing or environmental effects. Furthermore, reconciling the petrological and ice core constraints with proxies of Eldgjá's impacts presents a puzzle.To bridge this gap, we constructed a plausible volcanic forcing, combining the most recent and available volcanology and ice core records, and used a fully-coupled Earth system model to simulate the Eldgjá eruption. We simulate the volcanic aerosol and atmospheric composition changes resulting from long-lasting, stratospheric and tropospheric emissions of sulphur, chlorine, bromine, and fluorine in a pre-industrial Earth system.Our results help improve our understanding of the climate effects of prolonged Icelandic eruptions, and offer clues about the potential effects of the Eldgjá eruption on the population and environment at the time. Finally, we discuss the model results with regard to uncertainties in the volcanic forcing, experimental set-up, and the available proxy data.
Why does it rain in the desert? The dust record in Tunisia.
Authors: Bird Anna , Millar Ian , Wagner Doris , Fenn Kaja , Smedley Rachel , Mauz Barbara , Mansoura Moez , Rogerson Michael , Luetscher Marc , Lone Mahjoor , Elmejdoub Noureddine
Published: March 2024

North Africa is one of the regions identified by UNESCO as experiencing severe water stress, and further drying could be devastating for region that is also insecure. Tropical semi-arid regions, such as North Africa are highly sensitive to climate change, and climate predictions for this area suggest that this region will experience drying in the next decades and centuries. This contrasts with findings from palaeo-studies which show that, during the Pleistocene, global warming often correlates to humid phases. This project uses speleotherm records with palaoedust (loess) archives to assess the climate record over humid and dry periods to improve our understanding of past climate change in the sensitive but under-represented central northern Africa region. This presentation will focus on findings from the most important loess deposit in northern Africa, at Matmata in Tunisia.The loess sections within the Matmata Plateau have loess and soil horizons relating to a series of humid and arid phases during the Quaternary, a sequence that provides valuable insight into the origins and dynamics of desert deposits and the interplay between continental and maritime weather systems. Previous work, in the 1990s, on the Matmata loess has shown onset of loess deposition to be during a humid phase (~70 ka) with loess deposition continuing as the climate becomes more arid into the Upper Holocene. It is currently assumed that the source of this material is the Grand Erg Orient, based on a relatively old study (1987). However, new OSL data presented here shows that the onset of loess deposition was much older than previously thought (~300 ka), with the top of the sections dated at ~24 ka. It appears that deposition was not continuous with a large gap in the record from 143 – 45 ka. Gaps in sedimentation for the section older than ~140 ka are difficult to determine due to limited reliability of older OSL ages.Provenance analysis has been undertaken on many of the dated samples to establish past transport directions. Detrital zircon U-Pb data suggest that there is dominant Algeria-type source with some input from the north. The amount of this input varies over time with samples older than 200 ka showing a larger input from the north. 87Sr/86Sr and 143Nd/144Nd isotopes from different grainsize fractions tell a similar story, with a dominant west African source.