bluuebunny/crossref_metadata_2025 huggingface dataset:
Major Factors Governing the Trends and Interannual Variability in the Occurrences of Mixed Rossby-Gravity Wave Events
Authors: Na Mehak , Keshri Shreya , Ettammal Suhas
Published: February 2023

Mixed Rossby-Gravity (MRG) Waves are westward propagating synoptic scale equatorial disturbances which play a crucial role in the formation of tropical cyclones and tropical depressions, and they constitute a significant part of various modes of tropical variability such as the Madden-Julian Oscillation (MJO) and Quasi-Biennial Oscillation (QBO). In this study, we have investigated the trends and Inter Annual Variability (IAV) in the occurrence of upper tropospheric MRG events using ERA-I reanalysis data for the period 1979-2018. The MRG events are identified by projecting the upper tropospheric meridional winds onto the theoretical spatial structure of MRG waves. A steady increasing trend is observed in the occurrence of MRG events which is contributed by the MRG events associated with the intrusion of extratropical disturbances. The possible factors that govern the observed trends and IAV in the occurrences of MRG events are El Nino Southern Oscillation (ENSO), MJO and extratropical forcing. The MRG events over the central and Eastern Pacific contribute maximum to the IAV. ENSO explains about 25% of the IAV. It exhibits a positive correlation with non-intrusion MRG events and a negative correlation with intrusion MRG events. These observations have been investigated by exploring the strength and the extent of the westerly duct at 200 hPa and the Outgoing Longwave Radiation (OLR) during El Nino and La Nina years over the central-Eastern Pacific ocean. The convectively active state of the MJO over the Western Pacific explains 20% of the IAV over the central-Eastern Pacific. Besides ENSO, MJO exhibits a diametrically opposite correlation with intrusion and non-intrusion MRG events. The antisymmetric heating with respect to the equator, associated with the MJO, enhances non-intrusion MRG events. The subtropical easterlies forbid the intrusion of extratropical disturbances, thereby lowering the occurrences of intrusion MRG events. The increasing trend in the intrusion of extratropical disturbances explains the observed trend in the upper tropospheric MRG events. Such an increasing trend is not observed in the strength or extent of the upper tropospheric westerly duct over the central-Eastern Pacific.
Coherent modes of coastal sea level variability from altimetry and tide gauge observations
Authors: Oelsmann Julius , Calafat Francisco M. , Passaro Marcello , Piecuch Chris , Richter Kristin , Wise Anthony , Landerer Felix , Katsman Caroline , Hughes Chris , Jevrejeva Svetlana
Published: February 2023

Sea level dynamics in the coastal zone can differ significantly from that in the open ocean. The presence of the continental slope, shallow waters and the coastlines give rise to a variety of processes that mediate the response of coastal sea level to open-ocean changes and produce distinct spatiotemporal sea level patterns. Yet how exactly this interplay occurs and, more importantly, the extent to what coastal sea level variations differ from open-ocean variability remain poorly understood. In this work, we use coastal altimetry observations in combination with tide gauge data to determine patterns of coherent coastal sea level variations and the degree of decoupling between such variations and open-ocean changes.In a first step, we apply Bayesian mixture models to identify clusters of correlated tide gauge observations that explain a significant fraction of the coastal sea level variability. Using altimetry data, we find high regional coherency of along-shore coastal sea level variations, indicating common underlying mechanisms that cause these correlations.In light of previous research, we confirm that the correlation structures of these coherent patterns are often confined to the continental slopes, particularly in extratropical regions. In regions like the northeastern US continental shelf, correlations decrease with increasing water depth, indicating a decoupling of shelf sea and open-ocean variability. We investigate how these differences between coastal and open ocean sea level variations change as a function of time scale, i.e., from monthly or interannual variations to long-term trends, and validate these results against tide gauge observations. We derive across-shore correlation length scales that provide insights into the space scales of coastal sea level dynamics and are useful to understand how well gridded products can resolve such processes.We discuss possible causes of the coherent sea level fluctuations, such as wind forcing, coastally trapped waves, and large scale climate modes. The results motivate further research to better understand the driving mechanisms behind these coherent sea level variations, as well as the pathways linking remote forcing to coastal changes.
The impact of AMOC weakening on the global monsoon in EC-Earth3 water hosing simulations
Authors: DAgostino Roberta , Bellomo Katinka , Meccia Virna
Published: February 2023

Changes in Atlantic Meridional Overturning Circulation (AMOC) affect tropical precipitation through the coupling with the Hadley Circulation and cross-equatorial atmospheric heat transport. Climate model simulations project a possible weakening of the AMOC under global warming. Here, we run model experiments with EC-Earth3 where we artificially weaken the AMOC through the release of a freshwater anomaly at high latitudes. The simulated AMOC collapse of ~57% for 60 model years allows us to investigate atmospheric heat and circulation readjustment to AMOC weakening and impacts on tropical precipitation, including the global monsoon. We find that the Inter Tropical Convergence Zone (ITCZ) shifts equatorward and tropical precipitation decreases over its northern flank while it increases southward due to reduced northward oceanic heat transport. Global monsoon is also impacted by AMOC weakening: Northern/Southern Hemisphere monsoons are weaker/stronger than the control experiment, with different sensitivities according to different regions: monsoons systems in the Atlantic sector are strongly impacted by AMOC decline. We further explore interbasin anomalies in the zonal/meridional atmospheric heat transport and net energy input triggered by the AMOC decline by examining local Hadley and Walker circulation asymmetries. Given that a ~57% reduction in the AMOC strength is within the inter-model range of future projections by the end of the 21st century, our results have important implications for understanding the role of AMOC in future tropical precipitation response. 
Mapping vegetation cover on rewetted fen peatlands using hyperspectral spaceborne images from DESIS and PRISMA
Authors: Muthusamy Arasumani , Thiel Fabian , Pham Vu Dong , Hellmann Christina , van der Linden Sebastian
Published: February 2023

Undisturbed peatlands constitute relevant carbon sinks. However, drained or degraded peatlands cause carbon emissions and more than 90 % of the peatlands in Mecklenburg-Western Pomerania, Germany, have been drained. In order to achieve the goals for climate change mitigation, several initiatives have been taken to restore drained and degraded peatlands by rewetting. Previously, drained peatlands were used for agricultural and grassland production, which led to significant carbon emissions. The Paludiculture scheme was introduced to allow sustainable and climate-friendly agricultural production under permanently wet conditions, which allow carbon sequestration of the soil. Phragmites australis (Reed) and Typha spp. (Cattail) are key plants for paludicluture in rewetted areas of north-east Germany.It is necessary to regularly monitor the plant communities in rewetted areas, as this can be an indicator of rewetting success. Distinguishing peatland vegetation communities require high spectral resolution images, whereas multispectral images may show comparable spectral signatures in different peatland vegetation types. Recently launched hyperspectral sensors offer new possibilities regarding accurate vegetation monitoring in rewetted peatlands. In this study, we investigated multi-date hyperspectral images from DESIS, mounted on the International Space Station (ISS), and satellite-based PRISMA for peatland vegetation mapping. In addition to the increased spectral information, both sensors allow multiple observations per year, which was not the case for airborne hyperspectral data. The 30-m spatial resolution of both sensors, however, brings along multiple peatland vegetation communities within single pixels; hence we used a sub-pixel classification strategy using a Regression-based unmixing approach with synthetic training data. Our analyses focussed on the influence on map accuracy by i) the hyperspectral information and ii) the observation dates. We observed that combining April and June PRISMA (MAE = 16.4%) and April and June DESIS (MAE = 17.3%) datasets produced the best results for mapping the peatland vegetation fractions. Analysis of single dates showed that June data leads to slightly better results than April. We found that PRISMA images produced slightly better results than DESIS, which may be caused by the shortwave infrared information missing in the DESIS data. In contrast, DESIS has only visible and near-infrared bands (400-1000 nm) despite having a higher spectral resolution (2.55 nm) than PRISMA (10 nm). In conclusion, the hyperspectral information, especially from the short wave infrared > 1 µm, together with the multi-date observation could be shown to contribute to sub-pixel mapping accuracy. In the future, PRISMA and DESIS images can be coupled with EnMAP and the forthcoming SBG and CHIME missions to further improve the space-borne monitoring of rewetted peatlands.
Retrieval and validation of global tropospheric nitrogen dioxide (NO2) vertical profiles obtained via cloud-slicing TROPOMI partial columns
Authors: Horner Rebekah , Marais Eloise , Wei Nana
Published: February 2023

Observations of the vertical distribution of nitrogen oxides (NOx ≡ NO + NO2) in the troposphere are severely limited, despite its influence on ozone formation. Here, we derive vertical profiles of the NOx component NO2 by applying cloud-slicing to partial columns of NO2 from the space-based TROPOMI instrument. This yields seasonal means of NO2 volume mixing ratios at ~100 km resolution for multiple years (March 2018 to February 2022) on a global scale in the upper troposphere (180-320 hPa and 320-450 hPa), the middle troposphere (450-600 hPa and 600-800 hPa) and the boundary layer (800 hPa to the Earth’s surface). We evaluate our product against in situ NO2 measurements from NASA DC-8 aircraft campaigns over Canada (ARCTAS, ATom, INTEX-A), the Eastern US (ATom, SEAC4RS, INTEX-A), the North and South Atlantic (ATom), and the Central and South Pacific (ATom) and use our validated dataset to assess state-of-knowledge of global tropospheric NOx as simulated by GEOS-Chem.  In the middle troposphere, cloud-sliced NO2 has a mean value of 20-40 pptv and deviates by < 5 pptv where NO2 from aircraft observations exceeds the instrument detection limit. The consistency between cloud-slicing results and aircraft observations here is due to high sampling frequency and ideal conditions for cloud-slicing. Differences with aircraft observations are larger (up to 120 pptv) in the upper troposphere between 320-180 hPa where aircraft observations may be susceptible to biases and where cloud-sliced NO2 data are relatively sparse. In the boundary layer, retrievals consistent with the aircraft observations are only possible over marine environments where NO2 concentrations differ by < 35 pptv compared to > 450 pptv over terrestrial regions. This is because large land-based NOx sources cause steep vertical NO2 gradients that are problematic for cloud-slicing which assumes NO2 is well mixed throughout the troposphere. We find that NO2 concentrations above the Eastern US differ by < 20 pptv when comparing cloud-sliced tropospheric vertical profiles to simulated vertical profiles from the GEOS-Chem chemical transport model. However, GEOS-Chem consistently underestimates concentrations of NO2 in the remote troposphere, simulating concentrations that are 50% less than the mean cloud-sliced NO2 observations. This is a result of the limited number of current NO2 observations used to validate models like GEOS-Chem which are limited in both time and space. By deriving tropospheric vertical profiles from cloud-slicing satellite observations there is an opportunity to obtain routine NO2 observations which can then be compared to aircraft measurements and simulations from the GEOS-Chem model. From this, we can determine the environmental factors that impact tropospheric NOx on a global scale and address long-standing uncertainties in our understanding of NOx in the troposphere.
Diurnal and seasonal variations of clouds in the Tharsis Montes region of Mars using the Emirates eXploration Imager (EXI) observations
Authors: Yousuf Maryam , Osterloo Mikki , Edwards Christopher
Published: February 2023

Observations of clouds on Mars have long been studied to understand activity and the Martian water cycle. The Martian volcanoes have been shown to have associated cloud formations such as the Aphelion Cloud Belt (ACB) (Wolff et al., 2022), Orographic Clouds (Benson et al., 2006), and Perihelion Cloud Trails (Clancy et al., 2021). Previous studies provide insights into how these clouds appear and contribute to the atmosphere. The objective of this study is to provide a catalog of the life cycle of clouds observed by Emirates eXploration Imager (EXI) spatially (longitude, latitude) and temporally (Solar Longitude (Ls), local time) using the following wavelength channels 635nm (red), 546nm (green), 437nm (blue) and 320nm (ultraviolet which can be used to retrieve the water ice optical depth). To undertake this study, we identified the volcanic region (Olympus Mons and Arsia Mons) as the study region due to cloud presence in the area throughout the Martian year.  EXI is a camera on board the Emirates Mars Mission (EMM) – Hope Probe. EXI acquires 12-megapixel images and has sufficient radiometric calibration for detailed scientific analysis (Jones et al., 2021). It was developed to better understand several critical constituents (e.g., dust, water ice clouds, etc) geographic and diurnal distribution in the lower atmosphere (Jones et al., 2021). We will present the results of our database for clouds for Mars year 36. Benson, J., James, P., Cantor, B., & Remigio, R. (2006). Interannual variability of water ice clouds over major martian volcanoes observed by MOC. Icarus, 184(2), 365–371. https://doi.org/10.1016/j.icarus.2006.03.014Clancy, R. T., Wolff, M. J., Heavens, N. G., James, P. B., Lee, S. W., Sandor, B. J., Cantor, B. A., Malin, M. C., Tyler, D., & Spiga, A. (2021). Mars perihelion cloud trails as revealed by MARCI: Mesoscale topographically focused updrafts and gravity wave forcing of high altitude clouds. Icarus, 362, 114411. https://doi.org/10.1016/j.icarus.2021.114411Jones, A. R., Wolff, M., Alshamsi, M., Osterloo, M., Bay, P., Brennan, N., Bryant, K., Castleman, Z., Curtin, A., DeVito, E., Drake, V. A., Ebuen, D., Espejo, J., Farren, J., Fenton, B., Fisher, C., Fisher, M., Fortier, K., Gerwig, S., . . . Yaptengco, J. L. (2021). The Emirates Exploration Imager (EXI) Instrument on the Emirates Mars Mission (EMM) Hope Mission. Space Science Reviews, 217(8). https://doi.org/10.1007/s11214-021-00852-5Wolff, M. J., Fernando, A., Smith, M. D., Forget, F., Millour, E., Atwood, S. A., Jones, A. R., Osterloo, M. M., Shuping, R., Al Shamsi, M., Jeppesen, C., & Fisher, C. (2022). Diurnal Variations in the Aphelion Cloud Belt as Observed by the Emirates Exploration Imager (EXI). Geophysical Research Letters, 49(18). https://doi.org/10.1029/2022gl100477
Ground motion simulation of the 2021 Mw 5.2 Central Adriatic earthquake
Authors: Latečki Helena , Molinari Irene , Stipčević Josip
Published: February 2023

In the last few decades, several series of earthquakes in the Central Adriatic Sea have been detected and analyzed, indicating the complexity of the tectonics within the Adriatic microplate. The most recent earthquake series suggests higher seismic potential than what was previously assumed and opens questions regarding present-day tectonic stress distribution within the Adria microplate in general. Therefore, studying seismic activity and identifying active faults is crucial when it comes to better understanding of the seismotectonics of this area, and consequently, improvement of the seismic hazard estimation. In this work we focus on the Mw 5.2 March 27, 2021 earthquake which occurred in the Central Adriatic Sea close to the island of Vis (Croatia). To evaluate the expected ground motion parameters of the event, we make use of physics-based waveform modelling. We simulate the earthquake using a newly defined 3D crustal model which honors surface topography, reflects main geological features and is embedded within the existing regional crustal model EPCrust. We compute broadband seismograms by making use of the hybrid approach where low-frequency and high-frequency parts are obtained separately and then combined into a single time series. We compare simulated waveforms against the recorded data and validate our results by assessing the goodness of fit for different ground-motion metrics. We then focus on simulating the waveforms using different descriptions of the source in order to investigate how its parametrization affects final results. This allows us to get a better understanding about the physical properties of the driving forces and mechanisms responsible for the seismicity in this region.
Harmonizing Agricultural Long-Term Experiments data through A Geospatial Infrastructure
Authors: Dönmez Cenk , Hoffmann Carsten , Svoboda Nikolai , Hierold Wilfried , Specka Xenia
Published: February 2023

Long-Term Field Experiments (LTEs) are agricultural infrastructures for studying the long-term effects of different management practices and soil and crop properties in changing climate conditions. These experiments are essential to examine the impact of management and environment on crop production and soil resources on different soil textures and types. Some of those LTEs have average times of 20-50 years, even more than 100 years. These infrastructures are thus scientific heritages with high values of agricultural data; however, LTE-related information was difficult to find since it was scattered. To close this gap, we developed a geospatial data infrastructure, including an LTE overview map to compile and analyze the meta-information of the LTEs across Europe. The map provides a spatial representation of LTEs and the meta-information collected by extensive literature review and factsheets clustered in different categories (management operations, land use, duration, status, etc.) (BonaRes 2021; Grosse et al. 2021; Donmez et al., 2022). A threshold filter with a minimum duration of 20 years was applied, which results in a total of 500 LTEs across Europe and included into the map. The clusters of LTEs were geospatially analyzed to provide inputs for the agricultural sector, scientists, farmers and policy-makers. The fertilization treatment was the major research theme of collected and studied LTEs, followed by crop rotation and tillage trials. Bringing the meta information of dispersed LTEs through the development of the LTE overview map is expected to help developing a mutual management framework of efficient agricultural production by revealing the LTE potential internationally. This will contribute to scaling up the agricultural practices from site to landscape level for increasing the climate change adaptation to agricultural yield and management.
Inclusion of biochar hydrological properties in a C dynamic model with field data
Authors: Vaccari Maria Caterina , Pesce Simone , Balugani Enrico , Volta Antonio
Published: February 2023

Biochar is considered one of the most promising tools to increase soil organic carbon (SOC) sequestration to achieve IPCC climate change targets. Research on the effect of biochar on soil carbon dynamics and its indirect effect on soil moisture through models that need to be extended, tested and validated with long term experiments.Our work aimed at providing a starting point through the integration of two models: Criteria 1D and RothC to account the indirect effect of biochar on SOC due to changes in soil hydrological properties. In order to account the indirect effect of biochar on soil moisture, we modified the RothC-Biochar (Pulcher et al 2022), a modified version of RothC that account the biochar priming effect and biochar recalcitrance properties, modifying the calculation of Total Soil Moisture Deficit (TSMD), a parameter related to soil moisture in RothC, through the relation between TSMD and θ (soil water content) suggested in Farina et al 2013.Thus, we ran the CRITERIA 1D agrometeorological model to estimate the Van Genuchten water retention curve parameter from a multi-year field experiment (2017-2022) in a vineyard in Tebano (Ravenna, Italy), to estimate θ from field.Since 2017 in Tebano we applied biochar produced from vine clippings and pruning residues. We installed sensors for weather and soil moisture between plots in 2019, with 5TE probes we monitored soil moisture, temperature and conductivity and with MPS1 probes soil matrix potential.We applied a correction on the parameters that regulate the Van Genuchthen water retention curve function in CRITERIA 1D to account the effect of biochar on soil hydraulic properties. Then we compared the data obtained from the field probes with Criteria outputs to verify that the applied correction was accurate; finally, we use the Criteria results as input for RothC-Biochar.The simulation with the modified RothC-Biochar models suggests that applying biochar on agricultural field would result in an increase of 2 tC ha-1of native SOC after 4 years compared to a bare soil due to indirect effect of biochar on soil moisture. 
Trends in subtropical marine low-level cloud cover from 2007 to 202
Authors: Tesche Matthias , Bruder Sina
Published: February 2023

Marine low-level clouds play an important role in the Earth's energy budget. They reflect large amounts of incoming solar radiation that would otherwise heat the Earth's surface. Areas of persistent low-level stratocumulus clouds cover the subtropical eastern oceans where lower-tropospheric stability is high. Based on spaceborne lidar measurements, which allow to precisely identify clouds at different altitudes, we find that low-level cloud cover of Peruvian, Namibian, and Californian stratocumulus decreased by between 0.05 and 0.10 per decade between 2007 and 2021. A seasonally resolved analysis gives even stronger trends for those seasons in which low-level cloud cover is highest. No trend is found for Australian and Canarian stratocumulus. The decrease in low-level cloud cover is strongly tied to increasing sea-surface temperatures. Our analysis suggests statistical significant reductions in albedo for Namibian and Californian stratocumulus of 0.11 and 0.05, respectively, per 0.10 decrease in low-level cloud cover. Such changes will have a direct impact in the Earth's energy budget by reducing the cooling effect of major marine stratocumulus sheets.
Large Eddy Simulations of aerosol-cirrus interactions
Authors: Purseed Jhaswantsing , Bellouin Nicolas
Published: February 2023

The climate impacts of global aviation include CO2 effects and their so-called non-CO2 effects. Amongthose non-CO2 effects, the effects of aerosol-cirrus interactions are the least understood and the latestassessment of aviation radiative forcing could not give a best estimate and an uncertainty range [1]. Previousstudies [2, 3] have shown that a perturbation to the ice crystal number leads to a change in cirrus lifetimeand ice water path. In this talk, we investigate whether aerosol perturbations to ice nucleation can producelarge perturbations to cirrus ice crystal number.We study these interactions using the 3D Met-Office NERC Cloud model (MONC). MONC is a Large EddySimulation model coupled to the cloud micro-physics scheme, CASIM. We simulate two types of cirrus namelythe Gravity Wave cirrus (GW) and the Warm Conveyor Belt cirrus (WCB). The GW cirrus is thicker witha higher ice crystal number concentration (ICNC) compared to the WCB cirrus, which is consistent withaircraft observations [4]. We find that perturbing the formation stage of the cirrus cloud by injecting solubleaerosols leads to an increase in ice crystal number and a decrease in the initial crystal size. Furthermore,the ice clouds created in the presence of the injected soluble aerosols tend to have a higher ice water contentand an increased lifetime. Both GW and WCB cirrus clouds behave similarly to perturbation by solubleaerosols at the formation stage.In contrast, perturbing a pre-existing cirrus with soluble and insoluble aerosols does not change the propertiesof the ice cloud. Ice crystal growth by vapour deposition uses available water vapour during the lifetime ofthe cirrus [5, 6], which we find comes at the expense of activating aerosols that would lead to an increasein the ICNC. Hence, although cirrus clouds would be sensitive to a perturbation in their ice crystal numberconcentration, it is difficult to obtain such perturbations by injecting aerosols at cloud level, for example fromcommercial aircraft exhaust. Furthermore, even though these results do not completely preclude large cirrusperturbations from aviation aerosols in specific cases, they suggest that the corresponding global radiativeforcing is small.References[1] Lee et al. Atmospheric Environment. (2021). [2] Verma & Burkhardt. Atmospheric Chemistry and Physics. (2022).[3] Gilbert et al. In preparation. (2022).[4] Li et al. Atmospheric Chemistry and Physics Discussions. (2022).[5] Hill et al. Quarterly Journal of the Royal Meteorological Society. (2014).[6] Lohmann & Feichter. Atmospheric Chemistry and Physics. (2005).
An artificial intelligence reconstruction of global gridded surface winds
Authors: Zhou Lihong , Liu Haofeng , Zeng Zhenzhong
Published: February 2023

Wind speed data is widely used in climate-related studies and the renewable energy industry for, say, describing climate phenomena, doing attribution analysis and assessing energy resources. In-situ weather stations, reanalysis products and climate model simulations are the three primary wind data sources. Due to direct observations, in-situ weather stations show higher accuracy, especially on wind speed trends. Still, their fatal drawback is the data inhomogeneity in both spatial and temporal caused by the sparsely distributed stations and discontinuous observation records. Climate models and reanalysis products realize continuity but hardly reproduce observed wind speed trends. In this study, we use an artificial intelligence algorithm, the partial convolutional neural network (PCNN hereafter), to recover spatial-temporal gaps in in-situ weather observations. We demonstrate that PCNN can restore wind speed data and can work when 88% missing values exist. We then apply the PCNN-based model to generate a globally gridded monthly wind speed dataset (GGWS-PCNN) with a resolution of 1.25°×2.5° (latitude×longitude). This dataset is based on the in-situ observations from the HadISD dataset and assimilates wind patterns and physical laws from 34 CMIP6 climate models (128 ensembles). It allows us to investigate global wind-related phenomena, e.g., the "stilling" and "reversal" of terrestrial wind speed.Keywords: Wind speed reconstruction; Artificial Intelligence; Global dataset; In-situ observations; Climate model outputs
A exhaustive dataset of Sentinel-1 observations and derived information on the Mediterranean Sea
Authors: Colin Aurélien , Fablet Ronan , Husson Romain , Peureux Charles , Tandeo Pierre
Published: February 2023

The satellites of the Copernicus program routinely acquire data over the ocean. In particular, the Sentinel-1 mission carries a Synthetic Aperture Radar. This instrument, when used over the ocean surface, is able to estimate the sea surface roughness, which is affected by several meteorological and oceanic processes such as wind speed, rainfall, convective activity, or changes in surface viscosity due to pollution or biological slicks. Sentinel-1A and Sentinel-1B were launched in 2014 and 2016, respectively, and although Sentinel-1B has been out of commission since December 2021, Sentinel-1C is planned for launch in 2023. Between 2014 and 2022, around 102k wide-swath observations (with a width of approximately 250 km) have been acquired over the Mediterranean Sea, with a resolution of 10 by 10 meters. In parallel, deep learning models dedicated to the segmentation of SAR observations have been developed. Open Sentinel-1 datasets have recently been published [1,2], which enable the acceleration of research by sharing this time-consuming dataset gathering task.We therefore present the Mediterranean Sentinel-1 dataset. It contains the observations as well as their inferences by deep learning models. The segmentation maps produced include the detection of convection cells, the delineation of biological slicks, the estimation of rainfall, and the estimation of wind speed, built to reduce rain-induced errors. We show that the detection of biological slicks from Sentinel-1 shows similarity with Sentinel-3 ocean color, highlighting the synergies between both sensors. The concentration of biological slicks can indicate gyres and is demonstrated to be affected by ship traffic. The estimation of rainfall obtained from a previous study [3] is compared with European weather radar, indicating good agreement.[1] Wang, C., Mouche, A., Tandeo, P., Stopa, J., Longépé, N., Erhard, G., Foster, R., Vandemark, D., & Chapron, B. (2018). Labeled SAR imagery dataset of ten geophysical phenomena from Sentinel-1 wave mode (TenGeoP-SARwv) [Data set]. SEANOE. https://doi.org/10.17882/56796[2] Huang, L., Liu, B., Li, B., Guo, W., Yu, W., Zhang, Z., & Yu, W. (2018). OpenSARShip: A Dataset Dedicated to Sentinel-1 Ship Interpretation. In IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (Vol. 11, Issue 1, pp. 195–208). Institute of Electrical and Electronics Engineers (IEEE). https://doi.org/10.1109/jstars.2017.2755672[3] Colin, A., Tandeo, P., Peureux, C., Husson, R., Longepe, N., & Fablet, R. (2022). Rain Rate Estimation with SAR using NEXRAD measurements with Convolutional Neural Networks (Version 1). arXiv. https://doi.org/10.48550/ARXIV.2207.07333
Reconstruction of precipitated electron fluxes using auroral data
Authors: Robert Elisa , Barthelemy Mathieu , Cessateur Gael , Woelffle Angélique , Lamy Hervé , Bouriat Simon , Johnsen Magnar Gullikstad , Brändstörm Urban , Biree Lionel
Published: February 2023

Precipitations of auroral electrons characterize the relationship of the magnetosphere and the upper atmosphere, therefore state of near-Earth space depending on their localization and their intensity. One of the main gaps in both data and modelling is the monitoring of the precipitation of low-energy (0.02 – 35 keV) particles in the ionosphere. These particles are responsible of the surface charging on satellites, which lead to trigger electrostatic discharge (ESD) on components. This impact is the most recurrent in space and need to better understand. The method present here, allows an alternative to particle detectors that do not have access to this area.
From optical data, it can be very interesting to reconstruct low energy electron flux in the aurora region. Therefore, the interpretation of the auroral intensities is made using the Transsolo code, a kinetic code which use as input the electron flux and the solar EUV flux on the dayside. It calculates the transport of the suprathermal electrons along a line of sight or a vertical and the subsequent auroral emissions. A optimization method is worked to trying to retrieve electron flux from optical measurements.
The study present here is based on ALIS network data which provides very useful data (Brandstorm, 2003). Tomographic data of the volume emission rate are built from ALIS measurements (Gustavsson, 2000). From tomographic data and transsolo simulations, we adapt the optimization method to reconstruct energetic particles flux. We focus on measurements of the event of 05 March 2008 at 18:41:30 UT and 18:42:40 UT acquired by 5 stations and centred above Skibotn city. Results are presented in the form of maps of mean energy and total energy (corresponding to the energy flux) depending on geographic coordinates. 
Thickness estimation of CO2 transition layer using a deep learning
Authors: Jang Seonghyung , Lee Donghoon , Kim Byoung-Yeop
Published: February 2023

After CO2 injection into a reservoir, the behavior of CO2 depends on permeability, porosity, cap rock, reservoir fluids, CO2 characteristics, pressure gradient, and buoyancy effects. Therefore, the thickness of the reservoir is an essential parameter for CO2 monitoring. In the case of reservoir thickness prediction, it is practical to consider a geological reservoir as a transition zone in which the physical properties linearly change. In the transition zone, the seismic reflections in the stack section are the normal incident reflection coefficient with continuously changing velocity. Since this is composed of a function of the velocity ratio of the upper and lower layers, frequency, and transition zone thickness, the seismic signals apply to predict the thickness of the reservoir layer. In this study, we use the frequency characteristics with time-varying to estimate the thickness of the transition zone. First, we prepare the time-frequency spectrum with various thicknesses and then analyze it through deep learning to determine an optimum reservoir thickness. We use a convolution neural network (CNN) for predicting the transition zone thickness, which has two more hidden layers in the feature extractions. Unlike the fully connected layer, CNN is composed of a convolutional layer and a pooling layer and requires many data to prevent overfitting. Since CNN can efficiently process nonlinear data, it is applied to image classification and argumentation. For the numerical modeling experiment, we prepared a geological model in which the velocity of the shale layer (3000 m/s), cap rock, is greater than the lower sandstone layer (2200 m/s). We verify variation of phase and amplitude according to various transition zone thicknesses. For example, when the thickness is 10 m, it shows the phase changes at 65 Hz, and the amplitude decrease with increasing frequency. For the thickness of 50 m, the phase changes at the cut-off frequency of 13 Hz, and the amplitudes decrease until 25 Hz, increasing and decreasing repeatedly. We suggest that CNN is one of the methods to predict the thicknesses of CO2- injected reservoir using a time-frequency spectrum with various thicknesses.
Factors influencing sub-seasonal forecast skill of Greenland Blockings
Authors: Osman Marisol , Grams Christian M. , Beerli Remo
Published: February 2023

Greenland blocking (GL) resembles the negative phase of the NAO and features a strong positive Z500 anomaly over Greenland and a zonally aligned negative anomaly stretching from the eastern North Atlantic into Northern Europe. The prevailing westerly flow is then deflected southward and extends into the Mediterranean. It causes melting events of the Greenland Ice Sheet which can impact global sea-level rise and has strong downstream impacts on Europe. It occurs year-round, although is more common in winter (11.7%) compared to summer (9.1%). GL is forecast with good ability by S2S models. This skill is driven by the performance in winter, when GL is persistent. In this study, we explore whether the skill of GL blocking can be linked to external meteorological drivers or the prevalence of specific meteorological features. Re-forecasts using the European Centre for Medium-Range Weather Forecasts for the 1999-2019 period are considered and compared against ERA Interim reanalysis over the same period. We focus on the factors affecting the skill, as depicted by the Brier Skill Score, from lead times 6 to 10 days, where the skill is 30% to 70% smaller than the skill at lead time 1 day.Results show that most of the GL blocking events associated with low skill occur in spring. In this season, the model fails in forecasting the transition from Scandinavian Blocking to Greenland Blocking, in opposition to the rest of the seasons, when this transition is well predicted. The analysis of the role of large-scale processes that affect GL skill reveals that half of the forecasts of GL events initialized up to 30 days after a sudden stratospheric warming shows poor skill. In addition, the forecasts of GL events initialized with an active MJO in phase 6 and 7 present good skill whereas those forecast GL events initialized during an active MJO in phase 2 to 4 show poor skill. This link between large-scale factors and skill offers potential guidance in operational forecasting.
Lessons learned from the spatiotemporal analysis of long-term and time-variable young water fractions of large Central European catchments
Authors: Stockinger Michael , Stumpp Christine
Published: February 2023

The travel time of precipitation entering a catchment and leaving it as streamflow varies according to the flow paths it takes, with fast travel times posing a high risk to river water quality. However, investigating influences on travel times is challenging due to the complex water flow through heterogeneous landscapes. Recent studies investigated the fraction of streamflow younger than approximately three months (Fyw) using multi-year data (long-term Fyw) or one-year calculation windows to investigate its time-variability (time-variable Fyw). Nonetheless, the influences on time-variable Fyw and the demarcation between long-term and time-variable are not clear yet. Here, we investigated the long-term, the time-variable, and the Fyw derived from an exponential TTD model of nine major catchments in Central Europe and compared them to catchment characteristics and hydrometeorological variables. Additionally, one- to eight-year calculation windows were used and its impact on the variability of time-variable Fyw was investigated. All three methods of estimating Fyw led to similar results, indicating spatial organization of water flow in Central Europe. Spatial analysis further indicated a negative relationship between Fyw and catchment altitude. Contradicting and lacking spatiotemporal relationships to other investigated variables pointed to possibly unknown, region-specific influences on Fyw. With increasing calculation window size, the variability of time-variable Fyw results decreased. Long-term Fyw depended on the method used to define “long-term”, and many time series related factors, beside the actual target of investigation, i.e., catchment water flow, impacted Fyw. This finding points to difficulties in comparability of studies and catchments when using different window sizes, and we thus recommend future studies to calculate long-term Fyw using all data and one- to several-year time-variable Fyw to facilitate comparability.
Investigation of air emissions’ characteristics in the southeast part of Korea to create modeling emission inventories for PM2.5 predictions
Authors: Kim Hyeon-Kook , Kang Yeri , Song Chang-Keun
Published: February 2023

Reliable results for the fine particulate matter (PM2.5) predictions are very useful for air policy establishment to reduce air pollution and adverse health effects caused by PM2.5. To this end, it is necessary to establish reliable emission input data for air quality models based on air pollutants' emission inventory data. In this study, we examine the characteristics of major air pollutants emitted from various emission sources in the southeast region in Korea, one of the four regions being recognized as the air pollution is serious, using a gathered information on recent 10-year's air emissions. In addition, we search the points to be carefully considered for the development of the detailed modeling emission inventory necessary for the reliable predictions of PM2.5 in the Southeast region. AcknowledgementsThis research was supported by the FRIEND (Fine Particle Research Initiative in East Asia Considering National Differences) Project through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (Grant No.: 2020M3G1A1114615).Correspondence to: Chang-Keun Song (cksong@unist.ac.kr)
Assessment of Quaternary variations of the drainage pattern through morphotectonic investigations in Piedmont (North-western Italy)
Authors: Buleo Tebar Victor , Bonasera Mauro , Racano Simone , Fubelli Giandomenico
Published: February 2023

Drainage network systems are one of the more responsive elements to recent active tectonic from among all the topographic features. Their anomalies can be significant in areas with high relief energy or less noticeable where intense deposition rates might make capable tectonic signatures not visible. In addition, surface processes are even dominated by changes in climate. Since landscape evolution is the result of the combination of these elements, drainage network systems represent a key element for understanding the role and importance of different factors involved in the processes during Quaternary that have led to the formation of the current relief.The study area comprises two different zones in Piedmont region (North-Western Italy): the Western Po Plain and the Langhe and Monferrato hills, both located in a complex tectonic framework at which a juxtaposition on a crustal scale between Alpine metamorphic Units and the Ligurian Units of the Apennines takes place. A multi-disciplinary approach is proposed combining geomorphology and geostatistics, with the aim of obtaining a better understanding and knowledge of various aspects of the Quaternary evolution of the area on a regional scale.A morphometric analysis was carried out based on 5 m resolution DEM supported by geological and geomorphological field surveys. To assess the changes in the river network’s direction a quantitative geomorphic analysis of river pattern has been performed through Geographic Information System (GIS) and MATLAB® tools. Different parameters were calculated with the aim of detecting anomalies and the estimation of local uplift and different erosion rates.  Following the extraction of longitudinal river profiles, calculating Normalized Channel steepness index (Ksn) has been possible for assessing river incision, based on local channel slope, contributing drainage area and some other characteristics related to incision processes and basin hydrology. This step has also allowed the identification of knickpoints whose presence represent a deviation of steady-state streams condition and hence a transient phase of potentially landscape changes.  These anomalies are present whether they were produced by tectonic deformation or by different factors. In addition, a paleotopographic reconstructions of Pleistocene deposits have allowed the estimation of the thickness of the deposits and the reconstruction of the river patterns during this period.Preliminary results have provided relevant evidence of potentially recent and important changes in the regional drainage network of Western Po Plain resulting from the combination of tectonic activity during the Early Pleistocene and the climatic variation from the Middle and Late Pleistocene.
Modeling two high-temperature aquifer thermal energy storage cases under uncertain geological frameworks
Authors: Dashti Ali , Grimmer Jens C. , Geuzaine Christophe , Kohl Thomas
Published: February 2023

High-Temperature Aquifer Thermal Energy Storage (HT-ATES) manages the temporal mismatch between heat supply and demand periods. Up to 50 % of consumed energy by residents of metropolitans can be provided through this huge underground battery systems. This study evaluates risks and effects of geological structures for two HT-ATES candidates designed close to populated areas in central Europe. DeepStor, as the first example, is designed to store surplus heat in Meletta beds beneath the campus of the Karlsruhe Institute of Technology (KIT). A synthetic sealing fault is embedded in real topology of the Meletta beds to numerically simulate the temperature and pressure under such structural feature. The synthetic fault is relocated 16 times in the geological model and proved to only increase the pressure value up to 7 % in comparison to fault-free (base case) realization. The real tilted morphology of Meletta beds revealed that hot temperature tends to accumulate in the western side of the model while pressure increase is more notable in the reverse side, i.e. down dip. A simple function fitted to the pressure change and fault to well distance shows acceptable levels of reliability. Another showcase designed for the Greater Geneva Basin confirmed the insensitivity of the temperature and pressure to surfaces morphology of the Malm reservoir with 100 m thickness. Despite modulating the top and bottom contacts of the Malm from flat planes to randomly rugged surfaces, the results remain the same. The upper and lower surfaces are moved ± 8 and ± 10 m, respectively. This insensitivity indicates the local natures of the induced thermal regime in thick reservoirs and dispensability of some expensive exploration campaigns like 3D seismic.
Historical analysis of global distribution of and trends in wind droughts
Authors: Antonini Enrico , Virguez Edgar , Ashfaq Sara , Duan Lei , Ruggles Tyler , Caldeira Ken
Published: February 2023

Wind droughts, or prolonged periods of low wind speeds, can be a severe issue for electricity systems that are largely reliant on wind generation. Therefore, it is important for energy system planning to understand the depth and distribution of wind droughts and their trends over time. In this study, we analyze the ERA5 weather reanalysis from 1979 through 2021, using an energy deficit metric that integrates the depth and duration of wind droughts over an annual temporal scale. Our analysis shows that the most severe wind droughts in many places occurred well before wind power generation started to penetrate power systems. This prevalence of wind droughts in the historical record, combined with little evidence for strong trends in their prevalence, suggests a statistical analysis of weather reanalysis products could provide valuable guidance in designing electricity systems reliant on wind power that are robust to wind droughts.