bluuebunny/crossref_metadata_2025 huggingface dataset:
Ocean Eddy-rich Climate Simulation with IFS-FESOM
Authors: Ghosh Rohit , Cheedela Suvarchal K , Koldunov Nikolay , John Amal , Streffing Jan , Müller Vasco , Beyer Sebastian , Rackow Thomas , Sidorenko Dmitry , Danilov Sergey , Jung Thomas
Published: March 2024

Efforts to enhance climate model simulations by achieving higher resolutions to explicitly capture sub-grid scale processes constitute a central objective in contemporary climate modeling. In this pursuit, our focus is on resolving a pivotal element of the climate system—the ocean meso-scale eddies. At the Alfred-Wegener-Institute, we are working towards this objective by employing the ocean-sea ice model FESOM at approximately 5km horizontal resolution (NG5), coupled with the atmospheric model IFS at a 9km horizontal resolution (tco1279).This presentation showcases preliminary results from the control simulations of IFS-FESOM under 1950 radiative conditions. Furthermore, we provide an initial glimpse into results from a historical simulation starting in 1950 with the same model configuration. Our analysis illuminates how ocean eddy-rich regions are portrayed in our simulations relative to observations. We delineate the changes and improvements in key climate components, encompassing North Atlantic/Southern Ocean temperatures, NAO, atmospheric blocking, midlatitude storm tracks, ENSO, Monsoon, ITCZ, Hadley/Walker Cells, MJO, meridional overturning, gyre circulations, as well as Arctic/Antarctic Sea ice dynamics under such high resolution.Moreover, we endeavor to demonstrate how regional high-frequency weather and climate processes can be accurately represented in such simulations, including capturing the nature of regional extremes. In essence, our goal is to illustrate how advancing model resolution to resolve ocean eddies contributes to a more comprehensive representation of the climate system.
Unraveling the collisional history of the Western Carpathians through deep geophysical sounding
Authors: Soni Tanishka , Schiffer Christian , Mazur Stanisław
Published: March 2024

The Pieniny Klippen Belt (PKB) in the Western Carpathian branch of the Alpine-Carpathian-Dinaridic orogenic system is considered to be the surficial representation of the Alpine-Tethys suture. It is a few kilometres wide and about 600 km long unit between the Outer Western Carpathians and Central Western Carpathians and does not show typical characteristics of a suture (Plašienka et al., 1997; Schmid et al., 2008). In fact, the structural relationship between the PKB and surrounding units is ambiguous. The PKB is a sub-vertical unit with mainly shallow marine limestone and flysch deposits in a conspicuous “block-in-matrix” structure (Plašienka et al., 1997). This structure has been explained mainly by two theories: sedimentary structures formed by gravity sliding; and post-sedimentation tectonic shearing due to strike-slip movement affecting the heterolithic composition of the unit (Plašienka et al., 2012; Golonka et al., 2015). The presence of “exotic” sediments in the PKB and the southernmost units of the OWC along with their shallow marine deposition environment led to the theory proposing the presence of a continental sliver called the Czorsztyn Ridge in the Alpine Tethys, dividing it into two oceanic/marine basins: the Magura Ocean to the north and the Vahic Ocean to the south (Plašienka, 2018).A passive seismic experiment was designed and installed to provide insight into the deep lithospheric structure across the PKB, testing the presence of a tectonic suture along with relaminated remnants of the Czorsztyn Ridge, and potential remnants of subducted or underthrusted lithosphere. Eighteen broadband stations have been deployed in a ~N-S transect under the umbrella of the AdriaArray initiative, cutting across the PKB and the Neotethian Meliata suture to the south. The data obtained during up to three years will complement 10 other permanent and temporary broadband stations, forming an approximate 250 km long profile and will be primarily used to perform receiver function analysis and to build structural and velocity models of the lithosphere (i.e., Schiffer, 2014; Schiffer et al., 2023) beneath the Western Carpathians.Gravity and magnetic data will be used to construct a 3-D model of the subsurface complementing the seismic experiment. Preliminary assessment of the data has shown that the PKB is represented by an anomaly reaching at least until the 15 kms depth and, therefore, is a deep-seated feature. It leads to a tentative conclusion that the PKB’s “block-in-matrix” structure is rather of tectonic origin. The qualitative analysis of potential field data reveals the presence of three major elements in the deep basement of the northern Carpathians corresponding to the ALCAPA, European Platform, and a previously undefined wedge-shaped block under the Eastern Carpathians. The PKB follows the boundary between the ALCAPA and the remaining two domains.
Climatic controls on streamflow and groundwater dynamics in a semi-arid catchment: Long-term trends and importance of episodic events
Authors: Bjerre Elisa , Enemark Trine , Jessen Søren , Høgh Jensen Karsten
Published: March 2024

Groundwater is a vital water source in semi-arid and arid regions characterized by little and erratic precipitation and ephemeral river flow. In these regions, water scarcity is becoming more critical due to population growth, increasing irrigation demands, and climate change. Groundwater recharge here primarily occurs as episodic events and specifically as focused recharge during high river flow, but the controlling processes are poorly understood. Thus, understanding and quantifying the relationships between climate, streamflow and groundwater dynamics is crucial to assess the impact of climate change on future water availability. Historically, water resources assessments in Africa have relied on large-scale hydrological models, however, they often lack validation from groundwater observations. Here, we take an observation-based approach to identify climatic controls on streamflow and groundwater dynamics in the semi-arid Hout-Sand River catchment, Limpopo, South Africa. Using data spanning from 1940-2023, we analyze time series of precipitation, air temperature, stream discharge, and groundwater level and evaluate long term trends and relationships across a range of climatic indices and hydrologic and groundwater signatures. While we find no significant trends in long-term annual precipitation, the precipitation patterns are becoming increasingly extreme and exhibit higher intensities with longer dry periods. In response, streamflow patterns are changing towards longer no-flow periods although there is no significant trend in total annual flows. Long-term groundwater levels are not unanimously increasing or decreasing. However, we observe a dependence of streamflow and groundwater levels on multi-annual patterns of climate variability. Furthermore, preliminary results suggest that episodic precipitation and streamflow events contribute to the majority of total groundwater recharge, and that the recharge mainly occurs close to streams, i.e. as focused recharge. Finally, we aim to use machine-learning regression techniques to identify the most important controls on focused and diffuse recharge in order to perform spatial regionalization.
Legacy of last millennium timber use on plant cover in Central Europe: insights from tree rings and pollen
Authors: Seim Andrea , Antoine Emma , Marquer Laurent ,   dendro-pollen team
Published: March 2024

Throughout history, humans have relied on wood for constructions, tool production or as an energy source. How and to what extent these human activities have impacted plant abundance and composition over a long-term perspective is, however, not well known. To address this knowledge gap, we combined 44 239 precisely dated tree-ring samples from economically and ecologically important tree species (spruce, fir, pine, oak) from historical buildings, and pollen-based plant cover estimates using the REVEALS model from 169 records for a total of 34 1° x 1° grid cells for Central Europe. Building activity and REVEALS estimates were compared for the entire study region (4–15° E, 46–51°N), and for low (< 500m asl) and mid/ high elevations (≥ 500m asl) in 100-year time windows over the 1150–1850 period. Spruce and oak were more widely used in wooden constructions, amounting to 35% and 32%, respectively, compared to pine and fir. Besides wood properties and species abundance, tree diameters of harvested individuals, being similar for all four species, were found to be the most crucial criterion for timber selection throughout the last millennium. Regarding land use changes, from the 1150-1250’s onwards, the forest cover generally decreased due to deforestation until 1850, especially at lower elevations, resulting in a more heterogeneous landscape. The period 1650‒1750 marks a distinct change in the environmental history of Central Europe; increasing agriculture and intense forest management practices were introduced to meet the high demands of an increasing population and intensifying industrialization, causing a decrease in plant/palynological diversity, in particular at low elevations. Likely the present Central European landscapes originated from that period. Our results further show that land use has impacted vegetation composition and diversity at an increasing speed leading to a general homogenization of landscapes through time, highlighting the limited environmental benefits of even-aged plantation forestry.
GRACE Follow-On gravity-field results incorporating the ZARM ACC transplant based on high-precision environment modeling
Authors: Huckfeldt Moritz , Wöske Florian , Rievers Benny , List Meike
Published: March 2024

We have developed a GRACE-D accelerometer product that relies more heavily on modeled acceleration data instead of a transplant. Here we present our approach and a performance evaluation of our data products with different models, processing options and compared to transplant products from other institutes.Comparisons of the artificial acceleration data to the real ACT1B data for GRACE-C show that models related to the atmospheric drag (especially density and drag coefficient) are the limiting factors in the high precision environment modeling approach. Even though it is still possible to generate monthly gravity field solutions with a combination of ACT1B data for GRACE-C and artificial data for GRACE-D that show all prominent hydrological signals, we also implemented a minimalistic transplant where we estimate the atmospheric density from GRACE-C and transplanted it to GRACE-D.We compare our transplant data by incorporation of the GROOPS software to generate monthly gravity field solutions. This enables us to compare the results with other monthly solutions and the ITSG solutions, without getting differences due to the GFR processing tool.We publish the ZARM GRACE-D data product, all modeled non-gravitational accelerations and additional data on a publicly accessible server.
Spaceborne Water Vapor DIAL: Has the time come now?
Authors: Wirth Martin , Groß Silke , Fix Andreas
Published: March 2024

Water vapor is the key trace gas component of the air and involved in virtually all relevant atmospheric processes. To know the vertical profile with decent resolution is crucial in all cases. For example, there are several regions of the atmosphere where numerical weather prediction models show biases which are not understood. So, after aerosol/cloud and wind lidars have been very successfully applied within space missions, the natural next step would be the profiling of water vapor by a Differential Absorption Lidar (DIAL) from a satellite in a low Earth orbit. About 20 years ago the ESA EarthExplorer Proposal WALES went through phase A, but was not further selected due to the identified technological risks and the corresponding financial efforts. Thanks to the European spaceborne lidar missions Aeolus/2, EarthCare, and MERLIN now the major building blocks for a such water vapor DIAL have reached the necessary technological readiness to realize such a program within the financial limits of a typical Earth observation mission. We will review the benefits of water vapor profiling by lidar as compared to passive sensors for different applications and then present an updated system design based on the current European space lidar component pool. Finally, results from end-to-end performance simulations will be presented. This presentation is thought as an invitation to the community to think about possible applications of space-borne H2O-lidar data and the corresponding observational requirements.
Conceptualization and implementation of a global drought monitoring and forecasting system within the HydroSOS framework
Authors: Vu Tinh , Reinecke Robert , Abbasi Neda , Trautmann Tina , Weber Jan , Dietrich Stephan , Kneier Fabian , Lorenz Christof , Weller Malte , Koethe Harald , Kunstmann Harald , Döll Petra , Siebert Stefan
Published: March 2024

Forecasting systems focusing on upcoming flood and drought events are essential to support various aspects such as disaster risk reduction, climate change mitigation, or long-term policy and planning. In particular, multiple model-based early warning systems have been developed to allow the simulation of future floods and droughts at different temporal-spatial scales. However, despite the successful development of many innovative and state-of-the-art modeling systems in the academic fields, their transition into an operational system is challenging, and it may take several years to set up appropriate technical requirements, especially into a new IT infrastructure. In this talk, we hence outline these challenges for the example of the ongoing project OUTLAST (operational, multi-sectoral global drought hazard forecasting system), where the main goal is to develop a modeling system that is ready for operational use. OUTLAST will provide model-based near real-time monitoring using recent updated ERA5 climate data and seasonal forecasting of drought globally across different sectors (water supply, riverine and non-agricultural land ecosystems, rainfed and irrigated agriculture). The system consists of a model chain of three models: (1) bias correction of global seasonal forecasting products SEAS5, (2) the global hydrological model WaterGAP, and (3) the global crop water model GCWM. The drought status in both monitoring and forecasting phase from OUTLAST will be provided globally for the next six months and be freely accessible via the HydroSOS portal, a Hydrological Status and Outlook System hosted by the World Meteorological Organization (WMO).Highlights of OUTLAST are the ability to run the whole system within a cloud-ready automated workflow to ensure seamless integration into the HydroSOS framework. This includes the so-called “trigger” to automatically download the newly released climate data (ERA5 and SEAS5) from the source (ECWMF). To achieve this goal, each model and its dependencies in the model chain in OUTLAST are encapsulated in a "container" by the core developer in the research institution before being transferred to run in an IT infrastructure at an external government institution. The containers will then be orchestrated to enable the upscaling of the system based on computational requirements and the availability of hardware resources. This approach aims to (i) enable a seamless transition of OUTLAST into operation, (ii) avoid any conflict with the host operating system, and (iii) ensure a fast boot system in case one of the servers fails. We hope that the proposed infrastructure design can serve as a blueprint for other efforts to transfer scientific workflows into an operational environment. 
Estimation of methane emissions at European scale with a special focus on Austria
Authors: Wittig Sophie , Raju Anjumol , Nabavi Seyed Omid , Vojta Martin , Redl Peter , Hoheisel Antje , Hirtl Marcus , Groot Zwaaftink Christine , Stohl Andreas
Published: March 2024

In recent years, methane (CH4) has attracted increasing scientific attention as the second most abundant anthropogenic greenhouse gas (GHG) in the atmosphere. Due to the high reduction potential and the relatively short atmospheric lifetime of around 9 years, mitigation measures can become effective within a relatively short period of time. However, the current estimates of CH4 fluxes from emission inventories are still subject to uncertainties at both global and regional scale.An effort to reduce uncertainties from those bottom-up flux estimates is given by inverse modelling, which provides a robust tool to verify GHG emissions by combining GHG observations as well as atmospheric transport modelling and statistical optimization.In this study, we use an inverse modelling approach to estimate CH4 fluxes at European scale for the year 2022. Additionally, we use the European in-situ observation network to explore the feasibility of reducing uncertainties in CH4 fluxes in Austria, a European country with a limited availability of stationary observations. This work is part of the Austrian ASAP18 flagship project “GHG-KIT: Keep it traceable”.Hereby, the inverse modelling tool FLEXINVERT is used, which is based on the backward simulations of the Lagrangian particle dispersion model FLEXPART (FLEXible PARTicle). In particular, we investigate to what extent prolonged backward trajectories of 50 to 100 days contribute to better constrain the CH4 fluxes. In an attempt to estimate background concentrations as accurately as possible, we use global CH4 concentration fields obtained with the chemical transport model FLEXPART (CTM).
What determines the strength and latitudinal extent of the equatorial zonal flows on Jupiter and Saturn? 
Authors: Duer Keren , Galanti Eli , Kaspi Yohai
Published: March 2024

Jupiter's equatorial zonal flows reach wind velocities of ∼ 100 m/s, while on Saturn they are three times as strong and extend about twice as wide in latitude, despite the two planets being overall dynamically similar. Recent gravity measurements obtained by the Juno and Cassini spacecraft uncover that the depth of zonal jets on Saturn is about three times greater than on Jupiter. Here we reveal, using high-resolution 3D simulations, that the atmospheric depth is the determining factor controlling both the strength and latitudinal extent of the equatorial zonal flows, consistent with the measurements for both planets. We show that the atmospheric depth is proportional to the convectively-driven eddy momentum flux, which controls the strength of the zonal flows. These insights provide a comprehensive explanation for the observed differences in the equatorial regions of Jupiter and Saturn and offer new understandings into the dynamics of gas giants.
Toward Holistic Perspective on Dam Efficacy in Transboundary Hydro-Extremes Management
Authors: Omer Abubaker , Elagib Nadir , Wada Yoshihide , Pokhrel Yadu , Kim Hyungjun
Published: March 2024

Research on assessing dams preparedness to mitigate hydrological extremes has grown under climate change and water conflicts. However, discerning the success or failure of these strategies remains challenging, especially in Transboundary Rivers. Here, we use a meta-analytic approach to examine 14 moderators of dam efficacy in flood and drought risk management. We synthesize impact assessment datasets from 287 articles for 12 transboundary basins across the globe. Findings show that forest cover and gross domestic product enhance dam efficacy in flood control. In flood hotspots, the synergy of dam management and institutional factors is the paramount determinant of dams performance. Conversely, the efficacy in the drought-prone basins is governed mainly by the interplay of institutional and socioeconomic factors. Climate aridity, precipitation anomalies, and hydropower dams lessens the dams effectiveness in mitigating both hydrological extremes. We argue that endorsing adaptive management through dams in transboundary basins requires a holistic approach. Thus, we emphasize accounting not only for the physical and engineering aspects, but also for the intertwined environmental, socioeconomic, and geopolitical implications.
Halokinetic growth wedges in platform carbonates: thoughts on subsidence and carbonate production rates
Authors: Fernandez Oscar , Sanders Diethard , Ortner Hugo , Grasemann Bernhard , Leitner Thomas
Published: March 2024

The Northern Calcareous Alps (NCA) in the Eastern Alps (Austria) developed during the Triassic as a Tethys-facing salt-rich passive margin. Extensionally-driven salt tectonics, mobilizing evaporites of Late Permian to Early Triassic age on the Tethyan passive margin, started as early as the early Middle Triassic and lasted through to the end of the Triassic. Here we document multiple examples of salt-related growth geometries in the central NCA, with specific emphasis on their dimensions and the implications these have on the balance between subsidence and carbonate production rates. The interaction between these two factors controlled the distribution of facies within the sedimentary growth wedges and the development of the transitions from shallow-water platforms into basinal domains >200 m in depth. The interplay between subsidence, carbonate production, and external factors (ocean currents) appear to have been critical for the persistence of long-lived intra-platform embayments, whose origin and development have long puzzled geologists.The geometries and sedimentary architectures observed in the central NCA are directly comparable to those documented in other salt-rich basins such as the southern Atlantic passive margin or the (now inverted) Pyrenean rift. Excellent exposure and continuity over a large area render the Triassic of the central NCA an outstanding location for understanding the development of carbonate platforms above salt substrates.
An inclusive assessment framework for exploring climate-resilient nutrition security in sub-Saharan Africa
Authors: Jennings Stewart , Challinor Andrew , Macdiarmid Jennie , Pope Edward , Crocker Thomas , Anderson Weston , King Richard , Whitfield Stephen , Sarku Rebecca , Chomba Christian , Nawiko Masiye , Rutting Lucas , Veeger Marieke
Published: March 2024

Achieving climate-smart nutrition security in sub-Saharan Africa is an urgent challenge due to increasing climate risks to agricultural production, population growth and food price volatility This necessitates an integrated evidence base that takes into account not only future food system modelling but wider academic expertise and stakeholder knowledge and the plausible and desirable transformations that these information streams can provide. Accordingly, we use the integrated Future Estimator for Emissions and Diets (iFEED) to explore scenarios of food system transformation towards nutrition security. iFEED integrates climate, crop and land use modelling to explore scenarios of relevance to the policy landscape, as informed by stakeholders, assessing the adequacy of energy and nutrient supplies to meet dietary requirements at a population level. Our results show that calories are not always sufficient at the population level in extremely hot and dry years by mid-century in Zambia, even when maximising food production on available land. The majority of micronutrients also remain below population requirements. An alternative scenario where crops for population level nutrition security are prioritised shows that there are larger calorie shortfalls in extremely hot and dry years, although more micronutrient requirements are met than in the production-focused scenario. Both scenarios show benefits, and we point to ways forward that address the challenges to achieving climate-resilient nutrition security in the region. We also introduce our latest thinking on a new inclusive assessment framework that aims to expand iFEED to incorporate bottom-up disruptive seeds work and top-down modelling across spatial scales to deliver socially-equitable nutrition security in Kenya.
The changing statistics of storm surges across the Northwest of Ireland in a warming world.
Authors: Ahmed Tasneem , Cucco Andrea , Quattrochhi Giovanni , Bendoni Michele , Creedon Leo , Brandini Carlo , Taddei Stefano , S Gharbia Salem
Published: March 2024

Unequivocal change in the climate system has put coastal regions around the world at increasing risk from climate-related hazards like storm surge flooding. With studies demonstrating an increase in the frequency of storm surges along the Northwest coast of Ireland, within the EU H2020 project SCORE (Smart Control of the Climate Resilience in European Coastal Cities) a numerical modelling approach has been undertaken using SHYFEM (System of HYdrodynamic Finite Element Model) to simulate the storm surges into 2100 for the NW of Ireland under different Climate scenarios.  
Using the significant grid flexibility offered by the finite elements within SHYFEM, unstructured grids are implemented for two computational domains. One confined to the region of interest, specifically the Donegal Bay, namely the Limited Area Model (LAM) and the other extended to span the entirety of the North Atlantic Basin namely the Basin Scale Model (BSM). The two model applications are designed to capture the development of storm surges due to wind shear stresses and barometric pressure fluctuations associated with the passage of storm systems across the North Atlantic and to quantify the influence of the tides on the tide surge interaction. Given the large tidal excursion in the region, baroclinicity is neglected and the models are implemented in the barotropic mode. The LAM is forced with surface atmospheric forcing (pressure and winds) from ECMWF and sea surface height (SSH, including eleven tidal components) from CMEMS at its open boundary, whereas the BSM is solely forced with the atmospheric forcing. Extensive calibration of wind drag and bottom friction coefficients for the LAM and BSM using tidal gauge observations for 2020, shows high P. Corr and acceptable RMSE. Only negligible differences, around 3 cm, are seen in the surge magnitudes between the LAM and the BSM implying the negligible non-linear interaction of the tides on the storm surge dynamics in the Donegal Bay.  Thus, the BSM has been forced with atmospheric forcing obtained from CMIP6 climate models to predict the impact of climate changes on storm surge intensity and frequency under different climate scenarios up to 2100. Finally, by accounting for the tidal contribution, total water levels projections have been determined thus facilitating the generation of useful statistics (for instance Annual exceedance probabilities) and flood maps to inform relevant policies for coastal resilience. 
Mapping Worldwide Ground Deformation in High-Strain Areas with SAR PS/DS Interferometry and Sentinel-1 Imagery
Authors: Gomba Giorgio , De Zan Francesco , Brcic Ramon , Eineder Michael
Published: March 2024

The motivation for this study is to help providing a better understanding of the behavior of the earth's crust in high strain areas. High strain areas are regions of the Earth's crust, associated with tectonic plate boundaries, where the rates of ground deformation are particularly high. These areas are characterized by high seismic activity, making them of significant concern. The ability to estimate ground deformation in these regions is critical for understanding the underlying geological processes and for assessing the potential risk of future seismic events. Interferometric Synthetic Aperture Radar (InSAR) has shown great promise in delivering millimetre-scale ground displacement information over long distances across plate boundaries. In this project, we aim to globally measure ground deformation using the InSAR Persistent and Distributed Scatterer (PS/DS) technique, focusing on the regions where the second invariant of the strain is higher than 3 nanostrain per year.Due to the large amount of data that has to be processed, we use the high-performance data analytics platform made available within the framework of the Terra_Byte project, a cooperation between the German Aerospace Center (DLR) and the Leibniz Computer Centre (LRZ). This enables us to process large volumes of data efficiently. We use the IWAP processor to apply the PS/DS technique to time-series of seven years of SAR images acquired by the Sentinel-1 mission. To improve the accuracy of our analysis and reduce the influence of ionospheric variations we use CODE total electron contents maps. The impact of solid earth tides (SETs) is limited by using the IERS 2010 convention. We use ECMWF reanalysis data to correct for tropospheric delays, which are the biggest error source and limiting factor for the interferometric performance at large distances. The influence of soil moisture and vegetation growth on distributed scatterers is limited by the full covariance matrix approach used in the interferograms generation. Finally, we calibrate and compare our results with GNSS measurements to show a detailed picture of ground deformation.The results of this project will be publicly available on a global scale, including: velocity maps, timeseries, line-of-sight projection vectors. The product palette will allow custom calibration or 2D decomposition by the user. Possible applications are: the large coverage and homogeneous processing characteristics of the data could serve as a baseline reference or comparison for other studies. Geoscientists will be able to use the deformation measurements to gain a better understanding of geological processes, with the dense PS/DS measurements filling in the gaps between existing GNSS survey data, contributing to the advancement of scientific knowledge in this field.
Geological and Hydrogeological Settings of springs in Samaria Gorge (western Crete, Greece)
Authors: Manoutsoglou Emmanouil , Lazos Ilias , Steiakakis Emmanouil , Vafeidis Antonios
Published: March 2024

Samaria Gorge is located in the southern and western parts of the prefecture of Chania, in the White Mountains (Western Crete), and forms the main structure of one of the most important National Parks of Greece. It extends for approximately 13 kilometres, with a general N-S direction and exposes one of the essential lithostratigraphic sections of the Plattenkalk Group, the tectonically lowermost paraautochthonous group of metamorphosed rocks that structure the core not only of the White Mountains of Western Crete but also of the major mountains of the island (Tallaia, Psiloritis, Lasithiotika). The gorge runs through a stream that starts about 2 km north of the settlement of Samaria and flows downstream to the sea. In some places, the stream flows subsurface and reappears at topographically lower positions. This situation continues up to Kefalovrysia location , where the stream flows up the riverbed to the Sooth Cretan Sea. During the wet season of the year, the stream receives large amounts of water from the watershed, while during the dry season, it receives the outflows of a relatively small number of springs scattered along the Samaria Gorge. Based on the aforementioned, the main water source during the summer season comes from the the springs, located in the metamorphosed carbonate rocks with siliceous interlayers of the Plattenkalk Group.The tourist development of the area (with an increasing trend of tourists passing through the gorge), combined with the need to preserve the highest natural beauty of the area, requires full fire safety as well as an improvement of the provided tourist services, which inextricably depends on the quantity and quality of the area’s available water in the various stops of the thousands of tourists inside the gorge as well at its southern exit (Agia Roumeli settlement), where the route terminates. In order to cover to the maximum extent the water supply - hygiene needs of the thousands of tourists, the local community needs both the coverage of any firefighting requirements and the rational management of the existing water resources, as well as the investigation for additional water resources from potential underground aquifers.Therefore, collecting as much information as possible, related to the springs located within the gorge, is necessary. Beyond their spatial distribution, it is essential to determine the quantitative and qualitative features of the water of each spring. At the same time, the mapping around the springs is also crucial, where the steep topographical relief favours this procedure. This mapping will contribute help to the interpretation of the spring's formation. The presentation and discussion of the conclusions related to the spring's geological mapping within the Samaria gorge is the paper's objective.Acknowledgment: This research is financially supported by the Green Fund “Forest Protection and Upgrading 2019” under “Other Nationals. Green Fund”.
Assessing landslide risk on a Pan-European scale
Authors: Caleca Francesco , Lombardo Luigi , Steger Stefan , Dahal Ashok , Tanyas Hakan , Raspini Federico , Tofani Veronica
Published: March 2024

Assessing landslide risk is a fundamental step in planning prevention and mitigation actions in mountainous landscapes. To date, most landslide risk analyses address this topic at the scale of a slope or catchment. Whenever the scale involves regions, nations, or continents, the landslide risk analysis is hardly implemented. To test this theoretical framework, we present a practical case study, represented by the European landscape. In this contribution, we take the main Pan-European mountain ranges and provide an example of risk assessment at a continental scale. We consider challenges like cross-national variations landslide mapping and digital data storage. A two-stepped protocol is developed to identify areas more prone to failure. With this initial information, we then model the possible economic consequences, particularly in terms of human settlements and agricultural areas, as well as the exposed population. The analytical protocol firstly results in an unbiased landslide susceptibility map, which is combined with economic and population data. The landslide risk is presented in both the spatial distribution of possible economic losses and the identification of risk hotspots. The latters are defined through a bivariate classification scheme by combining the landslide susceptibility and exposure of human settlements. Ultimately, the exposed population is represented during the two sub-daily cycles across the study area.
Modular seismo-acoustic float technology for coastal and open ocean observation
Authors: Bonnieux Sébastien , Sigloch Karin , Hello Yann , Rocca Frederic
Published: March 2024

Lagrangian floats are used since the early 2000s for monitoring temperature and salinity of the oceans, and more recently for recording tele-seismic waves. This technology is originally dedicated to global monitoring because it’s drifting with oceanic currents over thousands of kilometers. Recent developments have shown that the floats can also be equipped with an anchoring or semi-anchoring system to prevent the current drift. It opens up even more possible applications for many multidisciplinary ocean science studies. However, it also highlights the needs of modularity to handle different users, and evolving needs, while reducing development time without affecting reliability and cost of the instrument. We introduce some use cases from seismology to biology to identify the main requirements of modularity and discuss about software and hardware limitations. We present our approach of modular software, with a domain-specific language, allowing deployment of several applications, on a float equipped with  high and low frequency hydrophones for multidisciplinary acoustic monitoring. A first prototype will be deployed in 2023 and further developments are to come in the next years.
Drought risk perception and adaptive measures of livestock farmers in NE Romania
Authors: Margarint Mihai Ciprian , Albulescu Andra-Cosmina , Niculita Mihai , Wu Jianshuang , Tarolli Paolo
Published: March 2024

Droughts represent the main climatic hazard in NE Romania, affecting all agricultural activities to different extents, depending on their timing and intensity. This work investigates the drought risk perception of livestock farmers, together with their coping strategies, through a downscaled approach. Extensive fieldwork complemented by interviews and a survey was carried out during the summers of 2022 and 2023, with the main goal of gathering data from the most drought-sensitive and impacted farmer typology: livestock farmers that practice grazing, depending entirely on the amounts of precipitation and their distribution during the grazing period.The questionnaire was applied to 185 farmers with different farm settings. This included 64 questions (with response types grouped in 5-point Likert scale, dichotomic, multiple choice, or open items), structured as: (i) the risk perception of the farmers regarding climate-related hazards (awareness, perceived trends of climate hazards, impacts on water and feed supply, animal health, pasture quality, preparedness, trust in authorities); (ii) farm settings (type, size, water supply, restrictive factors, production specificity, animal breed, partnership status, perspectives), and (iii) farmer profile (age, education level, experience, implication, place of living, heat vulnerability, satisfaction level). The statistical analysis was performed in R (univariate, bivariate, and multivariate analysis).The results include a broad range of correlations and insights, from which we selected an initial subset statistically significant. Respondents considered droughts the most impactful climatic hazard, followed by heat waves, both in the last and the next 10 years. Also, about 75% of the farmers reported an increase in drought intensity and frequency in the last 10 years. In terms of preparedness, 58% of the participants reported that they implemented drought preparedness measures, although they estimate their preparedness level as medium (2.82 mean, 1.1 std). Medium to low levels were also reported by farmers when talking about trusting authorities at county (1.85 mean, 0.82 std), national (2.29 mean, 1.15 std) or European (2.34 mean, 1.26 std) scales to reduce the impact of droughts.As drought risk perception is a prominent factor to be acknowledged and integrated into drought mitigation strategies, these findings can inform decision-making at regional and local scales. This study marks the start of drought risk perception research in Romania, being the first to address this topic in the country of reference and one of the few and most detailed in Europe.
Effect of long-range transported fire emissions on aerosol and cloud properties at high latitudes: In situ measurements and satellite observations
Authors: Kommula Snehitha M. , Buchholz Angela , Gramlich Yvette , Mielonen Tero , Hao Liqing , Pullinen Iida , Vettikkat Lejish , Joutsensaari Jorma , schobesberger Siegfried , Tiitta Petri , Leskinen Ari , Rees Dominic Heslin , Haslett Sophie , Siegel Karolina , Lunder Chris , Zieger Paul , Krejci Radovan , Romakkaniemi Sami , Mohr Claudia , Virtanen Annele
Published: March 2024

Global warming and climate change-induced rise in Earth’s temperature have increased the frequency of forest/wildfires over the past decade. Therefore, understanding the effect of fire emissions on aerosol-cloud interactions is crucial for improving Earth system models.         We present observations from in-situ measurements of aerosol properties at the Puijo SMEAR IV station in eastern Finland and the Zeppelin Observatory in Ny-Ålesund, High Arctic. Both stations are frequently inside low-level clouds due to their topographic prominence. During the autumn of 2020, fire emissions from the same active fire region in south-eastern (SE) Europe reached both stations after ~2 - 8 days of atmospheric aging. This enabled us to investigate the changes in aerosol and cloud properties for clouds formed under the influence of aged fire emissions (referred to as the ‘fire’ period) and under cleaner conditions with no fire emission influence at these stations (‘non-fire’ period). The aerosol hygroscopicity parameter (κchem) was derived from the chemical composition data obtained from online aerosol mass spectrometers and was used to derive the number concentration of cloud condensation nuclei (NCCN) from the measured particle size distributions.         At both stations, the aerosol number concentration in the accumulation mode and the cloud condensation nuclei concentration (NCCN) were higher during the fire period than during non-fire times. However, the aerosol hygroscopicity increased at Puijo but decreased a Zeppelin from the non-fire to fire period. At Puijo, in-situ measured cloud droplet number concentration (CDNC) was by a factor of ~7 higher when comparing fire to non-fire periods. This was in good agreement with the satellite observations (MODIS, Terra). At Puijo, the higher CCN concentrations during the fire period cause a depletion of the water vapor available for cloud droplet activation leading to larger observed activation diameters during cloud events despite the higher hygroscopicity of the aerosol particles.         These observations show the importance of SE European fires for enhancing the CCN activity in Finland and the high Arctic. Results from this study emphasize the complex interplay between particle size and chemical composition, and how fires even from sources far away can have strong impacts in these remote regions.
Carbon fluxes in Arctic and sub-Arctic freshwater ecosystems
Authors: Vogt Judith , Virkkala Anna-Maria , Wargowsky Isabel , Kuhn McKenzie , Madaan Simran , Göckede Mathias
Published: March 2024

Arctic and sub-Arctic regions host a large number of waterbodies that serve as carbon sources to the atmosphere within an environment that is predominantly characterized by carbon sequestration. The ongoing permafrost thaw in the warming Arctic is anticipated to alter the distribution of freshwater ecosystems, subsequently affecting their contribution to the overall carbon budget.Estimates of global carbon budgets largely disregard emissions caused by permafrost thaw, and also carbon budgets for freshwater ecosystems are highly uncertain to date. A general constraint in this field is data scarcity from remote northern regions. In addition, underlying processes specific to freshwater ecosystems remain poorly understood, especially given the landscape heterogeneity in high northern latitudes. To fill these gaps, our project aims at synthesizing new and existing carbon dioxide (CO2) and methane (CH4) flux data from freshwater ecosystems accompanied by environmental parameters (temperature, pH, water depth, etc.) across the Arctic-boreal domain on a site-level and at monthly resolution.This work is conceptually based on a range of previously published studies and will contribute to the Arctic-boreal carbon flux synthesis (ABCflux v2) that spans terrestrial, wetland and freshwater ecosystems. As of January 2024, we gathered data from almost 900 different freshwater sites with more than 2000 monthly CO2 and CH4 flux measurements. With the newly synthesized data, we aim to quantify the carbon budgets of freshwater ecosystems across the Arctic-boreal domain and evaluate their contribution to the global carbon budget. Additionally, the impact of environmental controls including temperature, pH, and water depth on the carbon cycle processes will be investigated. This dataset will provide a unique opportunity for benchmarking and verification of process-based models and remote sensing products. Finally, the synthesized dataset will be publicly available to the scientific community.
Copernicus POD Service – POD RESULTS BASED ON DORIS
Authors: Fernández Marc , Fernández Carlos , Peter Heike , Féménias Pierre , Nogueira Loddo Carolina
Published: March 2024

The Copernicus Precise Orbit Determination (CPOD) Service delivers, as part of the Ground Segment of the Copernicus Sentinel-1, -2, -3, and -6 missions, orbital products and auxiliary data files for their use in the corresponding Payload Data Ground Segment (PDGS) processing chains at ESA and EUMETSAT, and to external users through the newly available Copernicus Data Space Ecosystem (https://dataspace.copernicus.eu/).The CPOD Service is based on FocusPOD, a suite of tools for POD and geodesy powered by GMV MAORI, a new GMV in-house Flight Dynamics & Geodesy library, written from scratch in modern C++ and python. The CPOD Service makes use of GNSS measurements to generate the orbital products, and of Satellite Laser Ranging (SLR) measurements for validation purposes. Recently, DORIS-processing capabilities have been added to FocusPOD to generate orbit solutions based on this geodetic technique, which is available on-board Sentinel-3 and -6 missions.The purpose of this work is to present the DORIS processing capabilities recently developed, including DORIS RINEX data parsing, observation preprocessing steps, and precise orbit determination results. The highlight will be the achievable accuracy based on DORIS and an analysis of the obtained residuals depending on the chosen parametrisation, including validation against GNSS-based solutions and SLR.
Abrupt climate changes triggered with GLAC-1D ice sheet, but not with ICE-6G_C, in simulations of the Last Glacial Maximum/Deglaciation
Authors: Ivanovic Ruza , Rome Yvan , Gregoire Lauren , Snoll Brooke , Pollard Oliver , Perez Jacob
Published: March 2024

In the course of glacial terminations, the increases in greenhouse gas concentrations, summer insolation and the ice sheet demise can trigger episodes of millennial-scale variability. Such variability was observed during the last deglaciation, between 19 ka BP (thousand years ago) and 8 ka BP, in the form of  the abrupt North Atlantic temperature shifts of the Bølling–Allerød Warming (14.5 ka BP) and Younger Dryas (12.900 ka BP).In some climate models, abrupt climate changes are generated by modifications to the boundary conditions and freshwater discharge. Despite much study, the sensitivity of climate simulations to ice sheet geometry and meltwater is complex and not fully understood, which is a caveat when considering the impact of the rapid demise of the Northern Hemisphere ice sheets during the last deglaciation. In a new set of last glacial maximum HadCM3 simulations that can produce millennial-scale variability, we studied the influence of two ice sheet reconstructions, ICE-6G_C and GLAC-1D, and their associated deglacial meltwater history, on the simulated chain of events of the last deglaciation.In this experiment, our simulations using the GLAC-1D ice sheet reconstruction produced abrupt climate changes. Triggered by freshwater released close to the Nordic Seas and Iceland Basin deep water formation sites, these simulations display abrupt shifts in the Atlantic Meridional Overturning Circulation (AMOC) that are decoupled from the meltwater flux. In contrast, the reconstructed ICE-6_G ice sheet modifies the North Atlantic wind patterns in the model, preventing convection in the Nordic Seas and intensifying the Iceland Basin deep water formation. As a result, no abrupt climate changes are simulated with ICE-6G_C ice sheets and the AMOC decreases almost linearly with the introduction of freshwater.The simulations do not capture the timing of the last deglaciation chain of events, but the modelled abrupt changes replicate the main Northern Hemisphere characteristics of the Bølling Warming/Younger Dryas transitions, and are very similar to Dansgaard-Oeschger events.