bluuebunny/crossref_metadata_2025 huggingface dataset:
Drought effects investigation of a forested site at different spatial scales with eddy covariance technique, cosmic ray sensors, electrical resistivity tomography and 2 meters deep soil moisture and matric potential profile
Authors: Gisolo Davide , Canone Davide , Comina Cesare , Vagnon Federico , Gentile Alessio , Ferraris Stefano
Published: March 2024

The forested area is growing in Italy. The eco-hydrological monitoring of such an ecosystem is not trivial, because of canopy height, deep root system and soil heterogeneity. Hence, it is important to merge multiple measurement approaches to quantify the ecohydrological dynamics at the sites. In addition, it is also important to consider multiple temporal and spatial scales from point measurements to areal measurements of the soil-atmosphere interactions. At the Bussoleno - Grangia dell’Alpe forest site (Piedmont, Northwest Italy), we monitored two years, and in particular, two growing seasons (2021 and 2022, with a severe drought in Italy) with areal measures in the atmosphere of actual evapotranspiration (ETa) estimated via eddy covariance technique overcanopy (25 m mast) and areal estimates of soil water content measured continuously with cosmic ray sensors. Moreover, the soil resistivity was measured at the plot scale with Electrical Resistivity Tomography (ERT) technique with several campaigns in which two measurement transects were explored. The point scale with continuous measurements was monitored via soil water content and matric potential probes installed at several depths between 0.1 m and 2 m. In addition, during the ERT campaigns, the soil water content of the first 30 cm profile was also measured via TDR probes in different locations of the experimental site. All this effort allows the reconstruction of a forest volume from about 3 m of soil depth to 23 m of height (height of the eddy covariance setup), including the whole canopy effect. Results highlight the consistency of the soil water content estimation with different approaches (cosmic ray sensors, ERT technique, TDR and capacitive probes). Moreover, using different soil moisture measurements, the ETa regimes can be correctly and well identified. Furthermore, the drought effects are explored also using eddy covariance technique, highlighting that, despite a very low water content above 2 m of soil depth, the vegetation is not severely stressed, likely because of its resilience (the site is characterized by low precipitation, usually below 600 mm/year).This publication is part of the project NODES which has received funding from the MUR –M4C2 1.5 of PNRR with grant agreement no. ECS00000036.
Icequakes beneath Thwaites Glacier eastern shear margin 
Authors: Smith Emma C. , Agnew Ronan , Booth Adam D. , Christoffersen Poul , Dawson Eliza J. , Gonzalez Lucia , Karplus Marianne , May Daniel F. , Nakata Nori , Pretorius Andrew , Summers Paul , Tulaczyk Slawek , Vietch Stephen , Walter Jake , Young Tun Jan
Published: March 2024

The stability of Thwaites Glacier, the second largest marine ice stream in West Antarctica, is a major source of uncertainty in future predictions of global sea level rise. Critical to understanding the stability of Thwaites Glacier, is understanding the dynamics of the shear margins, which provide important lateral resistance that counters basal weakening associated with ice flow acceleration and forcing at the grounding line. The eastern shear margin of Thwaites Glacier is of interest as it is poorly topographically constrained, meaning it could migrate rapidly, causing further ice flow acceleration and drawing a larger volume of ice into the fast-flowing ice stream.  

In this study, we present an analysis of ~4000 icequakes, recorded over a two-year-period on a broadband seismic array deployed across the eastern shear margin of Thwaites Glacier. The array consisted of seven three-component seismometers, deployed around a central station in a circle, roughly 10 km in diameter.  We use an automated approach to detect and locate “high-frequency” seismic events (10-90 Hz), the majority of which are concentrated in clusters around the ice-bed interface on the slow-moving side of the shear margin, as opposed to within the ice-stream itself. The event waveforms exhibit clear shear-wave splitting, indicative of the presence of an anisotropic ice fabric, likely formed within the shear margin, which is consistent with published radar studies from the field site. Initial analysis of the split shear-waves suggests that they can be used to better constrain the region's ice fabric, and likely used to infer past shear margin location and assess the future stability of this ice rheology.
A Benchmark Dataset for Radio Echo Sounding Data
Authors: Dreier Marcel , Gourmelon Nora , Koch Moritz , Seehaus Thorsten , Braun Matthias , Maier Andreas , Christlein Vincent
Published: March 2024

Melting glaciers and ice sheets contribute significantly to the global sea level rise, posing an existential threat to coastal regions. For that reason, many expeditions collect radio echo sounding data to track, model, and predict the changes in ice mass and thickness. However, manually analyzing the data collected to determine the thickness of the ice sheet and mountain glaciers is a time-consuming task, as the collected data often extends over tens to hundreds of kilometers. Hence, the development and utilization of automated and semi-automated tools have risen in popularity to alleviate the problem. Especially machine learning-based approaches show promising results as they can capture complex relationships in the data. However, such methods require large labeled datasets to achieve their full potential. Thus, we are currently gathering and cleaning data that will be released as a benchmark dataset for radio echo sounding data to train, test, and compare different approaches. In detail, the dataset will consist of 2D radar data with georeferenced labels for the position of the air-ice and ice-bedrock interface. We plan to incorporate radar data from multiple sources since the underlying radar system and expedition area play a significant role in depicting the data and the general difficulty of the task. That way, the performance of a system can be fairly assessed with the benchmark dataset without the evaluation results being skewed by external factors. We will further ensure a fair comparison by dividing the data of every source in an independent training, validation, and test set. This division will also allow us to use the benchmark dataset to train and compare systems specialized on only a single data source. Thus, future work can also utilize our benchmark dataset to develop systems specialized on only a single data source. Lastly, we will release a baseline model alongside the benchmark dataset to demonstrate its practicality. Thereby giving an initial point of reference that future work can compare to. 
 Ocean wave forecasting as an immersive public space
Authors: Autogena Lise , Portway Joshua , Bidlot Jean
Published: March 2024

HavObservatoriet is an artist-led research collaboration with the European Centre for Medium Range Weather Forecasts (ECMWF). In 2023 the project constructed a circular open-air ‘wave observatory’ in Vejle Klima Park, Denmark, in a newly landscaped harbour-facing area, designed to protect the city of Vejle against flooding. The observatory creates a public space within the park, sheltered from the wind and connected to the power of the ocean.HavObservatoriet is designed to simulate the latest forecasts for the ocean surrounding Denmark as one single circular animated digital visualisation that envelops the viewer in a combined statistical model of the behaviour of the sea surface. The system is connected to the latest ECMWF near-term ocean wave spectrum forecasts. It converts the spectral data from these forecasts into an animated simulation of the ocean surface which is rendered using a non-photorealistic particle-based rendering system. The panoramic image of the sea that surrounds the viewer is displayed at 1:1 scale - so a 1meter high wave appears 1 meter high on the screen. Because the screen wraps around the viewer, you can see a wave approaching from one direction, feel it wash over the building, and then disappear in the opposite direction.The screen shows the “view” from a single geographic location at a time, changing the location every few minutes to a new semi-random location around the coast of Denmark. Each selected geographic position of spectral data simulates the amplitude of waves at every wavelength and in every direction they travel. Sometimes the screen will be showing 10m high storm surges from the North Sea, or sometimes the tranquil waves from the east coast of Jutland.This presentation will explore the visual and performative nature of this installation and its possible role in the urban landscape. It will discuss future possibilities of this collaboration, and the ways in which such artistic interpretations of environmental data might impact on public engagement.(Note on environmental impact: To reduce power requirements for this project, a rendering technique was developed that only requires a small proportion of the LED screen to be illuminated at any one time. As most of the image is black and responds to ambient light conditions the observatory therefore requires very little power).
Long-term observations of CH4 and N2O fluxes in a subalpine Norway spruce forest using chamber and eddy covariance methods
Authors: Krebs Luana , Gharun Mana , Burri Susanne , Feigenwinter Iris , Meier Philip , Scapucci Liliana , Buchmann Nina
Published: March 2024

Methane (CH4) and nitrous oxide (N2O) substantially contribute to global greenhouse gas (GHG) emissions together with carbon dioxide (CO2). To understand their impact on future climate change, prioritizing the study of CH4 and N2O fluxes becomes critical. Forest ecosystems, primarily investigated for CO2 exchange, are less explored concerning their exchange of CH4 and N2O. Forests are known to be sinks for CH4, while their role in N2O fluxes varies, acting as either sources or sinks. However, comprehensive studies that concurrently examine CH4 and N2O fluxes in forests, particularly over extended periods and at high elevation, remain scarce. At high altitudes, measuring GHG fluxes with chambers during snowy periods is challenging, leading to a lack of winter flux data which are crucial for understanding flux dynamics related to freeze-thaw cycles and snow patterns. This study addresses this gap by investigating long-term CH4 and N2O fluxes in a subalpine Norway spruce forest (Davos, CH-Dav, ICOS Class 1 Ecosystem station, Switzerland), encompassing both soil and canopy interactions with the atmosphere.Over five years (2017, 2020-2023 for CH4; 2017, 2020 for N2O), we employed automatic chambers to measure forest-floor fluxes, complemented by below-canopy eddy covariance CH4 flux measurements starting from May 2023, as well as static chamber measurements in 2023. Our research objectives were to 1) characterize the magnitude and seasonal dynamics of CH4 and N2O forest-floor fluxes, and 2) compare CH4 fluxes using chamber and eddy covariance techniques to better understand the interaction of soil and vegetation with the atmosphere.We hypothesized that the forest floor primarily acts as a net sink for CH4, with soil temperature and snow dynamics being important drivers due to their impact on microbial activity and diffusion rates between soil and atmosphere. Given the low nitrogen availability at the study site, we anticipated very low N2O emissions. Additionally, we hypothesized that comparing CH4 fluxes from chambers and eddy covariance would reveal small differences in their magnitudes, attributable to the distinct measurement scales and scopes of these two techniques. Our results confirmed the forest floor as a consistent CH4 sink, exhibiting substantial short-term fluctuations driven predominantly by air temperature and snow cover. N2O fluxes were negligible over the two-year observation period. Our study contributes to a deeper understanding of how environmental drivers and seasonal dynamics influence CH4 and N2O fluxes in high-elevation forests.
Nanostructural and chemical evolution of garnet during high-strain deformation
Authors: Dubosq Renelle , Camacho Alfredo , Rogowitz Anna , Schneider David , Gault Baptiste
Published: March 2024

Garnet is a common high-pressure mineral in the Earth’s lithosphere. Considered a high-strength mineral stable across a wide range of pressure and temperature conditions, it is generally accepted that garnets can retain their microstructures and chemical composition during deformation and metamorphism. Therefore, the trace and major element compositions of garnet are commonly used for geothermobarometers and geochronometers to provide the conditions and timing of metamorphic events. We combine electron backscatter diffraction (EBSD), electron channeling contrast imaging (ECCI) and atom probe tomography (APT) on garnet from an eclogite facies mylonite in the Musgrave Province (central Australia) to investigate the mechanisms of element mobility during high-strain deformation under dry (
An Enthalpy-Hydrology Coupled 3D full-Stokes Flow Model of Thwaites’ Eastern Shear Margin
Authors: Martin Carlos , Hehlen Mark
Published: March 2024

The force balance of an ice steam determines its velocity, and along with cross sectional area, influences total flux of glacial ice to the ocean. Satellite datasets provide us strong time series velocity data, while radar, seismics, and geophysical inversion methods yield width and depth estimates within an ice column. However, should an ice stream widen or narrow, the flux of ice to the ocean could change perceptibly. Thwaites Glacier’s eastern shear margin is not topographically bounded, but rather arcs across a shallow subglacial rise of intermittent hills and valleys. To determine the stability of the margin it is imperative to understand the force balance and total energy of the glacier system along the shear zone. Driving forces are balanced by normal and shear stresses along the bed, and longitudinal shearing in the margin. The resistance (or lack thereof) creates deformational (frictional-sliding) heating which add energy to the system altering rate factor and meltwater generation, which in turn alter the viscosity and slip factors, making a complex feedback system.To analyze this system, we develop a 3D full-Stokes flow model in the Elmer/ICE finite element software. The model resolves at 500 m horizontally over realistic surface and bed topography from BedMachinev3. Model domains cover key data acquisition sites from the International Thwaites Glacier Collaboration, Thwaites Interdisciplinary shear Margin Evolution (ITGC TIME) seismic and radar field studies. To determine energy balance, we employ the enthalpy field equations which efficiently solve the thermal field, solve for water content generation, and couple nicely with variable rate factors. Models are initialized by a suite of 1D thermal profiles, converted to enthalpy values, derived from quartile statistics of RACMO2.3p1 surface specific mass balance data, and then advected to steady state flow. These models are then run with a flow-coupled glacier drainage system (GlaDS) and enthalpy relation to determine temperate ice distribution, and basal water production. Non-linear Coulomb and Weertman sliding laws are tested between scenarios of natural melt generation, through full drainage piracy of the upper Pine Island catchment, which will determine the effect of spatiotemporal variation in effective pressure (N) on shear margin stability.Through the suite of spin up models and scenarios, we aim to determine the stability of Thwaites Glacier’s eastern shear margin from perturbations in enthalpy from both sliding friction, and viscous heating from temperate ice generation over non-idealized bed topography and within the shear margin itself. Results will help inform catchment scale transient flow models which aid in determining sea level contribution and West Antarctic Ice Sheet stability.  
Indicators for anthropogenic and natural water contributions to a small river
Authors: Ruck Malina , Augustin Lea , Baumann Thomas
Published: March 2024

River quality is expected to change significantly as a consequence of climate change. Extended drought periods and decreasing groundwater levels will lower the contribution of groundwater to receiving streams and heavy rain will cause excessive surface runoff effects. Constant sources, like discharge from wastewater treatment plants or industrial installations, will be diluted in largely different ratios. The overall hydrochemical dynamics will, therefore, likely increase. This affects flood management schemes and other potential uses of river water. This study links trace substances (hydrochemistry, colloids) to the hydrological dynamics in the catchment. From this data the feasibility of infiltrating excess river water into a nearby aquifer (Flood-MAR) is assessed. The upper part of the study area is characterized by forests and meadows. There is a small village with one sewage treatment plant (1000 inhabitant equivalents) and a few hamlets. Additional emissions can be expected from surface runoff of one national road (deicing, tire abrasion, etc.). The hydrochemical characteristics show a decrease in the main cations and anions during a flooding event. Nitrate concentrations were low in both cases. Although particle concentrations were increasing during the flooding event, the overall concentrations were still below our expectations. This indicates that the meadows behind the retention dam, which were partly flooded, served as a settling ponds and filters. During low water conditions, organic material and algae were dominant. Few calcite particles and silicates are indicative of the composition of the quaternary gravels that make up the aquifer. The results confirm the risk assessment of the study area. The water quality during a flooding event met the legal thresholds set in the German Soil Protection Act, so infiltration into the downstream aquifer should be feasible.
Sea-land interaction along the Catalan coast (NW Mediterranean): Assessment of Submarine Groundwater Discharge (SGD) based on seawater nutrient concentrations 
Authors: Sanchis Martí , Garcés Esther , Ortego María Isabel , Folch Albert
Published: March 2024

Submarine Groundwater Discharge (SGD) has garnered attention in the assessment of sea-land interactions within coastal regions. SGD plays a crucial yet uncertain role in coastal ecosystems, involving the release of nutrient-enriched groundwater and recirculation seawater in the geological matrix into the sea. Its significance is particularly relevant in the oligotrophic Mediterranean Sea, characterized by low nutrient concentrations, making SGD a pivotal process in sustaining life within the sea-land transition zone.This study explores the impact of SGD along the 580 km of the Catalan coast (Western Mediterranean) an area densely populated where land-sea interactions and the effects of SGD on marine ecosystems may be substantial. Leveraging a 23-year dataset, the study seeks to establish connections between SGD and the quality of the coastal area. The primary focus lies in investigate SGD locations through the analysis of salinity and inorganic nutrient composition (NO3, NO2, NH4, PO4, and SiO4) at 70 coastal stations. A novel perspective, Compositional Data Analysis (CoDa), is employed for this purpose. The study also integrates land-based hydrogeological factors, such as the geological nature of the aquifer. Furthermore, it explores the correlations between nutrient composition and biological indicators, specifically chlorophyll in the coastal area, utilizing CoDa techniques. Chlorophyll, as an indicator of photosynthetic activity, serves as a marker for biological responses to nutrient changes induced by SGD.This innovative approach, centered on the compositional nature of the data, streamlines the identification SGD locations and enables a comprehensive assessment of its ecological impact. The outcomes of this study have the potential to provide valuable insights for the improvement of coastal ecosystem management.AcknowledgmentsThis work was funded by the Spanish Government grant no. PID2022-140862OB-C21/C22 and PID2021-125380OB-I00 funded by MCIN/AEI/10.13039/501100011033 and by ERDF A way of making Europe
More Droughts, More Irrigation? Modeling the Adaptive Behavior of German Farmers to Hydrometeorological and Socioeconomic Change 
Authors: Heilemann Jasmin , Nagpal Mansi , Werner Simon , Klassert Christian , Klauer Bernd , Gawel Erik
Published: March 2024

The shifting precipitation patterns and rising temperatures in Central Europe and Germany present an existential challenge for farmers. Recent severe summer droughts, such as those in 2003 and 2018, underscore the imperative for farmers to adapt to evolving climatic conditions, for instance through the application of irrigation in areas where it was previously unnecessary or economically unfeasible. However, expanding the currently only 3% irrigated agricultural area in Germany has the potential to significantly impact freshwater resources and hydrological processes.Here, we model the adaptive behavior of farmers regarding irrigation, by employing an empirically validated multi-agent system (MAS) model. This model simultaneously simulates decisions about annual crop choices, acreages, and irrigation water application. Spatially disaggregated, the MAS model is calibrated using an Econometric Mathematical Programming (EMP) approach, based on historical land use data for eight major field crops. To account for the implications of future climate change, we couple the MAS model with a statistical crop yield model driven by meteorological indicators and soil moisture anomalies derived from the mesoscale Hydrologic Model (mHM) for a EURO-CORDEX scenario ensemble (RCP2.6, RCP4.5, RCP8.5). Socioeconomic variables that influence farmers' decisions, including changes in crop prices, costs, and subsidies, are projected based on Shared Socioeconomic Pathway (SSP) scenarios.Across various combinations of SSP and RCP scenarios, we find a notable surge in irrigation water demand. This development is particularly pronounced in SSP3-RCP8.5, where the MAS model projects several irrigation hotspots with a high irrigation water demand. Shifts in cropping patterns thereby significantly affect the resulting irrigation water demand. To dissect the effects of hydrometeorological, socioeconomic, and policy changes on irrigation water demand, we conduct sensitivity analyses on individual parameters.The MAS model emerges as a robust tool for analyzing farmers' adaptive behavior and assessing the impact of diverse policies on future irrigation water demand. This research contributes valuable insights into agricultural adaption under changing environmental and socioeconomic conditions.
Extraction of topographic profiles of double ridges on Europa 
Authors: Haslebacher Caroline , Prockter Louise M. , Leonard Erin J. , Schenk Paul M. , Thomas Nicolas
Published: March 2024

Double ridges are a common linear feature on Europa’s surface. They can be identified by a central trough accompanied by two ridge crests. Usually, the elevation of double ridge crests is not higher than 300 meters (e.g. [1]). Some double ridges run almost perfectly straight for hundreds of kilometers, while others are curved, for example into a cycloidal shape. Several double ridge formation hypotheses exist, which can be separated into cryo-volcanism/-sedimentation and brittle deformation (an overview can be found in [2]). Each proposed formation mechanism results in a unique topographic profile, which allows these hypotheses to be tested. 

We extract topographic profiles of more than 1000 mapped double ridges (perpendicular to their orientation) from a shape-from-shading topographic map. The shape-from-shading topographical map and the double ridge map are based on regional mosaics of Europa (data by [3]), two north-south covering swaths of the trailing and leading hemispheres at the regional scale (~230 m/px). The two regional mosaics were obtained under consistent illumination angles by the solid-state imager (SSI) on the Galileo spacecraft. We map double ridges in the regional mosaics with the help of the deep-learning tool LineaMapper [4]. We manually inspect, adjust, and verify LineaMapper’s predictions while respecting disruptions caused by other cross-cutting surface features.  

With this methodology, we analyze topographic profiles of double ridges in the regional mosaics and match them with unique profiles predicted by cryo-volcanism/-sedimentation and brittle deformation hypotheses. By assuming that, for any lineament, the number of disruptions per kilometer length is a proxy for relative age, we can assess the evolution of double ridge profiles over time, with potential implications for the upcoming space missions Europa Clipper and JUICE. 

[1] F. Nimmo, R. T. Pappalardo, B. Giese. (2003). On the origins of band topography, Europa. Icarus, 166(1), 21-32. [2] A.C. Dameron & D. M. Burr. (2018). Europan double ridge morphometry as a test of formation models. Icarus, 305(1), 225-249. [3] M. T. Bland, L. A. Weller, B. A. Archinal, E. Smith, B. H. Wheeler, (2021). Improving the Usability of Galileo and Voyager Images of Jupiter's Moon Europa. Earth and Space Science, 8(12). [4] C. Haslebacher, N. Thomas, V. T. Bickel, (2024). LineaMapper: A deep learning-powered tool for mapping linear surface features on Europa. Icarus, 410(1).
Exploring Ice Sheet-Climate Feedbacks Across the Last Glacial Cycle: Insights from a Transient Sensitivity Ensemble 
Authors: Geng Marilena , Tarasov Lev
Published: March 2024

Ice sheet evolution profoundly influences the climate system through changes in orography, surface albedo, freshwater fluxes to the ocean, and ocean gateways. The changes to the climate system will, in turn, affect the ice sheets, leading to complex feedback loops. To date, the relative roles of these feedback loops have not been examined over a full glacial cycle. To address this, we employ the glacial earth system model of intermediate complexity LCice in transient simulations of the complete last glacial cycle. Through ensemble-based sensitivity experiments, we isolate the impact of individual ice sheet orography, albedo, meltwater input, Bering Strait opening/closure, and glacio-isostatic adjustment on the climate system and back onto the ice sheet evolution itself. To assess possible state dependencies, we compare the individual impact of ice-climate feedbacks on both the ice sheet growth and decay phase around MIS 5d (Last Glacial Inception) and MIS 2 (Last Glacial Maximum). The sensitivity of the North American and Eurasian ice sheets to some feedbacks changes from MIS 5d to MIS 2, suggesting a potential threshold behaviour and complex non-linear dynamics. Our analysis also examines which characteristics of last glacial cycle ice sheet evolution are relatively robust and which are more likely to be highly sensitive to incompletely resolved feedback loops. This work thereby not only improves our understanding of paleo ice/climate coupled dynamics but also identifies feedback pathways that are likely to generate the largest uncertainties in coupled ice and paleoclimate modelling.
On the use of weather generators for the estimation oflow-frequency floods under climate change scenarios
Authors: Beneyto Carles , Aranda José Ángel , Francés Félix
Published: March 2024

The present work presents a novel methodology based on the use of stochastic Weather Generators (WG) for the estimation of high return period floods under climate change scenarios. Starting from the premise that the 30-years climate projections, commonly used for future flood studies, do not provide enough information to obtain accurate extreme quantile estimations (especially in arid and semi-arid climates), we propose to exploit the available information by performing a regional study of maximum precipitation of the bias-corrected climate projections (mid-term and long-term), the outputs of which will improve the WG implementation.This methodology has been applied in a case study, Rambla de la Viuda (Spain), a typical Mediterranean ephemeral river located in eastern Spain. The river is ca. 36 km in length and 1513 km2 in catchment surface, with a remarked variability: large floods are a significant element of this irregular hydrological regime, producing up to 80% of annual discharge volume. Precipitation and temperatures were obtained from the EUROCORDEX project: twelve combinations of Global Circulation Models and Regional Circulation Models were evaluated for a RCP8.5 emissions scenario.The results obtained shown a clear increase in maximum and minimum temperatures for both projections (up to 3.6ºC), this increase being greater for the long-term projection, where the heat waves intensify importantly in both magnitude and frequency. In terms of precipitation, the results are similar, with precipitation quantiles increasing for practically all models and for both projections, although slightly reducing the annual amount of precipitation. The long synthetic series of precipitation that fed a fully-distributed hydrological model translated into substantial shifts in the river flows regimes, presenting, in general, lower flows during the year but increasing the frequency and magnitude of extreme flood events, reaching 100 years return period quantile values up to 58% higher at the river outlet and up to 130% at a smaller upper subcatchment. These results have demonstrated the solidity and effectiveness of the proposed methodology. In the field of meteorological modeling, the results have been consistent and satisfactory, demonstrating the methodology's ability to accurately represent the complexities of extreme climate patterns. Likewise, in the hydrological field, the methodology has exhibited an effective capacity to represent and simulate the processes related to the water cycle, offering coherent and satisfactory results in the estimation of low frequency flood events under climate change scenarios. This consistency in the robustness of the methodology, both in meteorological and hydrological modeling, supports its applicability and reliability in diverse environments and climatic conditions.
Forcing mechanisms of the half-precession cycle in western tropical Pacific temperature
Authors: Wu Zhipeng , Yin Qiuzhen , Berger André , Guo Zhengtang
Published: March 2024

The western equatorial Pacific (WEP) plays an important role on global and regional climate. Its temperature reconstructions during the Quaternary display orbital-scale variations, containing major cycles of ~100, 40 and 20 kyr. In addition to these longer cycles, the half-precession cycle is also reported in a recent reconstruction, but the forcing mechanism deserves further study. Here we perform a systematic study on the half-precession cycle in the WEP temperature and related mechanisms. We first analyze existing temperature reconstructions to test whether there is robust half-precession cycle through time. We then use transient climate simulations to investigate its forcing mechanism. Our results show that the half-precession cycle is a robust feature in the long-term evolution of the WEP temperature, but its strength varies in time. Our model results further show that the half-precession cycle in the WEP temperature is mainly driven by maximum equatorial insolation, and its strength is modulated by eccentricity and the conditions of CO2 and ice sheets. Our simulated half-precession cycles in the WEP temperature provide a possible explanation for the half-precession signal recorded in proxy records.
Study of the variations of the feeding system at Mt. Etna during the paroxysmal activities by using infrasonic data.
Authors: Amato Gabriele , Minio Vittorio , Sciotto Mariangela , Spina Laura , Watson Leighton M. , Cannata Andrea
Published: March 2024

The maim objective of this work is to investigate the structure of the superficial portion of the plumbing system at Mt. Etna in terms of interconnection among the conduits and internal variations linked to eruptive activity. For this purpose, the lava fountains that occurred in the years from 2011 to 2015 were taken into consideration, for a total of 51 events, and the infrasonic signals recorded by two stations were analysed. We extracted the infrasonic events, and analysed the evolution in time of the spectral content by using normalized and non-normalized pseudospectrograms, peak and mean frequency values. In addition, the sources of the events were located. We noted how, although the eruptions took place at South-East and Voragine craters, the infrasonic events recorded before and after the lava fountains are mostly generated by the North-East Crater. Most of the energy of these events is comprised in the frequency range 0.1 – 2 Hz. Furthermore, in most of the lava fountain episodes, we observed a decrease in the frequency peaks of the infrasonic events after the eruptions. To interpret the variations of the plumbing system responsible for these spectral changes, as well as the interconnection among the conduits feeding the main craters, we model the infrasonic events from the North-East Crater as an acoustic resonance of the crater and conduit, whose length changes with time as magma ascends or descends in the conduit.
Indirect impacts of region-specific heat extremes along the global supply network 
Authors: Wu Xudong , Quante Lennart , Levermann Anders
Published: March 2024

The last decade has witnessed a surging occurrence of extreme heat worldwide. This can directly dampen local production capacity and also induce indirect repercussions through the global supply network. Yet, the cascading effect of region-specific extreme heat may differ greatly, which is by far poorly understood. By combining temperature observations with Acclimate—a dynamic agent-based model, we identify the region-specific temperature threshold for dampening local production and investigate the response of the global supply network to extreme heat in a region-by-region manner. Economic agents with significant repercussions on the globe are identified and indirect benefits along the global supply network from local heat adaptation are revealed. The outcome of this study supports common but differentiated adaptation strategies towards extreme heat.
Integrating groundwater flow models with physical oceanographic models in coastal regions
Authors: Jin Jiangyue , Espino Manuel , Fernández Daniel , Folch Albert
Published: March 2024

Abstract Amidst increasing human activities and complex interactions between the ocean and land, coastal zones have emerged as dynamic yet vulnerable regions within global ecosystems. Understanding the interplay between groundwater and the ocean is crucial for studying submarine groundwater discharge (SGD) and seawater intrusion (SWI), thereby protecting coastal environments and water resources. This study aims to propose a coupling strategy between groundwater flow models and physical oceanographic models to accurately simulate the interactions between coastal groundwater and the ocean.In this research a three-dimensional hydrodynamic model based on TELEMAC-3D was first constructed to simulate marine conditions under varying salinities and temperatures. Subsequently, a groundwater model using MODFLOW6 was developed. An efficient coupling strategy was introduced through the integration of Python, facilitating precise integration of the hydrodynamic and groundwater models. Validation results of the coupled model against published experimental results demonstrated high accuracy, closely replicating laboratory outcomes within acceptable error margins.By combining three-dimensional hydrodynamics with groundwater modeling, this study not only represents an innovative attempt at coupling but also provides a robust tool for understanding the complex mechanisms of interaction between the ocean and land.
Non-line-of-sight GNSS Signal Classification for Urban Navigation Using Machine Learning 
Authors: Pan Yuanxin , Icking Lucy , Ruwisch Fabian , Schön Steffen , Soja Benedikt
Published: March 2024

The reception of non-line-of-sight (NLOS) signals is a prevalent issue for Global Navigation Satellite System (GNSS) applications in urban environments. Such signals can significantly degrade the positioning and navigation accuracy for pedestrians and vehicles. While various methods, such as dual-polarization antennas and 3D building models, have been proposed to identify NLOS signals, they often require additional equipment or impose computational burdens, which limits their practicality. In this study, we introduce a machine learning (ML)-based classifier designed to detect NLOS signals based solely on quality indicators extracted from raw GNSS observations. We examined several input features, including carrier-to-noise density and elevation, and analyzed their relative importance. The effectiveness of our approach was validated using multi-GNSS data collected statically in the city of Hannover. To establish ground truth (i.e., a target) for training and testing the model, we used ray tracing in combination with a 3D building model of Hannover. The developed ML-based classifier achieved an accuracy of approximately 90% for NLOS signal classification. Furthermore, a vehicle-borne data set was used to test the utility of the ML-based signal classifier for kinematic positioning. The performance of the ML-aided positioning solution was compared against a solution without NLOS classification (raw solution) and with the ray-tracing-based classification results (reference solution). It was found that the ML-based solution demonstrated positioning precisions of 0.47 m, 0.55 m and 1.02 in the east, north and up components, respectively. This represents improvements of 64.6%, 33.4% and 36.6% over the raw solution. Additionally, we examined the performance of the ML-based classifier across various urban environments along the vehicle trajectory to gain deeper insights.
The impact of AOD assimilation on surface PM analysis and forecast with the global CAMS system. 
Authors: Flemming Johannes , Ades Melanie , Di Tomaso Enza , Inness Antje , Huijnen Vincent , Jones Luke , Paschalidi Zoi , Razinger Miha , Remy Samuel
Published: March 2024

Surface air pollution is a major hazard for society because of its negative impact on human health, crops yield and on other aspects of the economy. Monitoring the air quality with in-situ instruments is routinely carried out in many countries. These air quality networks have limited coverage. They  are often very sparse or are not even present in many parts of the world, that suffer from the worst air quality.  Satellite observations of atmospheric composition provide the unique prospect to contribute to a more spatially complete monitoring of surface air pollution. However, among several other limitations, only vertically integrated measures of the pollution concentration can usually be retrieved from satellites, and not the surface concentration.  The relation between total column information and surface concentrations depends on the shape of the vertical profile. The correlation may be especially poor in the case of lofted air pollution plumes originating from long range transport.   Data driven methods (machine learning, statistic etc.) are used to infer surface concentrations from satellite observations based on in-situ surface observations. An alternative approach is data assimilation of satellite retrievals in an atmospheric model, a method which has been developed for numerical weather forecasting.  The global forecasting system of atmospheric composition of the Copernicus Atmosphere Monitoring Service (CAMS) applies 4D-VAR data assimilation to satellite retrievals of Aerosol optical depth (AOD), Ozone, Carbon Monoxide and Nitrogen Dioxide (NO2) to correct the model initial conditions and consequently also the PM2.5 and PM10 surface concentrations.  In our presentation, we will give an overview of the usefulness of atmospheric composition (AC) satellite data assimilation for monitoring of surface air quality with the global CAMS system. We will specifically show to what extent AOD assimilation improves the analysis and forecast of surface PM2.5 for different regions and at different temporal and spatial scales. In particular we will discuss the correlation between AOD and PM2.5 in the observations and in the model. We will also discuss the influence of the model performance and aspects of the data assimilation procedure on the impact of AC satellite data assimilation on surface concentrations.
Assessing the vulnerability to climate change of tree species for urban afforestation
Authors: Gala Cristiano , Curci Gabriele , Pace Loretta , Marucci Alessandro , Del Tosto Dina
Published: March 2024

Nature-based solutions are now a key part in climate change adaptation, particularly for urban environments. The integration of natural systems within the urban fabric has the potential to increase cities’ resilience to the predicted changes in climate. Urban forests are one of the most used methods for adding ecosystem services to an urban environment and at the same time address urban-specific climate change challenges such as heat-island effect, intense rainfall and water management. However, the effects of climate change in the long-term on urban forests are not often taken into account when planning interventions such as afforestation. Species selection for urban forests should, among other factors, be based on an assessment of local future climatic conditions, so to ensure the long-term viability of the project. Here we propose a methodology easily applicable to any place in Europe. We use data from interpolated publicly available climate datasets and species distribution data from the European Tree Atlas in order to analyse climatic niches for tree species in Italy. These climatic ranges are then compared to local climatic data, obtained from homogenised time-series measured by a weather station in the city of L’Aquila. The results are summarised in a suitability matrix providing vulnerability scores for each species based on predicted climate changes for the local area. The analysis ranks the species which are less vulnerable to projected future climate conditions. The application to the pilot area of L’Aquila suggests that some species already present will still be suitable also in future climate (e.g. Quercus pubescens) while others will not (e.g. Quercus petraea), and species not traditionally present may become suitable (e.g. Quercus ilex). The importance of obtaining accurate local climate data from observations is a key aspect for municipalities to consider as results of this analysis are greatly dependent on this.
High-resolution simulation of French Polynesia climate
Authors: Casnin Amarys , Bellon Gilles , Hopuare-Klouman Marania , Caillaud Cécile , Laurent Victoire , Martinoni-Lapierre Sophie
Published: March 2024

Islands of French Polynesia, located in the tropical Pacific Ocean, are small – Tahiti, the largest is about 50 km long – and can exhibit complex orography due to their volcanic origin. In order to simulate properly the atmospheric flow and convective motions over these islands, the non-hydrostatic model AROME is used at high-resolution (2.5 km) to produce a 20-year simulation of the climate over the Society Islands as well as part of the Tuamotu archipelago and Austral Islands. This simulation enables to evaluate AROME ability to simulate these island climates, particularly in terms of rainfall and wind.AROME is significantly better than the quasi-hydrostatic regional climate model ALADIN with coarser resolution (20 km) at simulating the climate of French Polynesia, and provides a better description of this climate than the available gridded observation products.By comparing model’s precipitation to observed precipitation at weather stations, results generally show a correct simulation of mean daily rainfall and diurnal cycles. There is however a dry bias for windward stations over Tahiti and a wet bias for leeward stations. These biases remain relatively weak and less pronounced than the biases of other gridded datasets such as IMERG and CMORPH satellite estimates.The model also simulates winds that compare well to in situ observations and other gridded data. The typical island effect on low-level circulation is well simulated by AROME contrary to ERA5 and satellite data.
Pyrogenic Carbon production in eucalypt forests: implications for the carbon cycle in fire-prone ecosystems
Authors: García-Carmona Minerva , Santín Cristina , Doerr Stefan
Published: March 2024

Wildfires play an important role in the carbon cycle, influencing both atmospheric carbon concentrations and terrestrial carbon storage. Pyrogenic carbon (PyC) derived from incomplete biomass combustion during wildfires is currently considered a relevant carbon sink at the global level. In order to assess the quantitative importance of PyC production, accurate data on PyC generation in different ecosystems and under a range of fire conditions are needed. In this study, we focus on the fire-prone continent of Australia, specifically on eucalypt forests, which are the most common type of native forests. Eucalypt forests, subjected frequently to both wildfires and human-prescribed fires, provide an important context for understanding PyC dynamics.We conducted comprehensive pre-fire and postfire fuel inventories and quantified all pyrogenic materials generated in three representative eucalypt forests in Sydney, Melbourne, and Perth. Experimental fires, simulating low to medium-severity wildfires, were used to quantify PyC conversion rates in the main fuel components: forest floor, understory, down wood, and overstory (comprising only tree bark as these fires did not affect the crowns).Our results show an average pyrogenic carbon conversion rate of 24% for eucalypt forests. This translates to 9 t C ha-1 of the carbon affected by the fire being emitted to the atmosphere, while 3 t C ha-1 is transformed into PyC, underscoring the relevance of PyC in carbon budgets from eucalypt forest fires. The conversion rates varied substantially among fuel components, with the bark component exhibiting the highest conversion rate, at approximately 40%, and the down wood component displaying the lowest rate at around 15%. Intermediate conversion values were reported for forest floor and understory components. Given the recurrent nature of fires in eucalypt forests in Australia, both naturally and under human-prescribed conditions, our findings suggest that PyC production plays a significant role in the carbon cycle, of sufficient magnitude to be considered in global carbon budget estimations.