bluuebunny/crossref_metadata_2025 huggingface dataset:
An adaptive and flexible Climate Risk Assessment Framework for regions
Authors: Bachmann Michaela , Mechler Reinhard , Higuera Roa Oscar , Pirani Anna , Pal Jeremy , Reimann Lena , Mazzoleni Maurizio , Buskop Ted , Mysiak Jaroslav
Published: March 2024

With climate change increasingly affecting people, assets and the environment, Climate Risk Assessments (CRA) are seeing strong attention for understanding the scope and scale of climate risks in order to plan and implement adaptation and climate risk management responses.In the context of the EU Horizon 2020 project CLIMAAX we developed an inclusive and harmonized CRA framework adapted for NUTS-1 and NUTS-2 level. This framework aligns with state-of-the-art methodologies and is further complemented by a user-friendly toolbox tailored for risk quantification across European regions. Our approach integrates insights from UCPM documents, European National Adaptation Plans and Strategies, peer-reviewed literature as well as existing CRA frameworks and international standards to respond to needs, recent advancements and best practices in the CRA field. The framework was collaboratively developed with five European pilot regions to ensure feasibility and applicability while pursuing adaptive flexibility.The practical need of the CRA framework led to a five-step assessment cycle (with special emphasis on key risk assessment as a novelty), underpinned by a conceptual context addressing principles, technical choices (e.g. future scenarios) and participatory processes. The framework allows for toolbox extension (the risk analysis) as well as indicates entry points for Climate Risk Management and Adaptation options thereby creating a feedback loop within the CRA cycle. To address compound and multi-hazards aspects of risk, the framework is designed to tackle complexity by referring to a variety of options such as workflows for climate risk quantification or qualitative options together with participatory processes and stakeholder inclusion.The developed CRA framework brings together practical needs and scientific, standardized knowledge. However, further insights are needed to efficiently connect climate risk estimations with climate risk management and adaptation strategies to support communities and regions in their efforts towards building climate resilience.
Study of stable isotope in daily precipitation for the lower Brahmaputra region at Guwahati.
Authors: Nanda Madhusmita , Nair Archana M
Published: March 2024

This study analysed the stable isotopic composition of daily precipitation from a monitoring station established in Guwahati located near the bank of the lower Brahmaputra region. Between September 2022 and December 2023, the precipitation samples were collected for hydrogen and oxygen stable isotope analysis. The analysis was performed following the conventional analytical procedure for laser-based, off-axis integrated cavity output spectroscopy (ICOS) in Liquid Triple Isotopic Water Analyser (L-TIWA). The preliminary study helps to define Local meteoric water line (LMWL) in the Lower Brahmaputra region. The pre-monsoon samples show regression line with slope lesser and an intercept greater than Global meteoric water line (GMWL), but the monsoon samples are showing a trend line similar to GMWL. The smaller intercept difference in the pre-monsoon and monsoon rainwater samples indicates the moisture sources of precipitation in this region originating from the Indian summer monsoon more than the western disturbances. The enrichment of heavier isotopes in precipitation of different seasons might be the result of a complex interplay between atmospheric circulation, moisture sources, elevation effects, and transport processes. Further analysis by using air mass back trajectories models and GIS tools will be able to understand and correlate the diverse origin of moisture and observed daily isotopic variability.
Evaluation of the heat shelters availability in the city of Lyon, during a hot summer day at the end of the century.
Authors: David Damien , Salles Marjorie
Published: March 2024

At the end of the century, during the hot summer days, the thermal environment will be unbearable in most of the outdoor spaces of the cities. The few locations where the thermal environment will remain moderate will constitute heat shelters. The present study analyses the evolution of the quantity and the nature of the outdoor heat shelters, in a 27km2 central portion of the Lyon conurbation, during a hot summer day that is representative of the climate at the end of the century.A specific methodology has been applied to perform such an analysis. The weather data for the representative hot summer day (RHSD) was selected within a database of weather projections made available by the CORDEX project. The RHSD represents weather conditions that may happen statistically once every 5 years, during the 14th of July, in Lyon, at the end of the century. Then, mean radiant temperature and operative temperature predictions were performed using the SOLWEIG micro-meteorological model. The heat shelters were defined as the outdoor locations where the operative temperature is below 37°C. With this definition, the heat shelters may not provide thermal comfort, but prolongated stays in the heat shelters would be safe for most of the population. The quantity of available heat shelters was measured through the heat shelter area per capita, which represents the total of the area covered by the heat shelters divided by the number of inhabitants in the domain.During the RHSD, the heat shelters area goes below  per capita between 10:15 and 17:45, and reaches  between 15:00 and 16:00. During this period, the outdoor public domain is not able to provide heat shelters. This result suggests that people will have to adapt their way of life to the disappearance of heat shelters in the core of the afternoons, in order to avoid prolongated stays in the outdoor public environment.The observation of the heat shelter maps reveals that, between 9:00 and at 19:00, the heat shelters are exclusively located within shaded areas. Continuous tree covers are more efficient than buildings to provide heat shelters: between 13:00 and 14:00, heat shelters are exclusively located in the core of the urban forests. In the streets, the capacity of shaded areas to provide heat shelters highly depends on the presence of surfaces (buildings façade or soil) that reflect the solar radiation toward the shaded areas. This result invites to rethink the way climate adaptation solutions should be designed in cities.
Biotic and abiotic  heterogeneity show contrasting GPP and growth trends in mediterranean forests
Authors: Dalmonech Daniela , Vangi Elia , Collalti Alessio
Published: March 2024

The Mediterranean basin is a well-known drought-prone region, making forest ecosystems potentially vulnerable to drought episodes, heat waves and dry spells. In the last two decades, extreme weather events affected different regions of Europe including mediterranean áreas. This led to significant impacts on forest ecosystems, with extensive mortality events, episodes of crown dieback, and identified reduced tree growth at local level. The predictive abilities to depict early warning signals of negative extreme-induced impacts, well before that the mortality event might occur, are pivotal for monitoring Mediterranean forests. The 3D-CMCC-FEM model, a detailed ecophysiological process-based model, is here applied at gridded level over the Basilicata region, in southern Italy. The model is run on a regular 1x1 km grid for the period 2005-2019 to simulate, among others, gross primary productivity, carbon allocation and tree growth, processes which are controlled by abiotic, e.g. meteorological conditions, and biotic factors, e.g. trees reserve pools, in a mechanistic manner. This modeling approach allows discriminating the degree of decoupling of  carbon assimilation, and tree growth , e.gcarbon woody accumulation. As a result of such interaction between processes and factors, the model  highlighted different emerging patterns of the system under investigation. In particular, results show pronounced differences between European beech dominated areas and oaks dominate areas of the region. Generally, despite a significant drop of summer GPP in beech forests and an overall negative GPP trend, in accordance with remote-sensing based data, the tree growth rate is still positive. Oppositely, the oaks dominated forests show contrasting patterns, with areas where positive trends in GPP can be accompanied by positive but even negative trends in tree growth. The 3D-CMCC-FEM is shown to identify areas which might be prone to statistically significant negative trends in tree growth and, thus, likely to be prone to higher mortality risk in the near future. Indeed, these negative growth trends can not be explained only in terms of forest aging, but also in terms of abiotic factors. Our results show how the diverse degree of coupling between assimilation and growth between different species might be predicted by the model and leading to increase our capability to detect early signals of declining growth, which might already occur in spite of an apparent full recovery after a drought event at canopy level.
Perspectives on the Desert dust Contribution to Ice Nucleation in Mixed-phase Clouds and Associated Radiative Forcing
Authors: Pérez García-Pando Carlos , Chatziparaschos Marios , Costa-Surós Montserrat , Gonçalves Ageitos María , Georgakaki Paraskevi , Nenes Athanasios , Kanakidou Maria , van Noije Twan , Le Sager Philippe , Kanji Zamin A. , Brodrick Philip , Grant Kathleen
Published: March 2024

Wind-driven erosion of arid and semi-arid surfaces produces desert dust, the primary source of ice-nucleating particles (INP) in the atmosphere. These particles play a crucial role in the phase partitioning of mixed-phase clouds (MPCs) by influencing heterogeneous freezing processes. As global warming progresses, the shift from ice to liquid water in MPCs is anticipated to increase cloud reflectivity, potentially cooling the planet. However, the uncertainty surrounding this negative cloud-phase feedback is substantial, mainly due to uncertainties in the magnitude, spatiotemporal distribution, and trends of INP.In dust-enriched environments, MPC glaciation is intricately linked to dust abundance and INP efficiency. Increased dust concentrations may enhance ice crystal formation, reducing overall cloud albedo and inducing a positive radiative effect, thereby diminishing the negative cloud-phase feedback. Currently, significant knowledge gaps impede the accurate representation of INP abundance, trends, and physical/chemical properties, hindering our understanding of its impact on ice formation in MPCs and climate.This review assesses the current state-of-the-art in representing and quantifying the contribution of desert dust to ice nucleation in MPCs and its associated radiative forcing. Additionally, we offer a perspective on how new observational constraints, such as historical dust trends, satellite retrievals of quartz and feldspar surface abundances, recent measurements of mineral size distributions and mixing state at emission, and improved modeling with tailored ageing schemes, could help mitigate the existing uncertainties in estimating dust forcing via interactions with mixed-phase clouds.
Geochemical characterization of Mediterranean Outflow Waters in the modern ocean: Nd isotopes, carbon cycle and new export constraints
Authors: Pena Leopoldo D. , Campderrós Sara , García-Solsona Ester , Paredes-Paredes Eduardo , Frigola Jaime , Rodríguez-Díaz César Nicolás , Lucas Arturo , Calvo Eva , Pelejero Carles , Cacho Isabel
Published: March 2024

The North Atlantic Ocean plays a critical role in the global circulation system, regulating the penetration of surface waters into the deep ocean, but also in key ocean biochemical cycles (e.g. carbon, oxygen, nutrients). Meridional heat and salt transport (i.e. buoyancy) drive the formation of different water masses and their circulation pathways. A relatively unknown but important element controlling the net meridional export of heat, salt and other chemical species into the North Atlantic is the Mediterranean Outflow Water (MOW): the salt injector. In this work, we present the first high resolution systematic study of traditional (T, S, Nutrients) and novel (Nd isotopes, alkalinity, pH) geochemical parameters of MOW waters from its source area at the Strait of Gibraltar up to the northern Iberian margin (Cantabric Sea). During the TRANSMOW cruise in spring 2021, over 500 seawater samples were collected along the main MOW pathway following its northward flow. A comprehensive suite of geochemical parameters including εNd, alkalinity, pH and preformed nutrients were analyzed for these samples. We show that MOW can be ‘traced’ unequivocally using εNd as a conservative tracer, a feature that opens a new set of possibilities to better estimate the contribution of MOW export to higher latitudes in the North Atlantic Ocean. Other parameters directly linked to the carbon cycle (alkalinity and pH) are also controlling the distinctive chemical properties of the Mediterranean waters.. One of the key advantages of these geochemical tracers is that they allow to better quantify export and mixing rates of MOW with North Atlantic waters. Using statistical tools such as the Optimum Multi-Parameter Analysis (OMPA) on an array of conservative tracers we have quantified mixing rates and exports between different water masses. These results will be fundamental to better constrain paleoreconstructions in the sedimentary record using different proxies such as Nd and B isotopes (for water mass distribution and pH), B/Ca ratios (for seawater carbonate ion saturation) and even new experimental proxies such as Na/Ca (for salinity).
Constraining electrification of volcanic plumes through numerical simulation
Authors: Herzog Michael , Nair Vishnu , Van Eaton Alexa , Mansell Ted
Published: March 2024

Technological improvements over the past decade have dramatically increased lightning detection from explosive eruptions worldwide. The underwater Hunga Tonga-Hunga Ha’apai volcano eruption in January 2022 in Tonga produced more lightning than any storm yet documented in the modern satellite era. These observations of volcanic lightning capture the imagination of the public and provide novel ways to monitor explosive hazards in near real time. In this presentation, we present the first results from the numerical simulation of the electrification of a volcanic plume using the volcanic plume model ATHAM. The electrification mechanisms of fracto-emission and triboelectrification along with the macroscopical transport of the charge carrying plume components have been modelled in ATHAM to make this the first numerical model to quantify volcanic electrification. We also present first results of discrete lightning discharges which are diagnosed as continuous branching regions defined by local net charge density and electric potential. 

The enhanced modelling capability of ATHAM opens new routes into the study of explosive eruptions and nowcasting of volcanic ash hazards for aviation and downwind communities. 
Simulated response of urban drainage networks to heterogeneous precipitations
Authors: Costamagna Elisa , Boano Fulvio , Ridolfi Luca
Published: March 2024

In urban areas, drainage networks are usually formed by small subnetworks, hence resulting in small-sized basins with fast times of response. For this reason, the prediction of pluvial flood hydrographs in urban basins is hampered by considerable uncertainty due to the spatial and temporal variability of rainfall intensity, which is difficult to characterize with the sparse observations from the limited amount of rain gauges that are typically available. To better understand and quantify this uncertainty, the drainage network of Turin is considered as a case study. The city of Turin has >800.000 residents and is located in Northwestern Italy on a relatively flat area bordering a hill on the East. The area is mostly urbanized, and it receives an average precipitation of around 800 mm per year. The drainage network was developed since the end of the 19th century as a separate network that receives only stormwater from a catchment area of around 100 km2, for a total network length of around 1200 km. At present, the network experiences some criticalities due to infrastructure ageing and urban development, and occasional flooding episodes are observed at some points.The sensitivity of flood hydrographs at the basin outlet to spatial and temporal patterns of rainfall intensity is analyzed using a SWMM hydraulic model of different parts of the drainage networks. Spatial and temporal variability of rainfall intensity over the area is quantified using the observations of a set of 20 rain gauges. Then, the analysis of the sensitivity of the flood hydrograph in a monitored subnetwork is performed based on two rain gauges (2 km apart) and one flow meter at the basin outlet. The results provide valuable insight into the response of urban drainage networks to heterogeneous spatial fields of precipitation.
Measuring Greenhouse Gas Exchange from Paddy Field Using Eddy Covariance Method in Mekong Delta, Vietnam
Authors: Vu Hoang Ngoc Khue , Jocher Georg , Le D. A. Vu , Le T. Son , Bui T. An , Ho Q. Bang , Pham Q. Huong
Published: March 2024

Agriculture is an important economic sector of Vietnam, the most common is wet rice cultivation. Wet rice cultivation is known as the main contributor to national greenhouse gas emissions. To better understand greenhouse gas exchange in wet rice cultivations and to investigate the factors influencing carbon cycling and sequestration in these types of ecosystems, since 2019, the first eddy covariance station has been installed in a paddy field in Long An province, Mekong Delta, Vietnam. The station is equipped with state-of-the-art equipment for CO2 and CH4 gas exchange and meteorological ancillary measurements. Data from the station are processed following the ICOS recommendations (Integrated Carbon Observation System) for CO2. For CH4, data are separately processed and gap-filled using a random forest model from methane-gap fill-ml, a machine learning package, as there is no standard method for CH4 flux gap-filling yet. Finally, the CO2 equivalent (CO2eq) based on CO2 and CH4 fluxes was estimated. The study area implemented a new water management practice called alternate wetting and drying, which helps to save water and reduce methane emissions. This practice resulted in the minor release of 0.8 kg CH4 per hectare in 2020 and 0.67 kg CH4 per hectare in 2021. However, CO2eq from the rice fields was negative, indicating that the rice fields acted as a sink for CO2eq, with -5.54 kg CO2eq per hectare in 2020 and -7.03 kg CO2eq per hectare in 2021. On a provincial level, rice cultivation activities in Long An, with a total area of 498293 ha, resulted in a CO2eq uptake of 2760 and 3503 tons in 2020 and 2021, respectively. This result is in contrast to the initial hypothesis that rice fields are a source of greenhouse gases. However, N2O was not investigated in this study, which is also known as a strong greenhouse gas.
The heat flow data assessment project: Transformation of the global heat flow database
Authors: Neumann Florian , Fuchs Sven , Norden Ben , Balkan-Pazvantoğlu Elif , Petrunin Alexej , Elbarbary Samah , Jennings Samuel , Elger Kirsten , Frenzel Simone , Ott Nikolas , Maes Stephan , Data Assessment Group Global Heat Flow
Published: March 2024

Since its establishment in 1963, the International Heat Flow Commission (IHFC) has fostering and curating the Global Heat Flow Database (GHFDB). The dynamic nature of techniques and methodologies used in heat-flow density determination has necessitated regular updates to the database. Despite its widespread utility, the GHFDB faces challenges arising from variations in measurement techniques and data quality. Ongoing efforts are dedicated to overcoming these challenges, aiming to elevate the database's accuracy and reliability, thus solidifying its value within the scientific community. Multiple iterations of the GHFDB exist, primarily focused on characterizing the quality of individual heat-flow data points. However, the establishment of a new, authenticated GHFDB demanded the development of a fresh reporting standards for heat-flow data submitted to the IHFC. This new framework, derived from a collaborative global initiative, incorporates 62 metadata fields. This comprehensive approach became imperative due to the escalating volume of data and the diverse methodologies employed, necessitating a standardized scheme to evaluate the quality of heat-flow density determinations consistently. This update provides insights into the community-driven initiative initiated in 2021, targeting the reassessment of approximately 1,414 publications containing 73,033 global heat-flow data points. A noteworthy aspect of this initiative is the introduction of a novel quality scheme, unifying three independent criteria into a combined score. This score encompasses quantified uncertainty, methodological quality, and the status of overruling effects. The integration of these criteria facilitates a swift comparison of heat-flow data, instantly revealing any missing data or inadequately documented information. The introduction of this quality scheme empowers users to efficiently select reliable heat-flow values tailored to their specific research purposes.
Real-time monitoring the hydrothermal outgassing of the active Campi Flegrei caldera through seismo-acoustic observations
Authors: Delle Donne Dario , Morelli Rebecca Sveva , Caliro Stefano , Soldovieri Maria Grazia , Benincasa Aldo , Buonocunto Ciro , Bobbio Antonella , Caputo Antonio , Gammaldi Sergio , Nardone Lucia , Rufino Francesco , Orazi Massimo
Published: March 2024

Fumarolic and hydrothermal activities represent the shallow evidence of volcanic degassing within calderas, offering valuable insights for volcano monitoring. This phenomenon is particularly significant at the Pisciarelli fumarolic field in the Campi Flegrei caldera, Italy, where a continuous and vigorous release of hydrothermal and magmatic fluids occurs. This fumarolic outgassing is also associated with a persistent harmonic tremor and a persistent subtle infrasonic wavefield. Following the recent bradyseismic crisis at Campi Flegrei caldera, we established a permanent seismo-acoustic array to enhance real-time monitoring of temporal changes in fumarolic outgassing in Pisciarelli area. In particular, we exploited the seismo-acoustic wavefield produced by outgassing to assess its intensity and dynamics. Notably, we identified two distinct infrasonic sources, concurrently active and linked to 1) intense boiling in a water pool and 2) overpressurized steam release from fumarolic vents. The well-correlated temporal variations in infrasonic and seismic amplitudes offer insights into the hydrothermal system's outgassing mechanism. Specifically, they shed light on changes in the shallow hydrothermal reservoir pressure changes driving the outflow of hydrothermal gas. The integration of acoustic and seismic observations enhances our understanding of the dynamic nature of fumarolic outgassing at Campi Flegrei caldera. This improved understanding contributes to assessing volcanic risk for the caldera, as any modifications in fumarolic outgassing may indicate pressure changes in the hydrothermal reservoir. 
Photogrammetry as a tool to study the formation and evolution of aeolian ripples on a flat bed eroded by impact
Authors: Carpy Sabrina , Collet Aurore , Valance Alexandre , Ould el Moctar Ahmed , Massé Marion , Mangold Nicolas
Published: March 2024

The experiments of aeolian impact ripples are carried out in a wind tunnel at atmospheric pressure and temperature. A spatial and temporal study of wavelength, flux and friction velocity correlated with the appearance and development of aeolian impact ripples has been studied using photogrammetry. Digital Elevation Models have been generated, providing a wealth of information such as spatial evolution, temporal evolution, wavelength, erosion rate, migration speed and mass flow rate. In particular, we seek to relate ripple migration velocities to the mass flow rate of the system and the retroactive effect of aeolian impact ripples on the mass flow rate for different flow velocities.This experimental study focuses on morphological changes of aeolian impact ripples and their migration velocity at different evolution stages for grain size ~310 µm in order to investigate if there is a difference in wavelength between initial formation and full development time. We also investigate aeolian impact ripples development conditions according to saturated and unsaturated flux.
Assessment of the correlation between site-specific nonlinear soil behavior for Japanese KiK-net stations and geological, geotechnical parameters 
Authors: Loviknes Karina , Bergamo Paolo , Cotton Fabrice , Fäh Donat
Published: March 2024

The geometry and soil conditions at a site can strongly influence the ground shaking induced by an earthquake and an important part of seismic hazard assessment is therefore to characterize such site effects. At stiff sites and for weak ground motions, the soil response behaves linearly, however, for larger ground motions and softer sites the site response becomes nonlinear and thus more challenging to assess. Because recordings of such strong shaking are rare, nonlinear soil parameters are often defined from laboratory measurements and numerical simulations. However, the increase of available ground motion data, in particular from sites with recordings from both weak and strong motions, has increased the possibility of deriving nonlinear site parameters directly from empirical data. In this study, we take advantage of the comprehensive KiK-net network in Japan, consisting of stations with recording instruments at both surface and at depth. We use the surface-to-depth ratios of each event recorded by each station, to systematically capture the empirical effects of nonlinear soil response on the local response. Station-specific parameters for the degree of nonlinearity and PGA thresholds for the onset of nonlinear behaviour are then derived and the statistical correlation between these parameters and a selection of geotechnical and geological indicators are investigated. Our results show that - although finding site parameters suitable for predicting nonlinear site effects remains challenging as the nonlinear soil-behaviour is largely site-specific - proxies describing the depth to bedrock, sediment thickness and characterization of the shallowest part of the soil layer display a certain degree of potential for prediction.
Ambient noise interferometry to investigate temporal changes in the São Jorge Island (Azores) subsurface structure associated with the 2022 seismic crisis. 
Authors: Silveira Graça , Carvalho Joana , Schimmel Martin , Mendes Virgílio , Dias Nuno , Custódio Susana , Fontiela João , Hicks Stephen P. , Ferreira Ana
Published: March 2024

In March 2022, a seismic crisis was declared in São Jorge Island. Despite the regular seismotectonic activity observed in the Azores Central Group, São Jorge has not exhibited significant activity since the crisis associated with an eruption in 1964. Between the fall of 2021 and the end of 2022, approximately 12,000 earthquakes (magnitudes up to ML 3.8) have been recorded, with the seismicity and geodetic modelling pointing to a magmatic intrusion. Intrusions cause gas release, fluid circulation, and pressure perturbations in the subsurface volcanic system that often induce changes in seismic velocity. Here, we probe spatial-temporal changes in the seismic velocity structure beneath São Jorge using ambient noise interferometry.In this study, we analyzed data continuously recorded between January 2021 and December 2022 by two permanent stations (PMAN and ROSA) operated by the Instituto Português do Mar e da Atmosfera (IPMA) to investigate the presence of subsurface structural changes in response to the seismic crisis. Data were cut into 1-hr length files and filtered between 1 and 3 Hz for autocorrelation, and between 0.1 and 1.0 Hz for cross-correlation. We applied the Phase Auto- and Cross-Correlation (PAC and PCC) method to the filtered data. This method is based on phase coherence and is amplitude-unbiased. PAC and PCC functions were then linearly stacked over three days to achieve a stable noise response. To infer changes in the velocity structure, we analyzed the waveform similarity values for different time lag windows. We compared the waveform similarity results with meteorological data and ground deformation inferred from GPS. Additionally, relative velocity changes have been estimated. The two analyzed stations exhibit different waveform-similarity results. Preliminary interpretation of PMAN results (closer to the island center) show, in the second half of 2022, a very slight recovery of the waveform similarity at shorter lag times (shallower depths) that decreases again in the fall of the same year. Globally, data from this station exhibits a more systematic decorrelation when the crisis was declared, most likely due to perturbations in the seismic structure between < 8 - 10 km and deeper than 15 km. This work is a contribution to RESTLESS (DOI:10.54499/PTDC/CTA-GEF/6674/2020) and GEMMA (DOI:10.54499/PTDC/CTA-GEO/2083/2021). It was also funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC) – UIDB/50019/2020 (https://doi.org/10.54499/UIDB/50019/2020), UIDP/50019/2020 (https://doi.org/10.54499/UIDP/50019/2020) and LA/P/0068/2020 (https://doi.org/10.54499/LA/P/0068/2020).
A machine-learning-based approach for predicting the geomagnetic secular variation
Authors: Sato Sho , Toh Hiroaki
Published: March 2024

We present a machine-learning-based approach for predicting the geomagnetic main field changes, known as secular variation (SV), in a 5-year range for use for the 14th generation of International Geomagnetic Reference Field (IGRF-14). The training and test datasets of the machine learning (ML) models are geomagnetic field snapshots derived from magnetic observatory hourly means, and CHAMP and Swarm-A satellite data (MCM Model; Ropp et al., 2020). The geomagnetic field data are not used as-is in the original time series but were differenced twice before training. Because SV is strongly influenced by the geodynamo process occurring in the Earth's outer core, challenges still persist despite efforts to model and forecast the realistic nonlinear behaviors (such as the geomagnetic jerks) of the geodynamo through data assimilation. We compare three physics-uninformed ML models, namely, the Autoregressive (AR) model, Vector Autoregressive (VAR) model, and Recurrent Neural Network (RNN) model, to represent the short-term temporal evolution of the geomagnetic main field on the Earth’s surface. The quality of 5-year predictions is tested by the hindcast results for the learning window from 2004.50 to 2014.25. These tests show that the forecast performance of our ML model is comparable with that of candidate models of IGRF-13 in terms of data misfits after the release epoch (Year 2014.75). It is found that all three ML models give 5-year prediction errors of less than 100nT, among which the RNN model shows a slightly better accuracy. They also suggest that Overfitting to the training data used is an undesirable machine learning behavior that occurs when the RNN model gives accurate reproduction of training data but not for forecasting targets.
Supercooled liquid water representation with the LIMA 2-moment microphysical scheme during the ICICLE field campaign
Authors: July Wormit Mareva , Vié Benoît , Lac Christine
Published: March 2024

Supercooled cloud water is the source of a meteorological phenomenon with significant societal challenges: icing. Icing occurs when supercooled water droplets freeze upon contact with a solid surface and is even more intense with larger drops, resulting in stronger accretion. Anticipating the icing risk is crucial to ensure aviation safety, as ice on the fuselage can lead to a loss of lift. Icing as well occurs on wind turbines and train catenaries, making it a concern for both energy and transport sectors.Supercooled water is often underestimated in numerical models. Our objectives are first to assess the two-moment microphysical scheme LIMA (Vié et al., 2016), second to identify the physical processes which are responsible for the lesser supercooled water before improving them.To this end, numerical simulations of the research model Meso-NH (Lac et al., 2018) are compared to the observations of the ICICLE measurements campaign (https://www.eol.ucar.edu/field_projects/icicle). This airborne campaign was launched in February 2019 from Rockford (USA) by the USA’s Federal Aviation Administration. During 29 flights, microphysical parameters as the mixing ratio and the size of liquid and icy hydrometeors have been measured. These observations form an exceptional data set for studying the microphysical behaviour of models.19 days, including all the 23 research flights of the campaign, were simulated. An extensive evaluation of the simulations was carried out, both on a flight-by-flight basis using Meso-NH’s flight simulator, and statistically combining observations from all flights. During the campaign, several cases of classical freezing rain, and lake effect situations, were sampled, allowing for a robust evaluation of model performance in these situations.For lake effect cases, supercooled liquid water is forecast down to −30 °C, and mixed phase clouds are present between 0 °C and −10 °C, but cloud are almost completely icy around −20 °C. In freezing rain events, the precipitation tends to freeze again below the warm part of the cloud. To identify the sources of supercooled liquid water underestimation, a detailed analysis of microphysical processes budgets is performed. The impact of aerosols on forecasts is also investigated, using in-situ aerosol observations and CAMS reanalyses.
The role of water vapor and cloud radiative effects in monsoons: Perspectives from retrograde Earth simulation
Authors: Jalihal Chetankumar , Mikolajewicz Uwe
Published: March 2024

In a retrograde Earth simulation using the fully coupled MPI-ESM, we find that the climate in the Sahara goes from arid to monsoonal. By understanding this transition of the Sahara, we can gain insights into some of the key processes necessary for the existence of monsoons. We find that theories of monsoons based on land-sea thermal contrast and meridional shifts in the interhemispheric convergence zone (ITCZ) are not adequate to explain this change in the climate of the Sahara. Hence, we use the energetics of monsoons, which is based on local moist static energy and moisture budgets. In the regular forward-rotating Earth, the net energy input into the atmospheric column (NEI) is negative over the Sahara, implying a net energy import over the region. The reversed winds in the retrograde simulation advect moisture from the Arabian Sea and the equatorial Atlantic into the Sahara during the boreal summer. The greenhouse effect of water vapor instantaneously reduces the outgoing longwave radiation, thereby increasing the NEI. As NEI becomes positive, the Sahara exports energy, increasing convection (and, hence, monsoon precipitation). The increased cloud cover further enhances NEI through cloud radiative feedback, strengthening the monsoon. Therefore, we conclude that the radiative effects of water vapor and clouds are an essential ingredient for monsoons.
Analyzing Large-Scale Sediment Connectivity in a Central Asian Catchment Using Geospatial Datasets
Authors: Schwedhelm Hannah , Rüther Nils
Published: March 2024

Estimations of sediment transport capacities and sediment connectivity are of high importance for water management at the catchment scale. Large-scale modelling techniques are helpful tools to give insights of such sediment budgets. However, these modelling techniques often require locally obtained characteristic values of the river sections, such as discharge measurements or river width values. Obtaining such information by in situ measurements or remote sensing data can get time- and cost-intensive, especially in remote and mountainous regions. Instead, several geospatial datasets with global coverage exist and can fill these gaps, if used adequately. We, therefore, adjusted the CASCADE model toolbox to work with freely available geospatial datasets as input parameters and exemplarily applied it to the Naryn River in Central Asia, which includes five artificial dam structures. The river characteristics such as slope and width were taken from the SWORD river database, and the hydrological information was taken from the Flo1K dataset. With the adjusted CASCADE model, we obtained information on sediment transport capacities in the catchment at the reach scale. As the model also accounts for sediment connectivity, we identified deposition- and erosion-prone areas and, therefore, localized sediment sinks and sediment sources in the catchment. The results showed that the large dams in the catchment influence the sediment budget significantly, for example by reducing the sediment transport capacities upstream, by trapping sediments in their reservoirs and by increasing the sediment entrainment downstream. Since sediment connectivity is an important parameter for ecosystem health and sustainable river management, such qualitative assessments of the sediment connectivity within large catchments can be helpful for prioritizing sediment management measures and be a basis for informed planning of more sustainable hydropower plants.
Building a useful dataset for ICON output
Authors: Kluft Lukas , Kölling Tobias
Published: March 2024

Global kilometer-scale climate models produce vast amounts of output, posing challenges in efficient data utilization. For ICON, we addressed this by creating a consolidated and analysis-ready dataset in the Zarr format, departing from the previous cumbersome directory structure. This new dataset format provides a comprehensive overview of variables and time steps at one glance.To ensure swift and ergonomic access to the dataset, we employ two key concepts: output hierarchies and multidimensional chunking. We remapped all output onto the HEALPix grid, facilitating hierarchical resolutions, and pre-computed temporal aggregations like daily and monthly averages. This enables users to seamlessly switch between resolutions, reducing computational burdens during post-processing.Spatial chunking of high-resolution data further allows for efficient extraction of regional subsets, significantly improving the efficiency of common climate science analyses, such as time series and vertical cross-sections. While our efforts primarily integrate established strategies, the synergies achieved in resolution have shown a profound impact on the post-processing efficiency of our global kilometer-scale output.In summary, our approach, creating a single analysis-ready dataset, pre-computing hierarchies, and employing spatial chunking, addresses challenges in managing and extracting meaningful insights from increasingly large model output. We successfully tested the new analysis-ready datasets during well-attended hackathons, revealing significant usability and performance improvements over a wide range of real-life applications.
Pacific climate variability and its regional impacts in warmer, stabilised climates
Authors: Dittus Andrea , Maher Nicola , King Andrew , Sengupta Aditya
Published: March 2024

The El Niño Southern Oscillation (ENSO) in the tropical Pacific is the main mode of inter-annual climate variability and a key driver of regional climate across much of the globe. Future changes in its behaviour are highly policy-relevant as they would have large impacts across many regions and significantly affect ecosystems and livelihoods. In this presentation, we explore how ENSO variability evolves in multi-century experiments under fixed atmospheric concentrations of greenhouse gases, where global mean surface temperatures are slowly stabilising.We show how ENSO variability and its teleconnections change in a range of climate models and experimental designs. Idealised projections under fixed atmospheric concentrations of greenhouse gases across multiple levels of global warming, from 1.5°C to 5°C, are evaluated for the UK Earth System Model 1 alongside abrupt forcing experiments with the Community Earth System Model 1. We also include closely related experimental designs, such as emission-driven stabilisation experiments with ACCESS-ESM-1.5. The differences in how ENSO and its teleconnections respond to further warming in long, multi-century experiments under constant or slowly declining forcing conditions are compared and contrasted to the expected ENSO changes in rapidly warming, transient climate change projections. These differences are important to understand in the context of ambitious mitigation scenarios that aim to stabilise global temperatures at, or below, the Paris Agreement temperature targets. Preliminary results suggest that future ENSO variability is model dependent, but withing a single model framework independent of the level at which warming is stabilised at. 
Paleomagnetism and Relative Paleointensity of Estremenho Limestone Massif stalagmites, from Portugal
Authors: Dinis Rafael , Font Eric , Parés Josep , Carmo Janine , Trindade Ricardo , Vilhena Luís , Reboleira Ana Sofia , Hasözbek Altug , Jimenez-Barredo Fernando , Carvalho Emanuel
Published: March 2024

Speleothems magnetism is considered an excellent recorder of short-lived variations of the Earth’s magnetic field. Here we provide new geochronological, petrographic, paleomagnetic, and rock magnetic data of a stalagmite from the Estremenho Limestone Massif (from Central Portugal). The stalagmite was dated at 114.7 (±1.5) k.y. B.P. to 106.3 (±1.6) k.y. B.P. based on the U-Th series. This time interval is coeval with the age of the Blake Geomagnetic Excursion (~116.5 ± 0.7 k.y. B.P. and 112.0 ± 1.9 k.y. B.P.). Petrographic observations under a binocular stereo microscope of two thin sections located at the lower part of the stalagmite and scanning electron microscopic observation of rock fragments show the alternance of porous and compact columnar calcite and dendritic calcite, which are typical features of primary calcite precipitation. No significant gap in the calcite growth was identified along the two thin sections. After alternating field demagnetization, a viscous secondary magnetization was cleaned below 10 mT, followed by a primary magnetization pointing to the origin. Magnetic vectors have an average declination of 60.3° with a mean inclination of 20.1°. No geomagnetic excursion or reversal was identified along the stalagmite. Analysis of Isothermal Remanent Magnetization curves shows the presence of two components. Component 1 has a mean coercivity of ~35 mT and DP ~0,20-0.25, typical of pedogenic/detrital magnetite, and contributed to 75% of the total remanence. Component 2 has a mean coercivity of ~95 mT and DP ~0.30, interpreted as being hematite, and contributing to 25% of the total remanence. We also calculated relative paleointensity (RPI) based on the Pseudo-Thellier method. The RPI curve exhibits a consistent and gradual increase from the base to the top of the stalagmite, with a pattern of variation comparable to the reference curves of marine sediments from the Portuguese margin, in the same time interval. In summary, petrographic and magnetic data point to a primary origin for the calcite precipitation and the corresponding remanent magnetization. The absence of the record of the Blake excursion in this stalagmite still remains to be resolved. This work was supported by the SAMEPA project funded by FCT (ref. PTDC/CTA-GEO/0125/2021) and is part of the Ph.D. of Rafael Dinis (FCT-10216.2022.BD).
A long-term soil erosion modeling example in Central Europe over the last 150 years.
Authors: Falcao Raquel , Babuljaka Adam , Mazancová Martina , Dostál Tomáš , Van Rompaey Anton , Kaim Dominik , Krasa Josef
Published: March 2024

Land use and climate change are the main anthropogenic factors influencing soil erosion (Borrelli et al., 2020), the former providing instant and abrupt effects. This justifies the profusion of related studies and their relevance in providing support for public policies. Europe acknowledges this importance, as the 8th EAP includes the goal of no net land take by 2050. The Rimov catchment, in the southern part of the Czech Republic and partly in Austria, has undergone many land use changes in the region over the last 150 years. It has undergone two opposing processes in terms of their contribution to soil erosion potential: on one hand, agricultural land has been left for spontaneous vegetation recovery (therefore, reducing its potential for soil erosion); on the other hand, the enlargement of parcel size after the collectivization of agriculture has the potential to increase soil erosion. In addition, long-term soil erosion modeling should consider the effect of the change in the rain erosivity factor (R-factor), with the calibration of the model done with the rainfall data covering the study period, which will be considered on the hydrological modeling prior to the soil erosion modeling in this study. Using the WATEM/Sedem model, we analyze whether the regeneration of vegetation has been enough to counteract the effects of an increasing R-factor in the Rimov catchment.Research has been supported by project TUDI (European Union's Horizon 2020 research and innovation programme under grant agreement No 101000224) and by Program CELSA-fonds (Project The impact of depopulation on ecosystem services in Europe. A Pilot study in France, Czech Republic, and Poland No 3E220627)ReferencesThe European Parliament and the Council of the European Union, Decision (EU) 2022/591 of the European Parliament and of the Council of 6 April 2022 on a General Union Environment Action Programme to 2030. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32022D0591, 2022Borrelli, P., Robinson, D. A., Panagos, P., Lugato, E., Yang, J. E., Alewell, C., Wuepper, D., Montanarella, L., & Ballabio, C. (2020). Land use and climate change impacts on global soil erosion by water (2015-2070). Proceedings of the National Academy of Sciences, 117(36), 21994–22001. https://doi.org/10.1073/pnas.2001403117