bluuebunny/crossref_metadata_2025 huggingface dataset:
Overlapping US-Australia fire seasons reduce the window of opportunity for firefighting cooperation
Authors: Ribeiro Andreia F. S. , Richardson Doug , Quilcaille Yann , Batibeniz Fulden , Pitman Andrew , Zscheischler Jakob
Published: March 2024

Wildfires are a growing global challenge. In addition to becoming more widespread and intense due to climate change, the fire seasons in many regions are becoming longer. The lengthening of fire seasons reduces the window of opportunity for preparedness (e.g. prescribed burning of dry fuels before fire season onset) and increases the likelihood of spatially compounding fire risks due to overlapping fire weather seasons. These increased risks demand efficient global cooperation in sharing firefighting resources (e.g. helicopters, planes, firefighters), and of major concern, is how well-established international arrangements may be compromised or disrupted in the near future.Here we investigate increasing fire season lengths across two distanced fire-prone regions with typically distinct fire seasons and a long-term collaboration in sharing firefighting resources, Eastern Australia (EAU) and Western North America (WNA). We aim to test the hypothesis that spatially compounding fire weather events occur due to overlapping fire weather seasons, based on the Canadian Fire Weather Index (FWI). To robustly characterize the potential overlap, we make use of CMIP6 single model initial-condition large ensembles (SMILEs) for historical and future periods, and the ERA5 reanalysis. We define Fire Weather Days (FWD) as when the FWI exceeds a climatological threshold specific to each region, and we then estimate the total number of overlapping FWD per year for different time periods.We show that these distanced regions are becoming more likely to experience periods of overlapping FWD, which can compromise the human response in terms of firefighting. Most of the overlap occurs during boreal Autumn months, coinciding with the end of the fire season in WNA and the beginning of the fire season in EAU. Correlations between the number of overlapping FWD and the length of the regional fire season suggest that the main driver of the overlapping is the increasing early start of the fire season in EAU, rather than the late offset of the fire season in WNA. Additionally, we find that overlapping FWD is expected to increase in the future in a warming climate. As fire seasons overlap, the existing international collaborations will be increasingly constrained, and the window of opportunity for firefighting will shorten. 
Investigating the volcanic activity on Venus with Magellan data
Authors: Sulcanese Davide , Mitri Giuseppe , Mastrogiuseppe Marco
Published: March 2024

Previous studies have inferred volcanic activity on Venus from indirect evidence, including variations in atmospheric composition and thermal emissivity data [1, 2, 3]. More recently, a study hypothesized ongoing volcanic activity on Venus, evidenced by a volcanic vent that collapsed between two different Magellan observing cycles [4]. Expanding upon this premise, we are investigating the surface geology of Venus using the extensive radar and altimetric data acquired by the Magellan spacecraft.In particular, by properly processing the SAR images, we are conducting a detailed geomorphological analysis of Venus' surface, in order to identify and characterize various surface morphologies. Additionally, the altimetric data provided valuable insights into the topographical variations across Venus, further contributing to the geomorphological assessment.Our research not only enhances the understanding of the geology of Venus but also underscores the significance of radar imaging in the study of planetary surfaces, where no other imaging techniques are available. The findings highlight the crucial role of continued exploration of Venus, which could be greatly advanced by upcoming missions such as VERITAS and EnVision [5, 6]. Equipped with superior radar technology, these missions are expected to provide images of Venus's surface at an unprecedented resolution and signal-to-noise ratio, far surpassing that of the Magellan SAR, thus enabling a more detailed characterization of Venus's surface morphology. References1. Truong, N. & Lunine, J. Volcanically extruded phosphides as an abiotic source of Venusian phosphine. Proceedings of the National Academy of Sciences 118, e2021689118 (2021).2. Esposito, L. W. Sulfur dioxide: Episodic injection shows evidence for active Venus volcanism. Science 223, 1072-1074 (1984).3. Smrekar, S. E. et al. Recent hotspot volcanism on Venus from VIRTIS emissivity data. Science 328, 605-608 (2010).4. Herrick, R. R. & Hensley, S. Surface changes observed on a Venusian volcano during the Magellan mission. Science, eabm7735 (2023).5. Hensley, S. et al. VISAR: Bringing Radar Interferometry to Venus. In Proceedings of International EnVision Venus science workshop, Berlin, Germany (2023).6. Ghail, R. C. et al. VenSAR on EnVision: Taking earth observation radar to Venus. International journal of applied earth observation and geoinformation 64, 365-376 (2018).AcknowledgmentsG.M., D.S., and M.M. acknowledge support from the Italian Space Agency (2022-15-HH.0).
The experiment of the effects of rainfall intensity and substrate depth of an extensive vegetated roof
Authors: Grečnárová Jana , Danáčová Michaela , Tomaščík Matúš
Published: March 2024

Nowadays, extreme precipitation events are becoming more and more prevalent, which, in somesituations, can cause serious problems and damage. To avoid the impacts of extreme rainfall events,blue-green infrastructure elements are used to retain and slow down stormwater runoff. Examples arevegetated (green) roofs, widely considered a promising nature-based solution for urban stormwatermanagement.This experiment is focused on studying the influence of the retention capacity and the depth of theselected commercial substrate of extensive vegetated roofs. The rainfall intensity testing aims todemonstrate and explore new insights into vegetated roofs during severe extreme precipitation. Theactual experimental process was performed under laboratory conditions, where extreme rainfallintensities (2 - 4 mm/min) with a duration of 15 minutes were subsequently simulated using a rainfallsimulator. The main identifier of the quality and capability of the substrate used on the vegetated roofis the amount of runoff captured from the simulated rainfall intensity. The measured outputs will beused as inputs to predictions reducing stormwater runoff. The knowledge gained and the differentvariations of the simulations can significantly help in constructing and designing vegetated roofs andeffective urban stormwater management.Keywords: precipitation, retention capacity, vegetated roof, runoff,
The Cimmerian Dobrogea Aspiring Geopark from Romania: raising awareness on the geological heritage
Authors: Briceag Andrei , Seghedi Antoneta , Radan Silviu , Apotrosoaei Vlad
Published: March 2024

The Cimmerian Dobrogea Aspiring Geopark territory, located in the eastern part of Romania, covers an area of approximately 2,500 km2, overlapping 28 localities. It is a region with unique natural and cultural heritage, that includes an early alpine folding (Cimmerian), starting in the Upper Triassic, which reworks Paleozoic formations with a Hercynian history. The Geopark territory includes two paleontological reserves and 94 geosites, one of the most important being Deșli Caira Hill, a candidate for the international stratotype (GSSP) of the base of Anisian. The cultural heritage includes tumuli (isolated or grouped), fortresses and castra along the fortified border of the Roman Empire in the province of Moesia inferior, inner fortresses, but also many other archaeological sites, which prove a continuous habitation in this region since the Paleolithic. To raise awareness on the geological heritage, the Geopark team started a dialogue with local administration officials and school representatives to emphasize the exceptional value of the territory, by the integration of the geological, natural, and cultural elements. Thus, to highlight the geoheritage, plans are in motion to create a museum that will exhibit the geopark's most representative geological assets. In order to support the growth of this awareness campaign, our newly created Citizen Science Platform will be used. Citizen Science encourages the participation of non-professional citizens in scientific research that helps generate knowledge and information. The concept encompasses scientific activities that use volunteer "citizen researchers" for data collection, analysis, and dissemination of science, thereby consolidating their knowledge about geological heritage values.
Mapping thermal conductivity in Ireland to determine geothermal potential
Authors: Chambers Emma L. , Kiyan Duygu , Pasquali Riccardo , Fullea Javier , Meere Pat , Lebedev Sergei , Bean Chris , O'Reilly Brian
Published: March 2024

High-quality maps of the geothermal gradient and temperature are essential when assessing the geothermal potential of a region. However, determining geothermal potential is a challenge when direct measurements of in situ temperature and thermal property information are sparse, as is the case in Ireland. In addition, individual geophysical methods are sensitive to a range of parameters, not solely temperature. We develop a novel approach to determine the geothermal gradient using a joint geophysical-petrological thermochemical inversion (Chambers et al. Tectonophysics (2023) & Fullea et al. GJI (2021)), which requires seismic surface wave data, thermal property data, and additional geophysical and petrophysical datasets. The multi-parameter models produced by the integrated inversions fit the surface-wave, heat flow and additional data, revealing the temperature, lithospheric structure and geothermal gradient within the crust and mantle.Here we present the new methodology and resulting models of Ireland’s subsurface temperature with a focus on new thermal conductivity measurements and their impact on temperature. A new map of thermal conductivity (TC) for all of Ireland was generated using all existing measurements of thermal conductivity, in addition to 609 new measurements from the optical scanning technique and 86 using the Divided Bar Apparatus (DB) which we use in the inversion. Our new methodology produces results comparable to past temperature and geophysical measurements and models. Importantly, the maps are within error of direct borehole temperature measurements, providing confidence in the results. Lithospheric and crustal thickness play a key control on the temperature gradient with areas of thinner lithosphere resulting in elevated geotherms. In some locations, we observe geotherms elevated beyond expectations which result from high radiogenic heat production from granitic and muddy limestone rocks. This new methodology provides a robust workflow for determining the geothermal potential in areas with limited direct measurements. The final temperature model updates previous maps of Ireland and will be used for future geothermal exploration and utilisation.
Estimating methane emissions at high northern latitudes using regional data and global inverse modelling
Authors: Basso Luana , Rödenbeck Christian , Brovkin Victor , Georgievski Goran , Göckede Mathias
Published: March 2024

Atmospheric methane levels (the second largest contributor to climate change) have more than doubled over the last 200 years, though with highly variable trends over time. The relative contribution of different sources and sinks to the global CH4 budget remains uncertain despite ongoing efforts to improve the estimates based on various approaches, and particularly the causes for an accelerated increase in recent years remain unclear. Therefore, understanding and quantifying methane sources at global to regional scales is essential to reduce uncertainties in the global methane budget and its feedback with the climate system.Within the Arctic region, wetlands and lakes constitute a major natural source of methane. With temperatures rising at rates at least twice the global average over the last decades, Arctic permafrost is increasingly thawing. Associated disturbance processes hold the potential to increase methane emissions, and as a consequence result in a positive feedback to climate change. However, until now neither observations nor model estimates could provide clear evidence of such a trend in emissions. As a consequence, current and possible future contributions of Arctic ecosystems to the accelerated increase in the global atmospheric methane levels remain highly uncertain.To help reduce methane emission uncertainties in the high northern latitudes, we estimated global CH4 fluxes to the atmosphere using the Jena CarboScope Global Inversion System, with a strong focus of our analysis on the Arctic region. We used wetland flux from JSBACH model as prior and assimilated atmospheric observations from regional networks available over the last years for the region above 60°N latitude (a total of 23 towers) to quantify the methane emissions over this region between 2010 to 2020. We found a clear seasonal pattern with emission peaks during July and August. As a sensitivity test to evaluate the improvement to constrain the Arctic methane fluxes with the assimilation of the regional data, we also conducted an inversion using just the global background surface stations (a total of 30 global stations). We found higher mean annual methane flux to the atmosphere when assimilating the regional data, with the largest difference between May to August. These estimates were finally evaluated against an ensemble of inverse model estimates from Global Methane Project available for the period between 2010 to 2017.
Study of the Interplanetary Coronal Mass Ejection of November 3, 202
Authors: Arrazola Pérez David , Blanco Ávalos Juan José , Hidalgo Moreno Miguel Ángel
Published: March 2024

Interplanetary coronal mass ejections (ICMEs) transport magnetized plasma from the Sun. Magnetic clouds (MC) are closed structures immersed within ICMEs and form large-scale magnetic flux ropes. Their evolution in the solar wind is linked to the interaction with the surrounding solar wind and the magnetic force. In addition, these structures play a fundamental role in the propagation of solar energetic particles and cosmic rays observed by analyzing the flux variations of these particle populations. On November 3, 2021, one of these structures was observed at different solar distances by instruments aboard Solar Orbiter (SO) and instruments in Earth orbit.Magnetic clouds are closed structures immersed within interplanetary coronal mass ejections. These structures have an important effect on the propagation of solar energetic particles and cosmic rays that is observed as variations in the flux of these particle populations. The evolution of a MC observed on November 3, 2021, is analyzed using in situ observations made by Solar Orbiter (SO), at 0.84 AU, and ACE, at 1 AU, spacecrafts when they were aligned with the Sun. The magnetic configuration of the MC is described using a magnetic model by observing its evolution at both heliodistances and the effect on solar energetic particles and cosmic rays.
C2risk: Co-creating climate management tools for mobility infrastructures
Authors: Olano Pozo Jon Xavier , Boqué-Ciurana Anna , Skrynyk Oleg , Brichese Marianna , Panico Francesco , Calicchio Mario , Pantaneschi Serena , Balart Adrià , Dermitt Daniel , di Meglio Maurizio , Foria Federico , Miceli Gabriele , Aguilar Enric
Published: March 2024

Climate variability and change are societal challenges, necessitating urgent and comprehensive responses across many sectors. To confront these challenges effectively, these sectors must devise and execute adaptation and mitigation strategies. Such strategies should focus on minimising contributing factors to climate change and bolstering resilience against its repercussions. The urgency of these measures stems from the recognition that climate change permeates virtually every facet of our environment and daily life, calling for a concerted and enduring effort to safeguard our planet for future generations. A critical component of this endeavour is understanding the influence of meteorological and climatic conditions on specific sectors.We have embraced a co-creation methodology that actively includes stakeholders to tackle the complexities of climate variability and change, as Font et al. (2021) suggested. This methodology is particularly pertinent to critical infrastructures at various levels. Our inclusive approach gathers many participants, from high-ranking executive managers to hydrogeology specialists. This diversity in perspectives and expertise guarantees that the solutions devised are comprehensive and precisely tailored to meet the distinct needs and contexts of the mobility infrastructures affected by climate change. Such a collaborative process cultivates innovation while fostering a sense of ownership and commitment among all stakeholders, thereby enhancing the effectiveness and durability of the solutions.Our case study, executed in the Italian regions of Campania and Lazio, demonstrates the varied risks present in these areas and how they change over time and space. For this study, we utilized ERA5 land data, specifically downscaled to reconstruct historical climate scenario, and Cordex data for future climate projections. This presentation aims to transcend the mere explanation of climate data and show the whole process and journey to transform data into a climate service to assist decision-making in the mobility infrastructure sector. It is conveyed through an intuitive and reactive visual medium via a Shiny application crafted for accessibility to a diverse audience. This application proficiently exhibits the various calculated co-created indices over multiple intervals, rendering tailored information and making it more user-friendly and engaging for non-academic and non-climate-related users. Such a presentation style is instrumental in enhancing comprehension of climate change impacts and aiding in informed decision-making
Changes in the multipath value at ASG-EUPOS GNSS reference network stations in 2010-202
Authors: Tomaszewski Dariusz , Pelc-Mieczkowska Renata , Rapiński Jacek
Published: March 2024

The multipath phenomenon is one of the factors affecting the accuracy of GNSS positioning. It results from reflections of the satellite signal from objects in the vicinity of the GNSS antenna. There are groups of techniques that allow minimizing the impact of this error on positioning results. These include: antenna placement, the use of the appropriate type of antenna, the use of a professional receiver as well as proper post-processing of observations. However, it is impossible to completely eliminate the influence of multipath on the measurement results. In the case of carrier phase differential positioning, this error has two main effects. First of all, the multipath increases the initial search space for correct ambiguities. Consequently, the accuracy of the vector solution between the reference station and the rover receiver is affected. The authors of this article examined how the characteristics of the multipath error changed at the stations of the Polish network of ASG-EUPOS reference stations in 2010-2021. Two computational strategies were adopted to determine the multipath: Code Minus Carrier linear combination (CMC) and pseudorange multipath observable (MP). Based on the research, it was found how the multipath values changed depending on the change of the receiver and the terrain around the reference stations. It was determined which stations had high multipath values in 2010 and what changes occurred over the 11 years. Based on the carried out analyses, it was also recommended to perform periodic tests that would allow it to detect incorrect configuration or incorrect operation of receivers.
The impact of the expansion and contraction of China’s cities on CO2 emissions,2002-2021,evidence from integrated nighttime light data
Authors: Qian Jiaqi , Cai Danlu
Published: March 2024

Urbanization induced carbon dioxide (CO2) emissions have attracted widespread attention.A comprehensive attribution analysis model is designed to understand the inherent uncertainties in diagnosing the effects of urban expansion dynamics and modes on carbon dioxide (CO2) emissions. First, 68 selected cities across China are categorized into three types, including expanding, contracting, and staying cities, through developing an evaluation indicator system by integrating population, economy, construction, and social information. Next, the carbon dioxide (CO2) emissions of the cities were quantified. The Lasso method was employed to select the factors influencing CO2 emissions. For cities with different development modes, the XGBoost regression model with SHAP algorithm was employed to calculate the contribution rate of various factors to carbon emissions in different types of cities. Additionally, the analysis considered the temporal changes of these factors.The main conclusions are as follows:(i)Comparing urban built-up areas extracted from the nighttime light dataset with China's national land use and cover change dataset, the results reveal a minimum correlation of 0.72-0.82 and an average overall accuracy of 78%.(ii)The urbanization process of 68 cities exhibits a predominant pattern of normal fluctuations, with a coexistence of expansion and contraction. The results indicate that over the past 20 years, expanding cities have been concentrated mainly in coastal regions such as the Yangtze River Delta and the Pearl River Delta, while contracting cities are primarily found in inland areas characterized by traditional industrial cities. It is observed that the development processes of most cities involve an initial phase of intensive expansion (or contraction), followed by a gradual trend towards stability in the later stages.(iii)The factors influencing carbon emissions in expanding and contracting cities share commonalities and differences. Population and energy efficiency both have significant impacts on carbon emissions in different types of cities. For expanding cities, the impact of green area on carbon emissions is more pronounced. Conversely, in contracting cities, the influence of foreign trade is more significant.
Encoding the drag-based model in the artificial intelligence training process to predict CMEs’ travel times
Authors: Guastavino Sabrina , Piana Michele , Massone Anna Maria , Marchetti Francesco , Benvenuto Federico , Bemporad Alessandro , Susino Roberto , Telloni Daniele
Published: March 2024

The study of space weather impacts of coronal mass ejections (CMEs) requires the formulation, implementation and validation of predictive approaches to address issues such as the arrival of CMEs to Earth and, if so, its arrival time and speed. The problem of predicting the CMEs’ travel times has been addressed by means of empirical models, physics-based models, and artificial intelligence techniques. In this talk, we propose a physics-driven artificial intelligence (AI) method, in which we encode physical information into the process of neural network training. Specifically we include the drag-based model in the definition of the loss functions to minimize during the training process of a cascade of two neural networks fed with both remote sensing and in situ data. We show that including physical information in the AI architecture improves its predictive capabilities and the proposed physics-driven AI method leads to more accurate and robust results for the CMEs’ travel time prediction with respect to the purely-data driven AI approach.
Robust increase in CO2 effective radiative forcing in warmer climates
Authors: Smith Chris , Watson-Parris Duncan , Kramer Ryan , Andrews Timothy , Gjermundsen Ada , Mutton Harry , Feng Jing , Paynter David , Chadwick Robin , Douville Hervé , Roehrig Romain
Published: March 2024

The effective radiative forcing (ERF) is a robust predictor of future equilibrium warming. It is generally assumed that the ERF depends only on changes in atmospheric constituents and is independent of the background climate state. Building on recent work demonstrating that, in contrast, the instantaneous radiative forcing (IRF) for CO2 is strongly state-dependent, we show that the ERF for CO2 also increases in warmer climate states. We analyse a 4×CO2 atmosphere-only forcing in both control and warmer climate states in eight CMIP6-era models. Four models participated in the Cloud Feedback Model Intercomparison Project (CFMIP) which used pre-industrial SSTs in its control state and SSTs from near the end of the same model’s coupled abrupt-4×CO2 run in its warm state. In the other four models we used an AMIP climatology as the control state and a uniform increase in SSTs of 4 K above this AMIP climatology in the warm state. All eight models show an increase in 4×CO2 ERF, ranging from 0.1-0.5 W m-2, translating to a relative increase of 0.02-0.09 W m-2 K-1 or 0.2-1.1 % K-1. The increase is statistically significant in five of the eight models.Our findings have implications for derivation of simplified relationships of climate warming, for instance in the calculations of global warming metrics and in economic models, from which future climate change risks being underpredicted without a temperature adjustment.We also run aerosol forcing experiments under the +4 K climate, for which there is less agreement between models, but some show large changes in aerosol ERF under the warmer climate state, with potential implications for our ability to discern transient warming even with a more accurate understanding of present-day aerosol forcing. 
Prehistoric human hand-footprints on the central tibetan plateau after the post last glacial maximum
Authors: Gao Yuhai
Published: March 2024

Abstract: The adaptation and survival of prehistoric humans in the alpine and hypoxic environment of the Tibetan Plateau is the focus of multidisciplinary research. As an important prehistoric human hand-footprints site for the study of prehistoric human activities on the Tibetan Plateau, Quesang site has witnessed prehistoric human arrivals in the area at least twice, which occurred in the Middle Pleistocene, about 200ka and the early Holocene, about 7.2ka. The early and middle Holocene hand-footprints are distributed on the spring deposits near the modern active hot springs, which are distributed downstream along both sides of the gully. During a recent field investigation, we found a series of prehistoric human footprints and trampling marks on the travertine in the middle and lower reaches of the active spring. Through the stratigraphic and geomorphological analysis of travertine deposit, 3D modeling and morphological study of hand-footprints, as well as U-Th and OSL dating of hand and foot prints and strata, we have obtained the following results: Modern active hot springs were formed after 18ka, and a large amount of travertine was deposited near the spring mouth, on both sides and downstream of the gully. The newly discovered footprints and trampling marks are distributed on the middle and lower travertine sedimentary fans of the gully, which are formed in ~ 8.8ka and ~ 14ka, respectively. In the extremely cold and anoxic environment of the Tibetan Plateau, Quesang hot spring is undoubtedly a very attractive survival resource, attracting ancient humans to patronize here frequently for a long time. The discovery of hand-footprints also provides new evidence for the expansion and occupation of prehistoric humans on the Tibetan Plateau.Keywords：Post Last Glacial Maximum, hand-footprints, travertine, Quesang spring, prehistoric human activities
Observations of internal wave generation in Madeira island 
Authors: Reis Jesus , Gomiz-Pascual Juan , Peliz Álvaro , Caldeira Rui , Bruno Miguel
Published: March 2024

There is a considerable number of coastal regions where the interaction of barotropic tidal currents with the stratified water column over seamounts or sill topographies generates large amplitude internal waves. An example of this is the internal bores generated around the main sill of the Strait of Gibraltar. It is known that the vertical mixing induced by these phenomena induces a relevant biological response in both the generation place and remote areas. The present work analyses the generation of this kind of internal waves in the northern half of the submarine ridge between Madeira and the Desertas Islands (Portugal). Here, the interaction of a rather intense barotropic tidal current with the stratified water column and the abrupt ridge topography leads to the creation of hydraulic jumps that evolve into internal bores and solitons, which radiate outwards from the sill. These bores can be formed at both sides of the sill (eastern and western sides) in synchrony with the barotropic flow direction. The hydraulic jump that gives rise to the internal waves is generated after supercritical conditions are established over the sill (internal Froude number, Fr >1). While supercritical conditions prevail, the internal bore stands trapped on the downstream side of the sill. With the weakening of the barotropic current, the supercritical conditions are lost (Fr
Astronomical pacing and abrupt changes in North Atlantic biogenic sedimentation during the latest Miocene and Early Pliocene: the IODP Site U1562 case study
Authors: Karatsolis Boris Theofanis , Sinnesael Matthias , 395/395C scientists Expedition
Published: March 2024

The latest Miocene and Early Pliocene (7-3.6 Ma) include key paleoclimatic and paleoceanographic events such as the Messinian Salinity Crisis (MSC), the late Miocene to Pliocene biogenic bloom (hereafter referred as “biogenic bloom”) and its potential termination, as well as the warm early Pliocene, a commonly used analogue for future global warming. Limited information exists regarding how these events impacted North Atlantic ocean circulation and carbonate sedimentation, mainly due to the lack of continuous, high-resolution records in high latitudes. During the summers of 2021 and 2023, the International Ocean Discovery Program (IODP) Expeditions 395C and 395 drilled a transect of five sites in the North Atlantic (at ~60°N). Preliminary results indicate that IODP Site U1562 has continuous sediment recovery, significant variations in carbonate content, as well as good preservation of calcareous fossils across the latest Miocene to Pliocene, making it a suitable candidate for high-resolution paleoclimatic reconstructions. Here, we estimate carbonate sedimentation and paleoproductivity for this site using high-resolution X-Ray fluorescence (XRF) records, derived from elemental intensities measured in core half-sections. Ratios between biogenically derived and detrital elements reveal the orbitally controlled pacing of carbonate production/deposition, as well as a stepwise, sustained decrease in biogenic sedimentation that occurred during the early Pliocene. The latter shift could have been linked to ocean current reorganizations related to the termination of the MSC or the “biogenic bloom”. Finally, we use a cyclostratigraphic approach to explore the possibility of building an astronomically tuned age model for this site using the XRF records.
Towards a metabolic theory of catchments: scaling of water and carbon fluxes with size
Authors: Bassani Francesca , Fatichi Simone , Bonetti Sara
Published: March 2024

Allometric scaling relations are widely used to link biological processes in nature. They are typically expressed as power laws, postulating that the metabolic rate of an organism scales as its mass to the power of an allometric exponent, which ranges between 2/3 and 3/4. Several studies have shown that such scaling laws hold also for natural ecosystems, including individual trees and forests, riverine metabolism, and river network organization. Here, we focus on allometric relations at watershed scale to investigate “catchment metabolism”, defined as the set of ecohydrological and biogeochemical processes through which the catchment maintains its structure and reacts to the environment. By revising existing plant size-density relationships and integrating them across large-scale domains, we show that the ecohydrological fluxes (representative of metabolic rates of a large and diverse vegetation assemblage) occurring at the catchment scale are invariant with respect to its average above-ground biomass, while they scale linearly with the basin size. We verify our theory with hyper-resolution ecohydrological simulations across the European Alps, which represent an ideal case study due to the large elevation gradient affecting the availability of energy and water resources. Deviations from the isometric scaling are observed and ascribable to energy limitations at high elevations. Remote sensing data from semiarid and tropical basins are also used to show that the observed scaling of water and carbon fluxes with size holds across a broad spectrum of climatic conditions.
The value of spatially-differentiated  catchments descriptors for predicting characteristics of hydrological events in German catchments
Authors: Ziani Chahinaz , Ribbe Lars , Aala Safae , Tarasova Larisa
Published: March 2024

Catchments descriptors are widely used in hydrological science to infer dominant hydrological processes, identify, and transfer information across catchments and scales. However, persistent use of descriptors aggregated as spatially-lumped values (i.e., catchment averages), without considering their spatial variability within catchments might hamper the efficiency of these tasks. In this study, we use interpretable machine learning to investigate the value of topographically enhanced catchment descriptors (i.e., weighting them using distance to outlet, distance and height to the nearest drainage and stream order) belonging to seven distinct categories (i.e., climate, topography, land use, geology, hydrogeology, soil physical properties, and soil water properties) for predicting mean values, variability and seasonality characteristics of hydrological droughts and runoff events occurred in 401 German catchments in the period 1979-2002.We found that the spatially-differentiated catchment descriptors aggregated with topographical enhancing are able to predict droughts and runoff events characteristics more accurately than the lumped descriptors. The improvement is particularly promising for prediction of runoff event characteristics. Particularly, descriptors aggregated using height above the nearest drainage and stream order are essential for accurate prediction of variability of runoff events characteristics, while the proximity to the stream and to the outlet are more relevant for predicting their seasonality. In case of droughts, the descriptors weighted by the proximity to the stream improve the predictions of the variability and seasonality of duration and severity (i.e., deficit volume) of hydrological droughts. Moreover, we show that spatially-differentiated aggregation has the potential to identify the importance of descriptors that appeared irrelevant when aggregated in lumped way, particularly shading a light on the role of mean annual potential evapotranspiration and forest land cover descriptors for the prediction of mean values and seasonality of time scale of runoff events, and the role of groundwater yield and wetland land cover to predict the variability of time rise of runoff events. Our study highlights that development of the methods for spatially-differentiated aggregation has potential to disentangle the effects of different physio-geographical controls on event response in different catchments and to improve its predictability in ungauged locations.
 Evaluation of Some Atmospheric Transmittance Indices Over Nigeria
Authors: Obasi-oma Oluwatosin , Emmanuel Israel , Ojo Olushola , Adeyemi Babatunde
Published: March 2024

Atmospheric transmittance, encompassing parameters such as the clearness index, cloudiness index, and transmitting index, plays a pivotal role in the transfer of electromagnetic energy in the atmosphere. This research aimed to enhance our understanding of solar energy availability by investigating these transmittance indices across specific locations in Nigeria's diverse climatic zones. By analyzing satellite hourly data from MERRA-2 spanning ten years, the diurnal and spatial distribution patterns of solar radiation parameters and transmittance indices were examined. The research identified distinct patterns in the radiation parameters and transmittance indices. In the morning hours, radiation parameters exhibited an increasing trend from coastal to inland locations, while the afternoon period showed a reverse pattern for diffuse solar radiation. Clearness and transmitting coefficient demonstrated consistent increases from the coast inland during both morning and afternoon hours, whereas the cloudiness index displayed an opposite pattern. Moreover, the transmittance indices showed a gradual reduction from west to east during the evening. Coastal regions experienced average annual values of 100W/m2 for diffuse solar radiation, 1443W/m2 for direct solar radiation, and 500W/m2 for global solar radiation, while Sahelian regions recorded 104W/m2, 2081W/m2, and 678W/m2, respectively. The clearness index ranged from 0.35 to 0.54, the cloudiness index ranged from 0.15 to 0.46, and the transmitting coefficient ranged from 0.19 to 0.45 across the studied locations. The observed distribution patterns provide valuable insights into solar energy availability within Nigeria's climatic zones. The contrasting patterns between morning and afternoon periods suggest variations in atmospheric conditions. Importantly, the study emphasizes the significance of the transmitting coefficient in characterizing atmospheric transmittance and its role in defining radiation transfer variables. In conclusion, this research contributes to existing knowledge by evaluating atmospheric transmittance indices and their distribution patterns in specific locations across Nigeria. The findings underscore the importance of considering the transmitting coefficient alongside other parameters to accurately assess solar energy availability. Understanding these indices and their variations is essential for the effective utilization and management of solar energy resources.
Quantification of Temporal Variability of Soil Hydraulic Properties in an Agricultural Plot 
Authors: Kumar Saurabh , Srivastava Ajit Kumar , Ojha Richa
Published: March 2024

An improved understanding of temporal variability of soil hydraulic properties (SHPs) can lead to better prediction of soil water dynamics in agricultural fields. This study aims to quantify the temporal variations and trends in SHPs of an experimental agricultural plot in IIT Kanpur during rice and wheat crop seasons. Statistical analysis is performed to investigate the effects of crop-cover, sampling time and depth on temporal variability of SHPs. The soil samples were collected in 6 plots at depths of 10 cm, 25 cm, and 50 cm for the period 2022-23. The samples were analysed for variations in organic carbon content, bulk density (ρb), saturated hydraulic conductivity (Ksat) , saturated moisture content (θs), and soil water characteristic curve. The results show significant temporal variations in ρb and θs. The lowest temporal variation in observed in organic carbon content. The temporal trends in SHPs for both rice and wheat crops offer valuable insights into the dynamic nature of soil behaviour during crop cultivation. The findings of this study will contribute to better understanding of soil-water relationships, aiding farmers in optimizing irrigation practices and promoting sustainable agricultural management for improved crop productivity.
Coupled ensemble simulations of the Northern Hemisphere ice sheets at last two glacial maxima 
Authors: Patterson Violet , Gregoire Lauren , Ivanovic Ruza , Gandy Niall , Cornford Stephen , Sherriff-Tadano Sam
Published: March 2024

Coupled climate-ice sheet models can capture important interactions between the ice sheets and the climate that can help us better understand an ice sheet's response to changes in forcings. In this respect, they are a useful tool for simulating future ice sheet and sea level changes as a result of climate change. However, such models have large uncertainties related to the choice of climate and ice sheet parameters used. The same processes that operate today, also occurred in glacial times, and previous work has shown that simulating the North American ice sheet at the Last Glacial Maximum (LGM; ~21 ka BP) provides a strong benchmark for testing coupled climate-ice sheet models and recalibrating uncertain parameters that control surface mass balance and ice flow (Gandy et al., 2023).Here, we build on this work by performing the first coupled FAMOUS-BISICLES simulations of the last two glacial maxima, including all Northern Hemisphere ice sheets interactively. The ice sheet component of this model is capable of efficiently simulating marine ice sheets, such as the Eurasian ice sheet, despite the high computational cost of higher order physics. We simulate and compare both the LGM and the Penultimate Glacial Maximum (PGM; ~140 ka BP), since both periods displayed major differences in the distribution of ice between Eurasia and North America. Uncertainty is explored by running ensembles of 120 simulations, randomly varying the uncertain parameters controlling ice sheet dynamics and climate through Latin Hypercube Sampling. We also work on improving the representation of ice streams in the model through performing internal ice temperature spin ups and sensitivity tests varying till water drainage properties. The ensemble members are evaluated against empirical data on ice sheet extent and ice stream location to find combinations of parameters that produce reasonable simulations of the North American and Eurasian ice sheets for both periods. We determine the impact of the uncertainty in these parameters on the result and whether both ice sheets show similar sensitivities to the model parameters. These simulations will provide a starting point for analysing some of the interactions between the climate and the ice sheets during glacial periods and how they may have led to different ice sheet evolutions.
A reassessment of the role of atmospheric and oceanic forcing on ice dynamics at Jakobshavn Isbræ, Ilulissat Icefjord
Authors: Picton Hannah , Nienow Peter , Slater Donald , Chudley Thomas
Published: March 2024

Jakobshavn Isbræ (Sermeq Kujalleq) has been the largest single contributor to mass loss from the Greenland Ice Sheet over recent decades. Previous work has emphasised the dominant role of oceanic forcing on ice dynamics, with the short-lived (2016-2018) advance, deceleration and thickening of Jakobshavn attributed to decreased ocean temperatures within Disko Bay. Here, we use satellite imagery to extend observations of ice dynamics at Jakobshavn Isbræ between 2018 and 2023. We then employ hydrographic measurements, weather station data, and modelled estimates of surface runoff, to explore the role of climatic forcing on ice dynamics over this most recent five-year period. Between 2018 and 2022, Jakobshavn Isbræ accelerated significantly, with peak summer terminus velocity increasing by 79%, from 9.4 to 16.8 km/yr. Despite sustained surface lowering, peak solid ice discharge also increased, rising from 39.4 Gt/yr in 2018 to 54.7 Gt/yr in 2021. Whilst the initial onset of re-acceleration occurred in 2019, a dramatic speedup occurred between May and August 2020, with ice velocity increasing from 7.6 to 13.8 km/yr. In contrast to previous years, ice velocity remained high throughout the subsequent winter, thereby facilitating a peak velocity of 16.8 km/yr in July 2021.Jakobshavn Isbræ exhibited a typical seasonal calving cycle of winter advance and summer retreat throughout 2018 and 2019. However, a clear switch in dynamics was observed in 2020, with the terminus undergoing minimal readvance over the winter months. This shift coincided with a clear reduction in the extent of rigid mélange within Ilulissat Icefjord, in contrast to preceding years. Although sparse, hydrographic measurements indicate that the mean water temperature within Disko Bay was ~ 0.75⁰C higher in 2020, relative to 2019.We argue that the initial onset of reacceleration and thinning at Jakobshavn Isbræ was driven primarily by atmospheric forcing, with annual runoff in 2019 approximately double that observed in the other years. Furthermore, we emphasise that at glaciers close to floatation, such as Jakobshavn, surface thinning can significantly impact buoyant flexure, and hence rates of calving. However, we also provide evidence of oceanic forcing, postulating that increased water temperatures reduced the formation of rigid mélange in 2020, thereby facilitating sustained calving and elevated ice velocities throughout the winter months. Our study therefore highlights the critical importance of considering both atmospheric and oceanic forcing when investigating and predicting the future behaviour of ice dynamics at marine-terminating outlet glaciers.
Dynamic recrystallization within Europa’s ice shell: Implications for solid-state convection 
Authors: Mitri Giuseppe
Published: March 2024

Solid-state convection has been proposed to occur within Europa’s ice shell based both on the interpretation of observed geological activity during Galileo spacecraft exploration and theoretical investigations. Laboratory experiments have investigated the effect of grain size insensitive creep and grain size sensitive creep on the ductile behaviour of polycrystalline ice. The ice grain size and the ice impurities content and, consequently, the viscosity of the ice within Europa’s ice shell are poorly constrained, limiting the possibility to understand if solid-state convection can occur under Europa’s ice shell conditions. To investigate how diurnal tidal flexing and the internal dynamics of Europa’s ice shell influence the ice grain crystals’ evolution, we adopted a thermal-mechanical numerical model that uses finite differences and marker-in-cell techniques, implementing the dynamic recrystallization of the ice and the ice grain evolution in a self-consistent way with the numerical model. We found that solid-state convection within Europa’s ice shell can occur if it is diurnally tidally deformed, as the tidal stresses within the ice shell operate to reduce the ice grain sizes and the ice viscosity. We discuss future radio science experiments, in combination with radar sounder investigations, that will be capable of characterizing the possible presence of solid-state convection within Europa’s ice shell. Acknowledgements: G.M. acknowledges support from the Italian Space Agency (2023-6- HH.0).