bluuebunny/crossref_metadata_2025 huggingface dataset:
Tree stem-atmosphere greenhouse gas fluxes in a boreal riparian forest
Authors: Klaus Marcus , Öquist Mats , Macháčová Kateřina
Published: March 2024

The cycling of greenhouse gases in forest ecosystems is significantly influenced by tree stems. Yet, little is known about the variability and drivers of stem-atmosphere greenhouse gas fluxes, especially in managed boreal riparian ecosystems where environmental conditions vary substantially at small spatial scales and throughout the year. Here, we report magnitudes and drivers of tree stem-atmosphere fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) in a riparian buffer zone of a Swedish boreal forest that has been subject to recent forest clearcutting and historic ditching. For two full years, we conducted CO2 and CH4 flux chamber measurements on a monthly basis in 14 spruce trees (Picea abies) and 14 birch trees (Betula pendula) that grew between one and fifteen meters from a headwater stream. We also performed N2O flux measurements during three occasions. All trees were net emitters of CO2 and CH4 over the majority of the year, while N2O fluxes were close to zero. CO2 fluxes correlated strongly and positively with air temperature and followed distinct seasonal cycles peaking in summer. CH4 fluxes correlated modestly with air temperature and solar radiation and peaked in late winter and summer. Trees with larger stem diameter released more CO2 and less CH4, and trees that were nearer the stream released more CO2 and CH4. The CO2 and CH4 fluxes did not differ between spruce and birch in general, but correlations of CO2 fluxes with stem diameter and distance to stream differed between the tree species. The absence of distinct vertical trends in the CO2 and CH4 fluxes along the stems and their lack of correlation with groundwater levels and groundwater greenhouse gas concentrations point to tree internal production as the primary source of the tree stem gas emissions. Upscaled to the ecosystem, the tree stem CO2, CH4 and N2O emissions represented 52% of the forest floor CO2 emissions and 2.5% and 11.3% of the forest floor CH4  and N2O uptake, respectively, during the snow-free season. The snow cover season contributed 15% and 35% to annual tree stem CO2 and CH4 emissions, respectively. In contrast to other riparian zone studies, the stem gas fluxes in our study generally exhibited characteristics of an upland rather than a wetland ecosystem, likely because of historical ditching and subsequent groundwater level declines.
Following the tracers of magma mixing; mafic enclaves within volcanic rocks at the Methana peninsula
Authors: Giamas Vasileios , Kalantzi Lemonia , Koutsovitis Petros , Petrounias Petros , Ntaflos Theodoros
Published: March 2024

The presence of mafic enclaves within volcanic rocks, which present an evolved geochemical character, tends to be related to magma mixing. In the Hellenic Volcanic Arc, mafic enclaves are regularly encountered within the volcanics. There are a few reports regarding the islands of Santorini and Nisyros as well as in the peninsula of Methana. The petrographic and mineral chemistry data we present here concern enclaves only from the Methana peninsula. Enclaves in Methana vary in size (from a few cm up to hand-sized samples) and color (reddish to black) depending on their host lava. The typical mineral assemblage is amphibole + clinopyroxene + olivine + plagioclase ± spinel ± mica. Mineral phases of amphibole, olivine, and clinopyroxene form the major phenocrysts that are embedded within a matrix mostly of fine-grained plagioclase laths and fine-grained needle-shaped amphibole. Textural features of plagioclase reveal the predominance of wet conditions during their crystallization since their cores and/or intermediate growth zones are usually dissolved suggesting a hydrous and volatile enriched magma related to the mafic enclaves. The aforementioned mineral assemblage along with the latter petrographic features match with lamprophyric rocks and their typical porphyritic and panidiomorphic textures. This counterpart is further ascertained by the mineral chemistry of Mg-rich amphibole varieties, and primary forsterite-rich olivine as well as by the lamprophyre-related trends of clinopyroxene and mica. These preliminary results provide new insights regarding magma mixing processes that occurred at the western margin of the Hellenic Subduction Zone.AcknowledgmentsThis work is part of the first author's Ph.D. research, which is financially supported by the «Andreas Mentzelopoulos Foundation».
A 60.000-year tectonic record: speleoseismology insights from a fault zone
Authors: Novak Uroš , Šebela Stanka
Published: March 2024

Northwestern Dinarides is a region of slow tectonic deformation with rates of 2-4 mm/year. Active deformations are largely accommodated by thrusting and dextral strike-slip faulting. The region exhibits moderate to strong seismicity and swarming events. However, the absence of Quaternary sediments across majority of fault scarps does not allow paleoseismic trenching on active fault segments in order to reconstruct a paleoearthquake record of the area. Even so, Northwestern Dinarides are an analogue for karstic phenomena, such as caves and abundance of speleothem forms in them. Generating the region as an ideal testing ground for speleoseismology. The investigated site of Postojna Cave is a 24 km long cave system, located in SW Slovenia, crosscut by the right-lateral strike slip Dinaric fault system (NW-SE striking). The karstic massif in which the cave evolved is enclosed by two major regional active faults, Idrija, Predjama faults and a smaller, active, Selce fault. Postojna Cave presents a diverse array of speleothem formations, characterized by their various morphologies. Some of these formations exhibit signs of deformation or breakage, with certain instances suggesting possible alteration induced by tectonic and seismic activities.The investigated speleothems are located in an expansive cave chamber, on a subvertical fault zone with a Dinaric strike. The researched fault had a TM extensometer installed more than 20 years ago, to measure tectonic displacements within the fault. In the years 2009-2010 and in 2014 it exhibited displacements (tectonic transients) coinciding with major regional seismicity. The synchronous displacements and the abundance of deformed speleothems within a singular fault zone is why the location was chosen within the cave for sampling. Speleothems were sampled with a diamond corer in an overall distance of 50 m, along the strike of the fault. Specifically, fractures healed with speleothem in flowstone that is located directly within the fault core zone and on the hanging wall of the fault. Additionally, a few of youngest growth speleothems on fractured columns bridging the hanging wall and the footwall were included.U-Th geochronology was done on nine sampled deformed speleothems using MC-ICP-MS. The results revealed ages from approximately 55,000 years BP to too recent for analysis (
Harnessing Modern 3D Gravity Analysis Techniques: A Study of the Ligurian Offshore Area
Authors: Götze Hans-Jürgen , Strehlau Ronja , Anikiev Denis , Dannowski Anke , Scheck-Wenderoth Magdalena
Published: March 2024

This interdisciplinary study describes the integration of gravity field analysis, curvature techniques and various spatial applications. The data are based on land-based Free Air and Bouguer gravity data from the AlpArray Gravity Research Group, complemented by recent satellite missions. New seismic and seismological data from the AlpArray initiative and the German MB-4D Priority Program were used as independent boundary conditions for the 3D modeling and inversion of the gravity data. Prior to this modeling, Euler deconvolution, terracing/clustering techniques, and advanced filtering methods were employed to reveal intricate details of the region's gravitational signatures. For example, a distinct zoning of gravity is observed in the central part of the Ligurian Sea, pointing to traces of past rifting processes. Analysis of various curvature parameters (e.g., dip-, min-, max- and shape-curvature) of the processed gravity fields, in particular gradients and residual fields support the identified zonation of the gravity fields, which reflect the geological structures in the crust. The final 3D modeling of the Ligurian Sea area is based on a previous density model of the entire Alpine region and includes density distribution of the upper mantle. These densities were derived from tomographic velocity models, accounting for petrology, temperature, and pressure. Additional information of the upper crust was obtained from the refraction seismic results of the LOBSTER project, offering a comprehensive understanding of spatial phenomena. Calculations of the gravitational potential energy (GPE) provide additional information on local stresses, facilitating a deeper understanding of the flexural rigidity in the area. By elucidating the relationship between processing techniques and 3D modeling, this work advances interdisciplinary interpretation crucial for geological studies in the Ligurian offshore area.
The tectonic activity of the Central Range Fault in Taiwan: insights from patterns of erosion rate and geomorphic evidence in the eastern Central Range
Authors: Chen Chia-Yu , Willett Sean , Haghipour Negar , Christl Marcus
Published: March 2024

The rapid collision between the continental margin of the Eurasia Plate and the Luzon Arc on the Philippine Sea Plate has built the island of Taiwan. The suture zone of the arc-continental collision that divides the Coastal Range to the east and the Central Range to the west is called the Longitudinal Valley. The Central Range and the Longitudinal Valley are bound by the Central Range Fault, which has long been proposed as an active fault. Still, limited field evidence of its activity has prevented us from comprehensively understanding its fault trace, geometry, and faulting mechanism. Surface ruptures caused by the 2022 Taitung Earthquakes revealed that the Yuli Fault, which also ruptured in the 1951 earthquakes, is a west-dipping fault and belongs to the Central Range Fault. This event thus brought the Central Range Fault back into the spotlight. In this work, we looked for potential geomorphic signatures associated with the fault activity using geomorphic indicators such as channel steepness, channel width, and grain size distribution of sediments in the main drainage basins along the middle part of the eastern Central Range. The channel width was determined by mapping the channel borders using SPOT images captured in 2003 and 2022 to determine the potential variance induced by recent mass-wasting events. In addition, we collected detrital sediment samples from these basins to derive basin-wide erosion rates based on in-situ 10Be concentrations. We combined all these results to discuss the evolution of the landscape in response to the activities of the Central Range Fault.
Regional impacts of simulated irrigation in the IPSL climate model.
Authors: Tiengou Pierre , Ducharne Agnès , Cheruy Frédérique , Meurdesoif Yann , Arboleda Pedro
Published: March 2024

The recent years have shown increasing interest and effort to include simulation of irrigation in Earth System Models to better account for the effects of this anthropogenic process on climate. We present here preliminary results about the impacts of simulated irrigation on surface-atmosphere interactions using LMDZ and ORCHIDEE, the atmosphere and land surface components of the IPSL Climate Model. The DYNAMICO-LMDZ configuration, coupling the physics of LMDZ to the recent icosahedral dynamical core DYNAMICO, is run as a Limited Area Model (LAM) to conduct a regional study over North-Eastern Spain. The simulation domain encompasses the Ebro valley where the LIAISE (Land-surface Interactions with the Atmosphere In Semi-Arid Environment) field campaign was conducted in 2021. This campaign was specifically designed to provide better understanding of the local and regional impacts of irrigation and the surface heterogeneities it creates. A new representation of irrigation, based on a soil moisture deficit approach, has recently been developed in ORCHIDEE and simulations are run with and without it to assess the impacts of simulated irrigation in the model. Direct effects at the land-surface interface (soil moisture, turbulent fluxes, temperature) are studied first, before focusing on the structure of the boundary layer and precipitations. Field observations from the campaign are used to evaluate the model, and the outputs will also be compared to higher-resolution simulations that have been conducted using the Meso-NH model in the context of the LIAISE project. The impacts of irrigation will be studied using various resolutions of the LAM from 10 to 50km, to better understand the scales at which land-surface coupling processes can be explicitly resolved by the dynamics of the model, and assess the importance of parametrizating these processes.
SMILE: a new view on the dynamic magnetosphere
Authors: Escoubet C.-Philippe ,   The SMILE team
Published: March 2024

How the solar wind and the Earth's magnetosphere interact, involving kinetic, fluid and global scales processes, is one of the key questions in space plasma physics. In situ instruments on a fleet of solar wind and magnetospheric constellation missions now provide the most detailed observations of Sun-Earth connections over multiple scales, from the smallest of a few kilometres up to the largest of a few 10s of Earth radii. However, we are still unable to fully quantify the global effects of the drivers of such connections, including the conditions that prevail throughout geospace due to the limitations of point measurements. This information is the key missing link for developing a complete understanding of how the Sun gives rise to and controls Earth's plasma environment and space weather. This is where SMILE (Solar wind Magnetosphere Ionosphere Link Explorer) comes in.SMILE is a novel self-standing mission dedicated to observing the solar wind - magnetosphere coupling via simultaneous in situ solar ion and magnetic field measurements, soft X-ray imaging of the magnetosheath, magnetopause and polar cusps, and UV imaging of the northern hemisphere auroral oval. Remote sensing of the magnetosheath and cusps with soft X-ray imaging is made possible thanks to solar wind charge exchange (SWCX) X-ray emissions known to occur in the vicinity of the Earth's magnetosphere. SMILE is a joint mission between ESA and the Chinese Academy of Sciences (CAS) due for launch in the middle of 2025. SMILE science objectives as well as the latest scientific and technical developments, jointly undertaken by ESA, CAS and the international instrument teams, will be presented. SMILE will be complemented by ground-based observatories, in particular the newly funded Canada Space Agency SMILE Imaging Science project, as well as by theory and simulation investigations. This presentation will be dedicated to Graziella Branduardi-Raymont, SMILE mission Co-proposer and mission Co-PI, who passed away on 3rd November 2023.
Projections of emission, fate and impact of HFO-1234yf in China
Authors: Wang Yifei , Liu Lu , Zhang Jianbo
Published: March 2024

Hydrofluoroolefins (HFOs) are being used as substitutes for potent greenhouse gases hydrofluorocarbons (HFCs). However, the use and environmental impacts of HFOs are of great concern due to the rapid degradation of HFOs to produce persistent and phytotoxic trifluoroacetic acid (TFA), one of the per- and polyfluoroalkyl substances (PFAS). HFO-1234yf is the most widely used HFO and has the greatest formation potential of TFA. Here, we provided a comprehensive projection of HFO-1234yf emission in China during 2025-2060. GEOS-Chem was applied to simulate the atmospheric processes of HFO-1234yf and to characterize the distribution of the degradation product TFA. A water quality model was further adopted to assess the impact of HFO-1234yf emissions on surface terminal water body TFA concentrations in China. Under the Kigali Amendment to the Montreal Protocol, HFO-1234yf emission in China was estimated to increase from 1.5 to 79.0 kt in 2025-2060 with cumulative emission of 1.7 Mt. The annual deposition flux (dry plus wet) of TFA due to HFO-1234yf emission was expected to grow from 0.02 kg/km2/year in 2025 to 0.9 kg/km2/year in 2060, dominated by wet deposition. After continuous emission of HFO-1234yf from 2025 to 2060, the average concentration of TFA in terminal waters in China was projected to increase by 7.4 μg/L. The results of this study can provide scientific support for evaluating the environmental risks of HFOs uses and help in developing HFCs phase-out pathways for addressing climate change.
Global warming increases the proportion of more damaging heat extremes
Authors: Tian Yinglin , Kleidon Axel , Lesk Corey , Zhou Sha , Luo Xiangzhong , Alam Ghausi Sarosh , Wang Guangqian , Zhong Deyu , Zscheischler Jakob
Published: March 2024

Extreme heat events often result in considerable harm to both ecosystems and human populations. Heat extremes arise from diverse processes, resulting in heatwaves with distinct characteristics and therefore potentially strongly varying impacts and trends. Relying on the surface energy balance decomposition of temperature, we categorize terrestrial summer heat extremes from 1979 to 2020 into four types: Sunny-humid (36.5%), Sunny–dry (24.5%), Advective (25.0%), and Adiabatic (14.0%). Sunny-humid and Sunny-dry heat extremes are characterized by high-pressure systems and diminished cloud cover, resulting in heightened solar radiation. However, they diverge concerning soil moisture and latent heat fluxes. Conversely, the latter two types emerge from advective heating due to anomalies in the horizontal wind and adiabatic heating from air subsidence, respectively. Both are correlated with an upsurge in downward longwave radiation. Sunny-dry and Advective heat extremes lead to more detrimental effects on terrestrial ecosystem production (reducing net ecosystem uptake by 0.09 gC/m2/d and decreasing maize yield by 7.6%) and human health (raising the thermal stress index by 8.6 K and increasing human mortality by 3.3%), respectively.State-of-the-art climate models (CMIP6) generally replicate the relative proportions and the geographical distributions of the four types of heatwaves but tend to underestimate the Advective heatwave days. Under a high emission scenario (SSP585), the proportion of Sunny-dry and Advective heat extremes increases by 3.4% and 1.5%, respectively, while Sunny-humid and Adiabatic heatwave days decrease by 3.2% and 1.7%, respectively. This suggests, on top of the already expected increase in heatwaves, additional heat stress on both terrestrial carbon uptake potential and human populations. Our findings underscore the importance of distinction among different types of heat extremes and their impacts, paving the way to develop tailored adaptive.
Developing the First National Blue Carbon Inventory for the Isle of Man
Authors: Muir Hannah , Keenan Jacqui , Henthorn Rowan , Strong James , Reading David G. , Duncan Peter , Skov Martin W. , Hiddink Jan G. , Unsworth Richard K. F. , Warwick Phillip E. , Evans Claire
Published: March 2024

Temperate coastal ecosystems including seagrass, saltmarsh, and shelf-sea sediments are natural, long-term ‘blue carbon’ (BC) sinks, with the potential to be managed for carbon storage and sequestration. These BC hotspots could help offset unavoidable greenhouse gas emissions and contribute to nations' Net Zero ambitions. The Isle of Man, a self-governing British Crown Dependency situated in the Irish Sea, has territorial waters equivalent to approximately 85% of its total jurisdiction. The island's Government is actively developing a comprehensive BC management plan aimed at maximising carbon sequestration and restoring seabed biodiversity and ecosystem services.To inform the management plan, sediment cores were collected from three major BC habitats around the Isle of Man: seagrass, saltmarsh, and shelf-sea sediments. The cores were analysed using elemental analysis and isotope ratio mass spectrometry to quantify organic and inorganic carbon stores. Radioanalytical methods were employed to measure radionuclides (137Cs, 210Pb, 241Am, and 210Po), which were used to determine sedimentation rates and subsequently carbon accumulation rates. Complementary analyses, including grain size analysis, X-ray fluorescence, X-ray scans, and high-resolution imagery, provide a holistic understanding of the chemical, physical, and biological attributes of the sedimentary cores, illuminating the processes influencing BC storage. Furthermore, side scan sonar, drop-down video, and drone imagery have been used to assess the extent of existing seagrass meadows, which is central to informing spatial-management strategies, particularly in the establishment of seagrass conservation zones.Our findings will help to develop the first national BC inventory for the Isle of Man and set a precedent for co-designed, collaborative, evidence-informed approaches for the sustainable management of coastal ecosystems.
Statistical Survey of Ion Cyclotron Wave Signatures around Earth’s Magnetotail Dipolarizations
Authors: Hosner Martin , Nakamura Rumi , Panov Evgeny , Schmid Daniel
Published: March 2024

In the Earth’s Magnetotail fast earthward plasma flows (so-called Bursty Bulk Flows) with a duration of several minutes and velocities of several hundreds of km/s are regularly observed in in-situ measurements. These flows are frequently accompanied by embedded co-moving, and more dipolar-shaped, magnetic flux bundles. The leading edge of such flux bundles is called a Dipolarization Front (DF). Such Earthward moving flux bundles and DFs can be formed by magnetic reconnection in the Magnetotail, as well as by the Ballooning/Interchange Instability (BICI). For the latter mechanism, simulations of the BICI suggest that, away from the central plasma sheet, the BICI heads are accompanied by electromagnetic ion cyclotron waves, and such wave signatures were indeed observed by the MMS and THEMIS spacecraft between the neutral sheet and the magnetospheric lobes.In the present study we use years of data from NASA’s Magnetospheric Multiscale Mission (MMS) to compile a database of several hundred events. We analyze this database with the goal of a statistical description of such flux bundles with respect to ion cyclotron wave occurrence, and compare them to several parameters, such as magnetic field and plasma conditions, to further enhance the understanding of the large-scale context and origin of magnetotail dipolarizations.
Full-waveform modelling of coupling and site effects for DAS cables
Authors: Celli Nicolas Luca , Bean Christopher J. , O'Brien Gareth S.
Published: March 2024

The use of optical fibre cables to sense ground motion is one of the most researched topics in seismology at present day. By using the technique of Distributed Acoustic Sensing (DAS), a single fibre can be turned into thousands of seismic sensors, providing unprecedented spatial resolution. The instrument response of optical fibre cables, however, is largely unknown and difficult to separate from source, path, and directivity effects on seismic records, preventing us from using the information from the full seismic waveform.Here we present a full-waveform simulation scheme developed to model the DAS instrument response using a particle-based Elastic Lattice Model (ELM-DAS). The scheme allows us to simulate a virtual cable embedded in the medium and made of a string of connected particles. By measuring the strain along these particles, we are able to replicate the axial strain natively measured by DAS as well as the effects of irregular cable geometries. The scheme allows us to easily simulate complex properties of the material around the cable (e.g., unconsolidated sediments, nonlinear materials) as well as different degrees of cable-ground coupling, both of which are believed to be the key factors controlling the DAS instrument response.By simulating DAS cables in 2D, we observe that at the meter scale, realistic DAS materials, cable-ground coupling, and the presence of unconsolidated trench materials around it dramatically affect wave propagation, each change affecting the synthetic DAS record, with differences exceeding at times the magnitude of the recorded signal. By expanding the scheme to 3D, we can accurately include the effects of realistic, complex–and at times sub-wavelength—cable geometries and how they influence DAS records. Our observations show that cable coupling and local site effects have to be considered both when designing a DAS deployment and analysing its data when either true or along-cable relative amplitudes are considered.
High-resolution sedimentological and palaeoceanographic investigation of the Last Glacial Termination (T1) recorded on the western margin of the Svalbard (Arctic)
Authors: Gois Smith Fernando Sergio , Lucchi Renata Giulia , Bini Monica , Morigi Caterina , Ferretti Patrizia , Bronzo Laura , Douss Nessim
Published: March 2024

The Last Glacial Maximum (LGM) was defined based on the low stand sea-level records from the most recent period when global ice sheets reached their maximum volume, between 26,500 and 19,000 years before present. The end of this cold period was the last glacial termination (T1), occurred between 20 and 11.7 ka BP marking the transition to the current interglacial. During T1, the sea level rise responded to a variety of processes although the melting of the world widely distributed ice sheets was initially the main contributor and responsible for abrupt relative sea level rises known as meltwater pulses (MWPs) that deeply changed the Earth’s physiography. MWPs are short-lived global acceleration in sea-level rise resulting from intense glacial melting, surge of large ice streams into oceans and intense iceberg discharge during ice sheet disintegration. Nowadays, the main concerns related to the present fast global climate change is the possibility that sudden drastic ice loss from the Greenland and/or in the West Antarctic Ice Sheet would lead to a new abrupt acceleration of the relative sea level with consequent inundation of vast coastal areas and/or to cause an abrupt slowdown of the Atlantic Meridional Overturning Circulation (i.e. Golledge et al., 2019). To better understand the dynamics and risks associated with the onset of those events, their impact on thermohaline ocean circulation and climate it is pivotal the study of the well-preserved polar marine sediment records of the events occurred during the T1. Here, we present the results of a high-resolution sedimentological, micropaleontological and geochemical investigation of 3 sediment cores collected on the western margin of Svalbard and eastern side of the Fram Strait (Artic). The sediment cores were collected between 1322 m and 1725 m of water depth, in correspondence of the southern IODP sites that will be drilled during the IODP Exp-403 (June-August 2024).
Tail calibration of probabilistic forecasts
Authors: Allen Sam , Koh Jonathan , Ziegel Johanna
Published: March 2024

Probabilistic forecasts comprehensively describe the uncertainty in the unknown future outcome, making them essential for decision making and risk management. While several methods have been introduced to evaluate probabilistic forecasts, existing evaluation techniques are ill-suited to the evaluation of forecasts for extreme events, which are often of particular interest due to the impact they have on forecast users. In this work, we reinforce previous results related to the deficiencies of proper scoring rules when evaluating forecasts for extreme outcomes, demonstrating that classes of scoring rules cannot distinguish between forecasts with the incorrect tail behaviour. Alternative methods to evaluate forecasts for extreme events are therefore required. To this end, we introduce several notions of tail calibration for probabilistic forecasts, which allow forecasters to assess the reliability of their predictions for extreme outcomes. We study the relationships between these different notions, and provide several examples. We then demonstrate how these tools can be applied in practice by implementing them in a case study on European precipitation forecasts.
Identifying precipitation types over China using a machine learning algorithm
Authors: Wang Yi
Published: March 2024

In the context of global warming, changes in extreme weather events may pose a larger threat to society. Therefore, it is particularly important to improve our climatological understanding of high impact precipitation types (PTs), and how their frequency may change under warming. In this study, we use MIDAS (the Met Office Integrated Data Archive System) observational data to provide our best estimate of historical PTs (e.g. liquid rain, freezing rain, snow etc.) over China. We use machine learning (ML) techniques and meteorological analysis methods applied to data from the ERA5 historical climate reanalysis data to find the best variables for diagnosing PTs, and formed training and testing sets, which were input into ML training. We evaluate the diagnostic ability of the Random Forest Classifier (RFC) for different PTs. The results show that using meteorological variables such as temperature, relative humidity, and winds to determine different PTs, ERA5 grid data and MIDAS station data have good matching ability. Comparing the feature selection results with Kernel Density Estimation, it was found that the two methods have consistent results in evaluating the ability of variables to distinguish different PTs. RFC shows strong robustness in predicting different PTs by learning the differences in meteorological variables between 1990 and 2014. It can capture the frequency and spatial distribution of different PTs well, but this capture ability is sensitive to the training methods of the algorithm. In addition, the algorithm finds it difficult to identify events such as hail that are very low frequency in observations. According to the results of testing for different regions and seasons in China, models trained using seasonal data samples have relatively good performance, especially in winter. These results show the potential for combining a RFC with state-of-the-art climate models to effectively project the possible response of different PT frequencies to climate warming in the future. However, the training method of ML algorithm should be selected with caution.
Fault drainage state and frictional stability in response to shearing rate steps in natural gouge
Authors: Affinito Raphael , Elsworth Derek , Marone Chris
Published: March 2024

Elevated pore fluid pressures are frequently implicated in governing fault zone seismicity. While substantial evidence from geodetic and geological studies supports this notion, there is a notable scarcity of experimental observations of how fluid pressure influences fault stability during shear. Understanding the precise interplay between porosity, fault slip rate, and frictional stability is pivotal for assessing the significance of processes like dilational strengthening or thermal pressurization in the context of seismic hazards. Here, we prepare fault gouges from the Utah FORGE enhanced geothermal field injection well 16A at depths corresponding to seismic events (between 2050 – 2070m). Experiments were conducted inside a pressure vessel and loaded under a true-triaxial stress state, replicating in-situ stress conditions observed at the Utah FORGE site. The applied fault normal stress and during the experiments were held constant at 44MPa. Pore fluid pressure was varied between successive experiments (13, 20, and 27 MPa) to span a range of effective stresses to examine impacts on fault dilation/compaction and the successive frictional stability. Different fluid pressure boundary conditions: constant volume or pressure were applied to explore how changes in shearing rate influence gouge stability thought the fault drainage state. Our data indicate that the Utah FORGE samples are velocity-neutral and transition to velocity-weakening behavior at elevated pore pressure and shear strains >7. We find dilatancy coefficients e = ∆f/∆ln(v), where f is porosity and v is fault slip velocity, consistent with quartz-feldspathic-rich rocks ranging from 5–12^10-4, indicating a conditionally unstable regime. Furthermore, our results demonstrate that the boundary conditions for pore fluids influence frictional stability viachanges in effective normal stress. For example, when pore volume has zero flux, an expansion in the void volume during slip results in a decrease in pore pressure, transitioning the system towards frictional stability. Our results indicate that the connectivity of pore conduits may be more important than the imposed pore pressure conditions when considering the impact on fault stability. We suggest that the interplay between fault slip and fluid mobility within a fault is a delicate balance for predicting and managing seismic hazards.
Paleoclimate reconstruction based on speleothems from the Crimean Peninsula
Authors: Li Yidong , Dublyansky Yuri , Spötl Christoph , Cheng Hai , Tokarev Sergey , Amelichev Gennady
Published: March 2024

The paleoclimate and paleoenvironmental conditions of Crimea are scarcely known due to the lack of high-resolution archives in this area. Crimean speleothems have a high potential of providing valuable information and filling the knowledge gap on the paleoclimate in the northern part of the Black Sea area.We acquired six well-dated stalagmite records from Crimean caves which grew during different intervals of the Holocene and MIS 3 with a good overlap, spanning from 2.7 (± 0.1) to 58.0 (± 0.0) ka BP. Records of δ18O and δ13C show some resemblance to the Sofular record from the southern Black Sea coast. However, based on our knowledge of the modern pathways of moisture supply to Crimea (with only ca. 14 % of moisture originating from the Black Sea surface[1]), it can be expected that the controls of stalagmite δ18O values may be different in the south and north of the Black Sea. δ13C records show larger shifts than the δ18O records on the millennial time scale (e.g., Heinrich events) especially during MIS 3. None of the speleothems grew during MIS 2, probably reflecting arid and cold climate conditions.These records are being analyzed and compared with other paleoclimate records to better understand: (1) the local hydrological dynamics and climate history during the Holocene and MIS 3, (2) the differences in climate conditions between the southern and northern Black Sea regions, and (3) the spatio-temporal teleconnection between the North Atlantic realm and the study area. [1] Langhammer et al. (2021) doi: 10.1029/2021EA001727
SEM-EBSD reveals crystal plasticity in pyroclasts
Authors: Taddeucci Jacopo , Cimarelli Corrado , Pozzi Giacomo , Kendrick Jackie E. , Scarlato Piergiorgio
Published: March 2024

Electron BackScatter Diffraction can be used to measure misalignment in the lattice of crystals. Non-reversible crystal lattice deformation by migration of dislocations, i.e., crystal plasticity, has been observed and recreated under controlled experimental conditions in effusive volcanic rocks. There, crystal plasticity increases with increasing stressing of the magma, and precedes crystal failure. Here, we present the first observation of crystal plasticity in pyroclasts. We found lattice misalignment mainly in plagioclase microlites within ash- and lapilli-sized pyroclasts of mafic composition from explosive eruptions of Etna (Italy), Paricutin (Mexico), and Cumbre Vieja (Spain) volcanoes. Misalignment is found both in visibly curved and apparently undeformed crystals, its magnitude increasing with increasing aspect ratio of the crystals. Plastically deformed crystals are unevenly distributed within the pyroclasts, and often clustered. Similar to observations made in effusive rocks, crystal plasticity in pyroclasts is marked by the presence of broken crystals. But unlike the effusive case, fragments of broken crystals in pyroclasts show little or no plastic deformation, while more deformed crystals are found around zones with broken crystals. Textural evidence from natural and experimental samples show that these zones underwent localized damage by brittle fracturing. Coexisting broken and plastically deformed crystal reveal millimetre-scale patterns of stress localisation in magma during fragmentation
Exploring seasonal to interannual variability of the carbonate system in the southern Adriatic
Authors: Dentico Carlotta , Civitarese Giuseppe , Giani Michele , Rubino Angelo , Cardin Vanessa
Published: March 2024

Since the beginning of the industrial revolution, about 30% of total anthropogenic CO2 emissions have been absorbed by the world’s oceans, resulting in a global reduction in ocean pH. This process, commonly referred to as ocean acidification, is considered one of the greatest threats to marine ecosystems. Recently, it has been recognised that the regulation of oceanic CO2 uptake is controlled by the oceanic overturning circulation. Accordingly, the site of dense water formation in the Southern Adriatic (SAd), where the Eastern Mediterranean deep thermohaline circulation originates, could play an important role in CO2 sequestration and acidification of the Mediterranean Sea. The Southern Adriatic is characterised by a quasi-permanent cyclonic circulation and it is known that deep water forms in the centre of the gyre through winter open-ocean convection. In this contribution, we used data from several oceanographic cruises between 2008 and 2023 to investigate the spatial and temporal variability of the carbonate system properties in the Southern Adriatic. The vertical distributions of total alkalinity (AT), pH, inorganic nutrients, dissolved inorganic carbon (DIC) as well as CO2 partial pressure (pCO2), calculated with the CO2Sys software, are analysed. Time series of high-frequency pCO2 data from an automatic sampling system set up on the surface buoy of the E2M3A facility, operated by the Italian National Institute of Oceanography and Applied Geophysics (OGS), are also presented. E2M3A is moored in the centre of the southern Adriatic Pit (SAP) and has been collecting pCO2 data since 2015. We discuss the seasonal and interannual variations of the carbonate system variables and the influence of physical and biological processes on this variability. These results contribute to the understanding of the role of the Southern Adriatic in transporting and storing CO2 to the deeper layers and in inducing ocean pH changes. Furthermore, we emphasise the importance of an integrated oceanographic approach that combines fixed-point observations with hydrographic surveys to comprehensively investigate the response of the Adriatic Sea to climate change. 
Multispectral and SAR satellite data to assess drought impact on the productivity of mountain grasslands in the European Alps
Authors: Castelli Mariapina , Göhner Caroline , Alasawedah Mohammad , Mejia-Aguilar Abraham , Crespi Alice , Sicher Gabriel , Dovas Alexander , Stendardi Laura , Bartkowiak Paulina , Cuozzo Giovanni , Monsorno Roberto , Peratoner Giovanni
Published: March 2024

Drought events occur more and more often in the Alps, endangering the welfare of mountain agriculture. In this context, risk management instruments, like insurance, can help agricultural systems cope with production shortcomings and thus increase their economic resilience, prevent land abandonment, and maintain their functioning over time. In this work, we focus on Trentino-South Tyrol, in north-eastern Italy, where mountain grasslands play an important economic role as they provide forage for livestock farming and a place of recreation for tourists. In addition, they contribute to many ecosystem services including climate regulation, biodiversity and landscape conservation, and soil protection. In collaboration with stakeholders from the agricultural sector, we developed an index of productivity, the Grassland Production Index (GPI), which can be used at the end of the growing season to assess yield losses due to drought events. GPI is estimated from meteorological data and leaf area index (LAI) derived from Sentinel-2 multispectral data. LAI and GPI are validated by field measurements of LAI and dry matter yield covering two growing seasons at eight test sites per year. This is achieved by a well-established and replicable data collection protocol. The validation of the Sentinel-2 LAI with ground measurements showed an RMSE of 0.92 [m2 m−2] and an R2 of 0.81 over all the measurement sites. A comparison between GPI and yield showed, on average, an R2 of 0.56 at the pixel scale and an R2 of 0.74 at the parcel scale. Based on these promising validation results, the index was applied to estimate the insurance payments for four farms. An advanced version of GPI is under development in which we improve the Sentinel-2 LAI time series by a data fusion approach. Here, missing LAI values due to cloud coverage are estimated by machine learning algorithms with input features calculated from backscattering and soil moisture derived from Sentinel-1 SAR data. The application of the enhanced GPI for insurance purposes at the regional scale is foreseen at the end of the 2024 growing season. This work presents a real case study using GPI for drought impact assessment and investigates the potential of fusing optical and SAR data to improve the estimation of GPI.  
The GAPS Programme at TNG. TOI-5076b: a warm sub-Neptune planet orbiting a thick disk star in a wide binary system.
Authors: Greco Nino , Montalto Marco ,   The GAPS Programme at TNG: TOI-5076b.
Published: March 2024

Aims. We report the confirmation of a new transiting exoplanet orbiting the star TOI-5076.Methods. We present our vetting procedure and follow-up observations which led to the confirmation of the exoplanet TOI-5076b. In particular, we employed high precision TESS photometry, high-angular resolution imaging from several telescopes and high precision radial velocities from HARPS-N.Results. From the HARPS-N spectroscopy, we determined the spectroscopic parameters of the host star: Teff=(5070±143) K, log g=(4.6±0.3), [Fe/H]=(+0.20±0.08) and [α/Fe]=0.05±0.06. The transiting planet is a warm sub-Neptune with a mass mp=(16±2) M⊕, a radius rp=(3.2±0.1) R⊕ yielding a density ρp=(2.8±0.5) g cm−3. It revolves around its star every ∼23.445 days.Conclusions. The host star is a metal-rich, K2V dwarf, located at about 82 pc from the Sun with a radius of R⋆=(0.78±0.01) R⊙ and a mass of M⋆=(0.80±0.07) M⊙. It forms a common proper motion pair with a M-dwarf companion star located at a projected separation of 2178 au. The chemical analysis of the host-star and the Galactic space velocities indicate that TOI-5076 belongs to the old population of thick disk stars or thin-to-thick transition stars. The density of TOI-5076b suggests the presence of a large fraction by volume of volatiles overlying a massive core. We found that a circular orbit solution is only marginally favoured with respect to an eccentric orbit solution for TOI-5076b. The best-fit eccentricity for the system is e=(0.20±0.09).
Leveraging Citizen Science and Machine Learning for Plant Phenology Monitoring
Authors: Katal Negin , Rzanny Michael , Mäder Patrick , Wittich Hans Christian , Boho David , Wäldchen Jana
Published: March 2024

Plant phenology investigates the timing of critical events in a plant's life cycle, encompassing budburst, flowering, fruiting, and senescence, with their significance rooted in their responsiveness to environmental conditions. Despite the growing interest in phenology, challenges persist in documenting these processes due to their extensive spatial and temporal scales.While global phenological networks traditionally collect data at the individual scale, a concern is arising regarding the declining number of phenological observers, prompting questions about the future of these datasets. Simultaneously, the surge in plant identification apps among citizens has yielded a substantial volume of plant occurrence records, accompanied by plant images, spanning diverse temporal and spatial scales.In this study, we explore the viability of utilizing opportunistically captured plant observations gathered through a plant identification app to determine the onset of flowering. Additionally, we investigate how citizen science-based phenological monitoring can be enhanced by incorporating images generated by the app. To achieve this, we developed a machine learning-based workflow enabling the automatic annotation of thousands of images into specific phenological stages. Beyond examining the onset of flowering, our established methodology allows for the exploration of other phenological stages, such as budburst or fruiting, on a large scale.Subsequently, we compare these opportunistic phenological records with systematically collected data from phenological networks. This approach not only streamlines image annotation but also augments the usefulness of citizen science data for phenological monitoring purposes.
How far can we go in global flood inundation modelling?
Authors: Bates Paul
Published: March 2024

Over the last fifteen years, hydrodynamic modelling has, like so many branches of hydrology, made the leap from local to global scales.  Where once we may have applied our models to single river reaches a few 10s of kilometres in length, we can now build and execute models at ~30m spatial resolution over the entire terrestrial land surface.  In turn, this has allowed us to address scientific and practical questions that were hitherto impossible to answer.  For example, global inundation modelling can help us understand and quantify large scale hydrological and biogeochemical cycles and many questions in flood risk management, for example decisions about future government spending on flood defences, analysing the solvency of flood insurance portfolios under extreme conditions, or determining climate change impacts, require predictions of flood risk at national, continental, or even global scales.This paper therefore discusses the scientific developments that were needed to make this local-to-global transition possible and outlines what the latest generation of global inundation models now can (and cannot) do.  Finally, the paper looks at current limits to inundation modelling in terms of boundary conditions, flood defence data and model validation and considers the prospects for further improvements in model skill using the data from recently launched and forthcoming satellite missions such as SWOT and NISAR.
Hydrological indicators in an irrigated catchment with different crops in Spain: how research can contribute to fulfilling Sustainable Development Goals (SDG) through the basic indices for FabLabs.
Authors: Cuadrado-Alarcon Blanca , Taguas Encarnación V. , Domenech Ignacio , Mateos Luciano , Gomez-Macpherson Helena
Published: March 2024

The core of the 2030 Agenda for Sustainable Development, presents the 17 Sustainable Development Goals (SDGs), which constitute of a vital call for action by all world countries. “Clean water and sanitation”, “Industry, innovation and infrastructure”, “Sustainable cities and communities”, “Responsible consumption and production” and “Climate action”, among others, result a challenging field where scientists, farmers and other stakeholders should cowork to create successful tools and management protocols. FabLab approaches pursue to link scientific and technological elements and participatory actions of farmers, administrative institutions, companies and intermediaries for promoting open innovation environments to make technology-enabled products and practices adapted to local needs.In this study, different types of hydrological signatures evaluated in a catchment of 303 ha with different type of crops, owner profiles and irrigation patterns, are presented as a base to provide the thresholds for alerts and emergency systems related with floods, herbicide peaks and/or sediment loads. Data series of the values of rainfall, runoff, herbicide and sediments collected in the gauge station of the catchment outlet were checked to quantify the impact of rainfall events of different return periods on the catchment responses. The knowledge of these features and procedures is essential to create innovations along the water cycle and improve the alarm protocols and irrigation management in commercial farms.