bluuebunny/crossref_metadata_2025 huggingface dataset:
Using Machine Learning for Post-Simulation Diagnostics of Microphysical Process Rates with the ICON Model
Authors: Simm Miriam , Hoose Corinna , Çayoğlu Uğur
Published: March 2024

Clouds play an important role in the hydrological cycle and significantly affect the Earth's radiative budget. Cloud microphysics describes the formation and interaction of individual cloud and precipitation particles. Its representation in numerical weather prediction and climate models remains challenging. Due to their sub-scale nature, microphysical processes need to be represented by parametrization schemes, which often rely on simplifying assumptions. Furthermore, the large number and variety of cloud particles and numerous nonlinear interactions thereof render cloud microphysics extremely complex. Many of its aspects are poorly understood, and a comprehensive theoretical description does not yet exist.Detailed information about microphysical process rates is essential in order to establish a profound understanding of the microphysical pathways, feedback loops and aerosol-cloud interactions. In the ICON model, cloud microphysics is often parametrized with the two-moment scheme, developed by Seifert and Beheng (2006),  with six hydrometeor categories. However, due to the high number of processes, including the microphysical process rates in the model output results in approximately 20-50 additional three-dimensional output variables. If this output is generated in every time step of the model, this quickly requires immense storage capacities.Machine learning (ML) opens the possibility of generating on-demand offline diagnostics based on standard output variables as an alternative approach. Based on the two-moment bulk microphysics scheme, we trained a neural network to emulate the calculation of the process rates in the ICON model for warm-rain formation, reproducing earlier results of Seifert and Rasp (2020). As input, we use cloud and atmospheric state variables. We conducted simulations with the ICON model in a global configuration with 13 km grid spacing in order to generate training and validation datasets. In the initial stage of model development, this resolution seems sufficient, however, we plan on using a smaller grid spacing in a limited-area configuration to improve the accuracy of our results. We performed analyses using Mutual Information to unveil the dependencies between model variables and process rates and chose the predictors of the model accordingly. We compare different sets of predictors and activation functions in order to improve the model's predictiveness. Furthermore, we discuss the possibility of constructing a similar model for processes in mixed-phase and ice clouds.
Evidence of Flash/ Rapid Drought in India based on Precipitation Deficit- A new Climatic Threat
Authors: Kumari Pallavi , Vinnarasi Rajendran
Published: March 2024

Rapid intense droughts (Flash Drought) under climatic warming are of widespread concern owing to their catastrophic impacts on agricultural production, eco-system, and nation’s economy. Several studies highlight the need to develop an improved understanding of flash drought to manage its effect better, However the lack of consistent definitions have limited progress toward its assessments. A number of variables, climatic drivers are generally linked to flash drought development thus it is possible that no single description might adequately capture the flash drought. However, it is crucial to make sure that the rapid onset, fast intensification, and severe nature of flash drought can be identified and distinguished from more conventional drought (longer duration) events. With the increasing use of flash drought term within the scientific community, this study presents an evidence-based result by identifying flash droughts using pentad-scale precipitation series across India. The results demonstrate that one of the factors causing and accelerating the flash drought – rapid drought intensification and lasts for shorter duration (3 pentads to 18 pentads) is the meteorological variable precipitation. The results of this study can be further utilised in the accurate characterization of flash drought and its assessment with the strong evidence of precipitation series in finding of flash drought events across the nation.
Support vector regression-based model for the prediction of surface displacement and vibration using meteorological data
Authors: Hi Chi En , Chen Kate Huihsuan , Peng Wei , Huang Wan-Ru , Chen Hsiang Han , Wang Ko Chih , Ching Kuo En
Published: March 2024

Can we use environmental data to predict changes in surface displacement fields? Do severe weather events alter the near-surface geomechanical properties? The seasonal variations in GPS time series and crustal seismic velocities have been frequently observed at different study areas. Such variation has been tied closely to the cyclic hydrological loads [e.g., Costain et al., 1987; Heki, 2003; Roth et al., 1992], which its association with tectonic deformation remains debated. Using the 15 years meteorological, geodetic, and seismic data recorded in southern Taiwan (near Chaozhou fault where the background seismicity level is low), we aim to explore the possibility of predicting surface displacement and vibration using climatic variables (time series of temperature, precipitation, and wind velocity) and groundwater levels. Here the Support Vector Regression (SVR) model is developed for the prediction of the GNSS and seismic signals, while 15-yr datasets are divided into groups of 75%  and 25% datasets for model calibration and testing. When the predicted surface displacement is compared with the real data, the R-square values reach 95%, indicating the applicability of SVR model on long-term surface deformation prediction. In the future, long-term prediction model will be conducted to target several extreme weather events in Taiwan.
Pathways of Glacial Meltwater from the Hudson Strait into the North Atlantic Ocean: Insights from Eddy-Resolving Model Simulations
Authors: Martin Alis Sara , Marchal Olivier , Condron Alan , Chen Sean (Si-Yuan)
Published: March 2024

A long-standing question in paleoclimate research concerns the fate and consequences of the glacial water released into the ocean from the Laurentide Ice Sheet (LIS) during the last deglaciation. In this presentation, we will describe detailed simulations of the pathways of glacial meltwater released from the LIS which have been obtained from an eddy-resolving, regional configuration of the general circulation model of the MIT (MITgcm) coupled with a sea-ice model. Emphasis will be placed on glacial meltwater discharged from Hudson Strait into the Labrador Sea and on its interaction with the North Atlantic Current (NAC). Our regional configuration of the MITgcm represents the glacial Atlantic between 34.5oN and 67oN at a horizontal resolution of 1/20o, with 61 vertical levels (21 levels in the upper 100 m), and with continental shelves removed (sea level lowered by 130 m). The relatively fine spatial grid permits the simulation of the mesoscale eddy field and of the baroclinic structure of the buoyant current produced by the meltwater inflow. Surface forcing is provided by the atmospheric conditions during the last glacial maximum which have been simulated by a global climate model (Community Climate System Model v.3). Our preliminary results show that the meltwater current from Hudson Strait flows to the SE along the continental slope of Labrador and Newfoundland and sheds anticyclonic eddies which carry offshore meltwater and are entrained by the NAC near the Grand Banks. In turn, the meltwater influences the NAC through its effect on seawater density, suggesting a new mechanism by which glacial water fluxes may change large-scale circulation in the North Atlantic. In our presentation, attention will be paid on the influence of the meltwater on the strength and structure of the NAC near and downstream of the Grand Banks.
Feedbacks between turbulent air-sea fluxes and their role in the adjustment of the Earth Climate System
Authors: Dehondt Clément , Braconnot Pascale , Fromang Sébastien , Marti Olivier
Published: March 2024

In state of the art Earth System Models (ESM), the variables at the ocean-atmosphere interface (wind, air temperature, humidity, surface currents and SST) are linked to turbulent surface fluxes (momentum, sensible and latent heat) in a complex manner via bulk closures.Understanding how turbulent fluxes interact between them and with the ocean-atmosphere interface variables is a major scientific challenge because it connects local interactions with large scale energy and water cycles.These interactions between the different air-sea turbulent fluxes are difficult to diagnose from fully coupled ocean-atmosphere simulations due to the fact that in most modelling groups coupled and stand alone components do not necessarily use consistent forcing or representation of the air-sea fluxes. Also rigorous protocols between coupled and stand alone atmosphere and ocean simulations need to be implemented to be able to properly disentangle the role of different physical representation at the air-sea interface from global ocean-atmosphere-land adjustment feedbacks that may counteract the direct effects of air-sea fluxes modeling.Here we use an ensemble of fully coupled and stand alone simulations using a version of the IPSL ESM [1] based on the new DYNAMICO atmospheric dynamical core [2] and the ocean engine NEMO [3]. We analyse an ensemble of experiments differing by the the bulk formulation of the air-sea turbulent fluxes (NCAR, COARE3.6, ECMWF and LMDZng). The analyses will focus on the adjustment of the system in the different cases, especially on the differences in the transport of heat and water, mixed layer depth adjustement, feedback on ocean surface properties, intertropical convergence zone (ITCZ) and mid-latitude storm tracks.[1] Boucher O., Servonnat, J., Albright, A. L., Aumont, O., Balkanski, Y., Bastrikov, V., et al. (2020). Presentation and evaluation of the IPSL‐CM6A‐LR climate model. Journal of Advances in Modeling Earth Systems, 12, e2019MS002010. https://doi.org/10.1029/2019MS002010[2] Dubos, T., Dubey, S., Tort, M., Mittal, R., Meurdesoif, Y., and Hourdin, F.: DYNAMICO-1.0, an icosahedral hydrostatic dynamical core designed for consistency and versatility, Geosci. Model Dev., 8, 3131–3150, https://doi.org/10.5194/gmd-8-3131-2015, 2015. [3] “NEMO ocean engine”, Scientific Notes of Climate Modelling Center, 27 — ISSN 1288-1619, Institut PierreSimon Laplace (IPSL), doi:10.5281/zenodo.14648
Soil fertilization alters spatial and temporal distribution of amino-N in the rhizosphere of maize
Authors: Blagodatskaya Evgenia , Shen Guoting , Guber Andrey
Published: March 2024

Despite an importance and relatively high abundance of organic N in soil, it is uncertain how the distribution of organic N is affected by mineral N availability in the course of root development. We visualized amino-N content in seminal and lateral roots of maize (Zea mays L.) grown under reduced and full fertilization at the 4- and 6-leaves phases.  The intensity of amino-N hotspots was fertilization-, growth phase- and root-specific. Under reduced fertilization, amino-N content decreased in all root parts at the 6- versus the 4-leaves phase. Under full fertilization, the content of amino-N increased in seminal roots and lateral root tips but it decreased in seminal root tips with root growth. This suggests a potential functional differentiation of seminal and lateral root tips in the N-acquisition strategy in the course of plant growth. 
Building scientific and industry consensus on a monitoring, reporting, and verification (MRV) protocol for enhanced weathering (EW) in agriculture
Authors: Lambert Jonathan , Sutherland Kevin , Holme Ella , Savage Rhys , Hacker Neil , Science Team Isometric
Published: March 2024

Enhanced Weathering (EW) as a pathway for carbon dioxide removal (CDR) is gaining substantial momentum and projects are already being deployed at small scales around the world. In order to ensure the efficacy, additionality and safety of EW in agricultural settings, Isometric has developed a comprehensive and broadly-applicable monitoring, reporting, and verification (MRV) protocol. This protocol was constructed with substantial input from industry, academia and non-profit representatives in order to promote both rigor and implementability of MRV practices to EW projects. The MRV approach we propose focuses substantially on direct measurement to further the industry-wide objective of constraining EW (and the uncertainties associated with it) in agriculture systems before scaling. Through direct measurements in each step of the EW process, we aim to build databases that can be used in the future to drive the development of streamlined MRV approaches that are low in uncertainty, easy to implement, and cost-effective at large scales. In this presentation, we will highlight the unique aspects of our protocol and will detail the iterative and multi-stakeholder consensus-building process that we administered to construct and implement the protocol. Ultimately, the goal of our protocols is to support MRV that is grounded in the best-available science, is iterable, and that improves when new findings emerge. We intend to apply learnings from this EW-specific process to future versions of this protocol as well as to protocols for additional CDR pathways.
Time-scale turbulent transport extraction and high time resolution flux estimation using wavelet analysis
Authors: Destouet Gabriel , Besic Nikola , Joetzjer Emilie , Cuntz Matthias
Published: March 2024

Flux estimation from eddy-covariance flux tower measurements faces the problem of integrating fluxes only in the case of fully developed turbulence and in non-stationary environments with advective components. The standard eddy-covariance method operates on fixed-length signals, requiring the knowledge of a maximum correlation time-length as well as post-processing steps assessing the suitability and quality of the data. Statistical tests are carried out to assess if flux estimates were performed during sufficiently developed turbulence and if they were corrupted by advective components. Tests with friction velocity u* or σw, steady-state tests, and flux variance similarity are now standard during and after flux calculations. More elaborate methods such as ogive optimisation are used to deal with advection. An important disadvantage of all these statistical tests is that they discard the whole time interval such as half an hour if they detect failure.Time-scale (time-frequency) analyses have been used as an alternative to the standard time-analysis approach to estimate ecosystem fluxes. In particular, wavelet analysis, which is well adapted to the study of non-stationary and scale invariant processes such as turbulence, has been used in previous works. It presents the ability of separating the different components of the flux in time-scale space and as such could be an efficient alternative for flux estimation avoiding the above statistical tests.To address this problem, we propose a general framework for analysing fluxes in time-scale space, and propose a new method for identifying and extracting turbulent transport that avoids advective components and does not need statistical tests after the flux calculations. The new method is based on the analysis in time-scale domain of the amplitude of the vertical component of the Reynold stress tensor and can be seen as a time-scale transposition of standard tests mentioned above. As a direct consequence, we are able to estimate fluxes at high time resolution over times and scales with sufficiently developed turbulence. We show application of the framework at the beech forest site FR-Hes and demonstrate its relation with standard eddy covariance calculations. Our methodology is implemented in the Julia package TurbulenceFlux.jl and is readily available. The proposed framework and its code implementation is fully differentiable and hints to further investigations, such as the study of flux ecosystem response times, or sensitivity analysis against wavelet and averaging window parameters.
Impacts of climate-modified disturbance regimes on coastal ecosystems and their services
Authors: Hülsen Sarah , Dee Laura , Kropf Chahan , Colombi Nicolas , Bresch David
Published: March 2024

Coastal ecosystems, such as mangroves, coral reefs, salt marsh, seagrass, and kelp forests, provide crucial regulating, provisioning, and cultural services to human societies. Previous research has demonstrated the various ways in which these ecosystems can reduce disaster risk and contribute to climate change adaptation. Simultaneously, the potential effects of climate extremes and extreme weather events on ecosystem composition and functioning are increasingly gaining attention.While it is apparent that these ecosystems are subject to changing disturbance regimes under climate change, assessments of what these future disturbance regimes are likely to look like in the future have rarely been attempted and are often limited to single ecosystem and hazard pairs.Therefore, we propose a global multi-layer hazard assessment for coastal ecosystems to assess i) the changing disturbance regimes coastal ecosystems are exposed to with regards to tropical cyclones, storm surge, sea level rise, and marine heatwaves, ii) potential ecological responses to these changes, and iii) implications for ecosystem service provision. We will present preliminary results as a starting point for further discussion.
Shifting shorelines in a warming world: Deciphering coastal landscape sensitivity to climate change from the Paleocene Greenhouse of Arctic Svalbard
Authors: Jelby Mads E. , Vickers Madeleine L. , Jerrett Rhodri M. , Jochmann Malte M. , Marshall Chris , Price Gregory D. , Weijers Magnus , Anderskouv Kresten , Helland-Hansen William , Jensen Maria A.
Published: March 2024

Predicting the impact of the present-day global warming on the world’s shorelines is crucial for mapping future coastal hazards. Coastal environments are particularly sensitive to climate change, because the balance in the accumulation, distribution and erosion of nearshore sediments is controlled by various climate-forced parameters, including global eustatic sea level, regional source-to-sink routes, and local storms and floods. Simultaneously, coastal geomorphology and shoreline position are closely linked with local hydrology and vegetation distribution, such as peatlands, which are extremely sensitive to climate, humidity and precipitation. As a result, climate change may cause widespread coastal response in the form of shifting shoreline positions, changing landscapes and habitat modification of ecosystems. However, it remains uncertain how, and how much, coastal environments change with changing climate and temperatures in both time and space. Since the impact of global warming on the world’s shorelines remains to be seen, analyses of ancient sedimentary archives are vital for understanding climate-forced coastal changes.The Paleocene sedimentary succession in Arctic Svalbard is ideal for this purpose, because it: (i) forms a paralic sedimentary archive that was deposited in climates with characterized by atmospheric CO2 concentrations and global temperatures higher than, but comparable to, the present day; (ii) contains abundant fossil peat (coal) seams; (iii) represents various coastal landscapes, including beaches, lagoons, barriers, estuaries, deltas, wetlands and forests; (iv) records frequent shifts in relative sea level and corresponding nearshore hydrology and peat accumulation; and (v) was deposited near the pole, where signals of climate change are amplified.We present detailed facies-architectural reconstruction of the Paleocene strata in Svalbard, which delineates shoreline shifts controlled by sea-level changes, and we evaluate how coastal processes, environments and landscapes shift in response to temperature evolution, and aridity and humidity trends. Furthermore, we identify changes in shoreline geomorphology in response to shifts in paleotopography and vegetation build-up.
Reconciling risk-based and storyline attribution with Bayes theorem
Authors: Buschow Sebastian , Friederichs Petra , Hense Andreas
Published: March 2024

Current research on climate change attribution falls into two broad camps. Classic “risk-based” studies typically assess differences in the distribution of some climate variable between two scenarios: one representing factual conditions and one without man-made climate change. More recently, this line of investigation has been complemented by “storyline” approaches, which consider the impact of climate change, conditional on a particular state of the internal climate variability.The apparent gap between the two approaches can be bridged with Bayesian statistics. We demonstrate that a conditional attribution statement depends on two unconditional Bayesian decisions between the scenarios, one using all information and one using everything except the event of interest.To illustrate this result, we employ Gaussian mixture models to conduct conditional and unconditional attribution studies of European summer temperatures based on multiple CMIP6 ensemble simulations. We find that the resulting attribution statements can be either strengthened or weakened by the conditioning, depending on the estimated covariance structure. 
Performance of ASCAT soil moisture and MODIS snow cover satellite data for calibration of hydrologic models in poorly gauged catchments
Authors: Khalil Asma , Parajka Juraj
Published: March 2024

Remote sensing observations have significant potential for the setup and validation of hydrologic models and, consequently, predict runoff hydrographs in regions with limited runoff measurements. This study aims to analyze the spatial-temporal performance patterns of ASCAT soil moisture and MODIS snow cover to calibrate a conceptual hydrologic model in a large number of catchments in Austria. In the first step, the model (TUWmodel) is calibrated using satellite data only. Next, we analyze the regional and seasonal variability in model performance regarding snow cover error, soil moisture correlation and runoff efficiency. We compare the model efficiency of multiple objective calibrations to satellite data only to the performance of various regionalization strategies that transfer model parameters from the most similar catchments. Finally, we propose an alternative calibration strategy that combines satellite observations with a limited number of runoff observations, representing poorly gauged sites. The analyses are performed in 213 catchments in Austria representing diverse climate and physiographic conditions.
The influence of structural complexity of microbial habitats on soil organic matter decomposition: a theoretical analysis
Authors: Guseva Ksenia , Arellano Carlos , Rath Magdalena , Prinz Paul , Mohrlok Moritz , Kaiser Christina
Published: March 2024

The soil pore space constitutes a highly heterogeneous habitat that harbors a rich microbial diversity. Microbial processes within soils are intricately linked to the physical and chemical characteristics of micro-environments of pores where they reside. The dynamics of decomposition of organic matter therefore is shaped by the dispersion dynamics or spatial constraints imposed on microorganisms and their enzymes. Therefore, incorporating the complex soil architecture into computational models at the microscale is a crucial step to improve our predictions of the dynamics of soil organic matter (SOM) turnover.In this work, we employ theoretical models to elucidate the impact of soil structural complexity and heterogeneity on organic matter decomposition dynamics, and characterize mechanisms that enhance or constrain it. In the first part, we show the impact of compartmentalization of the substrate on enzyme activity, considering a scenario where microbes have no direct physical access to the substrate and only smaller freely diffusing enzymes can reach it. Our findings reveal that, in this context, enzyme lifetime imposes limitations on the turnover rate of the reaction, subsequently affecting the uptake and growth rates of microorganisms. In the second part, we examine the effect of soil architecture on microbial decomposition dynamics. Our results highlight two contrasting aspects necessary for rapid decomposition: on one hand there is a need for refuges/shelters where microbial activity is boosted trough accumulation of enzymes, and on the other there is a need for high connectivity (accessibility) of the pore space for the microbial population to spread. Through our examination, we unveil the intricate interplay between these apparently conflicting conditions and their profound effects on population growth and substrate decomposition rates.
How resolving are teleseismic forward and backscattered teleseismic P to S converted waves?
Authors: Gesret Alexandrine , Denise Emile , Janbein Ali
Published: March 2024

The Receiver Function (RF) technique, that aims to isolate P to S teleseismic converted waves, is largely used to image seismic discontinuities at depth. In particular, in subduction zones, the subducting crust has often be identified on RF as a Low Velocity Layer (LVL) embedded between the mantle of the overriding plate and the mantle of the subducting lithosphere. The arrival times and polarities of the forward Ps and backscattered Pps and Pss converted waves at the top and bottom of a LVL are sensitive to the backazimuth and ray parameter of the teleseismic events. We first demonstrate on a synthetic study that the thickness, the Vp/Vs ratio and the dip of a LVL can be retrieved by inverting the arrival times and polarities of these converted waves for a good azimuthal coverage. The Bayesian formalism allows us to also quantify the uncertainties associated to these inverted parameters.In several subduction zones, a high Vp/Vs ratio inside the oceanic crust has been estimated from the arrival times of the forward and backscattered P to S converted waves at the top and bottom of the LVL. In order to check if the signal periods associated to common filters could lead to an overestimation of the Vp/Vs ratio, we compute the wavelet response in conversion for a LVL typical of an oceanic crust. This multiscale analysis allows to illustrate that the LVL characteristics can be misinterpreted for the common frequency range due to interferences between the converted waves at the top and at the base of the LVL. For example, for a common dominant period of about 3s, the Vp/Vs of a typical oceanic crust will be largely overestimated and its thickness underestimated since a period smaller than 1s is required for a reliable interpretation. Indeed the true characteristics of a layer can be retrieved only if the ratio between the dominant period and the time delay (between the converted waves at the top and bottom of the LVL) is smaller than 1. This allows us to quantify, for the three kind of waves (Ps, Pps and Pss), the resolvable thickness of a LVL with respect to the Vp/Vs ratio and to the Vp velocity for a given signal period. The approach is finally applied to a real data example of teleseismic events recorded at a 3-component seismometer in order to reliably constrain the dip, the Vp/Vs ratio and the thickness of the oceanic crust at the top of the Hellenic subduction.
Pre-eruptive magmatic reservoir conditions controlling explosivity of a trachytic Plinian eruption: case for the Rungwe Pumice (Tanzania)
Authors: Cappelli Lorenzo , Wallace Paul A , Mbede Evelyne , Kwelwa Shimba , Abdallah Edista , Fontijn Karen
Published: March 2024

The eruptive style and explosivity of volcanic eruptions primarily depend on conduit dynamics (e.g., ascent rate and degassing efficiency) and the rheological behaviour of the pre-eruptive magma, which is controlled by its composition and conditions within the reservoir. In the case of highly alkaline magmas (i.e., agpaitic index > 1), the depolymerisation of silica bonds exerted by alkaline elements promotes a relatively low-viscosity rheological response and therefore theoretically less explosive eruptive behaviour, even for silica-rich magmas. However, several well-studied eruptions show that peralkaline magmas, like trachyte and phonolite, can also experience highly explosive Plinian events, suggesting other parameters might influence the eruption style. In the East African Rift, several such volcanoes with peralkaline magma compositions have erupted both explosively and effusively in the past. We investigated the pre-eruptive magmatic system of the Plinian eruption that produced the Rungwe Pumice (RP) deposit in southern Tanzania. The type section of the RP consists of a ~2.5 m thick fall deposit of peralkaline trachytic/phonolitic pumices. Syn-eruptive volatile exsolution is a crucial parameter controlling the eruptive style and is related to the volatile budget within the reservoir. Therefore, water concentrations in haüyne-hosted melt inclusions (MIs) were characterised using transmitted Fourier-transformed infrared spectroscopy. Preliminary results indicate substantial water concentrations within the reservoir (i.e., 2.60-5.59 wt.%) while the water retained by the glassy matrix of pumices reveals that the magma was almost entirely degassed during ascent. The modelled evolution of magmatic composition within the reservoir suggests closed conduit fractional crystallisation (~80% fractionation) of a parental mafic magma to generate the RP trachyte/phonolite within a compositionally homogeneous magmatic reservoir. Finally, by applying petrological models, we estimated a MI entrapping temperature of ~1147 ± 92 K and a minimum lithostatic pressure ranging from ~28 to 184 MPa (~1-7 km depth).
Exploring space plasma fluctuations at kinetic scales through stochastic process theory
Authors: Benella Simone
Published: March 2024

During the last decades, space missions provided in situ data of diverse space plasma environments with increasingly higher resolution. This enabled the possibility to investigate peculiar properties of fluctuations in the magnetic field and plasma parameters, transitioning from the magnetohydrodynamic (MHD) to the ion-kinetic regime. The ion-kinetic regime is characterized by a global self-similar scaling of fluctuations, in contrast to the local scale-invariance of the MHD ones. In a series of works, we developed a data-driven approach based on the Langevin equation in order to model statistical features of kinetic fluctuations. In practical terms, the stochastic process thus introduced represents the evolution of the magnetic field fluctuations as a function of the scale. As far as such fluctuations are of the Langevin type, their statistics evolve according to a Fokker-Planck equation. Studying the evolution of fluctuation statistics across the scales, e.g., structure functions, allows us to make predictions about global statistical properties, e.g., scaling exponents.In this work, we review recent results obtained by using data from the ESA/Cluster mission in near-Earth space. We give evidence that the dynamics of magnetic field increments at kinetic scales can be modeled as a stochastic process of the Langevin type, and that the correct scaling law of the structure functions can be obtained through the stochastic equation in the non-diffusive limit, by linking the drift term of the Langevin equation to the Hölder exponent. Finally, this model allows us to derive the asymptotic limit of individual sets of fluctuations, giving thus predictions on the trend expected at kinetic scales.
Genotypic variability of plant water use strategies during increasing atmospheric drought in 15 spring wheat (Triticum aestivum L.) genotypes
Authors: Ossola Emma , Köhler Tina , Carminati Andrea , Sadok Walid
Published: March 2024

The rise of global temperatures and shifts in precipitation patterns lead to increasing vapour pressure deficit (VPD), which was shown to have a detrimental impact on yield of many crops. A reduction in the transpiration rate (TR) at high VPD has been proposed as a key drought tolerance breeding trait to avoid excessive water loss. Our hypothesis is that with climate change, it will be more convenient for plants to have traits that restricts TR under high VPD levels. With this research we aimed to identify relevant hydraulic traits impacting plant water use during atmospheric drying.We measured water use and hydraulic traits of 15 different Minnesota spring wheat (Triticum aestivum L.) genotypes. We grew 45 plants (3 replicates for each genotype) in a climate chamber with controlled climatic conditions, while the soil was kept moist. After six weeks of growth, we monitored TR at 6 different VPD levels, between 0.5 and 2.8 kPa. Additionally, we measured maximum stomatal conductance (gs), leaf area (LA), plant hydraulic conductance (Kplant), stomatal density (SD), and root and leaf total biomass.Our findings show that total transpiration per LA, LA, and root/shoot-ratio differed significantly between genotypes. Conversely, transpiration sensitivity to rising VPD (indicated by the critical VPD upon which plants restricted transpiration, VPDBP), Kplant and maximum gs did not significantly differ between genotypes. However, we observed that plants with a low Kplant and a high maximum gs expressed a relatively low VPDBP, indicating a higher transpiration sensitivity to VPD. Our results align well with a hydraulic explanation of the TR response to increasing VPD and suggest that plant hydraulics play a key role in regulating TR during atmospheric drying. If the goal of future breeding is to modify plant water use under increasing VPD, targeting hydraulic traits has still much underexplored potential.
The drought response of European ecosystem processes via multiple components of the hydrological cycle
Authors: Poppe Terán Christian , Naz Bibi , Vereecken Harry , Hendricks Franssen Harrie-Jan
Published: March 2024

Droughts have become more frequent and severe in Europe over the last decade - a trend expected to continue. Recent studies have shown widespread responses of energy, water, and carbon fluxes in ecosystems to single drought years from flux observations. However, to better understand how ecosystems react to droughts, we need to gain explicit knowledge about the different factors that influence their response. In this light, it is crucial to associate the influence of droughts on diverse ecosystem types with particular compartments of the hydrological cycle (atmosphere, surface, soil, and groundwater reservoirs). For instance, during a drought, atmospheric dryness might be the dominant factor in arid regions as opposed to dry soils in humid regions.Here, we use states and fluxes of water and carbon (vapor pressure deficit, surface runoff, soil moisture, and water table depth) from the Community Land Model 5 in a 3 km resolution over Europe from 1995 to 2018 to determine the drought anomalies of ecosystem processes (gross primary production and evapotranspiration). Importantly, we apply a systematic drought concept integrating lags between deficits in a network of multiple sections of the hydrological cycle during a drought.Our analyses indicate that the dominance of a particular water resource in controlling ecosystem processes converges regionally and is predominantly consistent across drought events. This finding emphasizes using more comprehensive drought indices incorporating time lags and multiple water resources when analyzing ecosystem responses. Lastly, it identifies areas potentially threatened by droughts and their controlling water resource.
Global occurrences of very smooth plains patches on Mercury: geologic settings and implications for effusive volcanism
Authors: Lennox Annie , Rothery David , Malliband Chris , Balme Matt , wright Jack , Conway Susan
Published: March 2024

Introduction:  Large scale effusive volcanism, responsible for most of Mercury's 'smooth plains', is accepted to have ended by ca. 3.5 Ga [1]. We present local occurrences of smooth surfaces, often with the evidence for being topographically ponded. These examples are seldom larger than a few 10s of km across and are characterised by extremely smooth surfaces with a paucity of impact craters. Some of these deposits may provide evidence for a protracted phase of waning effusive volcanism post-3.5 Ga. We present a map of the global occurrences of very smooth plains patches and investigate their implications for the effusive volcanic evolution of Mercury.
Previously reported occurrences: :  During the Mariner 10 era, the partial geological map of H15 was unique in including small very smooth plains (pvs) deposits commonly associated with craters or tectonic features [2]. Similar patches have recently been identified in H10 [3] and an association with tectonic features was discovered (e.g. Calypso, Soya and Enterprise Rupes). Additionally, some patches of very smooth plains have been mapped in the survey of smooth plains deposits < 105 km of Wang et al. [4]. Previous works propose a range of origins which we will explore, namely:
·        Impact-related origin: Either as impact melt or fluidized impact ejecta
·        Small-volume effusive volcanic origin: where the age of such deposits are somewhat contested
Newly Identified occurrences: The global survey so far has identified approximately 500 potential patches, with varying confidence dependent on the degree of textural difference between the patch and surrounding terrain. These occur in a variety of settings, including low-lying areas of both smooth and intercrater plains, associated with craters or tectonic features, or catenae-hosted. Ongoing work involves mapping each patch, exploring emplacement scenarios and analysis of the association between patches and structural weaknesses.
Data and method: We map using NAC (single frame) and WAC (global mosaic) images obtained by MESSENDER’s MDIS. Mapping is carried out on a 116 m/p monochrome primary basemap; high-incidence east and west, and low-incidence angle secondary basemaps; a 665 m/p enhanced color mosaic; and a 665 m/p stereo-derived digital elevation model. Mapping is carried out using ArcGIS Pro. Each image is mapped in the projection most suited to that quadrangle.
 
References: [1] Byrne P. K., et al., (2016). Geophys. Res. Letters. [2] Strom et al., (1990). USGS Astorgeol. Sci. Center [3] Malliband C., et al. (2020). PhD Thesis. [4] Wang et al., (2021). Geophys. Res. Letters.
  
NOAA's Plans for its GEO Program from Today to 205
Authors: Heidinger Andrew , Lindsey Daniel , Joiner Joanna , Sullivan Pamela
Published: March 2024

NOAA’s Geostationary Operational Environmental Satellites (GOES) – R Series is now six years into its operational life with GOES-16 serving as GOES East, GOES-18 serving as GOES West, and GOES-17 in on-orbit storage.  The last GOES-R Series satellite (GOES-U) will launch in late April 2024.  Together the GOES-R satellites watch more than half the globe – from the west coast of Africa to New Zealand, and from Antarctica to the Arctic Ocean and will continue operations into the 2030s.To ensure the continuity of these critical observations, NOAA has initiated the mission that will follow GOES-R, the Geostationary Extended Observations (GeoXO) program.  GeoXO will expand the weather-centric mission of GOES-R's imagers and lightning mappers by adding a hyperspectral IR sounder (GXS).  GeoXO will expand beyond the weather mission by including hyperspectral sensors that measure atmospheric composition and ocean colour.    The first GeoXO launch is targeted for 2032 and the series is expected to be operational into the 2050s. This presentation provides a status on GOES-R operations and will also discuss GeoXO requirements, instrument status and  user readiness.
Assimilation of wide swath satellite altimetry to map geostrophic and internal tide signals of the ocean dynamics 
Authors: Bellemin-Laponnaz Valentin , Le Guillou Florian , Cosme Emmanuel , Ubelmann Clément , Blayo Eric
Published: March 2024

Mapping Sea Surface Height (SSH) from satellite altimetry is key to many scientific and operational applications. At the fine scales observed by SWOT, SSH variations are primarily driven by two types of dynamics - nearly geostrophic, Balanced Motion (BM) and wavy motion due to the Internal Tide (IT). These two processes differently affect ocean dynamics. The IT does not affect the surface horizontal transport of passive tracers (oil spills, plastics, algae…) unlike BM, but has a significant contribution to the vertical transport of heat, salt and nutrients. Separating BM and IT contributions to SSH variations will be essential in the mapping process. To a different extent, this separation is now common practice with high-frequency outputs of numerical simulations. Yet it is still an unresolved challenge for SSH maps computed with satellite observations like SWOT, which are sparse in space and time. This study introduces an innovative method to separate BM and IT components from SSH altimetric observations including SWOT. The method is based upon a data assimilation system combining two models - quasi-geostrophic for BM and linear shallow-water for IT. The inversion is performed with a weak-constraint four-dimensional variational (4DVar) approach, with two different sets of control parameters adapted to each component. A major, expected benefit of this approach lies in the potential to capture the non-stationary part of the internal tide component. The method outputs hourly SSH and surface velocity fields over a domain for both components. The work focuses on the North Pacific Ocean, because this zone has a strong mesoscale and submesoscale activity, including the two dynamics of interest. Observing System Simulation Experiments (OSSEs) are carried out over 20°x20° domains surrounding the SWOT crossovers. The experiments include both conventional Nadir and wide-swath SSH measurements, that are interpolated from the LLC4320 MITgcm simulation. The mapping algorithm performances are evaluated by comparing the outputs with the MITgcm referenced fields. The first results indicate that the assimilation system is able to separate the two targeted components, including the non stationary part of the internal tide. As this study is part of a PhD, the latest results available will be presented at the conference.
Evaluating sub-daily extreme precipitation from an ensemble of convection-permitting simulations: the role of topography.
Authors: Correa Sánchez Nathalia , Dallan Eleonora , Marra Francesco , Fosser Giorgia , Borga Marco
Published: March 2024

Past studies have shown that in orographically complex terrain, observed extreme precipitation intensity is impacted by elevation in different ways at different durations. Convection-permitting climate models (CPMs) are receiving increasing attention thanks to the more realistic representation of extreme sub-daily precipitation compared to coarser climate models. Two almost still unexplored themes concern: i) CPMs' ability to represent the observed relationship between precipitation and topography and ii) how the model ensemble uncertainty depends on elevation. To address these questions, we evaluate sub-daily extreme precipitation from an ensemble of eight CPM members (reanalysis-driven simulations) on topographically diverse terrains. We use observed data from rain gauges as benchmark. The analysis is conducted over the Eastern Italian Alps, where a strong relationship between precipitation sub-daily extremes and topography is observed (Dallan et al., 2023). We apply a non-asymptotic statistical approach (Simplified Metastatistical Extreme Value, SMEV) to estimate extreme precipitation return levels and assess their intra-model and inter-model uncertainties using a bootstrapped samples method. It is shown that the ensemble mean describes in a realistic way the precipitation extremes, with fractional standard errors of the mean-over-the-ensemble return levels ranging between 0,16 (24 hrs duration, 2 yrs return time) to 0,41 (1 hr duration, 100 yrs return time). We found that, compared to rain gauges, CPMs systematically underestimate extreme return levels in lowlands, whereas overestimate them at higher altitudes. Nevertheless, the CPMs can capture the relationship between rain depth and elevation, which is particularly important for 1-3 hrs duration. While the intra-model uncertainty decreases systematically with elevation at all durations, a more complex behaviour is observed for both inter-model and total uncertainty. These findings help to characterize the impact of elevation on the ensemble of CPM simulations, which is particularly required for the applications of these simulations for adaptation to future flood risk.REFERENCESDallan, E., Marra, F., Fosser, G., Marani, M., Formetta, G., Schär, C., & Borga, M. (2023). ID56. How well does a convection-permitting regional climate model represent the reverse orographic effect of extreme hourly precipitation? Hydrology and Earth System Sciences, 27(5), 1133–1149. https://doi.org/10.5194/hess-27-1133-2023.
Cratons are not all that stable!
Authors: Thybo Hans
Published: March 2024

Cratons are usually considered ‘old and stable’ geological units and, therefore, the do not receive as much consideration by geophysical data acquisition as active tectonic regions. However, abundant evidence shows that ‘stable’ cratons are modified substantially during their existence as demonstrated by geophysical data imaging cratonic lithosphere in several cases:(1) The Baltic Shield formed during the Svecofennian orogeny c. 1.7 Ga and its western parts were reworked by the Sveconorwegian/Grenvillian orogeny. Recent geophysical interpretations image a large body of crustal material in eclogite facies beneath the present Moho in the central shield. This body probably formed after the initial cratonization (Buntin et al., 2021).(2) The isopycnicity hypothesis proposes that a trade-off between composition and temperature of the lithospheric mantle maintains constant topography in cratons (Jordan, 1978) based on kimberlite data from South Africa. However, gravity data from Siberia shows that kimberlite pipes solely modify cratons in isostatic equilibrium (Artemieva et al., 2019). Therefore, kimberlite sampling is nonrepresentative, and the real composition of most cratonic mantle lithosphere is unknown.(3) Strong seismic anisotropy is observed in many cratons and is commonly attributed to the mantle due to frozen-in lithospheric features or asthenospheric flow. Recently it was demonstrated that a major part of the anisotropy resides in the crust of the Kalahara craton and that the fast axes are parallel to the strike of major dyke swarms and orogenic fabric (Thybo et al., 2019). This finding indicates significant craton modification by magmatic intrusion.(4) Modification by external stresses and induced magmatism may even split existing cratons.  Integrated interpretation of existing data and geodynamic modelling show that a linear sequence of volcanic harrats in the Arabian craton potentially represents the formation of a new plate boundary (Artemieva et al., 2022). It is probable that the extension in the northern Red Sea rift will jump to the volcanic lineament, which eventually will develop into new ocean spreading and effectively split the existing craton.ReferencesArtemieva, I.M.., Thybo, H. & Cherepanova, Y, 2019. Isopycnicity of cratonic mantle restricted to kimberlite provinces. Earth Plan. Sci. Lett. 505, 13-19, doi:10.1016/j.epsl.2018.09.034 (2019).Artemieva, I.M., Yang, H., Thybo, H. Incipient ocean spreading beneath the Arabian shield, Earth-Science Reviews, 226, 103955 (2022)Buntin, S., Artemieva, I.M., Malehmir, A., Thybo, H. et al. Long-lived Paleoproterozoic eclogitic lower crust. Nat Commun 12, 6553 (2021).Jordan, T. Composition and development of the continental tectosphere. Nature 274, 544–548 (1978)Thybo, H., Youssof, M. & Artemieva, I.M. Southern Africa crustal anisotropy reveals coupled crust-mantle evolution for over 2 billion years. Nat Commun. 10, 5445 (2019)