bluuebunny/crossref_metadata_2025 huggingface dataset:
The rapid surface uplift of the Eastern Alps. Evidence from cosmogenic nuclides and mapping of elevated low relief surfaces
Authors: Stüwe Kurt , Robl Jörg , Plan Lukas , Fabel Derek , Stuart Fin , Gradwohl Gerit
Published: March 2024

Surface uplift of the Eastern Alps is generally considered to have occurred more or less continuously over the last 30 Ma. During this period, the interplay of many kilometres of rock uplift and erosion has resulted in surface uplift of some 2-3 kilometres. However, reference frames that allow rock uplift and surface uplift to be distinguished are often hard to identify. Surface uplift rates can be determined in regions where erosion did not occur. That is classically done by the identification and dating of relicts of ancient base levels. In the Eastern Alps a suite of discrete elevated low relief landscapes (ELRLs) are present up to 3000 m surface elevation that have been identified as relicts of base levels. In this contribution we present a map of these ELRL landforms for much of the Eastern Alps and report cosmogenic 10Be, 21Ne and 26Al nuclide data from fluvial sediments sampled from 50 caves that are interpreted to have formed at the same time as the ELRL paleosurfaces. The samples that are interpreted to have been deposited during cave formation at the vadose-phreatic transition. As such, they form markers for base level and the time of their deposition in the cave may be interpreted as the time the cave was at base level. Our data indicate that the uplift rate of the Eastern Alps may be in the order of 200 – 500 m per million years for much of the Pliocene. This is significantly faster than previously thought and implies that much of the surface uplift of the Eastern Alps may have occurred since the late Miocene.
High resolution pH measurements at the edge of the Dotson Ice shelf using state-of-the-art autonomous technologies.
Authors: Pickup Daisy , Heywood Karen , Bakker Dorothee , Hammermeister Emily , Loucaides Socratis , Zheng Yixi , Lee Gareth , Yager Patricia , Hall Rob
Published: March 2024

The global ocean takes up about a quarter of anthropogenic carbon dioxide emissions, with the Southern Ocean playing a disproportionately large role. This uptake has led to changes in the Southern Ocean's carbonate chemistry, reducing pH through ocean acidification. The Amundsen Sea, West Antarctica, is surrounded by rapidly melting ice shelves, that may be impacting the carbonate balance of this coastal region. Near the Dotson Ice Shelf, we collected the first high-resolution, full-depth pH dataset using a Lab-on-Chip spectrophotometric sensor attached to an autonomous profiling ocean glider. The sensor collected data within 10 km of the Dotson Ice Shelf over a 19-day period in January/February 2022 and captured the variability that results from summertime biogeochemical and physical processes. In the upper 150 m, net primary production dominates variation in pH, producing a maximum pH of 8.34 (on the total hydrogen scale) in front of Dotson Ice Shelf, where chlorophyll fluorescence also peaks. Below 150 m, pH is generally lower, likely as a result of net respiration. The inflow of modified Circumpolar Deep Water near the east side of Dotson Ice Shelf exhibits a slightly elevated pH (0.05 units) compared to surrounding deep waters. The meltwater-laden outflow that exits on the west side of the ice shelf at depths between 300 - 500 m displays a lower pH (0.1 units) relative to the surrounding waters, which shoals and mixes, reducing pH in the overlying surface waters. In the coastal current along Dotson Ice Shelf, an unusual subsurface maximum in pH (0.1 units at 150 m, compared to surrounding waters) is observed and is also associated with increased chlorophyll fluorescence. Possible explanations for the observed features are discussed. These high-resolution findings reveal the potential of pH measurements on an autonomous vehicle for investigating difficult to access regions with glacial melt.
The solar cycle 25 multi-spacecraft solar energetic particle event catalog of the SERPENTINE project
Authors: Dresing Nina ,   SERPENTINE SEP Catalog Team
Published: March 2024

We present a new multi-spacecraft SEP event catalog for events observed in solar cycle 25. Observations from five different viewpoints are utilized, which are provided by Solar Orbiter, Parker Solar Probe, STEREO A, BepiColombo, and the near-Earth spacecraft Wind and SOHO. The catalog is an output of the SERPENTINE project, funded through the European Union’s Horizon 2020 framework programme. We provide key SEP parameters for > 25 MeV protons, > 1 MeV electrons, and ∼100 keV electrons. Furthermore, basic parameters of the associated flare and type-II radio burst are listed, as well as the coordinates of the observer and solar source locations.An event is included in the catalog if at least two spacecraft detect a significant proton event with energies > 25 MeV. SEP onset times are determined using the Poisson-CUSUM method. SEP peak times and intensities refer to the global intensity maximum. If different viewing directions are available, we use the one with the earliest onset for the onset determination and the one with the highest peak intensity for the peak identification. We furthermore aim at using the highest possible time resolution. Therefore, time averaging of the SEP intensity data is only applied if necessary to determine clean event onsets and peaks. Associated flares were identified using observations from near Earth and Solar Orbiter. Associated type II bursts were determined from ground-based observations in the metric frequency range and from spacecraft observations in the decametric range.The current version of the catalog contains 45 multi-spacecraft events observed in the period from Nov 2020 until May 2023, of which 13 were widespread events and four were classified as narrow-spread events. Using X-ray observations by GOES/XRS and Solar Orbiter/STIX we were able to identify the associated flare in all but four events. Using ground-based and spacecraft radio observations we found an associated type-II radio burst for 40 events. In total the catalog contains 141 single event observations out of which 18 (39) have been observed at radial distances below 0.6 AU (0.8 AU). We acknowledge funding by the European Union’s Horizon 2020 research and innovation program under grant agreement No. 101004159 (SERPENTINE).   
Two-source energy balance modelling of evapotranspiration over complex terrain
Authors: Deidda Paolo , Bartkowiak Paulina , Castelli Mariapina
Published: March 2024

In recent years the Adige basin, in northeastern Italy, has experienced extreme drought events which resulted in agricultural and water management issues. Evapotranspiration (ET), one major indicator of water use, plays an important role under drought conditions. On the other side, reliable estimates of ET are currently missing over mountainous and heterogeneous areas such as the Adige basin. This study aims to provide an estimate of ET which will be of benefit both to research and agricultural services. In the framework of the project RETURN (Multi-risk science for resilient communities under a changing climate) and of the Italian National Drought Hydrological Monitoring System, we estimate daily ET at high spatial resolution (below 100 m) over the Adige catchment for the period 2017-2022. Remote sensing has been widely used to compute spatially distributed ET maps from thermal infrared datasets. In particular, the two-source energy balance (TSEB) model has proven to perform well over different land types and climates. An implementation of TSEB was already developed to estimate high-resolution ET from Copernicus globally available products (Sen-ET), adopting the Sentinel-3 and Sentinel-2 constellations for estimating fine-scale land surface temperature. Moreover, the ERA5 reanalysis data and the Climate Change Initiative land cover map have been used to retrieve solar radiation and vegetation structural parameters. However, the use of these datasets presents some shortcomings over such a complex area as the Adige basin, mainly due to their coarse spatial resolution. In this study, Sen-ET is adapted for complex terrains by replacing the ERA5 solar radiation data, available at 30 km, with the Meteosat Second Generation (MSG) radiation dataset (3.5 km) and, additionally, substituting the current land cover map (300 m) with the 100 m grid size Corine Land Cover product. Furthermore, a correction factor is applied to the radiation dataset to consider topographic shading, slope, and aspect. A comparison with daily aggregated global solar radiation from 79 weather stations in the Alpine region, covering a wide range of elevations, resulted in an R2 of 0.95 and 0.75 for MSG and ERA5 respectively, showing that this approach could greatly improve the reliability of ET estimation. Future steps will focus on the impact of changing radiation and land cover input data on the accuracy of modelled ET. The results will be validated against observations at Eddy-covariance sites.
Image Management and Analytics integrated in geospatial workflows
Authors: Doerffel Guenter
Published: March 2024

Traditional imageery workflows in many cases still follow a Datset --> process --> result Dataset scheme.In todays world of high spatial and temporal imagery resolution and analytical cadence, this turns out tobe increasingly inpractical. This is backed by todays cloud based mass data storage and constant change detection requirements.So accessing Imagery as dynamic compilations and analyzing stacks, time-series, blocks upon demand, largely without producingpermanent internmeidate data has become a paradigm. Added to it is the demand to analyze the Imagery sources together with in-situsources, sensors, base geometries and other georelated data sources.This presentations will outline the capabilities and strategies of the ArcGIS Platform to fulfill these demands and referencecloud based data and processing as well as dynamic server analytics and traditional Desktop approaches - UI and Python/Notebook driven.Time-series analysis, DeepLearning/AI and combined Raster/Vector analysis will be used as examples. Target audience is anyone interested in geospatial analysis combining Imagery and other geospatial data sources.
How strong is land-atmosphere coupling in global storm-resolving simulations?
Authors: Lee Junhong , Hohenegger Cathy
Published: March 2024

The debate on the sign of land-atmosphere coupling has not been solved so far. On the one hand, studies using global coarse-resolution climate models have claimed that the land-atmosphere coupling is positive. But, such models use convective parameterizations, which is a source of uncertainty. On the other hand, studies using regional climate models with explicit convection have reported negative coupling. Yet, the large-scale circulation is prescribed in such models, and interactions with the ocean are neglected. In this study, we revisit the land-atmosphere coupling using a global fully coupled storm-resolving simulation that has been integrated at a grid spacing of 5 km over a full seasonal cycle, and we compare these results to a coarse-resolution climate model simulation using parameterized convection. We find that the coupling between soil moisture and precipitation is weaker and more negative in the storm-resolving than in the coarse-resolution simulation. Further analysis indicates that not only the feedback between soil moisture and evapotranspiration but also between evapotranspiration and precipitation is weaker in the storm-resolving simulation, in better agreement with observations. Reasons for the differences will be mentioned.
Causality in Water-Energy and Food nexus: A toy-model multitasking stochastic synthesis, highlighting the complexity and randomness in decision making
Authors: Markantonis David , Matina Kougia , Koutsoyiannis Demetris , Sargentis G.-Fivos
Published: March 2024

The water, energy, and food nexus underscores the intricate interdependence among these vital resources, highlighting the need for integrated and rational management. Balancing the synergies and trade-offs within this nexus is crucial for addressing global challenges related to resource security, environmental management, and societal well-being. While the elements of the nexus are interdependent, various parameters hinder their causal connections. In this study we create a stochastic toy model which links each part of the nexus to the other based on Hurst-Kolmogorov dynamics. The introduction of simple environmental and social variables to these interdependencies alters the model dynamics of the nexus. In this way, we observe that despite the apparent causality in the dependencies of the nexus, the complexity of the system does not reveal causation. Therefore, as the nexus is vital for social prosperity, we must explore other methods for decision making.
A remote-sensing-based framework to detect the rate of peat subsidence and associated CO2 emissions: A case study of the Biebrza Valley, Poland
Authors: Ghezelayagh Pouya , Oleszczuk Ryszard , Stachowicz Marta , Eini Mohammad Reza , Banaszuk Piotr , Kamocki Andrzej , Grygoruk Mateusz
Published: March 2024

Peatlands are vital ecosystems that provide essential ecological services, especially in carbon storage. Nevertheless, the decomposition of surface peat and subsequent carbon emission threaten to accelerate the pace of climate change. This study presents a framework designed to facilitate the estimation of peat subsidence and relevant CO2 emissions through the exclusive utilization of remote sensing techniques. In this study, the peatland subsidence in the Biebrza Valley, Poland, was estimated by using the Alaska Satellite Facility Interferometry Synthetic Aperture Radar on-demand cloud computing via a Small Baseline Set technique and seasonal-annual search approach covering the period from April 2015-April 2022. The amount of subsidence and associated carbon emission rates can be estimated by analyzing InSAR data from a selected period. The results reveal an annual peatland subsidence rate of 2.1 cm, verified through field surveys. An R2 value of 0.91, and an RMSE value of 0.23 cm indicate the reliability of this approach in estimating the subsidence. These findings unveil a troubling trend in the Biebrza National Park, with almost 88 MCM of its peatlands lost during the seven years from 2015-2022. Two different approaches were employed to estimate CO2 emissions associated with subsidence, each with three scenarios. Therefore, the estimation of annual peatland carbon dioxide loss, ranging from 3.24 to 5.36 tons per hectare through the remote sensing-based approach, compared to the broader range of 20.3 to 33.9 tons/ha/yr obtained from the common approach. It means that, based on the first approach, in the most optimistic scenario, the park is associated with a minimum of 1.35 million tons of carbon dioxide emissions during this period, potentially reaching as high as 2.26 million tons in the worst-case scenario. In contrast, the common approach indicates a wider range of emissions, ranging from 8.5 to 14.2 million tons over these years.
Parametric insurance for hydropower: Comparing alternative schemes combining hydrologic and market data
Authors: Scarpellini Lorenzo , Ficchì Andrea , Giuliani Matteo , Castelletti Andrea
Published: March 2024

The alteration in hydrological patterns due to climate change is causing a rise in the occurrence and severity of hydrological extremes like droughts and floods. This, in turn, is leading to conflicts over water resources and increasing financial risk for several economic sectors, such as hydropower and agriculture. Parametric insurance is a tool for hedging financial risks that is already used for making water-related sectors more resilient. With respect to traditional loss-based insurance, parametric schemes are more flexible, simple and cost-effective, and they also minimize moral hazard and promote further adaptation efforts.Parametric schemes rely on the definition of an index, correlated with revenue losses, and on predetermined thresholds to trigger payouts compensating for losses. Different conditions can be proposed to contract buyers, varying the payout structure, contract price (i.e., premium) and duration. For example, while in standard index-based insurance, a fixed premium is paid on an annual basis, in ‘collar’ contracts a premium is only paid in years when the index exceeds a pay-off threshold, i.e., when revenues are high. Indexes can also be designed in a variety of ways, but they should be highly correlated with losses, reliable and transparent. While simple indexes based on a hydrological variable are often preferred, multivariate indexes can, in some cases, be more suitable due to the multiple factors influencing revenue losses. This is the case for the hydropower sector, which is highly dependent on both hydrological and market variability. Different parametric insurance contract types have been proposed in the past for various sectors, but alternative schemes are seldom compared on the same system. In this study, we investigate the mitigation of economic impacts deriving from droughts and energy market variability on hydropower companies by comparing alternative parametric insurance schemes. Such alternatives are built considering a variety of payout structures, including standard and collar schemes, and both univariate and multivariate indexes based on hydro-meteorological and market variables. We test our methodology on three hydropower operators in the Lake Como system, in the Italian Alps, an area where global warming has caused local temperatures to increase more than double the global average and stakeholders are increasingly exposed to drought risk.Results show that the use of a multivariate index explicitly considering electricity prices greatly increases performance compared to a simpler univariate hydrological index. In addition, while both standard and collar contracts can effectively reduce revenue variability and improve revenue floor, the collar contract can provide better performance at a lower price. However, such more complex contracts are more sensitive to parameter values and their calibration should be performed carefully.
Through damage analysis and historical learning: a workflow for multi-hazard vulnerability assessment in cultural heritage preservation
Authors: Bosi Elena
Published: March 2024

Natural disasters and extreme weather events are defining this decade and will continue to do so in the future, impacting societies and ecosystems worldwide. The Sendai Framework for Disaster Risk Reduction, adopted to mitigate these risks, also significantly emphasizes the protection and preservation of cultural heritage. It calls for cooperation among national authorities to raise awareness about the impact of hazards on cultural heritage and aligns with the goals of international organizations such as ICOMOS. Although earthquake risk vulnerability has been extensively studied, research on other extreme events, such as landslides and floods, is still limited. Additionally, a growing body of literature on multi-hazard management deals with managing combined natural events. However, there has not been enough research explicitly addressing the vulnerability of cultural heritage.The research focuses on vulnerability as a multidimensional characteristic and its relationship to multi-scale architectural assets, including individual buildings, aggregates and historic urban cores. Vulnerability is determined by physical, social, and economic dimensions and explores its significance in different phenomena, including compounding and cascading events. A workflow is proposed, consisting of several steps: identifying significant events, assessing affected areas, evaluating the level of damage incurred, and conducting a vulnerability assessment. To understand how to address the issue of vulnerability assessment in a multi-hazard context, it is necessary to observe the effects of past disasters on the built environment.The proposed methodology follows an inductive approach. The first part of the study, which is also the current focus of the work, consists of the selection of suitable cases for field investigation, intending to analyze the level of physical damage, the geology and hydrology, the history of the environment and events, and the development of building techniques. These studies explore possible relationships between disasters, building techniques and changing settlement patterns. The second phase, transitioning from the particular to the general, will be displayed by defining a list of methodological guidelines based on a critical abstraction from the findings of the first phase. Specifically, this will involve moving from damage observation to vulnerability assessment. General multi-hazard vulnerability criteria for historic centres will be established to analyze practical implications and purposes, including raising community awareness through increased knowledge of the architectural heritage and reconsidering historical studies as essential tools to mitigate future vulnerability.
Engaging a highly-qualified crowd in an information system for natural hazards in mountain areas
Authors: Mayr Andreas , Rosendorfer Michael , Knaus Matthias , Rutzinger Martin
Published: March 2024

In recent times, we find an increasing number of people exploring mountain areas where they expose themselves to a variety of hazardous natural processes (e.g., rock fall, collapsing seracs, landslides, or torrential floods) and adverse conditions (e.g., eroded trails). Ongoing climate change with its destabilizing impact on glaciers and permafrost makes such hazards even more ubiquitous. Moreover, remote mountain areas are not covered by standardized management schemes for natural hazards and there is usually no systematic monitoring. However, many relevant observations are made by experienced alpine professionals (such as guides, rescue teams, park rangers, geoscientists etc.). The “AlpsWatch” project intends to build on co-creation of information by this “highly-qualified crowd” to establish an interactive information platform for natural hazards in a mountainous pilot region (Tyrol, Austria). The project develops and implements an easy-to-use mobile app where expert users can readily document and share their qualified field observations. The collected observations are synchronized and structured in a spatio-temporal database, which, in turn, can be accessed by the expert users. Thereby, the project contributes to more informed decision making on the mountain and during planning of activities and, thus, enables mountain professionals to enhance the safety of themselves and of their clients. A focus of the project will be on standardization and structuring of the observations, as well as on possibilities to automatically trigger requests for human intervention via quality checks, further investigation, or warning via authorities. We are also investigating possibilities to combine the crowd-based field observations with remote sensing and geomorphological process models. Thereby, we aim to improve the understanding of geomorphological dynamics and to develop more advanced and spatially continuous information products for natural hazards in mountain areas.
First Principle Description of Plasma Expansion using the Expanding Box Model. Implications for CGL Theory in the Solar Wind.
Authors: Echeverria Veas Sebastian , Moya Pablo , Lazar Marian , Poedts Stefaan , Asenjo Felipe
Published: March 2024

Multiscale modeling of expanding plasmas is crucial for understanding the dynamics and evolution of various astrophysical plasma systems. In this context, the Expanding Box Model (EBM) was used to add the expansion into the kinetic equations, allowing us to describe plasma physics in a new system of reference non-expanding and co-moving with the plasma. This system allows us to maintain a constant volume through non-inertial forces, and its interpretation is fundamental to describing plasma physics.We have employed the EBM formalism to incorporate the expanding properties of the system into the plasma dynamics, which mainly affects transverse coordinates (i.e., y y/o z). Coordinate transformations were introduced within the co-moving frame system to obtain the modified Vlasov equation. Our main goal is to develop a plasma physics theory through a novel first principle description in the expanding frame, which is fundamentally based on the (collisionless) Vlasov equation for the evolution of the velocity distribution functions. Based on this, the expanding moments, such as the continuity, momentum, and energy equations, can then be derived, and an MHD model of the plasma expansion can be developed. Finally, coupling the obtained moments and Maxwell equations, a CGL-like plasma description is developed in the EB frame to study the evolution of macroscopic quantities (temperature, magnetic field, parallel beta, and anisotropy).Our results show the expansion affecting the kinetic and fluid equations through non-inertial and fictitious forces in the transverse directions, which contain all the information related to the expansion. These are thus reflected by the equations derived for the expanding moments of the distribution function, including density, bulk (drift) velocity, and pressure (or temperature). Furthermore, we developed an ideal expanding-MHD model based on these modified moments, providing a new interpretation and comparison with the existing results when expansion is considered. The EBM modifies the conservative form of the two adiabatic invariants in the CGL approximation. Equations are solved for radially decreasing magnetic fields and density profiles to study the relations between plasma parallel beta and anisotropy within the expansion. 
Submarine braided channels in response to channel confinement shapes and inflow-to-sediment discharge ratios: Insights from physical experiments
Authors: Tsai Yun-Ting , Lai Steven Yueh Jen
Published: March 2024

Submarine braided channels, driven by turbidity currents, have been revealed on several deep-sea fans, displaying similar morphological features to fluvial braided rivers. Past experimental studies on submarine braided channels have shown that active braiding intensity (BIA) is proportional to fixed confinement width, dimensionless stream power (ω*) and dimensionless sediment-stream power (ω**). However, the field-scale submarine braided channels may not restrict to a fixed confinement width (B); instead, the confinement shape often exhibits gradual widening or narrowing. In this study, we use physical experiments to investigate the influence of confinement shapes and inflow-to-sediment discharge ratios (Qin/Qs) on the evolution of submarine braided channels. In the experiments, three confinement shapes were simulated: diamond, hourglass, and reversed trapezoid. The experimental results show that the BIA is strongly proportional to the varying confinement width, i.e., increasing confinement width facilitates the degree of braiding; decreasing confinement width suppresses the degree of braiding. The measured BIA is proportional to both the ω* and ω**. Additionally, increasing Qin/Qs causes a slightly decrease of BIA. The measured active width (Wa) is proportional to the bulk change (Vbulk). These relations all agree with the published trends of both fluvial and submarine braided channels. For the geometric properties of sandbars, the measured sandbar aspect ratio and sandbar compactness ratio remain constant regardless the change of confinement shape or Qin/Qs. Finally, the experimental results may aid our understanding to the morphological evolution of submarine braided channels and provide insights to the stacking patterns of hydrocarbon reservoirs. Keywords: submarine braided channels, turbidity current, physical experiment, confinement shape, active braiding intensity
Why nanoplastics do not enhance the transport of contaminants in the critical zone
Authors: Hofmann Thilo , Henkel Charlotte , Hueffer Thorsten , Castan Stephanie
Published: March 2024

The impact of nanoplastics on the co-transport of emerging contaminants is a subject of ongoing debate. Agricultural soils face potential contamination from micro- and nanoplastics through diverse agricultural practices. Various authors argue that the substantial surface area of small particles and their high sorption potential may considerably augment the mobility of numerous contaminants within the critical zone. Concerns have been expressed regarding the role of micro- and nanoplastics as carriers for organic contaminants into deeper soil layers, posing a potential threat to groundwater resources, particularly in agricultural soils where sewage sludge and plant protection products are frequently applied.In this study, we investigated the correlation between transport and desorption timescales by employing two diffusion models for micro- and nanoplastics ranging from 100 nm to 1 mm. To assess the transport of contaminants bound to these plastics, we examined the diffusion and partitioning coefficients of prominent agrochemicals and additives, along with commonly used polymers like polyethylene and tire material. Our modeling analysis reveals that the desorption rate of most organic contaminants is too rapid for micro- and nanoplastics to serve as effective transport facilitators in soil. Notably, the transport of contaminants facilitated by microplastics was observed to be significant only for highly hydrophobic contaminants under preferential fast-flow conditions.While micro- and nanoplastics could potentially introduce harmful contaminants into agricultural soils, our study suggests they do not significantly enhance contaminant mobility. Importantly, we found that nanoplastics, in particular, do not promote contaminant relocation under conditions relevant to almost all contaminants of concern.
Heavy-tailed flood peak distributions: What is the effect of the spatial variability of rainfall and runoff generation?
Authors: Macdonald Elena , Merz Bruno , Nguyen Viet Dung , Vorogushyn Sergiy
Published: March 2024

The distributions of many observed time series of daily precipitation and streamflow show heavy tail behaviour. This means that the occurrence of extreme events has a higher probability than would be the case if the tail was receding exponentially. To avoid underestimating extreme flood events in their occurrence probability or their magnitude, a robust estimation of the tail behaviour is required. However, this is often hindered due to the limited length of time series. One way of overcoming this is to enhance the understanding of the processes that govern the tail behaviour of flood peak distributions. Here, we analyse how the spatial variability of rainfall and runoff generation along with the tail behaviour of rainfall affect the flood peak tail behaviour in catchments of various size. To do so, a modelling chain consisting of a stochastic weather generator and a conceptual rainfall-runoff model is used. For a large synthetic catchment (>100,000 km²), long time series of daily rainfall with varying tail behaviour and varying degree of spatial variability are generated and used as input for the rainfall-runoff model. In the rainfall-runoff model, spatially variable runoff is generated by setting respective model parameters accordingly. The tail behaviour of the simulated precipitation and streamflow time series is characterized with the shape parameter of the Generalized Extreme Value (GEV) distribution.Our analysis shows that heavy-tailed rainfall tends to result in heavy-tailed flood peak distributions, independent of the catchment size. In contrast, first results regarding the effect of the spatial variability of rainfall on flood peak tail behaviour indicate that this relation varies with the size of the catchment. In large catchments, attenuating effects, for example through river routing, might have a stronger impact than in small basins. Regarding the runoff generation, the tail of flood peak distributions tends to be heavier when a fast runoff component is triggered simultaneously in a larger share of the catchment rather than when this is the case only very localized. This in turn is linked to more homogeneous catchment characteristics and rainfall patterns. The results of this study can help with improving the estimation of occurrence probabilities of extreme flood events.
Assessment of Suspended Sediment Dynamics in the Largest Peninsular Basin of India
Authors: Singh Anubhuti , Swarnkar Somil , Kundu Soumya , Prakash Shivendra
Published: March 2024

The Godavari River Basin (GRB), the biggest Peninsular Indian basin, has experienced a major decline in both streamflow and sediment discharge since 1965, with a particularly notable loss occurring after around 1990. Previous studies reported an overall decrease of suspended sediment load around 123 Mt/year in the GRB, which places it as the third highest among all major river basins worldwide. However, there is a lack of adequate understanding of the consequences of reservoir operations, variations in flow, and the broader dynamics of sediment.  Here, we employed a dataset provided by the Central Water Commission (CWC), India, to better comprehend the fluctuations in suspended sediment load and discharge throughout different regions of the GRB. Our research focuses on analyzing the relationship between the variability of suspended sediment load and its response to factors such as dam constructions and discharge fluctuations. Our research findings indicate that a significant number of gauging stations had a decline of more than 50% in suspended sediment load after 1990. Further investigation clearly demonstrates a substantial decrease in suspended sediment load after 1990 due to the entrapment of suspended sediment load induced by the installation of large-scale dams. The temporal change in suspended sediment load in the Godavari and its main tributaries is associated with the rise in human activities observed in recent decades. The findings of this study have important significance for recognizing the complex relationships between land use land cover, suspended sediment loads, soil erosion, and reservoir management in the GRB.  In addition, this study can provide valuable information for policymakers to adopt more effective reservoir management, soil erosion control, and soil-water conservation measures in the GRB.
The Thermosphere and Ionosphere System Responses to Subauroral Polarization Streams (SAPS) During the March, 17, 2013 Geomagnetic Storm
Authors: Wang Wenbin , Ling Dong , Merkin Slava , Wu Qian , Zhang Yongliang
Published: March 2024

During geomagnetic storms, a latitudinally narrow band of strong sunward plasma drifts occurs just equatorward of auroral electron precipitation in the afternoon to pre-midnight sector, which is termed subauroral polarization steams (SAPS). SAPS are produced when the downward Region-2 current is closed through the subauroral region of low ionospheric conductivity and a strong poleward electric field is established to ensure current continuity. SAPS are a manifestation of the strong coupling between the magnetosphere and the ionosphere and thermosphere system. In this study, we employ the high-resolution Multiscale Atmosphere-Geospace Environment (MAGE) model that is developed by the NASA DRIVE Science Center for Geospace Storms (CGS) to simulate the SAPS effects on the global thermosphere-ionosphere system during the March 17 2013 geomagnetic storm. We compare two MAGE model runs, one with SAPS in the entire simulation and the other with the SAPS drifts being turned off when the ionospheric electric fields are used to calculate ion frictional heating, neutral Joule heating, ion drag and plasma transport. By comparing the results from these two runs we quantify the effects of SAPS on the thermosphere and ionosphere system. Our results show that with SAPS ionospheric total electron content (TEC) and electron densities are enhanced in the afternoon sector at middle and high latitudes. This provides a strong source of ionization for the high-latitude convection pattern to transport the plasma into the polar cap to form the polar tongue of ionization (TOI) and patches. Therefore, SAPS facilitate the occurrence and strengthening of TOI. The MAGE simulations also show that the phase and speed of storm-time traveling atmospheric disturbances and neutral circulation are modulated by the SAPS, and the SAPS effects are thus transmitted globally to affect the behavior of the entire thermosphere and ionosphere system during the storm.
Observing plasma structures at multiple scale sizes in the high-latitude ionosphere with a suite of ground-based instrumentation. 
Authors: Maguire Sophie , Wood Alan , Themens David
Published: March 2024

The terrestrial ionosphere is a highly variable medium that affects the propagation of radio waves. Within the ionosphere, large-scale structures, such as polar cap patches, auroral forms, blobs, and polar holes, have been observed. Small-scale irregularities associated with these large-scale structures result from instability processes which can lead to scintillation of trans-ionospheric radio signals, such as those used for Global Navigation Satellite Systems (GNSS). To investigate plasma irregularities and scintillation in the high-latitude ionosphere, the Scales of Ionospheric Plasma Structuring (SIPS) experiment was conducted using a suite of ground-based instrumentation between the 3rd and 15th of January 2024.The aim of the SIPS experiment was to observe the high-latitude ionosphere across several scale sizes, and this required a variety of ground-based instruments, in conjunction with the Swarm satellites. The European Incoherent SCATter (EISCAT) radars were used to measure the plasma parameters, such as density, giving indication to the presence of large-scale plasma structures that were several hundreds of km in size. Medium-scale plasma irregularities, with scale sizes of several km, were inferred from the ground by the LOw Frequency ARray (LOFAR) and the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA). Smaller-scale irregularities less than 500m in scale size were inferred from the scintillation data from ground-based GNSS receivers giving an indication to the scintillation effects. To assist in the interpretation of the results, the Swarm Ionospheric Scintillation (SWIS) methodology was also used, which utilises data from the Swarm satellites to give a spectrum of irregularities to scale sizes down to 500m (Spogli et al., 2022). Using this array of observations, the relationship between irregularities of varying scale sizes could be explored, along with the formation and generation of small-scale irregularities due to instability mechanisms and the subsequent scintillation effects which can occur.The combination of both ground-based and space-based instruments in this experiment, observing and modelling the ionospheric plasma, gives unprecedented coverage of varying scale sizes which is not possible with individual instrumentation alone. 72 hours of EISCAT observation time was awarded for this experiment which was carried out over 5 nights in January 2024 between 18:00 and 23:59 UT. These experiments yielded a wealth of new results, the most significant of which will be discussed in this presentation.Spogli, L., Iman, R., Alfonsi, L., Cesaroni, C., Jin, Y., Clausen, L., Wood, A., & Miloch, W. J. (2022). Feasibility of a Swarm Ionospheric Scintillation (SWIS) proxy for L-band scintillation. AGU Fall Meeting 2022.
Floating solar power potential for the Alto Adige region of Italy
Authors: Dhawan Pranav , Dalla Torre Daniele , Menapace Andrea , Righetti Maurizio
Published: March 2024

This contribution investigates the untapped solar power potential across the lakes within the hydropower reservoirs nestled in the Alto Adige region of Italy. With the region housing more than 500 hydropower plants, amounting to approximately 90% of the regions electricity generation, these hydropower plants bear the burden of electricity generation within the region. Moreover, only 3.6% of the total energy is generated by solar energy. However, these plants boast large surface areas on the reservoirs which remains untapped. As the global energy demand surges and sustainable power sources become imperative, leveraging solar energy atop water reservoirs presents a promising opportunity. The study employs Geographic Information Systems coupled with solar radiation modelling to assess and quantify the solar energy capacity of these reservoirs. The region is characterized by a typical Alpine climatology with warm summers and cold and dry winters, and a complex topography of valleys and peaks. Considering the unique topographical characteristics and climatic conditions of the region, the research evaluates the feasibility and viability of harnessing solar energy over these reservoirs. Preliminary findings underscore the substantial yet underutilized solar power potential in this hydro-rich landscape, opening avenues for further renewable energy generation strategies. The outcome of this study is not only to contribute to enhancing the renewable energy portfolio of the region but also to advocate for innovative and sustainable approaches. This added power potential will be further utilized for reducing the load on hydropower plants during peak load times. Moreover, this can be integrated with pumped hydro storage systems for optimum electricity generation and flexibility of the energy systems.
Occurrence and load modeling of per- and polyfluoroalkyl substances in an urban watershed Vantaa River, southern Finland
Authors: Ulmanen Heta , Turtiainen Harri , Kultti Seija , Kuosmanen Niina , Pétré Marie-Amélie
Published: March 2024

Per- and polyfluoroalkyl substances (PFAS) are persistent environmental contaminants linked to multiple adverse impacts and they are ubiquitous in the Finnish aquatic environment. The Vantaa River watershed is densely populated and constitutes a reserve water source for water supply in the Helsinki Metropolitan area (1 million people).  The aim of this research was to quantify PFAS concentrations and test a load estimator software (LOADEST) to determine loads at the mouth of Vantaa River before it flows into the Baltic Sea. Weekly water sampling was conducted near a continuous gauging station (Oulunkylä station) between March 2023 and October 2023 resulting in 28 samples. Water samples were analyzed for 50 PFAS in a commercial laboratory in Finland. Instantaneous daily load (riverine export) of individual and total PFAS (g/day) were calculated from the measured PFAS concentration in the river and daily river discharge data. The USGS application LOADEST was used to calculate individual and total PFAS loads at a daily interval over the monitoring period.Σ50 PFAS concentration averaged 25 ng/L (range was 7-53 ng/L) and Σ50 PFAS load averaged 27 g/day (range was 6-121 g/day). Six PFAS constituted 83,4% of total quantified PFAS, perfluorooctane sulphonic acid (PFOS) and perfluoropentane acid (PFPeA) accounted for 40%. The total Σ50PFAS load at Oulunkylä was 4,7 kg over the entire monitoring period (197 days). In addition, the PFAS yield (kg/km2 yr) calculated by dividing the annual PFAS load by the drainage area was 5.15 10-3 kg/km2 yr in Vantaa River. Statistical measures of model performance indicated that LOADEST models for Σ50PFAS was within acceptable limits, with a Load Bias of –0.5% and a Nash-Sutcliffe Efficiency Index of 0.9. Further monitoring and modeling are warranted as this study shows that LOADEST can successfully be applied to the Vantaa River watershed, and it could be used to track the PFAS load reaching the Baltic Sea and follow the evolution of the system after restriction or ban of individual PFAS in Europe.
Chemical perturbations from Asian summer monsoon in the extratropical UTLS during PHILEAS
Authors: Hoor Peter , Riese Martin , Rolf Christian , Vogel Baerbel , Ploeger Felix , Borrmann Stephan , Engel Andreas , Höpfner Michael , Pöhlker Mira , Müller Rolf , Volk Michael , Ungermann Jörn , Köllner Franziska , Ziereis Helmut , Tomsche Laura , Johansson Sören , Lauther Valentin , Schuck Tanja , Schneider Johannes ,   PHILEAS TEAM
Published: March 2024

The Asian monsoon anticyclone (AMA) during northern summer is a major contributor to the transport of tropospheric air masses, rich in water vapour, aerosol precursors and surface emissions , into the UTLS. During previous HALO missions TACTS/ESMVal and WISE a significant impact of the monsoon export on the background composition of the lowermost stratosphere (LMS) could be observed. Recent observations during the research missions StratoClim and ACCLIP show evidence for a strong contribution of ammonium nitrate by the AMA to the UTLS aerosol budget and the Asian Tropopause Aerosol Layer (ATAL), likely relevant for cirrus cloud formation. These missions revealed that the northern central Pacific is a key region for the transition of air masses originating from the AMA and emissions from East Asia and China to cross the tropopause. Particularly, over the northern Pacific dynamical and diabatic forcings lead to a subsequent erosion of these eddies and to mixing into the background lower stratosphere. We will present first results from the PHILEAS mission, which took place between August and October 2023 over Anchorage/Alaska and Europe. We found strong perturbations of the gas phase and chemical composition in the UTLS region. These perturbations can be linked to the Asian monsoon and east Asian pollution sources as well as to Canadian wild fires, which occurred prior and during the measurements. Based on selected cases we will present clear evidence for cross tropopause transport and mixing of pollution from East Asian pollution and the AMA over the eastern Mediterranean as well as over the northern Pacific. We will show that these sources affected the aerosol as well as the gas phase composition of the lowermost stratosphere.
Follow the energy: Why using more offshore wind power weakens ocean dynamics and impacts marine ecosystems
Authors: Kleidon Axel , Badger Jake
Published: March 2024

Wind turbines harvest the kinetic energy of the winds in the lower atmosphere to generate electricity, thereby reducing the wind speed locally.  Over oceans, this can have direct consequences for the wind energy input into the oceanic mixed layer, as well as associated wave dynamics, ocean mixing, and the wind-driven circulation.  To estimate the potential relevance of these effects, we consider a scenario of 150 GW of installed capacity, as formulated by the Esbjerg declaration, which we distribute over a hypothetical area of 100 000 km2 in the North sea.  To do so, we budget kinetic energy fluxes within the lower atmosphere to estimate the impacts of wind energy use on frictional dissipation near the surface, and then use relationships inferred from the ERA-5 reanalysis to link frictional dissipation to different aspects of ocean dynamics.  Our first-order estimates show that the mean wind speed is reduced by 12% in this scenario.  Using the mean wind speed as an example case, such a reduction is associated with a more substantial reduction of surface friction by about 33%.  In this case, the ocean impacts are reflected in reduced wave heights by 14%, reductions in Stokes drift velocities at the ocean surface by 18%, wave power by 27%, and ocean mixing by 35%.  These basic energetic arguments highlight the need to assess and quantify the extent of impacts large-scale offshore wind power use is likely to have on ocean dynamics that need to be considered with the anticipated expansion in the coming decades.  This is necessary in order to mitigate potentially substantial and detrimental impacts on marine ecosystems.