bluuebunny/crossref_metadata_2025 huggingface dataset:
Overshoot dependence on the shock parameters
Authors: Borodkova Natalia , Sapunova Olga , Eselevich Victor , Zastenker Georgy , Yermolaev Yury
Published: March 2022

The structure of the solar wind plasma flow downstream of the ramp of the interplanetary and bow shocks was studied based on the BMSW plasma spectrometer installed onboard the SPEKTR-R spacecraft. Particular attention was paid to the overshoot region, where correlated oscillations of the ion flux and magnetic field are observed. They are formed by two populations of ions: the inflowing solar wind and the beam of coherent gyrating ions. Based on the statistical analysis it was shown that overshoots form both in supercritical and subcritical shocks. It is found that maximum values of the overshoot amplitudes are significantly influenced by the angle between the shock normal and magnetic field vectors, Mach number, plasma and magnetic compression at the shock front. It was established that the oscillation wavelength determined from the magnetic field measurements onboard the WIND spacecraft, on average, coincides with the oscillation wavelength determined from the ion flux on the SPEKTR-R, while the rates of relaxation of these oscillations can greatly differ. It was also shown that the estimates of the overshoot wavelength good correlate with the convected ion gyroradius.
Modelling the east-west asymmetry of energetic particle fluence in large solar energetic particle  events using the iPATH model
Authors: Ding Zheyi , Li Gang
Published: March 2022

Simultaneous observations of large Solar Energetic Particle (SEP) events by multiple spacecraft located near 1 AU during solar cycle 24  have shown an east-west asymmetry of the peak intensities of SEPs with respect to the source flare locations. Using the 2D improved Particle Acceleration and Transport in the Heliosphere (iPATH) model, we consider multiple cases with different solar wind speeds and eruption speeds of the Coronal Mass Ejections (CMEs) and fit the longitudinal distributions of time-averaged fluence by Gaussian functions in 8-, 24- and 48-hour respectively. The simulation results are compared with a statistical study of 28 3-spacecraft (SC) events. The east-west asymmetry shows a clear time-dependent and energy-dependent evolution. We suggest that the east-west asymmetry of SEP fluence (and peak intensity) is a consequence of the combined effect of an extended shock acceleration process and the evolution of magnetic field connection to the shock front. Our simulations show that the solar wind speed and the eruption speed of CMEs are essential factors for the east-west fluence asymmetry. 
Quantifying the impact of gravity waves on infrasound propagation using high-resolution global models for atmospheric specifications
Authors: Listowski Constantino , Stephan Claudia , Le Pichon Alexis , Hauchecorne Alain , Kim Young-Ha , Achatz Ulrich , Bölöni Gergely
Published: March 2022

Gravity Waves (GW) alter the propagation path of acoustic energy in the middle atmospheric waveguide and complexify the large scale picture where infrasound (IS) propagation is mainly driven by the seasonal changes in stratospheric winds. Thus, GW affect the detection capability of the IS station network of the International Monitoring System (IMS) established to monitor the compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Atmospheric models explicitly resolving a part of the GW spectrum are relevant tools to be considered for investigating the effect of GW on infrasound propagation, given increasing computing means made available by HPC facilities. Parabolic equation simulations allow accounting for the partial reflections induced by GW. They can be used to quantify the impact of GW on infrasound transmission loss, for instance. Here, we use atmospheric specification fields obtained in the framework of the Dynamics of the Atmospheric General Circulation Modeled on Nonhydrostatic Domains (DYAMOND). DYAMOND is an international project, initiated by the Max Planck Institute for Meteorology (MPIM) and the University of Tokyo. It describes a framework for the intercomparison of high-resolution global models. It mainly focuses on the troposphere, but some models were run with a high enough top so that GW are resolved up to the stratosphere. Lidar observations are used to validate the model at Observatoire de Haute Provence (France) and we investigate the potential energy of GW activity across the IMS. By filtering out small-scale perturbations (GW) in atmospheric specifications and comparing parabolic equation simulations with and without GW, respectively, we quantify the impact of GW on the main atmospheric waveguide. We focus on the transmission loss derived at the surface, and more particularly in the shadow zones, for different national or IMS infrasound stations during the (northern hemisphere) winter.
Mapping newly emerging islands and nunataks in Greenland improves existing bed elevation datasets
Authors: Bjørk Anders , Zhang Enze , Morlighem Mathieu , Dunk Mathilde , Fleischer Amanda , Thage Kathrine , Mouginot Jeremie , Abbas Khan Shfaqat
Published: March 2022

While great improvements in our understanding of the subglacial landscape has occurred in recent years, the majority of the land beneath the Greenland Ice Sheet is still unmapped. With this study we map newly emerging land masses using Landsat 8 and Planet Scope satellite imagery. By including new islands, nunataks, and ice-contact outcrops in the current bed elevation model BedMachine we are able to improve the reliability of both pro glacial bathymetry as well as subglacial topography in all areas where new land is emerging.

The previous official Greenland wide mapping occurred in 1978-1987 and was done on the basis of aerial photographs recorded at scale 1:150.000. Here, we manually update new island - and ice contact bedrock outcrops using false color pan-sharpened Landsat 8 (15m) from 2019 and verifying our results with Planet Scope satellite images (3m) from 2019 and 2021. With the mapping of newly emerged islands and bedrock outcrops, existing bathymetric and ice thickness products can be updated. As existing models (eg. BedMachineV3) is limited by the available input, it is common to see large assumed ice sheet thicknesses where nunataks are now exposed. Likewise, many newly mapped islands are appearing in places where fjord depths were expected to be several hundreds of meters.

While traditional methods fcor collecting bedrock elevations below the ice and ocean surfaces are associated with extremely high logistical costs, our approach can in a quick and affordable manner update existing med models with valuable data. This addition will result in more accurate ice flow and fjord circulation models, which will ultimately give us better predictions of future sea-level rise. We argue that with the ongoing retreat and downwasting, these systematic mapping efforts should ideally take place on a biannual basis.  
Dissolved organic matter may induce water-stable aggregates in various soil textures
Authors: Bucka Franziska B. , Felde Vincent J.M.N.L. , Peth Stephan , Kögel-Knabner Ingrid
Published: March 2022

The interactions between mineral particles and soil organic matter (SOM) are an important factor for soil structure formation. Percolating dissolved organic matter (DOM) from upper soil horizons is considered an important input pathway of organic carbon (OC) into subsoils. While DOM sorption processes have been extensively studied, the effect of DOM input on soil structure formation has rarely been looked at systematically. We conducted a 30-day laboratory incubation experiment to investigate the process of DOM-induced structure formation in artificial model soils with three contrasting textures (clay loam, loam, sandy loam).

The soil texture defined the pore system and the flow characteristics of the soil solution, leading to a lower liquid retention and faster soil solution turnover in the sand-rich soils. In contrast, the OC retention was unaffected by the soil texture, indicating that only the clay minerals and iron oxides, but not the texture-defining quartz grains, contributed to the OC sorption.

The total microbial biomass, as well as the CO2-release were unaffected by the texture. In contrast, the microbial community composition showed a texture-dependent development with a higher proportion of fungi and gram-positive bacteria in the sand-rich mixtures. This suggests that texture-related architectural features of the pore space shape the microbial community composition.

It could be shown that the biochemical processing of the percolating DOM solution was sufficient to induce the formation of large macroaggregates in all textures without requiring mechanical stress or the presence of physical OM nuclei. Very low OC concentrations (< 0.8 mg g-1) could support the water-stability of the formed aggregates, although they were not sufficient to provide any meaningful stability against mechanical loads.
Decomposing the direct and indirect radiative effects by mineral dust aerosols in CMIP6
Authors: Haugvaldstad Ove , Olivié Dirk , Schulz Michael , Storelvmo Trude
Published: March 2022

Mineral dust aerosols play an important role in the Earth’s radiative budget. Dust aerosols interact with radiation in both the longwave and shortwave spectrum through direct radiative effects by absorption and scattering, and indirect effects through influencing cloud microphysical properties. Understanding dust-climate interactions are becoming increasingly important as effective air quality measures are reducing anthropogenic aerosol emissions and desertification in arid and semi-arid regions of the world are projected to increase in the face of climate change. 

In this work, we aim to better understand dust-climate interactions in the CMIP6 models by diagnosing the dust direct and indirect effects in 9 CMIP6 models participating in the piClim-2xdust experiment under AerChemMIP. The piClim-2xdust experiment doubles the dust emission in the model while keeping the other aerosols at pre-industrial levels. This means that any changes to the clouds and clear sky top of the atmosphere energy balance can be attributed to dust-cloud or dust-radiation interactions. We assess the robustness of the dust radiation and cloud response in the CMIP6 models and discuss the impact of differences in the representation of dust aerosols between the models.
Microplastics in Indian freshwater systems – is an anthropogenic influence measurable?
Authors: Lechthaler Simone , Waldschläger Kryss , Sandhani Chavapati Gouse , Sannasi Annamalaisamy Sannasiraj , Vallam Sundar , Schwarzbauer Jan , Schüttrumpf Holger
Published: March 2022

Microplastics are detected in most environmental compartments and hence receive a great deal of attention, especially in aquatic environments where rivers act as pathways for microplastics. Currently, a particularly high input of microplastics through Asian rivers is assumed predominantly by modelling data, while field measurements are scanty.

Three rivers in South India were considered for this purpose to focus on their microplastic loads. The emphasis was on the comparison of microplastic concentrations in urban and rural rivers to identify if the anthropogenic influence control the loads. While two rivers in the megacity Chennai (Tamil Nadu) were found to have an average microplastic concentration of 0.4 microplastic particles/L, a rural river near Munnar (Kerala) had an average concentration of 0.2 microplastic particles/L. The results show higher loads in the urban area with a high anthropogenic influence by wastewater discharges and waste disposal through high number of residents dumping directly by the river. Fibres were the predominant shape (64.13%), black was the predominant particle colour (44.80%) and polyethylene and polyprolyene were the predominant polymers (each 46.67%) detected within the identified particles of all samples.

Rough estimates of annual microplastic discharge from the Adyar River (Chennai) into the Bay of Bengal are found to be as high as 11.6 trillion microplastic particles. This study, which is one of the first baseline studies for microplastic loads in South Indian streams, should be complemented with further environmental sampling during pre-monsoon, monsoon and post-monsoon seasons to get more detailed information on the storage and transportation of fluvial microplastics and to understand the seasonal effect on the river flow characteristics as well as the fate of microplastics.
Cold pools observed during EUREC4A: detection and characterization from atmospheric soundings
Authors: Rochetin Nicolas , Touzé-Peiffer Ludovic , Vogel Raphaëla
Published: March 2022

A new method is developed to detect cold pools from atmospheric soundings over tropical oceans and applied to sounding data from the EUREC4A field campaign, which took place south and east of Barbados in January-February 2020. The proposed method uses soundings to discriminate cold pools from their surroundings: cold pools are defined as regions where the mixed-layer height is smaller than 400 m. The method is first tested against 2D surface temperature and precipitation fields in a realistic high-resolution simulation over the western tropical Atlantic. Then, the method is applied to a data set of 1068 atmospheric profiles from dropsondes (launched from two aircrafts) and 1105 from radiosondes (launched from an array of four ships and the Barbados Cloud Observatory). We show that 7 % of the EUREC4A soundings fell into cold pools. Cold pools soundings coincide with i) mesoscale cloud arcs, ii) temperature drops of about 1 K compared to the environment and moisture increases of about 1 g kg -1. Furthermore, cold pool moisture profiles exhibit a "moist layer" close to the surface, topped by a "dry layer" until the cloud base level, and followed by another moist layer in the cloud layer. In the presence of wind shear, the spreading of cold pools is favored downshear, suggesting downward momentum transport by unsaturated downdrafts. The results support the robustness of our detection method in diverse environmental conditions and its simplicity makes the method a promising tool for the characterization of cold pools, including their vertical structure. The applicability of the method to other regions and convective regimes is discussed.
Snow accumulation over the world's glaciers (1981-2021) inferred from climate reanalyses and machine learning
Authors: Guidicelli Matteo , Gabella Marco , Huss Matthias , Salzmann Nadine
Published: March 2022

The scarcity and limited accuracy of snow and precipitation observation and estimation in high-mountain regions reduce our understanding of climatic-cryospheric processes. Thus, we compared the snow water equivalent (SWE) from winter mass balance observations of 95 glaciers distributed over the Alps, Canada, Central Asia and Scandinavia, with the cumulative gridded precipitation data from the ERA-5 and the MERRA-2 reanalysis products. We propose a machine learning model to downscale the gridded precipitation from the reanalyses to the altitude of the glaciers. The machine learning model is a gradient boosting regressor (GBR), which combines several meteorological variables from the reanalyses (air temperature and relative humidity are also downscaled to the altitude of the glaciers) and topographical parameters. Among the most important variables selected by the GBR model, are the downscaled relative humidity and the downscaled air temperature. These GBR-derived estimates are evaluated against the winter mass balance observations by means of a leave-one-glacier-out cross-validation (site-independent GBR) and a leave-one-season-out cross-validation (season-independent GBR). The estimates downscaled by the GBR show lower biases and higher correlations with the winter mass balance observations than downscaled estimates derived with a lapse-rate-based approach. Finally, the GBR estimates are used to derive SWE trends between 1981 and 2021 at high-altitudes. The trends obtained from the GBRs are more enhanced than those obtained from the gridded precipitation of the reanalyses. When the data is regrouped regionwide, significant trends are only observed for the Alps (positive) and for Scandinavia (negative), while significant positive or negative trends are observed in all the regions when looking locally at single glaciers and specific elevations. Positive (negative) SWE trends are typically observed at higher (lower) elevations, where the impact of rising temperatures is less (more) dominating.
Insights for the Partitioning of Ecosystem Evaporation and Transpiration in Short-Statured Croplands 
Authors: Paul-Limoges Eugénie , Revill Andrew , Maier Regine , Buchmann Nina , Damm Alexander
Published: March 2022

Reducing water losses in agriculture needs a solid understanding of when evaporation (E) losses occur and how much water is used through crop transpiration (T). Partitioning ecosystem T is however challenging, and even more so when it comes to short-statured crops, where many standard methods cannot be applied. In this study, we combined biometeorological measurements with a SPA-Crop model to estimate T and E at a Swiss cropland over two crop seasons with winter cereals. We compared our results with two recent data-driven approaches: the Transpiration Estimation Algorithm (TEA) and the underlying Water Use Efficiency (uWUE).

Our results showed that the available energy reaching the soil through the crop canopy can highly vary depending on growth and climatic conditions. Despite large differences in the productivity of both years, the T to evapotranspiration (ET) ratio had relatively similar seasonal and diurnal dynamics, and averaged to 0.72 and 0.73 for both crop seasons. Our measurements combined with a SPA-Crop model provided T estimates similar to the TEA method, while the uWUE method underestimated T even when the soil and leaves were dry. T was strongly related to the leaf area index, but additionally varying due to climatic conditions. The most important climatic drivers controlling T were found to be the photosynthetic photon flux density (R2=0.84 and 0.87), and vapor pressure deficit (R2=0.86 and 0.70). Our results suggest that site-specific studies can help establish T/ET ratios, as well as identify dominant climatic drivers, which could then be used to partition T from reliable ET measurements.

 
Transport of non-spherical desert dust particles 
Authors: Drakaki Eleni , Amiridis Vassilis , Tsekeri Alexandra , Mallios Sotirios , Papangelis George , Spyrou Christos , Ryder Claire , Katsafados Petros
Published: March 2022

The long–range transport of larger than expected dust particles has been established in numerous observational studies. However, dust transport models struggle to simulate the observed particle size distributions. Studies utilizing a new version of WRF-chem code that contains the full size range of dust particles (0.2-100μm in diameter), estimated that approximately 80% reduction in the particles’ settling velocity is required for the particles to be transported from the desert towards the Cape Verde. Here, we examine the effect of the dust particles’ shape in the dynamics of coarse and giant long-range transport. We specifically apply a new drag coefficient for spheroids in idealized atmospheric WRF-chem simulations above the Atlantic Ocean. Additionally, since there is much confusion about the definition of the size of non-spherical dust particles, where some studies define size as the diameter of a sphere with the same volume, while others as the particles’ maximum, we perform simulations comparing the spherical and spheroid dust particles using both those two different approaches. The results are encouraging for the explanation of long –range dust transport, however more processes should be re-visited, including the dust radiation effects of non-spherical articles.

Acknowledgements

This research was supported by D-TECT (Grant Agreement 725698) funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme. Eleni Drakaki is funded by Stavros Niarchos Foundation (SNF) Fellowship.

 
Characteristics of hydroacoustic sources of natural and anthropogenic origin
Authors: Pilger Christoph , Steinberg Andreas , Gaebler Peter , Schwardt Michaela
Published: March 2022

We report on a review of multiple sources and source characteristics of hydroacoustic signals recorded at the six hydrophone stations of the International Monitoring System for verifying compliance with the Comprehensive Nuclear-Test-Ban Treaty.  We present a comprehensive list of hydroacoustic sources as well as their general waveform shape and individual spectral source characteristic, i.e. the time duration, source intensity, frequency content and signal variation.

We identify and investigate numerous natural sources like earthquakes, volcanoes, icebergs and marine mammals as well as anthropogenic sources like explosions, airgun surveys and shipping activity. We show selected example events and associated references, collected in the course of the joint research project "Metrology for low frequency sound and vibration - 19ENV03 Infra-AUV". We further use freely available recordings from e.g. seismic stations for cross-validation purposes.

This overview provides the basis for an open-access systematic source classification, where only few, fragmentary event catalogues are available up to now and in situ identification of sources and calibration of instruments are difficult and complex. This work is applicable to future activities in automatic source detectors and event catalogs, sensor calibration activities using remote excitation sources and data comparison with other hydroacoustic measurements. We invite the scientific community to discuss useful source labels for such a compilation and useful datasets for comparison and validation.

 

 
Role of large-scale advection and small-scale turbulence on vertical migration of gyrotactic swimmers
Authors: Marchioli Cristian , Bhatia Harshit , Sardina Gaetano , Brandt Luca , Soldati Alfredo
Published: March 2022

Using DNS-based Eulerian-Lagrangian simulations, we investigate the dynamics of small gyrotactic swimmers in free-surface turbulence. We consider open channel flow turbulence in which bottom-heavy swimmers are dispersed. Swimmers are characterized by different vertical stability, so that some realign to swim upward with a characteristic time smaller than the Kolmogorov time scale, while others possess a re-orientation time longer than the Kolmogorov time scale. We cover one order of magnitude in the flow Reynolds number, and two orders of magnitude in the stability number, which is a measure of bottom heaviness. We observe that large-scale advection dominates vertical motion when the stability number, scaled on the local Kolmogorov time scale of the flow, is larger than unity: This condition is associated to enhanced migration towards the surface, particularly at low Reynolds number, when swimmers can rise through surface renewal motions that originate directly from the bottom-boundary turbulent bursts. Conversely, small-scale effects become more important when the Kolmogorov-based stability number is below unity: Under this condition, migration towards the surface is hindered, particularly at high Reynolds, when bottom-boundary bursts are less effective in bringing bulk fluid to the surface. In an effort to provide scaling arguments to improve predictions of models for motile micro-organisms in turbulent water bodies, we demonstrate that a Kolmogorov-based stability number around unity represents a threshold beyond which swimmer capability to reach the free surface and form clusters saturates.
The impact of stochastic mesoscale weather systems on the Atlantic Ocean
Authors: Renfrew Ian , Zhou Shenjie , Zhai Xiaoming
Published: March 2022

The ocean is forced by the atmosphere on a range of spatial and temporal scales. In numerical models the atmospheric resolution sets a limit on these scales and for typical climate models mesoscale (<500 km) atmospheric forcing is absent or misrepresented. Here we use a novel stochastic parameterization – based on a cellular automaton algorithm – to represent spatially coherent weather systems realistically over a range of scales, including down to the ocean grid-scale. We show that the addition of mesoscale atmospheric forcing leads to coherent and robust patterns of change: a cooler sea surface in the tropical and subtropical Atlantic, deeper mixed layers in the subpolar North Atlantic, and enhanced volume transport of the North Atlantic Subpolar Gyre and the Atlantic Meridional Overturning Circulation. Convection-permitting atmospheric models predict changes in mesoscale weather systems due to climate change, so representing them in climate models would bring higher fidelity to climate projections.
A laboratory model for iron snow in planetary cores
Authors: Huguet Ludovic , Le Bars Michael
Published: March 2022

Top-down solidification has been suggested in the liquid cores of small planets, moons, and large asteroids. An iron snow is then thought to exist, consisting of the crystallization of free iron crystals at the top of these cores and of their settling in a stably stratified ambient, until they remelt in a hotter, deeper region. This inward crystallization and associated buoyancy flux may sustain dynamo action by convection below the remelting depth. However, thermal evolution models are up-to-now oversimplified, assuming a constant-in-time and homogeneous-in-space buoyancy flux at the bottom of the snow zone. We have shown from analog experiments that the buoyancy flux is heterogeneous in time and space, with intense snow events, corresponding to an explosion of frazil-ice,  separated by quiescent periods where the snow zone supercools. We found that a wide range of crystal sizes exists, with large crystals overshooting the convection region and challenging the thermodynamic equilibrium hypothesis underlying the evolution models. The spatio-temporal variability of the energy source obviously impacts the shape and intensity of the generated magnetic field, which may provide alternative explanations for the observed and surprising features of Mercury's and Ganymede's magnetic fields.
Identifying drivers for heat waves using wavelets and machine learning approaches
Authors: Buschow Sebastian , Keller Jan , Wahl Sabrina
Published: March 2022

The driving mechanisms of extreme heat events are known to live on a range of spatio-temporal scales. The occurrence and severity of a heatwave can be influenced by (a) slow variations in the ocean and sub-surface, (b) planetary tele-connections, (c) variations in the jet-stream and synoptic weather systems, as well as (d) local-scale feedbacks.

While important progress has been made on each of these individual contributions, fewer studies have attempted to draw a unified picture including them all. We approach this task with tools from classic statistical modeling, as well as image processing machine learning. With the help of wavelet-transforms, predictor variables can be separated into individual scales. Together with local variables and global principal component time-series, these potential drivers are supplied to a statistical learner with the task of reconstructing the field of heatwave occurrences. Contributions from individual scales can then directly be identified, either via variable selection before or during learning, or by measures of feature importance applied to the trained models.

We demonstrate this approach for the case of summer heatwaves in the ERA5 reanalysis. If successful, our  framework can also be transferred to other extreme events such as droughts, cold spells or wind storms.
Antarctic ozone hole modifies iodine geochemistry on the Antarctic Plateau
Authors: Spolaor Andrea , Burgay François , P. Fernandez Rafael , Turetta Clara , Cuevas Carlos A. , Kim Kitae , Kinnison Douglas E. , Lamarque Jean-François , De Blasi Fabrizio , Barbaro Elena , Corella Juan Pablo , Vallelonga Paul , Frezzotti Massimo , Barbante Carlo , Saiz-Lopez Alfonso
Published: March 2022

Polar stratospheric ozone has decreased since the 1970s due to anthropogenic emissions of chlorofluorocarbons and halons, resulting in the formation of an ozone hole over Antarctica. The effects of the ozone hole and the associated increase in incoming UV-radiation on terrestrial and marine ecosystems are well studied, however the impact on geochemical cycles of ice photoactive elements, such as iodine, remains almost unexplored. Here, we present the first iodine record from the inner Antarctic Plateau (Dome C) that covers approximately the last 212 years (1800-2012 CE). Our results show that iodine concentration in ice remained fairly constant during the pre-ozone hole period (1800-1974 CE) but has declined twofold since the onset of the ozone hole era (~1975 CE), closely tracking the total ozone evolution over Antarctica. Based on ice core observations, laboratory measurements and chemistry-climate model simulations, we propose that the iodine decrease since ~1975 is caused by enhanced iodine re-emission from snowpack due to the ozone hole driven increase in UV-radiation reaching the Antarctic Plateau. These findings suggest the potential for ice core iodine records from the inner Antarctic Plateau as an archive for past stratospheric ozone trends.
Current practices in catchment characterization: data sources, aggregation approaches, derived descriptors and their value
Authors: Tarasova Larisa , Gnann Sebastian , Yang Soohyun , Hartmann Andreas , Wagener Thorsten
Published: March 2022

A common way to characterize catchments is to use catchment descriptors that summarize important physical aspects of a given catchment, often by aggregating large geospatial datasets into a single number. Such descriptors aim at extracting information that can inform us about different aspects of catchment functioning, help us to infer dominant hydrological processes, identify similarity among different sites, and transfer information across them. In this study we analyze a large sample of research articles indexed in Scopus, that were returned from the search words “catchment characteristic”, “catchment descriptor”, “catchment attribute”, “catchment indicator” or “catchment property”, to identify current practices of catchment characterization in hydrological science and related disciplines.

We particularly focus on analyzing the variety of data sources on which catchment descriptors are usually based (e.g., digital elevation, land use, lithographic and soil texture maps), on identifying how the datasets are aggregated into catchment descriptors, and on exploring how the value of those descriptors is assessed.

Based on this large sample of studies that cover diverse research areas (e.g., water quantity, water quality, lake research, aquatic ecosystems), different types of studies (e.g., data-based analysis, hydrological and statistical modeling, field studies) and various application purposes (e.g., descriptive site comparison, catchment clustering/classification, quantitative driver/control identification, regionalization), we provide a categorized overview of practices that are currently used for catchment characterization. This overview will provide guidance for future studies by summarizing the status quo and its strengths and limitations, and by providing suggestions for future research.
Role of measured and simulated water content patterns for landslide early warning systems 
Authors: Halter Tobias , Lehmann Peter , Wicki Adrian , Stähli Manfred
Published: March 2022

Landslide early warning systems based on rainfall intensity and duration thresholds neglect the role of antecedent rainfall events on the hydration state that defines the disposition of a steep slope to fail in forthcoming rainfall events. Water content, water potential and mechanical strength of the soil largely depend on the antecedent rainfall signature and the soil hydraulic properties. To investigate how soil moisture information can be used for LEWS, six soil moisture measuring stations have been installed in the Napf-Emmental region as part of an ongoing pilot study to develop a territorial LEWS in Switzerland. In order to estimate the spatial distribution of the initial water content and its effect on landslide frequency and magnitude, we combine water content patterns from these stations, topographic disposition and regional rainfall data. The calculated soil water content patterns are used as input for landslide triggering simulations using the hydromechanical model framework STEP-TRAMM. STEP-TRAMM calculates the load distribution between mechanically interacting soil columns that may result in progressive failure culminating in hazardous landslides. Using landslide inventory data for the pilot region, we calibrate and validate the landslide model and evaluate the role of uncertainty in initial water content pattern on landslide characteristics and rainfall thresholds. We found high correlations between the measured and simulated water content based on rainfall characteristics and topographic disposition (R2 = 0.94), allowing a reasonable estimate of the spatial distribution of the initial water content which underlines the outcome of further landslide triggering simulations.
Changes in groundwater, rainfall, snowmelt and river water contribution to floods in the 1900-2100 period for a wetland catchment
Authors: Berezowski Tomasz
Published: March 2022

Climate drives the hydrological response in a more complex way that would result from a water balance analysis. I this study such a complex, spatiotemporal behaviour of flooding a wetland catchment is presented over 200 years. The study site is the Biebrza River catchment located in north-eastern Poland. This medium size catchment, especially its floodplain, was preserved in a relatively unchanged state in the last centuries. The yearly floods in the wetland floodplain are driven by complex contribution water from precipitation, snowmelt, groundwater, and upstream river. The hydrological simulations were conducted using a fully-integrated groundwater-surface water hydrological model (HydroGeoSphere). The historical simulations were driven by the NOAA Twentieth Century Reanalysis, whereas the future climate simulation was driven by an ensemble of EURO-CORDEX downscaling datasets for rcp26, rcp45, and rcp85 pathways. The contribution of different water sources to the floods was analysed using the hydraulic mixing-cell method. The results show spatiotemporal trends and year-to-year variation of the flooding water composition, depth and extent in the analysed period. This complex response stresses the importance of taking into account full hydrologic system interactions, such as climate, timing and hydraulic feedbacks for climate change analysis.
Digitized Inerting Process in a Protective Atmosphere in a Continuous Line Industrial Plant for the Inertization of Silicates and Asbestos Materials, for recycling in the Powder Metallurgy Industry, in the Aerospace, Arms and Defense Industry.
Authors: Tuccitto Paolo
Published: March 2022

This is a digitalized industrial plant in a continuous line, composed by a low temperature furnace and a high temperature protective atmosphere furnace, connected by a conveyor belt where anthropomorphic robots are used in the loading-unloading of asbestos materials and quality control with devices used in NASA space programs. This invention allows the inertization of asbestos fibers for the recycling of Secondary Raw Material in Powder Metallurgy, for the production of new highly refractory and hard metal alloys, with applications in the field of air and land transport, electrical and electronic engineering, missile engineering, nuclear, aerospace, biomedical, nanotechnologies, for military applications and technologies in defense systems and armaments, precious metals and for the production of refractory material. - Paolo Tuccitto Patent IT. n°30653/2020 and EU N°EP21425060/2021
Moisture sources of the Amazon carbon source
Authors: Staal Arie , Tejada Graciela , Gatti Luciana
Published: March 2022

Among the greatest threats to the global climate is the possibility that the Amazon rainforest, Earth’s largest carbon stock, becomes a net carbon source. To estimate the Amazon’s carbon budget, Gatti et al. (2021) performed 590 atmospheric vertical profiling measurements from four sites using aircraft over the course of eight years. They found that intact forests of the southeastern Amazon already act as a carbon source. This is likely related to decreased precipitation levels, stressing the importance of maintaining or enhancing precipitation levels in that region. The level and variability of precipitation partly depends on the land cover at the location where the moisture has evaporated. Forests in the Amazon enhance evapotranspiration, which significantly contributes to regional precipitation levels. This spatial connection between evapotranspiration and precipitation implies a causal link between forest cover at a certain location and the carbon budget at remote locations. To determine these evapotranspiration-precipitation connections, we use a high-resolution Lagrangian atmospheric moisture tracking model forced with ERA5 reanalysis data. We determine the seasonally changing spatial distributions of the moisture sources of different parts of the Amazon that have different carbon dynamics. We obtain land characteristics of these moisture-source areas to explore the potential of forest restoration for maintaining or regaining the carbon sink in the Amazon. We find that, on average, about one-third of the precipitation in the area identified as a carbon source originates as evaporation from land, the majority of which in this region itself. We find seasonality in the amount of moisture that is recycled within this region, peaking in the fourth quarter. The results indicate that deforestation in the southeastern Amazon may accelerate the carbon emissions from remaining intact parts of the Amazon. Further, they show where forest restoration may be prioritized to prevent these emissions.
Landslide susceptibility mapping of Chitral, northwestern Pakistan using GIS
Authors: Ahmad Said Mukhtar
Published: March 2022

Landslide susceptibility mapping of Chitral, northwestern Pakistan using GIS

Mukhtar S. Ahmad1, *, Mona Lisa1, Saad Khan2 Munawar Shah3

1Department of Earth Sciences, Quaid-I-Azam University, Islamabad 45320, Pakistan

2Bacha Khan University Charsadda, Pakistan

3Department of Space Science, Institute of Space Technology, 44000 Islamabad, Pakistan

1mukhtargeo44@gmail.com

1lisa_qau@yahoo.com

2saadkhan@bkuc.edu.pk

3shahmunawar1@gmail.com

*Corresponding author: mukhtargeo44@gmail.com

Abstract

Landslides are the most frequently occurring geohazard in rugged Himalayan mountainous terrains. They often cause significant loss to life and property, and therefore landslide susceptibility mapping (LSM) has become increasingly urgent and important. In this study, LSM is carried out in the Chitral district of the Hindukush region in northwestern Pakistan. Several Geographic Information System (GIS) based models (such as Analytical Hierarchy Process (AHP), weighted overlay) has been used to build landslide inventory and susceptibility maps. The study incorporated nine main factors (including human-induced parameters, such as distance from road; topographical parameters, such as slope, aspect, and landcover; geological parameters, such as lithology, distance to fault, seismicity; hydrological parameters, such as rainfall and distance to stream) to generate LSM, further classified in five classes, very high susceptibility zone, high, moderate, low, and very low susceptible zone. It is concluded that most of the landslides in the study area are the result of steep slopes of mountains, followed by precipitation and earthquake. Landslide in the form of rockfall is mostly due to the active seismicity of the Hindukush region. The predicted susceptible zones of landslide in the study area are in good agreement with the past landslide localities, which is an indication of the susceptibility mapping of landslides in the region.
CGC: an open-source Python module for geospatial data clustering
Authors: Ku Ou , Nattino Francesco , Grootes Meiert , Izquierdo-Verdiguier Emma , Girgin Serkan , Zurita-Milla Raul
Published: March 2022

With the growing ubiquity of large multi-dimensional geodata cubes, clustering techniques have become essential to extracting patterns and creating insights from data cubes. Aiming to meet this increasing need, we present Clustering Geodata Cubes (CGC): an open-source Python package designed for partitional clustering of geospatial data. CGC provides efficient clustering methods to identify groups of similar data. In contrast to traditional techniques, which act on a single dimension, CGC is able to perform both co-clustering (clustering across two dimensions e.g., spatial and temporal) and tri-clustering (clustering across three dimensions e.g., spatial, temporal, and thematic), as well as of subsequently refining the identified clusters. CGC also entails scalable approaches that suit both small and big datasets. It can be efficiently deployed on a range of computational infrastructures, from single machines to computing clusters. As a case study, we present an analysis of spring onset indicator datasets at continental scale.
High resolution exposure modelling at landscape-level – on the development of a mechanistic drift module for SWAT+
Authors: Fuchs Mike , Gebler Sebastian , Lorke Andreas
Published: March 2022

Modelling environmental concentrations of pesticides at landscape-level is of growing interest for pesticide registration and product stewardship, including higher-tier studies in risk assessment, mitigation measures, monitoring support and decision making. Typically, runoff, drainage, and leaching are taken into account, using different modelling concepts. However, the modelling of spray drift often is simplified or neglected in landscape-level models. For example, the Soil and Water Assessment Tool (SWAT) does not consider spray drift for pesticide transport simulation. Hence, external offline calculations of spray drift are necessary, with the pesticide masses added to the channel network via point sources. Although this is a pragmatic solution for including spray drift, future scientific questions in high spatial and temporal resolution require adequate integrated processes on landscape‑level. Hence, the goal of this project is to: (i) develop and validate a standalone spray drift model that can be used with other modelling approaches in a modular manner, and (ii) implement that model into SWAT+.

Our spray drift model consists of two parts. First, a mechanistic droplet model predicts the trajectories of individual droplets. Second, a 2D Gaussian diffusion model predicts longitudinal advection as well as vertical and lateral dispersion of droplets. This modelling approach allows for a reasonable tradeoff between accuracy and computational expenses. The following inputs are considered: (i) weather conditions, (ii) drop size distribution, (iii) physio‑chemical properties of the active ingredient, and (iv) operational characteristics (e.g., nozzle count, boom height and width, applied amounts and volumes, and forward driving speed).

It is planned to validate the model against an ensemble of computational fluid dynamics simulations. Additionally, the approach will be evaluated using high resolution SWAT+ models of medium sized agriculturally dominated catchments in Germany. We expect the implementation of spray drift to improve modelling performance for different research questions e.g., the sensitivity of aquatic pesticide concentrations on landscape-level regarding application timing.
Using cotton pads to sample the stable water isotopes of throughfall inside tree canopies
Authors: Stockinger Michael , Ziesel Georg , Stumpp Christine
Published: March 2022

Stable water isotopes (δ18O, δ2H) are used as tracers in hydrology to study the components of the terrestrial water cycle. The stable water isotopes of precipitation are affected by the passage of rainfall through tree canopy, resulting in a change of the tracer signal. Several processes within the canopy are thought to be responsible for this, including evaporation, liquid-vapor equilibration, redistribution, and legacy effects. However, it is currently not clear which processes dominate under which conditions, and predictions of these changes are not yet possible. This is partly due to a lack of high resolution throughfall data, as previous studies usually sampled throughfall in evaporation-reducing bulk containers placed under canopy. Here we propose to hang commonly available cotton products in tree canopy, let them soak up rainfall water, and subsequently measure the stable water isotopes directly from the wet cotton products using the direct liquid-vapor equilibration method in the laboratory. First, four products (two types of tampons, two types of cotton pads) were evaluated in terms of the minimum amount of water drops necessary for a reliable measurement, their price, and ease of handling. Cotton pads had the overall best rating and were therefor hung in a coniferous tree placed in a rainfall simulator. With a fixed rainfall intensity, we tested how long the cotton pads can be left hanging before significant isotopic changes due to evaporation occurred. While cotton pads that were on the outer edge of the canopy showed significant deviations after only half an hour, cotton pads inside the canopy as well as close to the stem could be left hanging for one hour. As a comparison, throughfall was also collected using a bulk sampler under the canopy, and this sample showed no significant changes even after four hours. It can thus be assumed that due to the comparatively low amount of water in the cotton pads (even if soaking wet), evaporative changes of isotope values had a stronger impact on the remaining water compared to the bulk throughfall sampler. This study presents first laboratory results and further tests, in the laboratory or in the field, are called for.
Historic river floodplain engineering causes channel pattern shift from multiple to single-thread rivers
Authors: Larsen Annegret , Engelmann Charlotte , Fuelling Alexander , Candel Jasper , Bork Hans-Rudolf , Larsen Joshua Redder
Published: March 2022

It is well-known that floodplain fine-grained alluvial sedimentation rates have been increasing due to human impact. In most catchments, the onset or acceleration of floodplain deposition is dated to medieval times, which has been attributed to increased hillslope soil erosion due to high population densities causing deforestation and slope instability. The also increasing river sediment load has then changed rivers into a single-thread, meandering channel pattern, which is now considered to be the ultima ratio in river restoration. In this presentation, we challenge this view and argue that current channel pattern and shape are related to historic channel engineering, and are hence not the product of fluvial processes associated with a meandering, or avulsing single-thread river system. Here, we present a study from a mountainous region in central Europe (Germany), in which we reconstruct the natural, pre-medieval channel pattern of two low order streams (3rd and 4th Strahler order), and their transition into the current, single-thread channel pattern which is characterised by meanders. This study is based upon a multi-proxy analysis of the chrono-stratigraphy, cross-valley ground penetrating radar, river surveying, analysis of historic maps, and hydrological data for channel pattern prediction. Finally, based on our analysis, we suggest that currently observed channel widening processes and island formation likely represent a tendency of the studied streams to re-create a braided channel pattern, which should be embraced by river management instead of forcing streams into a meandering pattern, as multi-thread, braiding channels are the most natural condition for these streams,  producing a sustainable and resilient river ecosystem.  