bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of 3D coastal mesoscale structures and transports from multiplatform observations and a data reconstruction method
Authors: Manso Ivan , Rubio Anna , Jordà Gabriel , Carpenter Jeffrey , Merckelbach Lucas , Declerck Amandine , Delpey Matthias , Hernández-Carrasco Ismael , Mader Julien , Caballero Ainhoa
Published: March 2021

The role of coastal mesoscale variability in the modulation of surface along-shelf and cross-shelf exchanges in the SE Bay of Biscay has been demonstrated by several works, from land-based and satellite observations, including high resolution current fields from high-frequency (HF) radars. However, the characterization of physical processes and associated transports at subsurface levels from observations remains a challenge since observations are often too scarce to offer the required spatio-temporal resolution and coverage. In addition to the numerical modelling, the use of methods to reconstruct three-dimensional (3D) current fields from the combination of multiplatform data offers an alternative approach for the study of 3D properties of mesoscale coastal processes, and an improved background to explore bio-physical interactions. Studying the physical properties of coastal mesoscale structures at subsurface levels, where primary production and plankton concentration peak, is key to understand the coupling between physical and biological processes. In this work, we use a previously validated data-reconstruction method and different CMEMS products (coastal simulations, observations from HF radar, satellite, mooring) and glider data, to better characterize the 3D structure of a coastal mode-water eddy and its associated water volume transport. Different Lagrangian properties (maps of particle density, residence times, Lagrangian eddy kinetic energy) obtained at surface and subsurface levels provide a new insight into the water volume transports associated with the main coastal processes in the area.
Calibration of sea ice drift forecasts using random forest algorithms
Authors: Palerme Cyril , Müller Malte
Published: March 2021

There is a growing demand for accurate sea-ice forecasts in the Arctic due to increasing maritime traffic. Although the capabilities of numerical models steadily improve, sea-ice forecasts produced by numerical prediction systems are affected by biases. In order to reduce forecast errors, statistical methods can be used for calibration.

In this study, two calibration methods have been developed for calibrating sea-ice drift forecasts from an operational prediction system (TOPAZ4) in the Arctic. These methods are based on random forest algorithms, a machine learning technique suitable for assessing non-linear relationships between a set of predictors and a target variable. While all the algorithms developed in this study use the same set of predictors, two set of algorithms have been developed using either buoy or synthetic-aperture radar (SAR) observations for the target variable. Furthermore, different algorithms have been developed for predicting the direction and the speed of sea-ice drift, as well as for different lead times. The random forest algorithms use predictor variables from sea-ice concentration observations during the initialization of the forecasts, sea-ice forecasts from the TOPAZ4 prediction system, wind forecasts from the European Centre for Medium-Range Weather Forecasts, and some geographical information.

The performances of the calibrated forecasts have been evaluated and compared to those from the TOPAZ4 forecasts using buoy observations from the International Arctic Buoy Programme. Depending on the calibration method, the mean absolute error is reduced, on average, between 5.9 % and 8.1 % for the direction, and between 7.1 % and 9.6 % for the speed of sea-ice drift. However, there is a large spatial variability in the performances of these algorithms, and the random forest algorithms have particularly poor performances in the Canadian Archipelago, an area characterized by narrow channels and the presence of landfast ice.
Source-dependent variations in organic carbon degradation rates in lake sediments 
Authors: Han Xingguo , Tulo Julie , Deng Longhui , Fiskal Annika , Schubert Carsten , Winkel Lenny , Lever Mark
Published: March 2021

Lake sediments are globally important organic carbon (OC) sinks. Biomolecule chemical reactivity, adsorption and physical shielding have been suggested as important factors in controlling OC degradation rates in sediments. Yet, few studies have investigated the relative importance of these variables, or traced how OC from different organismal sources changes over time due to source-dependent variations in degradation rates.

We investigate the factors that control organic biomolecule degradation based on analyses of eukaryotic DNA, biomarkers, and (macro)molecule compositions (using pyrolysis-GC/MS) in sediments of five lakes in central Switzerland that differ in trophic state. We specifically target biomolecules of dominant phytoplankton groups (diatoms, green algae), and terrestrial vascular plants. We show that the decay rates of diatom DNA are significantly higher than those of diatom lipid biomarkers and (macro)molecules, consistent with the higher chemical reactivity of DNA. However, the decay rates of green algal DNA and vascular plant DNA are much slower than those of diatom DNA and similar in magnitude to their corresponding membrane lipids and (macro)molecules. In the case of vascular plant biomolecules (DNA, lignin, polyaromatic compounds), no significant biomolecule degradation was detected over the time scales studied (1-5 centuries).

Our results suggest that chemical reactivity and physical shielding, but not adsorption, are key variables controlling organic biomolecule decay in the lakes studied. In the case of green algae and vascular plants, greater chemical resistance of cell wall structural components to microbial attack appears to facilitate long-term preservation of even highly reactive, intramolecular compounds, such as DNA. These findings have important implications for the use of sedimentary eukaryotic DNA records to reconstruct past environmental changes.
The identification of meaningful variables from Sentinel-2 time series data for effective tree species classification
Authors: Koch Tiziana L. , Rüetschi Marius , Waser Lars T.
Published: March 2021

Sentinel-2 time series provide large amounts of data and information which can be easily used to classify tree species with machine learning algorithms. In addition to the original Sentinel-2 bands, further data such as indices, phenological metrics or even synthetical images can be derived. While tree species classifications highly benefit from such additional data resulting in improved prediction accuracy, severe drawbacks have to be considered - For large data sets, large storage is needed, the computation time expands and a linkage to ecological or phenological reasons behind the usage of these variables can hardly be drawn. Therefore, the implemented variables should be limited to the ones, which are meaningful and on the same time providing the best prediction accuracy. To identify meaningful variables from original Sentinel-2 images and the additionally calculated data first we used basic correlation analyses and subsequently feature selection methods in combination with the commonly used Random Forest algorithm. We classified the most common forest tree species in the Swiss canton of Grisons, which is mountainous and characterized by diverse landscapes. The presented approach will lead to higher efficiency for classifying tree species and additionally provides potential conclusions regarding ecological patterns beyond the distinction of tree species by remote sensing data. Moreover, the proposed approach can also be used to improve classifications or predictions of other outcome variables for vegetated areas with Sentinel-2.
Development of a Spatially Upscaled Soil Spectral Library (SUSSL) of cropland signatures for EO sensors data simulation and calibration/validation of topsoil organic carbon prediction models
Authors: Chabrillat Sabine , Milewski Robert , Kuester Theres , Dvorakova Klara , van Wesemael Bas
Published: March 2021

Optical remote sensing and in particular hyperspectral or imaging spectroscopy remote sensing has been long proved to be an adequate method to predict topsoil organic carbon (Corg) content with good accuracy when the soils are well exposed and undisturbed. Several recent studies demonstrated further in science cases the potential of multispectral Copernicus Sentinel-2 data for bare soils Corg prediction, although challenges were reported related to the impact of disturbing factors. Disturbing factors that can affect the prediction and performances of soil surface properties from optical remote sensing are several and can be e.g. due to mixing in the field-of-view with partial vegetation cover depending on the landscape fragmentation. Most pixels at the remote sensing level are composites and in croplands, mixtures of soils with trees or green plants, or mixture with crop residues after harvest are likely. Another factor might be the presence of residual soil moisture or standing water after rain events. Soil reflectance decreases with increasing soil moisture and increasing soil roughness. Soil Surface roughness changes are observed due to variations in soil texture and to variable microtopography. Possible angular and solar illumination changes may affect the soil reflectance as well.

In the frame of the ESA WORLDSOILS Project (https://www.world-soils.com) aiming at developing a pre-operational Soil Monitoring System to provide yearly estimations of soil organic carbon at global scale based on space-based EO data, we are working on the development of a spatially upscaled soil spectral library (SUSSL). The SUSSL is based on a sub-selection of the European LUCAS soil database, and includes simulation of realistic scenarios of ‘landscape-like’ cropland reflectance data with effect of mixture with green and dry vegetation, effect of varying soil moisture content, and effect of variable soil roughness. This database is further convoluted to the different spectral response functions of several EO sensors to simulate EO view of surface reflectances in croplands. In a next step, the SUSSL shall be used for the test and validation of different correction, disaggregation and unmixing techniques to assess the capabilities of the retrieval of undisturbed surface reflectance, to which soil prediction models can be applied with increased accuracy. In this talk, we will present the database developed, including methodological choices and parameter selections for the simulation of the different disturbing effects. Further, preliminary assessments will be shown on the uncertainties of the undisturbed vs. disturbed signal and impact on soil properties prediction.
ScanArray - Seismological study of the connection between topographic change and deep structure in Fennoscandia
Authors: Thybo Hans , Bulut Nevra , Grund Michael , Mauerberger Alexandra , Makushkina Anna , Artemieva Irina , Balling Niels , Gudmundsson Olafur , Maupin Valerie , Ottemøller Lars , Ritter Joachim , Tilmann Frederik
Published: March 2021

The Baltic Shield is located in northern Europe. It was formed by amalgamation of a series of terranes and microcontinents during the Archean to the Paleoproterozoic, followed by significant modification in Neoproterozoic to Paleozoic time. The Baltic Shield includes a high mountain range, the Scandes, along its western North Atlantic coast, despite being a stable craton located far from any active plate boundary.

The ScanArray international collaborative program has acquired broad band seismological data at 192 locations in the Baltic Shield during the period between 2012 and 2017. The main objective of the program is to provide seismological constraints on the structure of the lithospheric crust and mantle as well as the sublithospheric upper mantle. The new information will be applied to studies of how the lithospheric and deep structure affects observed fast topographic change and geological-tectonic evolution of the region. The recordings are of very high quality and are used for analysis by suite of methods, including P- and S-wave receiver functions for the crust and upper mantle, surface wave and ambient noise inversion for seismic velocity, body wave P- and S- wave tomography for upper mantle velocity structure, and shear-wave splitting measurements for obtaining bulk anisotropy of the upper and lower mantle. Here we provide a short overview of the data acquisition and initial analysis of the new data with focus on parameters that constrain the fast topographic change in the Scandes.

 
The local and remote atmospheric impacts of Africa’s 21st century aerosol emission trajectory
Authors: Wells Chris , Voulgarakis Apostolos
Published: March 2021

Aerosols are a major climate forcer, but their historical effect has the largest uncertainty of any forcing; their mechanisms and impacts are not well understood. Due to their short lifetime, aerosols have large impacts near their emission region, but they also have effects on the climate in remote locations. In recent years, studies have investigated the influences of regional aerosols on global and regional climate, and the mechanisms that lead to remote responses to their inhomogeneous forcing. Using the Shared Socioeconomic Pathway scenarios (SSPs), transient future experiments were performed in UKESM1, testing the effect of African emissions following the SSP3-RCP7.0 scenario as the rest of the world follows SSP1-RCP1.9, relative to a global SSP1-RCP1.9 control. SSP3 sees higher direct anthropogenic aerosol emissions, but lower biomass burning emissions, over Africa. Experiments were performed changing each of these sets of emissions, and both. A further set of experiments additionally accounted for changing future CO2 concentrations, to investigate the impact of CO2 on the responses to aerosol perturbations. Impacts on radiation fluxes, temperature, circulation and precipitation are investigated, both over the emission region (Africa), where microphysical effects dominate, and remotely, where dynamical influences become more relevant. 
Water accessed differently by Larix decidua according to an alpine gradient
Authors: Ceperley Natalie , Ba Rokhaya , Beria Harsh , Michelon Anthony , Larsen Joshua , Venneman Torsten , Schaefli Bettina
Published: March 2021

Vegetation is the primary connection between land and atmosphere, thus the main player mediating the consequences of a changing climate on land cover and hydrology. A protected alpine catchment, with a larch grove (Larix decidua) at the upper limit of the forested area, the Vallon de Nant (Vaud alps, 1200 – 3050 m. a.s.l.), was chosen as a study site in parallel with ongoing hydrological observation. We analyzed the stable isotopes of water, δ18O and δ2H, in the xylem extracted from samples of 10 trees in 2 transects just above and below 1500 m. a.s.l. over the course of the 2017 and 2018 growing seasons.  We compared isotopic ratios withconcurrent observations of isotopes in precipitation, stream, soil water, and groundwater.  Isotopic content of xylem water was found to be fairly consistent, independent of the date within the season, and closely resembled shallow soil water, suggesting that recent precipitation dominated the water source.   Our results support that vegetation could experience a drought due to low levels of rainfall before the streamflow is impacted. Furthermore, they affirm current discussions that water source is elevation dependent for trees in mountain ecosystems, with summer precipitation being favored by higher elevation trees, such as these. This preference has significant implications when we project current changes of quantities of rain falling as snow versus rain in the future. And more importantly, changes the view of forest from that of a water “user” to that of a store and player in complex feedback mechanisms.
Evaluation of cropping system prototypes combining naturally nutrient-rich crop species, organic residues, and effective microorganisms to agrobiofortify local foods in iron and zinc in Senegal
Authors: Noumsi-Foamouhoue Emmanuel , Fernandes Paula , Legros Samuel , Sarr Mame Makhtar , Diouf Diarra , Ndienor Moussa , Médoc Jean-Michel
Published: March 2021

In Senegal, a large part of women of childbearing age (over 35%) and children under 5 years of age (over 40%) suffer from malnutrition by iron and zinc deficiencies. These deficiencies result from low iron and zinc levels in crop products. The low solubilization and mobility of iron and zinc in Senegalese soils can contribute largely to this problem. Among the potential causes are high concentrations of calcium carbonates of iron oxides and zinc oxides, of low levels of moisture and of organic matter.

Agrobiofortification through agroecological systems using the application of organic soil amendments rich in micronutrients is now considered one of the best ways to transfer micronutrients from the soil to the plant.

This study aims to evaluate different agroecological systems established with a combination of: (i) existing agricultural practices that can improve the nutritional quality of crop products, (ii) organic residual products (ORPs) selected according to their availability in time and space and their micronutrient content, (iii) effective microorganisms (EM) according to their level of efficiency in the mineralization of the ORPs and the solubilization of iron and zinc, and (iv) crop species according to their natural richness in micronutrients.

Existing agricultural practices were selected by a territorial diagnosis. The study zone highlighted the good performance of monoculture and associated crops, with field application of cow dung and poultry manure.

ORP and EM were selected by incubation under controlled conditions for 28 days at 28°C of the soil-ORP-EM mixtures (collected in the study area). Poultry droppings and sewage sludge, and the EM designated as groundnut-South Groundnut Basin were selected.

Crop species were selected by crushing and chemical analysis of frequently consumed local harvest products. Two varieties of cowpea (Lisard and Yacine) and sweet potato (Cri Apomudem and Beauregard) with a natural richness in iron and zinc were selected.

The evaluation of the agronomic impact of the cropping systems established from the different components selected will be exemplified, together with the description of the elementary options. An assessment of the environmental impact of the ORPs will be outlined.
Preserving High Value Legacy Collections for Future Research – The McNaughton Collection
Authors: Blereau Eleanore , Bellenger Amanda , McInnes Brent
Published: March 2021

During his long career in ionprobe geochemistry, Professor Neal McNaughton built up an impressive collection of samples. Professor McNaughton served as SHRIMP geochronologist for the Centre of Global Metallogeny at the University of Western Australia (1994-2005), the Western Australia Centre for Exploration Targeting (2005-2007), and the John de Laeter Centre (JdLC) at Curtin University (2007-2019), and upon his retirement he donated his collection of epoxy mounted samples to the GSWA. This collection of over 1000 mounts containing over 4000 samples is full of irreplaceable samples, representing over 20 years of geochronological research and development on the SHRIMP II in the JdLC. The collection is a highly valuable resource for future geochemical and geochronological research however, the entire collection lacked a digital footprint. When this project started there was a distinct lack of a unified approach for geoscience metadata or a template for preserving such a collection. In a jointly funded effort by AuScope, GSWA and Curtin University a digital sample catalogue of the collection with digitised materials was successfully created. We operated under the FAIR data principals and utilised International Geo Sample Numbers (IGSNs) as persistent identifiers to create the most impactful, accessible and visible product. The final catalogue, associated metadata and digital materials are now publicly available online on a number of digital platforms such as Research Data Australia and GSWA’s GeoVIEW.WA and the mounts are able to be borrowed from GSWA for future analysis. These efforts allowed the preservation of physical materials for future loans and analysis as well as visibility in our digital age. We will outline the template and workflow utilised by this project that can be used to preserve similarly high value collections and by current facilities, universities and researchers in their ongoing research, as well as insights for future efforts.
Effectiveness of green roofs in reduction of rainfall-fed runoff: A case study in Dublin, Ireland
Authors: Basu Bidroha , Sarkar Basu Arunima , Sannigrahi Srikanta , Pilla Francesco
Published: March 2021

Increase in extreme rainfall and storm events due to climate change and decrease in water retention in soil due to urbanization has increased the risk of flooding in cities globally. Since majority of the cites are mostly developed, expanding the conventional urban drainage system to account for the excess runoff produced by the rainfall event has limited scope. The challenge is to develop sustainable urban drainage systems (SUDS) to reduce runoff and create a flood control system in major cities. One of the SUDS that are becoming popular is the use of nature-based solutions (NBSs). A set of conventional NBSs to mitigate flood risk include bioswales, bio-retention, tree pits, infiltration trenches. However, even though their performance in flood control is found to be effective, they require considerable land area for deployment, which might be difficult to obtain in cities. For this purpose, green roofs have becoming popular as an alternative NBS in flood control, as it does not require any additional land area for deployment. This study investigates the effectiveness of a green roof in reduction of runoff via real-world case study. A green roof deployed in the CHQ building located at the city centre in Dublin, Ireland has been considered for the study. The green roof has a total size of 70 sq. m. Performance of the green roof in runoff reduction was measured based on rainfall and water retention data collected at four modular units, each having 1 sq. meter area, located at the centre of the roof with an IoT weight scale. The data has been collected for 1 week at 3-minute interval, and the reduction in runoff with and without the presence of the green roof has been estimated. The performance of the green roofs in runoff reduction was found to vary between 20-40% depending on the intensity of storm events.
The use of artificial neural networks in the problem of classifying cloud types in wide-angle images of the visible hemisphere of the sky.
Authors: Veremev Nikita
Published: March 2021

Within the framework of meteorology and oceanology, the importance of the cloud mass and the type of clouds cannot be underestimated. When describing and studying weather, precipitation and the movement of air masses over the ocean, the amount and type of clouds determines the flows of precipitation, their intensity, helps to predict the weather and the content of various impurities in the air, which makes the study of the properties of cloud cover one of the key aspects of meteorological and oceanological research.

The types of clouds are determined by the specialist, visually comparing the picture of the sky over the ocean with the guideline documents, the use of which reduces the possibility of the human factor affecting the determination of these parameters.

For an accurate study, study of the dynamics and dependence of climatic models on the conditions of cloud types, long-term measurements of the same type and the continuity of their methods are required. However, all these data are very unevenly distributed over the Earth's surface, and the number of ship observations is greatly reduced.

Thus, taking into account the importance of reliable determination of data related to cloudiness and the problems of their accuracy, the relevance and need to automate the determination of cloud types are obvious.

As a result of the work, an algorithm was obtained that allows classifying cloud types based on photographs taken during long-term sea expeditions.
Bender Element Test and Numerical Simulation of Sliding Zone Soil with Gravels of Huangtupo Landslide
Authors: Chen Yu
Published: March 2021

In order to study the effect of the different consolidation pressure, loading-unloading path and gravel content on the shear modulus of the small strain of sliding zone soil, a set of consolidation bender element test device was developed. The device consists of three parts: a consolidation system, a deformation measuring system, and a shear wave testing system. The consolidation system is composed of a traditional consolidation instrument and the plexiglass cylinder box. The sample is cylindrical in shape and has a size of 50 mm×50 mm. The consolidation displacement is measured by a digital display micrometer. Shear wave testing system is a wave velocity measurement system made of piezoelectric ceramic. The experimental results show that the device can control the consolidation pressure and measure the vertical deformation, measure the shear wave velocity of the sliding zone soil in real-time, and then study the variation rule of the small strain shear modulus of the sliding zone soil with gravels. The shear modulus of the sliding zone soil increases with an increase in the consolidation pressure. The shear modulus of the unloading of sliding zone soil is larger than that of loading. Under the loading pressure of 200 kPa and 400 kPa, the shear modulus of the sliding zone soil first decreases and then increases with an increase in the gravel content. In the process of unloading, the shear modulus of the sliding zone soil increases with an increase in the gravel content. 
How geomorphology shapes groundwater transit times at the hillslope scale?
Authors: De Dreuzy Jean-Raynald , Gauvain Alexandre , Leray Sarah , Marçais Jean , Roques Clément , Vautier Camille , Gresselin Frédéric , Aquilina Luc
Published: March 2021

We investigate how geomorphological structures shape Transit Time Distributions (TTDs) in shallow aquifers. We show that the TTD is determined by integrated features of the groundwater structure and of the repartition of seepage in convergent/divergent hillslopes of constant slope. More specifically, the coefficient of variation of the TTD (standard deviation divided by the mean) scales linearly with the mean distance of the groundwater volume to the river. The extent and structure of seepage modify the groundwater contribution to the transit time distribution and increase its variability.

Extensive 3D simulations were performed to determine the TTDs synthetic convergent, straight and divergent hillslope models of constant slope. The recharge was applied uniformly on top of the aquifer and transferred to the receiving stream through steady-state groundwater flows, return flows and saturation excess overland flows. Without seepage, TTDs evolve from uniform- to power law-like- distributions depending on the average distance of the groundwater volume to the river. Remarkably, the coefficient of variation of the TTDs scales linearly with the groundwater volume to the river at any hillslope convergent/divergent rate in agreement with a theoretical prediction based on three analytical approximations. With seepage, the TTD progressively displays three separate modes corresponding (1) to the rapid saturation excess overland flows, (2) to the intermediary circulations ending up in seepage area and (3) to the slower circulations going from a recharge upstream the seepage zone to a discharge in the river. The coefficient of variation additionally depends on the extent of the seepage area.

Applied to a natural hillslope in the crystalline basement of Normandy (France), the same synthetic analysis demonstrates that the coefficient of variation is not only determined by the extent of the seepage zone but also by its structure in relation to the geomorphological local and global organizations. These results suggest the possibility to assess the variability of transit times by combining geomorphological analysis, surface soil saturation observations and environmental tracers.
Hydrofractures and crustal-scale fluid flow
Authors: Bons Paul D. , de Riese Tamara , Gomez-Rivas Enrique , Naaman Isaac , Sachau Till
Published: March 2021

Fluids can circulate in all levels of the crust, as veins, ore deposits and chemical alterations and isotopic shifts indicate. It is furthermore generally accepted that faults and fractures play a central role as preferred fluid conduits. Fluid flow is, however, not only passively reacting to the presence of faults and fractures, but actively play a role in their creation, (re-) activation and sealing by mineral precipitates. This means that the interaction between fluid flow and fracturing is a two-way process, which is further controlled by tectonic activity (stress field), fluid sources and fluxes, as well as the availability of alternative fluid conduits, such as matrix porosity. Here we explore the interaction between matrix permeability and dynamic fracturing on the spatial and temporal distribution of fluid flow for upward fluid fluxes. Envisaged fluid sources can be dehydration reactions, release of igneous fluids, or release of fluids due to decompression or heating.

 

Our 2D numerical cellular automaton-type simulations span the whole range from steady matrix-flow to highly dynamical flow through hydrofractures. Hydrofractures are initiated when matrix flow is insufficient to maintain fluid pressures below the failure threshold. When required fluid fluxes are high and/or matrix porosity low, flow is dominated by hydrofractures and the system exhibits self-organised critical phenomena. The size of fractures achieves a power-law distribution, as failure events may sometimes trigger avalanche-like amalgamation of hydrofractures. By far most hydrofracture events only lead to local fluid flow pulses within the source area. Conductive fracture networks do not develop if hydrofractures seal relatively quickly, which can be expected in deeper crustal levels. Only the larger events span the whole system and actually drain fluid from the system. We present the 10 square km hydrothermal Hidden Valley Mega-Breccia on the Paralana Fault System in South Australia as a possible example of large-scale fluid expulsion events. Although field evidence suggests that the breccia formed over a period of at least 150 Myrs, actual cumulative fluid duration may rather have been in the order of days only. This example illustrates the extreme dynamics that crustal-scale fluid flow in hydrofractures can achieve.
Spanish coast resilience face to storm and beach renourishment monitored from space. 
Authors: Beck Anne-Laure , Martinez Sanchez Jara
Published: March 2021

The increasing storm frequency and strength due to climate change, coupled with human activities along the coast unbalance the coastal dynamics. A constant monitoring is necessary to better understand and mitigate the effect on Spanish coastal environments. Spain has around 8 000 Km of coastal areas along the Iberian Peninsula, the Balearic and Canary island. These coasts have a high coastal geomorphology variability, from rocky coasts with large estuaries on the Atlantic face in the northwest of the Iberian Penisula, to long sandy beaches with dunes systems and large wetlands in the southwest. On the Mediterranean coast, low rocky cliffs and sandy beaches with a wide variety of coastal infrastructures and deltas. Although in-situ measurements are highly efficient on capturing coastal parameters and features at a given time, the cost of continuous acquisition campaigns for the whole coast is dissuasive. Earth Observations provide wide spatial coverage over a large temporal scale allowing us to develop a methodology adapted to all coastal morphologies and dynamics to follow the impact of climate change and human activities on Spain’s top touristic attraction, it’s coasts.

Our developed methodology uses the instantaneous boundary between land and sea on satellite images extracted using an algorithm based on the Liu & Jezek methodology. The use of the Canny edge detection is improved by a local adaptive threshold applied on a band ratio image. NDVI, BNDVI, GNDVI or others are applied depending on coastal features and natures to extract with high precision the land/ sea interface. Is then applied to the obtained waterlines waves, slope and tide correction to obtain inter-comparable lines to build some time-series product at different time scale. The spatial scale of the changes due to coastal dynamics within the coastal environment is a challenge for change detection due to the shifts between earth observations. The application of a geo-location method helps with the spatial accuracy constraint and ensure an accurate change detection by monitoring real movements and therefore allow us to capture coastal change at different temporal and spatial scales.
Transfer of the Fukushima accident-derived radiocesium by hydrological processes in Japanese forests
Authors: Kato Hiroaki , Shinozuka Tomoki , Akaiwa Satoru , Iida Hikaru , Saidin Zul Hilmi , Onda Yuichi
Published: March 2021

In Japan's forests, field data on the distribution and migration of radiocesium deposited by the Fukushima Daiichi Nuclear Power Plant accident, from the initial dynamics to the distribution in the forest over ten years, have been vigorously collected. The results have been published in an IAEA technical report (IAEA- TECDOC-1927, 2020) as a database of migration parameters to be compiled by an international project (MODARIA II: Modelling and Data for Radiological Impact Assessments) promoted by the International Atomic Energy Agency (IAEA). Radiocesium's transfer mechanisms in the forest by hydrological processes and the runoff through the water system were summarized based on investigations in experimental forests and watersheds in Fukushima Prefecture. Besides, we outlined the missing links that need to be clarified by re-analysis of existing data and additional experiments based on previous studies on Fukushima and Chernobyl. Finally, we discussed the direction of future monitoring surveys.
Identifying source regions for airborne particles in East Antarctica, Dronning Maud Land, using backward trajectory modelling
Authors: De Causmaecker Karen , Delcloo Andy , Mangold Alexander
Published: March 2021

Atmospheric composition plays an important role in present and near-future climate change. Airborne particles can serve as cloud condensation and ice nuclei and have therefore a strong influence on cloud formation and thus also on precipitation. This is in particular of interest in Antarctica, since precipitation is the only source of mass gain to the Antarctic ice sheet, which is expected to become the dominant contributor to global sea level rise in the 21st century. A detailed insight into the transport pathways and distribution of airborne particles is therefore essential.
 
At the Belgian Antarctic research station Princess Elisabeth in Dronning Maud Land, East Antarctica, aerosol particles and their characteristics are measured. Atmospheric particles have been collected on filters during the last three austral summers for organic and inorganic chemical analysis by high-volume sampling. In addition, the atmospheric particle number concentration, size distribution and optical particle properties have been measured since 2010.

The geographical source regions of airborne particles in Dronning Maud Land remain however to a large extent unknown. In this work, we investigate the climatology of the particle properties with respect to their source regions. To that end, we use the FLEXTRA model to calculate 10-day 3D backward trajectories over the past 10 years. We apply a non-hierarchical cluster method to identify and classify the dominant source regions.
Adaptation of SWAT hydrological model to study runoff processes in the mountainous Baksan river basin (the North Caucasus, Russia)
Authors: Durmanov Ivan , Rets Ekaterina , Kornilova Ekaterina , Kireeva Maria
Published: March 2021

In past years, there has been an intensive deglaciation in the North Caucasus. Glacier area has decreased by almost 27%, since 1960. This is reflected in the decrease of August and July monthly runoff by 2–20%. To study the processes of river runoff in mountainous areas, the SWAT hydrological model was adapted for the Baksan River. Baksan is a mountain river, located in North Caucasus. It originates from the glaciers of Mount Elbrus and flows in a foothills to Malka River (Caspian sea basin).

As input parameters we used meteorological data from ERA5 reanalysis and data from 4 meteorological stations with period of observations 1977-2019. Also soil database, glacier data and DTEM were used. For model calibration we used SWAT-CUP tool with daily river runoff data from 2 gauges in Baksan basin. Results of modelling were compared with ECOMAG hydrological model, which used similar input parameters. Advantages and disadvantages of each model were analyzed in conditions of mountain river runoff.

This work was financial supported by RFBR (Project 20-35-70024)
Marine cold air outbreaks in Fram Strait – General increase in March and a special case in 2020
Authors: Dahlke Sandro , Solbes Amelie , Maturilli Marion
Published: March 2021

Marine Cold Air Outbreaks (MCAOs) are common features above the open water surfaces of the Nordic Seas. They are characterized by marked vertical temperature gradients, which typically persist over several days, and strongly shape air-sea heat exchanges, convection, weather and boundary layer characteristics in the affected region. Based on the novel ERA-5 reanalysis product, we are analyzing climatological and recent aspects of MCAOs in the Fram Strait region of the North Atlantic, which is a “hot spot” particularly during winter and early spring. MCAOs in Fram Strait occur preferably when persistent low pressure systems occupy Northern Scandinavia and the Barents/Kara Sea, which exerts strong zonal pressure gradients across Fram Strait. Based on the vertical gradients of potential temperature, occurrence frequencies of MCAOs of different strengths are investigated.  It is found that MCAOs of moderate strength occur at an average of 7-9 days per month between December and March, while especially strong MCAOs occur at an average of 1-3 days in that time. Regarding the former, March is the only month for which a significant trend of +1.7 days/month/decade was found over the 1979-2020 period. While regional MCAO expression is dependent on both the relative location of the ice edge and on the atmospheric circulation, MCAO increase in Fram Strait in March can be explained mainly with the latter and the associated zonal pressure gradient.

February and March 2020 serve as examples of particularly strong and persistent MCAOs in Fram Strait. The record-breaking strong polar vortex at that time, which had received global attention in the media and literature, had left its associated footprint in near surface and tropospheric circulation fields, hence providing anomalous northerly flow across the ice edge in Fram Strait. While this clearly shaped MCAOs in Fram Strait, associated anomalies were also observed in the North Atlantic Sea Ice edge, and were even detected in upper air profiles and sea ice conditions on Svalbard.

For the detailed study of such northerly advection events, atmospheric data gathered during the year-long MOSAiC expedition 2019/2020 in the central Arctic are expected to provide valuable information in the upstream direction of the anomalies in Fram Strait.
On the relationship between Indian Ocean Dipole, Indian summer monsoon and ENSO
Authors: Cherchi Annalisa , Terray Pascal , Ratna Satyaban Bishoyi , Meccia Virna , K.P. Sooraj
Published: March 2021

The Indian Ocean Dipole (IOD) is one of the dominant modes of variability of the tropical Indian Ocean and it has been suggested to have a crucial role in the teleconnection between the Indian summer monsoon and El Nino Southern Oscillation (ENSO). The main ideas at the base of the influence of the IOD on the ENSO-monsoon teleconnection include the possibility that it may strengthen summer rainfall over India, as well as the opposite, and also that it may produce a remote forcing on ENSO itself. The Indian Ocean has been experiencing a warming, larger than any other basins, since the 1950s. During these decades, the summer monsoon rainfall over India decreased and the frequency of Indian Ocean Dipole (IOD) events increased. In the future the IOD is projected to further increase in frequency and amplitude with mean conditions mimicking the characteristics of its positive phase. Still, state of the art global climate models have large biases in representing IOD and monsoon mean state and variability, with potential consequences for properties and related teleconnections projected in the future. This works collects a review study of the influence of the IOD on the ISM and its relationship with ENSO, as well as new results on IOD projections comparing CMIP5 and CMIP6 models.
Ocean science in action: communicating cutting edge advances in marine research and technology via Massive Online Open Courses
Authors: Jacobs Zoe , Popova Ekaterina , Cox Lucy , Gill Daniel
Published: March 2021

MOOCs or Massive Open Online Courses are picking up momentum in popularity. Unlike regular courses, MOOCs can attract many thousands of enrollees around the world and engage broader audiences outside of academia, such as governent officials and NGOs. With scientific communication and policy engagement practices shifting online due to the current pandemic, MOOCs can be seen as a digital tool that acts as a confluence for education, public engagement and capacity development. In this presentation we will introduce you to a MOOC “Ocean Sceince in Action: Addressing marine ecosystems and food security”, which attracted ~1800 participants from over 100 countries for its first run in October 2020 with these numbers continuing to increase for subsequent runs (the next started on 18th January). The MOOC aims to introduce the participants to innovative marine technologies and their applications used to tackle the challenges of the sustainable management of marine ecosystems with specific lectures focussed on food security, impacts of climate change on marine ecosystems and fisheries, the sustainable development goals and the Ocean Decade 2030.

Marine autonomous systems are becoming ever more reliable and easy to use for environmental observations – at a fraction of the cost of a research ship. Earth observation satellites monitor the oceans daily, collecting a wide range of marine data, most of which are freely available from global archives. Ocean models of increasingly high resolution make it possible to explore regional ecosystem dynamics and gain insights into reasons for variability and change. Engaging participants globally into the cutting edge research and the use of marine data requires novel approaches to engagement, communication and teaching. Using elements of MOOC created by SOLSTICE (Sustainable Oceans, Livelihoods and food Security Through Increased Capacity in Ecosystem research in the Western Indian Ocean) program, this presentation will explore how research projects can create inspiring and informative digital content to communicate their findings to achieve a long lasting legacy of their results and better inform managers and politicians responsible for decision making.   
Surface soil moisture data assimilation for irrigation amounts and timing estimation in semi-arid regions
Authors: Ouaadi Nadia , Jarlan Lionel , Khabba Saïd , Ezzahar Jamal , Merlin Olivier
Published: March 2021

Irrigation is the largest consumer of water in the world, with more than 70% of the world's fresh water dedicated to agriculture. In this context, we developed and evaluated a new method to predict daily to seasonal irrigation timing and amounts at the field scale using surface soil moisture (SSM) data assimilated into a simple  land surface model through a particle filter technique. The method is first tested using in situ SSM before using SSM products retrieved from Sentinel-1. Data collected on different wheat fields grown  in Morocco, for both flood and drip irrigation techniques, are used to assess the performance of the proposed method. With in situ data, the results are good. Seasonal amounts are retrieved with R > 0.98, RMSE <42 mm and bias<2 mm. Likewise, a good agreement is observed at the daily scale for flood irrigation where more than 70% of the irrigation events are detected with a time difference from actual irrigation events shorter than 4 days, when assimilating SSM observation every 6 days to mimics Sentinel-1 revisit time. Over the drip irrigated fields, the statistical metrics are R = 0.70, RMSE =28.5 mm and bias= -0.24 mm for irrigation amounts cumulated over 15 days. The approach is then evaluated using SSM products derived from Sentinel-1 data; statistical metrics are R= 0.64, RMSE= 28.78 mm and bias = 1.99 mm for irrigation amounts cumulated over 15 days. In addition to irrigated fields, the applicationof the developed methodover rainfed fieldsdid not detect any irrigation. This study opens perspectives for the regional retrieval of irrigation amounts and timing at the field scale and for mapping irrigated/non irrigated areas.
Temporal and spatial variations of sandstorm and the related meteorological influences over northern China in the 21st century
Authors: Yang Jie , Zhao Tianliang
Published: March 2021

In this study, we used the sandstorm data of 233 meteorological stations in northern China, conventional meteorological observation data and MODIS-NDVI data in the 40 years from 1980 to 2019 to analyze the spatio-temporal variation of sandstorms in northern China and its related meteorological effects in this century.

The results show that: 1) The average number of sandstorm days in northern China has been fluctuating and decreasing since the beginning of this century, and increasing from 2017 to 2019. Spring is the main season of dust storm, and the springtime proportion of sandstorm days decreases year by year. 2) In the 1980s and 1990s, sandstorms covered almost covered the whole northwest region; Since the beginning of this century, the range of sandstorm days in the whole Northwest China has shown an obvious decadal downward trend. The spatial pattern of sandstorm days in northern China has been shrinking and moving westward since 2000, and the dominant position of the Gobi Desert in the Asian dust source region has been decreasing year by year. The high sandstorm days were located in the Taklimakan Desert with the increasing trend of sandstorm days year by year. 3) The temporal and spatial variation of sandstorm days in northern China is closely related to the increase of vegetation cover with the greenness and wetness of the land surface, the decreases of average wind speed and gale days, and the significant increase of annual precipitation in northern China after 2000.