bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular Changes in Dissolved Organic Matter After Soil Rewetting
Authors: Orme Alice , Benk Simon , Lange Markus , Zerfaß Christian , Pohnert Georg , Gleixner Gerd
Published: March 2021

The intensity and occurrence of droughts is projected to increase due to climate change. Dried soils release high concentrations of dissolved organic matter (DOM) into subsurface waters when they are rewet, the so-called rewetting peak. To more accurately predict the role of rewetting of soils after drought on the carbon cycle in a changing climate, it is important to understand the processes behind this DOM release.

The DOM rewetting peak origin is disputed between soil organic matter (SOM) from breakdown of soil particles; accumulated root exudates; and microbial release due to a change in osmotic potential through osmolytes or cell bursting. To better understand the origin of the rewetting DOM peak, we took a rewetting series of soil water samples from different vegetation types between December 2018 and April 2019 for targeted and untargeted metabolomics. Initial results using untargeted ultrahigh-resolution mass spectrometry analysis revealed a clear temporal trend, indicating that vegetation-independent molecular changes occur following rewetting. An increase in O/C and a decrease in H/C over time was observed which is attributed to microbial decomposition, supported by a decrease in m/z over time. We also observed an increase in the content of lipidic compounds (R > 0.6) following rewetting. This indicates that cells do not burst upon rewetting and, over time, microbial activity increases, suggesting that the DOM rewetting peak is caused by a lack of decomposition, rather than a high production, of organic matter.
Determining hydrological barriers in wetlands with InSAR methods: several iconic cases worldwide
Authors: Jaramillo Fernando , Liu Dan , Aminjafari Saeid , Wang Xuan
Published: March 2021

Hydrological connectivity is a critical determinant of wetland functions and ecosystems by controlling the movement of biogeochemical elements within wetlands and the flow of water between their hydrological units. Hydrological barriers exist when this connectivity is impaired, either by man-made infrastructure, agriculture developments, or naturally restricted by soil and ground composition. Determining hydrological barriers in wetlands is challenging due to the costs of high-resolution and large-scale monitoring, but radar observations can become a useful tool for such task. We here use an Interferometric Synthetic Aperture Radar (InSAR) to identify hydrological barriers in several iconic wetlands worldwide, with particular focus on the Baiyangdian wetland system in Northern China. For the first, we use Sentinel 1A and 1B data covering the period 2016-2019, while for the rest we rely on ALOS PALSAR data. We calculated profiles of water level change across hydrological transects showing high coherence and visualized them in maps. For instance, in the case of the Baiyangdian wetland, we find that of the 70 transects studied, 11% of all transects are permanently disconnected by hydrological barriers across all interferograms and 58% of the transects are conditionally disconnected. The occurrence of hydrological barriers varies between wetlands, with permanent barriers more related to ditches, infrastructure and the specific wetland landscape, and conditional barriers more to low water levels during dry seasons. This study highlights the potential of the application of wetland InSAR to determine hydrological barriers for wetland management and restoration.
Assessing the utility of climate variability information in streamflow forecasting
Authors: Patel Prem Lal , Sharma Priyank , Teegavarapu Ramesh
Published: March 2021

The prediction of total and peak streamflows are essential for effective management of water resources systems. A data-driven approach, Model Tree (MT), is applied to predict daily streamflows for a tropical river basin in India. The Tapi River drains a total area of 65,225 km2, wherein more than 20 million people are directly or indirectly dependent on it for their water and food requirements. The MT approach executes piece-wise linearization of a non-linear process for the input parameter space and develops linear regression models for each sub-space. The large-scale oceanic-atmospheric oscillations, such as El Niño-Southern Oscillation (ENSO), exert considerable influence on the hydroclimatic conditions across the globe. Based on the Oceanic Niño Index, the warm and cool phases of ENSO are identified as El Niño and La Niña, respectively. It is found that the El Niño and La Niña are associated with drier and wetter than normal conditions respectively across the Tapi basin. Hence, the hypothesis that incorporation of climate variability information would help in enhancing the predictive performance of the model is being tested. A daily-time step model for streamflow prediction is developed considering various hydrometerological inputs observed for the period 1975-2013 to predict streamflows at the catchment outlet. Additionally, two separate models, viz., El Niño- and La Niña-specific models, are developed considering the observed variables corresponding to these phases, and their skill of prediction with respect to the overall model is evaluated. The evaluation of the developed models is further carried out through a suite of statistical error and performance indices, and inferences are drawn.
Global glacier monitoring with TanDEM-X remote sensing – advances, challenges and requirements from the perspective of a multi-decadal approach        
Authors: Malz Philipp , Sommer Christian , Farias David , Seehaus Thorsten , Braun Matthias
Published: March 2021

Mountain glaciers are key indicators of the changing climate conditions worldwide. Observations in recent decades suggest that their immediate atmospheric environment is changing more rapidly than it does elsewhere. Therefore, in addition to a network for measuring climatic parameters, a continuous investigation of glacier changes is indispensable.

The Terra SAR-Add-on for Digital Elevation Measurement (TanDEM-X) mission has achieved two complete space-borne surveys of the Earth's surface and thus of all existing glaciers during its mission lifetime. This study exhibits the methodological and technical findings generated over the period 2011-2019 for multi-temporal investigations – and culminates in a recommendation map for the ongoing and follow-up bi-static SAR acquisitions.

The opportunities which TanDEM-X datasets open up for glacier monitoring are demonstrated: high spatial resolution of up to ~10 m, independence of cloud cover and daylight, smooth and homogenous elevation change fields. This enables wide spatial coverage of the observations throughout climatic and altitudinal zones. However, there are also challenges and limitations to multi-temporal glacier change monitoring. We provide initial conclusions from our repeat studies in Patagonia, the tropical Andes, the Alps and Himalaya/Karakoram. Influences such as seasonality, terrain and latitude on measurement accuracy are being investigated.

The results of this work highlight the capabilities of TanDEM-X data with our current processing strategy: We show where major uncertainties arise from, where our products complement other methods, and where they surpass them. Our analysis forms a contribution to the Regional Assessments of Glacier Mass Change (RAGMAC) initiative for a better understanding of observation disparities and collaboration potentials in glacier monitoring by remote sensing techniques. Based on our findings we will point to research needs and propose strategies for a continuous global acquisition and to partially overcome some of the deficiencies, where possible.
Conduit processes of the Sf. Ana (TGS) sub-Plinian-Vulcanian eruption sequence of the Ciomadul volcano (SE Carpathians)
Authors: Kiss Balázs , Karátson Dávid , Aradi László , Szepesi János , Biró Tamás , Sági Tamás , Szilágyi Veronika , Kis Zoltán
Published: March 2021

The Sf. Ana crater is the young volcanic crater of the dacitic Ciomadul volcano located at the SE end of the Călimani-Gurghiu-Harghita volcanic chain in the Eastern Carpathians. The crater was formed at ~60-30 kyr-s ago probably by several eruptions. The Sf. Ana also called as TGS eruption sequence was the main event that shaped the crater to the present form. The eruption produced fall and PDC deposits, but it is unclear what caused the change in the eruption style. The stratigraphically controlled analyses of the Mohos Layered Pyrolcalstic Sequence (MLPS) provide deep insight into the evolution of the eruption. Assuming that juvenile clast density is primarily controlled by the magma vesiculation within the conduit, the processes close to the fragmentation level can be studied. The vesicularity, vesicle texture, microlite texture, and glass H2O content of the juvenile pyroclasts were studied to reveal the conduit processes. The juvenile clasts show textural evidence for different stages of the vesiculation from bubble nucleation to collapse indicating degassing and outgassing processes in the conduit. The increase of the juvenile clast density upward in the MLPS and the sharp increase of the dense clasts in the PDC deposits indicate the effect of magma column heterogeneity on the eruption style. The conduit heterogeneity was induced by the effective outgassing of the slowly ascending magma portion due to the evolution of vesicle textures together with localized shearing. The eruption column collapse was preceded by a vent failure event which caused densification in the conduit. Banded pumices suggest that the observed conduit heterogeneity was small scale.

 

The study is supported by the PD130214 project National Research, Development, and Innovation Fund of Hungary.
The optical behaviour of snow during a melting season at Ny Ålesund (Svalbard, Norway)
Authors: Salzano Roberto , Lanconelli Christian , Esposito Giulio , Giusto Marco , Montagnoli Mauro , Salvatori Rosamaria
Published: March 2021

Polar areas are the most sensitive targets of the climate change and the continuous monitoring of the cryosphere represents a critical issue. The satellite remote sensing can fill this gap but further integration between remotely-sensed multi-spectral images and field data is crucial to validate retrieval algorithms and climatological models. The optical behaviour of snow, at different wavelengths, provides significant information about the micro-physical characteristics of the surface and this allow to discriminate different snow/ice covers. The aim of this work is to present an approach based on combining unmanned observations on spectral albedo and on the analysis of time-lapse images of sky and ground conditions in an Arctic test-site (Svalbard, Norway). Terrestrial photography can provide, in fact, important information about the cloud cover and support the discrimination between white-sky or clear-sky illuminating conditions. Similarly, time-lapse cameras can provide a detailed description of the snow cover, estimating the fractional snow cover area. The spectral albedo was obtained by a narrow band device that was compared to a full-range commercial system and to remotely sensed data acquired during the 2015 spring/summer period at the Amundsen - Nobile Climate Change Tower (Ny Ålesund). The results confirmed the possibility to have continuous observations of the snow surface (microphisical) characteristics and highlighted the opportunity to monitor the spectral variations of snowed surfaces during the melting period. It was possible, therefore, to estimate spectral indexes, such as NDSI and SWIR albedo, and to found interesting links between both features and air/ground temperatures, wind-speed and precipitations. Different melting phases were detected and different processes were associated with the observed spectral variations.
The Mechanics of Landslide Mobility with Erosion
Authors: Pudasaini Shiva P. , Krautblatter Michael
Published: March 2021

Erosion can dramatically change the dynamics and deposition morphology and escalate the destructive power of a landslide by rapidly amplifying its volume, turning it into a catastrophic event. Mobility is the direct measure of the thread posed by an erosive landslide as it plays a dominant role in controlling the enormous impact energy. However, no clear-cut mechanical condition has been presented so far for when and how the erosive landslide gains or loses energy resulting in enhanced or reduced mobility. We pioneer a mechanical model for the energy budget of an erosive landslide that delineates the enhanced or reduced mobility. A fundamentally new understanding is that the increased inertia due to the increased mass is not related to the landslide velocity, but it is associated with the distinctly different entrainment velocity emerging from the inertial frame of reference. The true inertia can be much less than incorrectly proposed previously. We eliminate the existing erroneous perception and make a breakthrough in correctly determining the mobility of the erosive landslide. We reveal that the erosion velocity plays an outstanding role in appropriately determining the energy budget of the erosive landslide. Crucially, whether the erosion related mass flow mobility will be enhanced, reduced or remains unaltered depends exclusively on whether the newly constructed energy generator is positive, negative or zero. This provides a first-ever explicit mechanical quantification of the state of energy, and thus, the precise description of mobility. This becomes a game-changer and fully addresses the long-standing scientific question of why and when some erosive landslides have higher mobility, while others have their mobility reduced. By introducing three important novel mechanical concepts: erosion-velocity, entrainment-velocity and energy-velocity, we demonstrate that the erosion and entrainment are essentially different processes. With this, we draw a central inference: that the landslide gains energy and enhances its mobility if the erosion velocity is greater than the entrainment velocity. The energy velocity delineates the three excess energy regimes: positive, negative and zero. We establish a mechanism of landslide-propulsion that emerges from the net momentum production, providing the erosion-thrust to the landslide. Analytically obtained velocity quantifies the effect of erosion in landslide mobility and indicates the fact that erosion can have the major control on the landslide dynamics. We have also presented a full set of dynamical equations in conservative form in which the momentum balance correctly includes the erosion induced change in inertia and the momentum production. This is a great advancement in legitimate simulation of landslide motion with erosion.
The unexpected salinity trend shifts in upper Tropical Pacific Ocean under the global hydrological cycle framework
Authors: Shi Huangyuan , Du Ling
Published: March 2021

The secular change of ocean salinity is regarded as an indicator of the global water cycle by measuring the surface freshwater flux which is the most important component of earth hydrological budget. Under the effect of remarkable global warming, the surface salinity patterns in ocean basins illustrated that the intensified water cycle resulted in the continuous and significant freshening phenomena in tropical ocean. With the recent boom in salinity measurements and observations, the variability of surface salinity was examined to explore its relationship with anthropogenic warming. In this paper, we found that the salinity varied on the decadal to centurial time scales and responded significantly to the global warming in tropical Pacific Ocean by using the multi-source reanalysis datasets. An unexpected distribution was figured out and what is noteworthy is that, the robust salinification occurred in the central tropic Pacific in the first two decades of 21st which was demonstrated by Argo observations. Nevertheless, it did not follow the typical salinity patterns that ‘wet get wetter’ mentioned by several literatures and illustrated a significant trend shift. Similarly, the subsurface ocean salinity revealed the same shift but an opposite tendency to that on surface. It may involve that the controlling influence of surface freshwater reduced and the impact of ocean thermodynamic adjustment became gradually pronounced to the upper ocean. The salinity budget suggested that salinity advection and subsurface entrainment played key roles to induce the reversed trend of salinity change. In addition, the isopycnals variability caused by wind-driven ocean pumping and subtropical gyre may be acted as a trigger of the salinity enhancement in the upper ocean. What’s more, the impact of PDO decadal shift and the moderate global warming was seemed to be the essential factors to change the feedback of ocean-atmosphere processes, potentially and was finally reflected on ocean salinity field.
Analysis of teleconnection patterns during extreme warm summers and heatwaves over Europe with a rare event algorithm
Authors: Ragone Francesco , Bouchet Freddy
Published: March 2021

Several studies in recent years have highlighted the role of quasi stationary planetary and synoptic scale waves in the occurrence of extreme events such as heatwaves and cold spells. The advancement of our understanding of the dynamical properties and predictability of these events is however hindered by the poor statistics of extreme events in observations and numerical simulations. Recently we have shown how the problem of sampling extreme events in climate models can be tackled using rare event algorithms, numerical tools developed in statistical physics to reduce the computational effort required to sample rare events in dynamical systems. Here we study extreme warm summers and heatwaves over France and Scandinavia in present-day climate conditions, applying a rare event algorithm to ensemble simulations with the CESM1.2 general circulation model. The application of the rare event algorithm concentrates the ensemble members on dynamical trajectories leading to extreme seasonal and subseasonal temperatures for the target regions. In this way we generate samples of extreme heatwaves orders of magnitude larger than what is feasible with direct sampling, and we perform with high degree of precision composite and spectral analysis of dynamical quantities conditional on the occurrence of the extremes. We show how extreme warm summers and heatwaves are associated to low wavenumber hemispheric teleconnection patterns, and how the most extreme summers are related to the succession of rare subseasonal heatwaves. We then discuss the application of these methods to the detection, prediction and analysis of the dynamics of atmospheric Rossby waves related to the formation of extreme heatwaves and other time persistent extreme events.
Development and validation of a geospatial model for monitoring indicators of the Sendai framework using the example of flooding in Ecuador
Authors: Urrutia Manuel , Riembauer Guido , Valdiviezo-Ajila Angel A. , Jímenez Stalin , Andrade Antonio R. , Walz Yvonne
Published: March 2021

The Sendai Framework for Disaster Risk Reduction (SFDRR) provides a concrete agenda for evidence-based policy for disaster risk reduction as a key component of the post-2015 global development agenda. However, the progress of implementing the seven Global Targets of the SFDRR at the national level via the monitor of a set of thirty-eight indicators is obstructed due to a lack of available, accessible, and validated data on disaster-related loss and damage, especially in developing countries. This weakens the accuracy, timeliness, and quality of the Sendai monitoring process. In the case of floods, which account for the highest number of people affected by hazards,[WY1]  there is a strong need for innovative and  appropriate tools for monitoring and reporting flood impacts.

The country of Ecuador and their validated national flood loss and damage database, which stretches back to 1970, is a stark counterpoint to the norm and serves as the case study for this research. In this research we develop a geospatial model approach, which combines earth observation-based information products with additional geospatial data to result quantitative measures for selected indicators of the SFDRR and validate them based on an existing database on flood loss and damage in Ecuador. Specifically, we build on automated  derivation of flood event characteristics from a full year of Sentinel-1 synthetic aperture radar data to assess flood hazard in Ecuador, and complement this with geospatial data on flood-related exposure and vulnerability to model selected indicators of the SFDRR in a spatially explicit way. The validation process of this geospatial model is conducted in reference to in situ loss and damage data related to flooding for the years 2017, 2018, and 2019. The derivation of information products is conducted in close collaboration with the National Service for Risk and Emergency Management of the Government of Ecuador, the country office of the United Nations Development Program, and the United Nations Office for Disaster Risk Reduction. It is thereby assured that the development and validation of this methodology is in line with the national and international approach of implementing the SFDRR.

 
Verification of the European subseasonal forecasts of wind speed and temperature
Authors: Goutham Naveen , Plougonven Riwal , Omrani Hiba , Parey Sylvie , Tankov Peter , Tantet Alexis , Drobinski Philippe
Published: March 2021

The skill of predicted wind speed at 100 m and temperature at 2 m has been assessed in extended-range forecasts and hindcasts of the European Center for Medium-Range Weather Forecasts, starting from December 2015 to November 2019. The assessment was carried out over Europe grid-point wise and also by considering several spatially averaged country-sized domains, using standard scores such as the Continuous Ranked Probability Score and Anomaly Correlation Coefficient. The (re-)forecasts showed skill over climatology in predicting weekly mean wind speed and temperature well beyond two weeks. Even at a lead time of 6 weeks, the probability of the (re-)forecasts being skillful is greater than 50%, encouraging the use of operational subseasonal forecasts in the decision making value chain. The analysis also exhibited​ significant differences in skill in the predictability of different variables, with temperature being more skillful than wind speed, and for different seasons, with winter allowing more skillful forecasts. The predictability also displayed a clear spatial pattern with forecasts for temperature having more skill for Eastern than for Western Europe, and wind speed forecasts having more skill in Northern than Southern Europe.
Apocalypse then! Apocalypse now? Using the Laacher See eruption (13ka BP) for Realistic Disaster Scenario design
Authors: Riede Felix
Published: March 2021

Approximately 13ka BP, the Laacher See volcano (East Eifel volcanic field, Rhenish Shield) erupted cataclysmically1. The details of this eruption as well as its impact on climate, environments and human in the near and far fields have been intensely researched offering rich data for designing Realistic Disaster Scenarios that consider, specifically, the potential consequences of renewed volcanic activity in the Eifel and, more generally, the consequences of similar extreme events/natural hazards on societies in Europe2. In this paper, I review the available evidence relating to the Late Pleistocene eruption with particular focus on (i) new climate modelling3, (ii) the impacts of the tephra-fall on ecosystem services4,5 and (iii) the disruption to contemporaneous forager migration and communication networks6,7. Building on this, I reflect on how this evidence has recently fed into a special museum exhibition that places a Laacher See-type eruption in the year 2100 (https://www.moesgaardmuseum.dk/en/exhibitions/after-the-apocalypse/). Combing principles of evidence-based climate communication8–10, Realistic Disaster Scenario thinking11,12 and state-of-the-art exhibition design, the exhibition addresses likely impacts on economy, travel/communication networks, politics and culture within the context of Anthropocene warming as projected by the IPCC scenarios.

 

 

References:
Local adaptation of a Lessepsian invader species to winter conditions in the Mediterranean Sea
Authors: Silva Raposo Débora , Morard Raphaël , Schmidt Christiane , Kucera Michal
Published: March 2021

In recent decades the “Lessepsian” migration caused a rapid change in the marine community composition due to the invasion of alien species from the Red Sea into the Mediterranean Sea. Among these invaders is the large benthic foraminifera Amphistegina lobifera, a diatom-bearing species that recently reached the invasion front in Sicily. There it copes with colder winters and broader temperature than in its original source, the Red Sea. It is not yet known how (or if) the population from the invasion front has developed adaptation to this new thermal regime. Understanding the modern marine invasive patterns is a crucial tool to predict future invasive successes in marine environments. Therefore, in this study we aim to evaluate the physiological responses to cold temperatures of A. lobifera populations at three different invasive stages: source (Red Sea), early invader (Eastern Mediterranean) and invasion front (Sicily). For this, we conducted a culturing experiment in which we monitored the responses of the foraminifera (growth, motility) to temperatures of 10, 13, 16, 19°C + control (25°C) over four weeks. To address what is the role of their endosymbionts in the adaptation process, we also monitored their photosynthetic activity (Pulse Amplitude Modulation - PAM fluorometer) during the experiment. The growth rate of the foraminifera was reduced for all populations below 19°C as well as the motility, reduced until 16°C and dropping to zero below 13°C. The response of the endosymbionts was however different. There was a reduced photosynthetic activity of the Red Sea and Eastern Mediterranean populations at colder temperatures observed by the lower maximum quantum yield (Fv:Fm) and effective quantum yield (Y(II)), when compared to their initial levels and to the other treatments. In the meantime, the endosymbionts of the Sicily population stood out with the highest photosynthetic activity (Fv:Fm and Y(II)) in the treatments bellow 13 °C (P < 0.05). In conclusion, we observed that while the host responses were similar between the three populations, the endosymbionts from the invasion front population shows the best performance at colder temperatures. This suggests that the photo-symbiosis has an important role in adaptation, most likely being a key factor to the success of past and future migrations.
The TURNkey TB4 Achaia Array: Bridging School and Citizen Seismology through Earthquake Alerting
Authors: Melis Nikolaos S. , Liadopoulos Eustratios , Giannaraki Georgia , Kalogeras Ioannis , Boukouras Konstantinos
Published: March 2021

An extended strong motion array comprised mainly of low cost sensors has been deployed in the Achaia region: the Patras city and the Aigion, Kalavrita towns, Greece. It combines: 4 standard accelerometric stations operated by the National Observatory of Athens, Institute of Geodynamics (NOA), 15 P-Alert MEMS acceleration devices, already deployed and operated in public sector buildings, schools and private dwellings (the Patras P-Alert Array) and 40 Raspberry Shake 4D sensors, which are deployed through the newly established Test Bed 4 region (TB4) for the H2020 financed TURNkey project. Principal aim, in an operational approach, to estimate rapidly the intensity of a felt event in a highly populated urban environment and inform local Civil Protection Agencies and through them the final responders and the general public. Moreover, the deployment of these low cost sensors, especially in schools of the Achaia region, aims to involve the pupils/students, in primary and secondary education, towards exploring School Seismology exercises, in a region where strong felt earthquakes are very frequent. Simple exercises in class, using the recorded data after a felt event have been completed such as: locating the event, estimating the magnitude, show the distribution of max PGA values in the region etc. Taking advantage of the school – local community link, the resilience increase has been already demonstrated in the local communities through happenings, popularized seminars and local press postings. A connection with the Municipalities and the Communal public sector allows the expansion of the citizen involvement (Citizen Seismology) through the use of dedicated smartphone app (i.e. LastQuake@EMSC). Citizens are informed and also pass their felt experience. This allows improved estimation and distribution of the shaking in a second phase, useful for Civil Protection Agencies. The increase of the resilience and public awareness are under monitoring with the collaboration of local media. All data will be also used as input to a TURNkey under development central platform, serving as an EEW system, mainly focusing to schools in an application for the TB4 project region in Greece.
BEWATS: BEACH WASTE TRACKING SYSTEM USING SATELLITE, UAV’s and MARINE DYNAMICS MODELS. 
Authors: Dutta Omjyoti , Revilla-Romero Beatriz , Sanz-Díaz Adrian , Martin-Rodriguez Fernando , Mojon-Ojea Orentino , Mancho Ana , García-Sánchez Guillermo , Margarit Martín Gerard
Published: March 2021

Marine litter is a growing problem that advances parallel to economic and industrial development and seriously affects ecosystems. One of the most abundant pollutants are plastics. The BEWATS project focuses on innovative tools for remote marine litter control and management through satellite and UAV’s. The areas of study are currently at the Vigo coast in Galicia (North-West of Spain). In this area, there are many high natural value beaches including Nature Reserve and part of a National Park. These beaches are receiving an increasing amount of marine litter, mainly plastic, helped by strong currents in the area. Every few months, these beaches are clean and the collected litter information tracked. In this context, the BEWATS project concentrates on tracking the possible path through which marine litter reaches the area of interest. In this presentation, we will discuss how this is achieved by data fusion from UAV imagery, marine dynamics model simulations and Earth-observation satellite data (Sentinel-2). To detect possible marine litter, we have developed a novel synthetic data-based approach to marine litter detection using Sentinel-2 images and machine learning techniques. Within this approach, one can classify and quantify according to pixel-level litter fraction present. We have validated our approach with existing open-sourced available datasets.  

The BEWATS project is led by Vigo University, which provides UAV’s imagery, and the Spanish Research Council (CSIC) provides marine dynamics models for tracking waste routes and delineation of waste concentration zones. In this context, GMV provides Earth observation based solution of detecting marine litter. BEWATS is founded by the Biodiversity Foundation of the Spanish Ministry for the Ecological Transition and the Demographic Challenge.
Electrostatic waves in the shock ramp and their effect on plasma energetics.
Authors: Lalti Ahmad , Khotyaintsev Yuri , Graham Daniel , Vaivad Andris , Johlander Andreas
Published: March 2021

Energy dissipation at collisionless shocks is still an open question. Wave particle interactions are believed to be at the heart of it, but the exact details are still to be figured out. One type of waves that is known to be an efficient dissipator of solar wind kinetic energy are electrostatic waves in the shock ramp, such as ion acoustic waves with frequency around the ion plasma frequency or Bernstein waves with frequency around the electron cyclotron frequency and its harmonics. The electric field of such waves is typically larger than 100 mV/m, large enough to disturb particle dynamics. In this study we use the magnetospheric multiscale (MMS) spacecraft, to investigate the source and evolution of electrostatic waves in the shock ramp of quasi-perpendicular super-critical shocks, and study their effect on solar wind thermalization.
Mapping methane point emissions with imaging spectroscopy satellite missions
Authors: Guanter Luis , Irakulis-Loitxate Itziar , Sánchez-García Elena , Gorroño Javier , Zhang Yongguang , Liu Yinnian , Maasakkers Joannes D. , Aben Ilse
Published: March 2021

Imaging spectroscopy, also known as hyperspectral imaging, is a remote sensing technique in which images of the solar radiation reflected by the Earth are produced in hundreds of spectral channels between the visible and the shortwave infrared part of the electromagnetic spectrum (roughly 400–2500 nm). The 2100-2450 nm spectral window can be used for methane retrievals, as it has been demonstrated over the last years with airborne imaging  spectrometers, and very recently also with space-based instruments. Satellite-based hyperspectral images are acquired with a typical spatial sampling for satellite data of 30 m, a spatial coverage between 30x30 and 60x60 km per scene, and a spectral sampling of 10 nm. In this work, we will present an overview of the state-of-the-art of methane mapping with imaging spectroscopy missions. We will review the characteristics of the available missions, the main retrieval approaches, and will present examples of methane emission detection from a number of missions and locations around the Earth.

 
Using satellite soil moisture and rainfall data for the monitoring and the prediction of natural hazards
Authors: Vivaldi Valerio , Bordoni Massimiliano , Brocca Luca , Ciabatta Luca , Meisina Claudia
Published: March 2021

Rainfall-induced shallow landslides affect buildings, roads, facilities, cultivations, causing several damages and, sometimes, loss of human lives. It is necessary assessing the most prone zones in a territory where these phenomena could occur and the triggering conditions of these events, which generally correspond to intense and concentrated rainfalls. The most adopted methodologies for the determination of the spatial and temporal probability of occurrence are physically-based models, that quantify the hydrological and the mechanical responses of the slopes according to particular rainfall scenarios. Whereas, they are limited to be applied in a reliable way in little catchments, where geotechnical and hydrological characteristics of the materials are homogeneous. Data-driven models could constraints these, when the predisposing factors of shallow instabilities, allowing to estimate only the susceptibility of a territory, are combined with triggering factors of shallow landslides to allow these methods to estimate also the probability of occurrence and, then, the hazard. This work presents the implementation of a data-driven model able to assses the spatio-temporal probability of occurrence of shallow landslides in large areas by means of a data-driven techniques. The models are based on Multivariate Adaptive Regression Technique (MARS), that links geomorphological, hydrological, geological and land use predisposing factors to triggering factors of shallow failures. These triggering factors correspond to soil saturation degree and rainfall amounts, which are available thanks to satellite measures (ASCAT and GPM). The methodological approach is testing in different catchments of Oltrepò Pavese hilly area (northern Italy), that is representative of Italian Apeninnes environment. This work was made in the frame of the project ANDROMEDA, funded by Fondazione Cariplo.
Waves and Quasi-Periodic-Pulsations in Weak Active Solar Emissions
Authors: Oberoi Divya , Mohan Atul , Mondal Surajit
Published: March 2021

The presence of Quasi-periodic pulsations (QPPs) is found to be a common feature of flaring energy release processes on the Sun. They are observed all across the EM range from hard X-rays to radio and provide insights into the physical conditions in the coronal plasma and the processes involved in the generation of these waves and oscillations. There have been numerous observations of spatially resolved QPPs at higher energies, though there are fewer examples at radio frequencies. Spatially resolved observations of these phenomena are particularly rare at low radio frequencies and there are none which are associated with the weaker episodes of active emissions which are much more numerous and frequent. The key reason limiting such studies has been the lack of availability of spectroscopic snapshot images of sufficient quality to detect and characterise the low level changes in the morphology of the sources of active emissions. Together, the data from the Murchison Widefield Array (MWA), a SKA precursor, and an imaging pipeline developed to meet the specific needs of solar imaging, now meet this challenge and enable us to explore this rich and interesting science area. Our work has led to the discovery of several previously unknown phenomena - second-scale QPPs in the size and orientation of a type III source, with simultaneous QPPs in intensity; 30 s QPPs in the radio light curve of a type I emission source associated with active region loop hosting a transient brightening; and intermittent presence of an anti-correlation in the size and intensity of a type I noise storm source along with QPPs. In this presentation we will briefly summarise these recent results and discuss their implications.
Constraining uncertainty in projected precipitation over land with Causal Discovery
Authors: Debeire Kevin , Eyring Veronika , Nowack Peer , Runge Jakob
Published: March 2021

The models participating in the Coupled Model Intercomparison Project Phase 6 (CMIP6) deliver insights on the evolution of the Earth's  climate. The global precipitation changes follow the magnitude of the warming according to a recent study (Tebaldi, Debeire, Eyring et al., 2020) of the CMIP6 ensemble-mean. However, Earth systems models exhibit a large range in simulated precipitation projection over land. In this study, we present a potential approach to constrain the precipitation changes over land globally and regionally. This approach performs a process-oriented model evaluation similar to Nowack et al. study. We evaluate the ability of models to represent atmospheric dynamical interactions by applying Causal Discovery algorithm. We find a relationship between the ability to represent dynamical interactions close to the observations and the projected precipitation changes over land of the model. We show how this relationship can be used to constrain projection of precipitation over land.

 

References:

Nowack, P., Runge, J., Eyring, V. et al. Causal networks for climate model evaluation and constrained projections. Nat Commun 11, 1415. https://doi.org/10.1038/s41467-020-15195-y, 2020.

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Large eddy simulations of low-level turbulence caused by tree lines in the vicinity of an airfield
Authors: Fluck Stefan , Anet Julien G.
Published: March 2021

Obstacles in the vicinity of an airfield are sources of low-level turbulence that can adversely affect air traffic in critical flight phases close to the ground. The airfield in Yverdon in western Switzerland is surrounded by tall tree lines and is notorious for turbulence during take-offs and landings. This situation is even more pronounced when a strong northwesterly local wind, the Joran, prevails. Some parts of the tree lines to the north and to the west of the airfield were removed around 2017. To analyze the effect of the tree lines before and after their removal with respect to low-level turbulence, large eddy simulation tools can be applied to gain valuable insights.

In this study, the flow patterns in the vicinity of the airfield in Yverdon were analyzed by means of high-resolution large-eddy simulations with the PALM model system. This was conducted for different wind scenarios, as well as for two different tree line configurations. In PALM, a nested simulation approach was chosen, where the smallest domain was configured to a resolution of four meters and the larger domain to a resolution of 32 meters. The simulations were forced by COSMO-1 model reanalysis fields, in order to factor in the synoptic weather conditions of the respective days. We validated the model results by comparing the simulated fields with measurement data that were recorded by a sonic anemometer close to the airfield in July 2019, during which period one Joran event was captured.

The results of the simulations show in general good coherence with the measurement data at the mast position. The onset of the Joran event was also well captured in amplitude as well as in time. For each scenario, wind speed, wind direction and turbulence intensity were analyzed with the aim to investigate the effect of the removal of parts of the existing tree lines. The simulations show that the removal of the tree lines change the characteristics of the winds experienced by air traffic significantly. During the simulated Joran case, over the runway, the turbulence intensity is reduced by 0.12 (-27 %), while the mean wind speed increases by 1.78 m/s (+62 %). Furthermore, the lack of wind breaking from the tree lines introduces large crosswind components that were not present before. Similar effects were identified for the other analyzed wind directions.

These results show that the placement of obstacles in the vicinity of an airfield matters to aviation safety and large eddy simulation tools like PALM can produce very helpful insights into how they do so. This is an especially encouraging message regarding future airport infrastructure projects, as costly mistakes can be effectively avoided already during planning phases.
A rapid total nitrogen determination prototype for wastewater treatment plants online detection
Authors: Geng Jingxuan , Yang Chunhua , Lan Lijuan , Han Jie , Zhang Fengxue , Li Yonggang
Published: March 2021

The online automatic detection for the concentration of total nitrogen (TN) is a critical problem in wastewater treatment plants (WWTPs). The over-discharge of TN can cause severe environmental problems such as aquatic eutrophication and ecosystem dysfunction, and the TN concentration in each wastewater treatment process can also reflect the processing statement of WWTPs and ensure its stable operation. However, determining the TN concentration timely is always a difficult task. According to the traditional TN detection approach, the concentration of TN is determined after the oxidative digestion process, which is a complex chemical reaction process and usually requires 30 minutes to 1 hour. Considering the actual operation situation, this traditional method can hardly satisfy the real-time requirement of WWTPs, which can only be used as a kind of validation approach. To solve this problem, in this paper, we design a novel automatic detection prototype of TN. Instead of determining the concentration of TN after the process of oxidative digestion, the ultraviolet spectrum is used to non-destructive detect the concentration of nitrate during the whole oxidative digestion process. Based on the principle of competitive response and chemical reaction kinetics, for different water samples with different TN concentrations, their oxidative digestion processes are different even in the early reaction stage. Therefore, we can use the early reaction properties to determine the TN concentration, thereby shortening the necessary detection time. Based on experimental data collected from real water samples, our prototype can not only efficiently shorten the detection time of the TN concentration, but also ensure satisfactory detection accuracy.
Spectra of temperature fluctuations in the solar wind
Authors: Nemecek Zdenek , Šafránková Jana , Pitňa Alexander , Němec František
Published: March 2021

Turbulent cascade transferring the free energy contained within the large scale fluctuations of the magnetic field, velocity and density into the smaller ones is probably one of the most important mechanisms responsible for heating of the solar corona and solar wind and thus the turbulent behavior of these quantities is intensively studied. However, the temperature is also highly fluctuating quantity but behavior of its variations is studied only rarely. There are probably two reasons, first the temperature is tensor and, second, an experimental determination of the temperature variations requires knowledge of the full velocity distribution with a time resolution and such measurements are scarce. To overcome this problem, the Bright Monitor of the Solar Wind (BMSW) on board the Spektr-R spacecraft uses the Maxwellian approximation and provides the thermal velocity with 32 ms time resolution. We use these measurements and complement them with 10 Hz magnetic field observations from the Wind spacecraft propagated to the Spektr-R location and analyze factors influencing the shape of the temperature power spectral density. A special attention is devoted to mutual relations of power spectral densities of different quantities like parallel and perpendicular temperature, magnetic field and velocity fluctuations and their evolution in course of solar wind expansion.