bluuebunny/crossref_metadata_2025 huggingface dataset:
Satellite Data Application to Cover Lack of In-situ Observations for Mapping Precipitation and Direct Runoff in Semi-arid Basin
Authors: Akbari Mahdi , Torabi Haghighi Ali
Published: March 2020

Hydrological modeling in arid basins located in developing countries often lacks sufficient hydrological data because, e.g., rain gauges are typically absent at high elevations and inflow to ungauged areas around large closed lakes such as Lake Urmia is difficult to estimate. We tried to improve precipitation and runoff estimation in Lake Urmia, Iran as an arid basin using satellite-based data. We estimated precipitation using interpolation of rain gauge data by kriging, downscaling Tropical Rainfall Measuring Mission (TRMM), and cokriging interpolation of in-situ records with Remote Sensing (RS)-based data. Using RS-based data in estimations gave more precise results, by compensating for lack of data at high elevations. Cokriging interpolation of rain gauges by TRMM and Digitized Elevation Model (DEM) gave 4–9 mm lower Root Mean Square Error (RMSE) in different years compared with kriging. Downscaling TRMM improved its accuracy by 14 mm. Using the most accurate precipitation model, we modeled annual direct runoff with Kennessey and Soil Conservation Service Curve Number (SCS-CN) models. These models use land use, permeability, slope maps and climatic parameter (Ia) to represent the annual climatic condition of modeled basin in sense of wetness or dryness. In runoff modeling, Kennessey gave higher accuracy in annual scale. It was found that classification of years to wet, dry and normal states in Kennessey by default assumptions on Ia is not accurate enough for semi-arid basins so by solving this issue and calibration Kennessey model parameters, we made this model applicable for Urmia Lake basin. Calibrating Kennessey reduced the Normalized RMSE (NRMSE) from 1 in the standard model to 0.44. Direct runoff coefficient map by 1 km spatial resolution was generated by calibrated Kennessey. Validation by the closest gauges to the lake gave a NRMSE of 0.41 which approved the accuracy of modeling.
More than two decades of Faroe Bank Channel overflow: Stable, but warming
Authors: Larsen Karin Margretha Húsgarð , Hansen Bogi , Hátún Hjálmar , Østerhus Svein
Published: March 2020

Since November 1995, we have monitored the volume transport of Faroe Bank Channel overflow (FBC-overflow) and since 2001, the bottom temperature at the sill of the channel. The FBC-overflow is the coldest and densest overflow component and contributes approximately one third of the total overflow. Together with water that it entrains en route, it is therefore one of the main sources for North Atlantic Deep Water and the lower limb of the Atlantic Meridional Overturning Circulation (AMOC). In spite of reported AMOC weakening, the FBC-overflow has shown no signs of reduced volume transport. In contrast, a linear trend analysis indicated a weak (but non-significant) positive trend in volume transport of +5% from 1996 to 2018. The bottom water at the sill of the channel is the coldest component of the FBC-overflow and the densest overflow component overall. Since high-quality monitoring of the bottom water temperature began in summer 2001, the bottom water has warmed by approximately 0.2 °C with most of the warming occurring in two periods: 2004-2007 and 2015-2019. During the period, salinity has also been changing and the combined temperature/salinity effect on the density of the FBC-overflow will be discussed.
Downscaling of surface wind speed over the North Atlantic using conditional Generative Adversarial Networks
Authors: Krinitskiy Mikhail , Elizarov Svyatoslav , Gavrikov Alexander , Gulev Sergey
Published: March 2020

Accurate simulation of the physics of the Earth`s atmosphere involves solving partial differential equations with a number of closures handling subgrid processes. In some cases, the parameterizations may approximate the physics well. However, there is always room for improvement, which is often known to be computationally expensive. Thus, at the moment, modeling of the atmosphere is a theatre for a number of compromises between the accuracy of physics representation and its computational costs.

At the same time, some of the parameterizations are naturally empirical. They can be improved further based on the data-driven approach, which may provide increased approximation quality, given the same or even lower computational costs. In this perspective, a statistical model that learns a data distribution may deliver exceptional results. Recently, Generative Adversarial Networks (GANs) were shown to be a very flexible model type for approximating distributions of hidden representations in the case of two-dimensional visual scenes, a.k.a. images. The same approach may provide an opportunity for the data-driven approximation of subgrid processes in case of atmosphere modeling.

In our study, we present a novel approach for approximating subgrid processes based on conditional GANs. As proof of concept, we present the preliminary results of the downscaling of surface wind over the ocean in North Atlantic. We explore the potential of the presented approach in terms of speedup of the downscaling procedure compared to the dynamic simulations such as WRF model runs. We also study the potential of additional regularizations applied to improve the cGAN learning procedure as well as the resulting generalization ability and accuracy.
Century-Scale Shifts in Peat Hydro-Physical Properties as Induced by Drainage
Authors: Liu Haojie , Rezanezhad Fereidoun , Bernd Lennartz Bernd
Published: March 2020

Hydro-physical properties of peat influence the partitioning of rainfall into infiltration versus runoff, determine water flow and solute transport patterns, and regulate the carbon and nitrogen cycles in peatlands. Although soil hydro-physical properties of peat soils are well documented, little is known about the temporal dynamics of soil properties, especially at a century-scale. A data set of peat subsidence as well as bulk density (BD) increase rate following artificial drainage was assembled from the literature. The collected data cover a time period of up to 215 years of land drainage for different land use types (forest and agriculture). The results show that the subsidence rate and soil BD increase rate generally depend on land drainage duration and land use. The most severe shift in soil pore structure of peat used for forest and agricultural occurs within the first 10 and 40 years of land drainage, respectively. Peatland drainage reduces the number of macropores (>50 μm) but increases ultramicro- and cryptoporosity (<5 μm). In the long term, peat subsidence is responsible for more than 85% of soil water storage loss. In conclusion, the derived functions between subsidence rate as well as BD increase rate and drainage duration provide a new method to estimate hydro-physical properties (pore structure and saturated hydraulic conductivity, specific yield, soil water storage) of peat at a century-scale. The derived hydro-physical parameter values can be used for long-term hydrological modelling (back- and forward), especially if measured hydraulic parameters of peat are not available. However, additional research is required to reduce uncertainty.
A Study on Utilization Information of Disaster Site for Real-Time Situation Management
Authors: Kim Okju , Park Jinyi , park hyoungseong , lee junwoo
Published: March 2020

In the event of a disaster, most of the response systems are divided into final decision makers who direct overall situation management, preparation, response, and restoration work, and field managers who share the status of the actual disaster at the site and perform the tasks they are directed to.

Although major means of sharing situations between decision makers and field managers in Korea are used, such as telephone, messenger, and report, the information provided in simple text format was inconvenient to decision makers who have to issue business instructions after considering the surrounding status information and concerns over possible future damage.

In response, a GIS-based smart disaster situation management system was established to manage the situation quickly at the site of a disaster.

The system presents 32 types of information related to disaster safety produced by 12 agencies (the Korea Meteorological Administration, the National Transport Information Center, Korea Hydrographic and Oceanographic, etc.) on a single screen (e.g. weather/ ocean observation information, CCTV video information, etc.) and provides detailed location of disaster areas, location of damage sites and photos, and visualizing the weather information on a multidisciplinary basis to enable the decision panel to provide visualisation.

Through mobile applications, we have developed a function that allows field managers to upload information obtained from professional equipment (photo, radar, chemical measuring, etc.) directly into the system and will study various disaster site investigation information so that it can be used to support professional situation management in the future.
Integrated methods and a complex solution for flood protection and erosion control – A case study of the village of Vrbovce, Slovakia
Authors: Výleta Roman , Rattayová Viera , Hlavčová Kamila , Danáčová Michaela , Škrinár Andrej , Kohnová Silvia , Szolgay Ján
Published: March 2020

The aim of the study was an integrated application of methods for the identification and complex assessment of ecosystem responses to abiotic stress factors as extreme runoff, muddy floods and soil erosion processes.  The protection of land with flysch geological structures with regard to and the problems caused by extreme runoff are a very important task in water management. The unsuitable management of land and irresponsible land use causes the formation of flash floods on watersheds and results in accelerated soil erosion. The decreasing soil quality and excessive sedimentation of eroded material in the water structures, which are components of flood protection structures, are a consequence of accelerated soil erosion. Research on and the design of measures were realized on five small watersheds in the cadastral area of the village of Vrbovce, which is situated in western Slovakia, on the edge of the flysch zone of the White Carpathians. Flash floods regularly recur in the village of Vrbovce, and extreme runoff causes the formation of rill erosion on the arable land. The soil erosion was modelled by the Universal Soil Loss Equation and the topographic factor was calculated by the Usle2D program. The results of the calculations show that 96.19 % of the agricultural land is endangered by accelerated soil erosion, with the values of the average annual soil loss greater than the limit for the tolerance of soil erosion. We calculated the direct runoff for five selected watersheds of the Teplica river tributaries with the CN-SCS method. The flooded areas in the village were modelled by the 2D hydrodynamic model MIKE21. A set of measures, i.e., polders, an infiltration trench and agrotechnical measures on the arable land, was designed outside the built-up areas of the village of Vrbovce for the reduction of the extreme runoff and accelerated soil erosion. Measures for the Teplica river revitalisation in the village were proposed. From the estimation of effectiveness of the measures proposed follows that we were able to reduce the amount of the soil erosion to values permissible for the norm by the proposed measures.

Key words: soil erosion, flash floods, flood protection, erosion control and river revitalisation practices
Advanced distributed modelling of slope stability using root reinforcement and geostatistical parameterization of geotechnical soil properties
Authors: Masi Elena Benedetta , Stagnozzi Anita , Stagnozzi Silvia , Tonelli Gianluigi , Veneri Francesco , Tofani Veronica , Segoni Samuele
Published: March 2020

A physically based model for shallow landslide triggering (HIRESSS – HIgh REsolution Soil Stability Simulator) was applied in a 100 km2 test site in Central Italy (Urbino, Marche region). The objectives were assessing  the influence of additional cohesion provided by roots and testing the effectiveness of a geotechnical characterization performed in an another area, but on similar lithologies.

We performed two different simulations considering the rainfall event of January-February 2006, which triggered 14 landslides in the area. For both the simulations, rainfall data were fed into the model using the measurements at hourly time step of a nearby rain gauge station, while soil thickness was estimated using a state-of-the-art empirical model based on geomorphological parameters derived from curvature, slope gradient, lithology and relative position within the hillslope profile. Geotechnical input data were varied among the two simulations. In the first one, a few in-situ and laboratory tests were performed to characterize the main lithologies, while the remaining lithologies were characterized using literature data. In the second simulation, the main geotechnical and hydrological parameters (cohesion, internal friction angle, soil unit weight, hydraulic conductivity) were fed into the model using a geostatistical characterization performed on hundreds of measurements carried out in another Italian region, with similar lithologies. Furthermore, in the second simulation the additional cohesion provided by the plant roots was also taken into account.

The results obtained with the two simulations were validated considering the landslide dataset collected by field work and image interpretation shortly after the rainfall event studied. We discovered that the second simulation provided much more reliable results, with the areas surrounding the landslide locations characterized by much higher values of failure probability.

The outcome is very important to address future research in distributed slope stability modelling because it proved that: (i) additional root cohesion is an important factor that can be used to get more reliable results; (ii) when in need of characterizing the geotechnical parameters of the study area, instead of using just a few measurements performed therein, it is preferable to integrate also data coming from different areas but with similar lithologies if they were robustly characterized in geostatistical terms purposely for distributed slope stability studies.
Electrical characteristics and environmental conditions of lightning-ignited fires in the Iberian Peninsula and Mediterranean France between 2009 and 2015
Authors: Pérez-Invernón Francisco J. , Huntrieser Heidi , Soler Lopez Sergio , Gordillo-Vázquez Francisco J. , Navarro-Gonzalez Javier , Reglero Victor , Montanyà Joan , van der Velde Oscar A.
Published: March 2020

About 5% of the wildfires in the Mediterranean basin are produced by lightning [1]. Lightning-ignited fires tend to occur in remote areas and can spread significantly before suppression. The occurrence of lightning-caused fires is closely related with intense drought periods and high temperatures [2]. Therefore, drier conditions and higher temperatures in a changing climate are expected to lead to a future increase in lightning-ignited fires occurrence. The development of a lightning-ignited fire parameterization for Earth system models arises as a necessary tool to predict the future occurrence of these extreme events and to study their impact on atmospheric chemistry.

Long Continuing Current lightning (LCC-lightning), preferable taking place in dry thunderstorms, is believed to be the main precursor of lightning-ignited fires. This was originally proposed by McEachron and Itagenguth in 1942 [3] working with laboratory sparks, which suggested that ignition by natural lightning is usually caused by a discharge having an unusual long-continuing current phase. Later in 1967 this hypothesis was confirmed by Fuquay et al. [4].

In this work, we analyse three fire databases of lightning-ignited fires in Spain, Portugal and Southern France between 2009 and 2015. Furthermore lightning measurements from the World Wide Lightning Location Network (WWLLN) and the Earth Networks Total Lightning Network (ENTLN), and land and atmospheric variables from the new ERA-5 reanalysis are combined to investigate the electrical characteristics and environmental conditions of the fires. This preliminary data analysis will be useful to set new relationships between the characteristics of thunderstorms and the initiation of wildfires. It is the first step towards the development of a detailed lightning-ignited fire parameterization for the atmospheric chemistry-climate model EMAC.

[1] Vázquez, A., and Moreno, J. M. (1998). Patterns of lightning-, and people-caused fires in peninsular Spain. International Journal of Wildland Fire, 8(2), 103-115.

[2] Pineda, N., and Rigo, T. (2017). The rainfall factor in lightning-ignited wildfires in Catalonia. Agricultural and Forest Meteorology, 239, 249-263.

[3] McEachron, K. B., and Itagenguth, J. It (1942), Effect of lightning on thin metal surfaces, AIEE Trans., 61, 559-564, 1942.

[4] Fuquay, D. M., Baughman R. G, Taylor, A. R. and Hawe, R. G. (1967). Characteristics of seven lightning discharges that caused forest fires. Journal of Geophysical Research, 72 (24).
Assessing groundwater sustainability and the influence of water transfer project in Sugan Lake Basin, northwest China
Authors: Yang Zhengqiu , Hu Litang
Published: March 2020

In order to meet the ecological water requirement, a water transfer project that divert river flow from the Sugan Lake Basin to the Dunhuang Basin is under consideration. Inter-basin water diversion project is an effective tool to deal with the uneven distribution of water resources and climate change. However, there is still a lack of research on hydrogeology in the Sugan Lake Basin at present. In this study, FEFLOW software was used to establish a numerical model and it was well calibrated by FEPEST. The result shows that the infiltration of the river surged in 2017–2018 so that the groundwater storage significantly increased in resent year. Under four water transfer scenarios, model was used to predict and analyze the influence of transfer project. When the diversion plan had implemented, the groundwater drawdown gradually increased from west to east in the upstream zone and the gobi zone. The biggest groundwater drawdown were 51.10 m, 56.70 m, 62.34 m and 68.02 m in four transfer conditions. In addition, groundwater level of wetland at most decline by 3.80 m, 4.06 m, 4.30 m and 4.77 m. Water diversion also made a great impact on the spring flow in the basin. The rate of Middle Spring reduced to 0.75 × 108 m3/a – 0.81 × 108 m3/a after 100 year, and it would reduce to 0.20 × 108 m3/a – 0.40 × 108 m3/a when groundwater system was steady. Nevertheless, the direct discharge from groundwater to lakes basically was not affected. The developed model and results will help to make an effective management of water resources.
Satellite monitoring of ground and structure deformations applied to Colosseum archaeological park
Authors: Russo Alfonsina , Della Giovampaola Irma , Spizzichino Daniele , Leoni Gabriele
Published: March 2020

Archeological sites and cultural heritage are considered as critical assets for the society, representing not only the history of region or a culture, but also contributing to create a common identity of people living in a certain region. In this view, it is becoming more and more urgent to preserve them from natural and anthropogenic hazard as well as from negative effects due to climate changes. In the present paper, we will focus on ground deformation measurements obtained by satellite SAR interferometry and on the methodology adopted and implemented in order to use the results operatively for conservation policies in the Colosseum Archaeological Park (PAC). The integrated monitoring project of the PAC was inspired by the desire to build a system of protection and conservation at the service of sustainable exploitation. With these objectives, the PAC has launched a static and dynamic monitoring project consisting of five pillars: i) a dedicated database of all the historical and archaeological data of the monuments, (digital documentation archive implementation); ii) implementation of visual monitoring activities, (a dedicated app will allow to send data to the central system); iii) satellite monitoring program (historical and routine analysis of the satellite data) that will flow directly into the system and will be analysed in order to monitor possible ground deformation; IV) in situ monitoring from traditional ground diagnostic instruments; v) experimental activities, such as the use of H-BIM applications. Basically, the project carried out the creation of a multi-parameter system of permanent monitoring of the whole archaeological area, with associated indicators of risk level, for which it is necessary the combined use of new technologies. Some examples of satellite monitoring application will be presented and illustrated in order to stress the roles of new Earth Observation technologies in the field of conservation and maintenance polices. Considering the limitations of all the interferometric techniques, in particular the fact that the measurement is along the line of sight (LOS) and the geometric distortions, in order to obtain the maximum information from interferometric analysis, both ascending and descending geometry have been used. The interferometric techniques need to use a stack of SAR images to separate the deformation phase contributions from other spurious components (atmospheric, orbital, etc.). The objective is to find a nominal behavior of the site in response to critical events and/or related to natural degradation of infrastructures in order to prevent damages and guide maintenance activities. The first results of this cross correlated analysis showed that some deformation phenomena are identifiable by SAR satellite interferometric analysis and it has also been possible to validate them on field through a direct survey.
Multiplatform analysis of a large anticyclonic eddy in the Algero-Provencal basin in 2019
Authors: Alvera-Azcárate Aida , Barth Alexander , Troupin Charles , Beckers Jean-Marie , Evers-King Hayley , Pascual Ananda , Aguiar Eva , Tintoré Joaquin
Published: March 2020

A large anticyclonic eddy formed in April 2019 in the Algero-Provencal basin between Mallorca and Sardinia, and lasted until November 2019. While mesoscale activity is usually high in this part of the Mediterranean basin, the formation of such large (about 150 km in diameter) and long-lived eddies is not common. The eddy formed from a filament originated in the Algerian coast and was visible in multiple sources of satellite data, including sea surface temperature and ocean colour from Sentinel-3, until summer. Because of the warming of the surface layer, during summer months the eddy remained as a subsurface structure, evidenced by the sea level anomaly derived from altimetry data. A surface signal developed again in November, and the eddy finally dissipated in December 2019. According to CMEMS model data, in its strongest period the eddy reached about 300 m in depth, and during its sub-surface period the center was located at about 100 m depth. While at the surface the temperature signal was very clear, model data suggest the salinity anomaly was stronger than temperature, especially at depth. Such large and long-lived eddies have an impact in the basin currents, specifically in the transport of cold water from the northern to the southern part of the western Mediterranean basin, influencing the ecosystem there. The impact of the presence of this eddy, its long duration and the additional mesoscale and submesoscale activity that originated in its surroundings are investigated using a combination of remote sensing data, in situ data and model data.
Nitrogen use efficiency of different slurry management in the pre-alpine grassland region – a 15N tracing experiment
Authors: Zistl-Schlingmann Marcus , Kwatcho-Kengdo Steve , Schreiber Mirella , Berauer Bernd , Jentsch Anke , Kiese Ralf , Dannenmann Michael
Published: March 2020

Grasslands of the alpine and pre-alpine region do not only sustain economic soil functions such as fodder production for local dairy and cattle farming but also important ecological soil functions such as water and nutrient retention, erosion and flood protection and habitat provision for extraordinarily high plant and animal biodiversity. The current management in the more intensively used grasslands in this region is based on fertilization with liquid cattle slurry, which is assumed to be prone to high N leaching and gaseous N emissions with their undesired consequences for soil, air and water quality.

In order to assess the nitrogen use efficiency and trade-offs such as greenhouse gas emissions and nitrate leaching of liquid slurry surface application under the auspices of climate change, we set up a 15N cattle slurry labeling experiment, combined with a space for time climate change experiment using plant-soil mesocosms and lysimeters. The 15N signal was traced in the plant-soil-microbe system for an entire year to assess productivity, plant nitrogen use efficiency, soil nitrogen retention and nitrogen losses. We found surprisingly low plant nitrogen use efficiency (recovery of less than ¼ of the applied 15N in harvested plant biomass), soil N retention (ca ¼ 15N recovery) and high environmental N losses (ca ½ of the 15N tracer remained unrecovered). The estimates of N losses based on unrecovered 15N were in good agreement with independent measurements of gaseous and hydrological N losses. Due to very high productivity and associated N exports with grass harvests, total N exports exceeded total N inputs. Such soil nitrogen mining was especially pronounced in the climate change treatments and was supported by increased soil nitrogen mineralization.

We also tested alternative slurry management (slurry injection into the soil, slurry acidification) that is supposed to increase nitrogen use efficiency. Slurry acidification but not slurry injection slightly increased plant nitrogen use efficiency and reduced nitrogen losses, however could overall not prevent significant soil nitrogen mining.

Consequently, both surface application and the more modern techniques of liquid cattle slurry fertilization showed low nitrogen use efficiency and promoted soil nitrogen mining. This is asking for a re-consideration of traditional fertilization regimes based on solid manure mixed with straw, a management that over historical timescales likely contributed to the build up of the large nitrogen stocks in pre-alpine grassland soils.
Recent fire activity in the boreal forests of central western Siberia is unprecedented in the past 5000 years: palaeoenvironmental evidence contextualises a burning issue
Authors: Feurdean Angelica , Diaconu Andrei Cosmin , Florescu Gabriela , Galka Mariusz , Hutchinson Simon M. , Pfeiffer Mirjam , Kirpotin Sergey , Tanţău Ioan , Vannière Boris
Published: March 2020

Although wildfire events in Siberia have increased in frequency and intensity over recent decades, in the absence of long-term records, it is not clear how far this trend deviates from baseline conditions. Short-term datasets categorise the forest fire regime in Siberia as one of surface, litter fires alternating withdevastating crown fires, although there is significant variability within this region likely reflecting vegetation composition. However, a comprehensive understanding of how vegetation composition and properties determine fire regimes remains lacking. To address this question we used two peat records spanning the last 2500 yr and a 5000 yr, respectively of charcoal morphologies-derived fire regime, pollen-based vegetation dynamics and stable isotope and testate amoebae-based climate reconstructions from boreal forests in central western Siberia, combined with fire-related functional traits of key boreal tree species. Compared to the trend over the 5000 yr period (mean fire return interval=FRI of 400 yr), our reconstructed mean FRI of 145 yr for the last five centuries is notably the shortest in the record. Most fires in this area tend to be surface, litter fires, although over the last centuries surface fires show an increased trend towards crowning. Frequent fires between 5000 and 4000 cal yr BP and 1500 cal yr BP to the present were concurrent with the dominance of invader species (primarily Betula) and fire endurer (mainly herbs) with prevalence of resisters (Pinus sylvestris, Pinus sibirica). Longer fire return intervals (up to 500 yr) between 4000 and 1500 cal yr BP were associated with the dominance of fire resisters with a considerable proportion of fire avoiders (Abies sibirica and Picea obovata). The rising number of fire episodes and the intensification of fire events over the past 1500 years have likely promoted fire-adapted plant communities (invaders and endurers) that can rapidly reach maturity, contributing to the reduction of avoider and resister species. This trend demonstrates that fire avoider species particularly fail to regenerate if the intervals between fire episodes are too short and thatan increasing number of fire episodes can drive land cover towards more fire-adapted plant communities. Our long-term perspective shows that the current fire regime lies significantly outside baseline conditions, which may drive future change in forest composition towards an increased prevalence of invader species. This study also contributes to an understanding of disturbance regimes in Pinus-Betula forests and considers the potential of tree species to adapt to new fire regimes.

 
Sea ice and atmosphere interactions and predictability: preliminary results using HadGEM3
Authors: Flocco Daniela , Hawkins Ed , Ponsoni Leandro , Massonnet Francois , Feltham Daniel , Fichefet Thierry
Published: March 2020

Arctic sea ice extent has steadily declined in the past 30 years. Aside from the global impact on climate change, regional information on the sea ice presence and on its impact on oceanic and atmospheric patterns has witnessed a growing interest. There is a growing need for seasonal-to-decadal timescale climate forecasts to help inform local communities and industry stakeholders.

Here we examine the influence of sea-ice thickness observations on the predictability of the sea-ice and atmospheric circulation. We perform paired sets of ensembles with the HadGEM3 GCM starting from different initial conditions in a present-day control run. One set of ensembles start with complete information about the sea-ice conditions, and one set have degraded information. We investigate how the pairs of ensembles predict the subsequent evolution of the sea-ice, sea level pressure and circulation within the Arctic and beyond with the aim of quantifying the value of sea-ice observations for improving predictions.
Saturated biosorbents: shift from waste to new class of materials
Authors: Robalds Artis
Published: March 2020

The use of biosorbents (adsorbents of natural origin, such as, plant derived material) has been regarded as an alternative to traditional wastewater treatment methods (such as chemical precipitation or ion exchange), as it is environmentally friendly and cost-effective process. Literally hundreds of different biosorbents have been tested in laboratory scale sorption experiments, however, the traditional research of biosorbents (i.e., the use of biosorbents in the treatment of polluted waters) seems to be a dead-end direction, with technological problems that are difficult to overcome, and process has found no application on industrial scale until now. For example, biosorbents are short-lived, as the biomass decomposes in the solution, and as a result, it is fragile to technological operations such as mixing or pumping. There are also problems with regeneration and reuse of biosorbents. It explains why this process has not been implemented in industrial scale so far. In addition, the focus in biosorption studies has always been more on the “removal” (i.e., concentration of pollutants into a biosorbent, however this material will become a waste after the biosorption), but not so much on the “recovery”. Therefore, there is an opportunity, as well as challenge to apply biosorption principles in unconventional manner. A new concept will be proposed, with shift away from adsorption of toxic elements to adsorption of essential elements. 
Impact of different inizialization procedures on near-term predictability of ocean biogeochemistry
Authors: Bernardello Raffaele , Sicardi Valentina , Ortega Pablo , Doblas-Reyes Francisco
Published: March 2020

With the world population rapidly increasing and the related spectre of a global food crisis, the necessity to improve our ability to manage world's fisheries has never been more pressing. One important step in this direction is the improvement of near-term (i.e. seasonal to decadal) predictions of Net Primary Production (NPP). NPP is the rate of production of phytoplankton biomass, the primary source of food for marine animal life and thus a fundamental environmental variable to be taken into account in fishery management strategies. Here, we present results from a suite of simulations carried out with the Earth System Model EC-Earth3. These simulations include reconstructions of the biogeochemical state of the ocean for the period 1958 to present and a set of near-term predictions covering the period from 1979 to present. The simulations are designed to test the ability of two different initialization techniques to provide predictive skill to the simulation. One initialization technique is based on data-assimilation of physical fields only while, the second technique proposed is based on an attempt to partially reconstruct 3D nutrient fields. This combines information from climatological nutrient fields and reconstructed water masses variability. This combination is meant to exploit the ability of mode and intermediate water masses to propagate a signal on nutrient distribution on interannual timescales providing a source of predictability for nutrients and thus for NPP. Skill scores are used to validate these retrospective predictions derived from both techniques in order to obtain a complete evaluation of the predictive capability of the modelling system.
Activation of persulfate by different biochars for the degradation of sulfamethoxazole
Authors: Manariotis Ioannis D. , Kemmou Liana , Magioglou Elena , Frontistis Zacharias , Vakros John , Mantzavinos Dionissios
Published: March 2020

Advanced oxidation processes (AOPs) based on persulfates have become very popular for in-situ water/wastewater treatment since persulfates are more stable and less costly than other oxidants such as hydrogen peroxide. The conversion of persulfates to sulfate radicals requires an activation agent, including transition metals, high temperature, ultraviolet irradiation, ultrasound irradiation, and microwaves. Recently, there have been several reports concerning the use of carbonaceous materials such as graphene, graphene oxide, carbon nanotubes, and activated carbons as persulfate activators. Biochars, the solid residue produced from biomass thermal decomposition with no or little oxygen at moderate temperatures, are low-cost materials with high surface area and desirable physicochemical properties in terms of pore size distribution, the number of functional groups, and minerals that can be employed as catalytic supports.

The aim of this work is to test whether biochar produced from malt spent rootlets (MSR) and olive kernels are suitable activators of persulfates for the degradation of sulfamethoxazole (SMX) under various operating conditions and aqueous matrices.  Olive kernels and MSR were pyrolyzed at 850 and 900oC, respectively.  The actual matrix effect on degradation was minor and so was the effect of radical scavengers. Persulfate activation seems to occur on the biochar surface through interactions with the surface functional groups, generating radicals that are not released in the solution.
Possible correlation beteen the pre-seismic geomagnetic signal and the M6.4 earthquake generated in the coastal zone of Albania, on November 26, 2019
Authors: Stanica Dumitru , Stanica Dragos Armand
Published: March 2020

A catastrophic earthquake of magnitude Mw6.4 generated at 10km depth hit coastal zone of Albania on November 26-th 2019, at 2h54min UTC. The earthquake was intensively felt at about 34km far, in Tirana City, where a lot of damages have occurred. Consequently, in order to identify the anomalous geomagnetic signature before the onset of this earthquake, we retrospectively analyzed the data collected on the interval October 15–November 30, 2019 at the two geomagnetic observatories: Panagjurishte (PAG)-Bulgaria and Surlari (SUA)-Romania, the last one taken as reference. The pre-seismic geomagnetic anomalous signal is postulated to be due to the electrical conductivity changes, most probably associated with the earthquake-induced tectonic stress, followed by rupture and electrochemical processes deployed along the Adria plate subduction zone. To identify a pre-seismic geomagnetic signal related to this earthquake we used: (i) polarization parameter BPOL which should be time invariant in non-seismic condition and it becomes unstable before the onset a seismic event; (ii) Strain effect-related to the anomalous geomagnetic signals identification. Thus, the daily mean distributions of the BPOL and its standard deviations (SD) are performed for the both observation site (PAG and SUA) by using the FFT band-pass filter analysis in the ULF range (0.001Hz - 0.0083Hz). Further on, a statistical analysis based on a standardized random variable equation was applied for the two particular cases: a) the assessment of the singularity for anomalous signal, related to the Mw6.4earthquake, observed on the daily mean distributions of the BPOL*(PAG) and BPOL*(SUA); b) the differentiation of the transient local anomalies associated with Mw6.4earthquake from the internal and external parts of the geomagnetic field, taking Geomagnetic Observatory (SUA) as reference, and the result is presented as daily mean distribution of the BPOL*(PAG-SUA). Finally, on the BPOL*(PAG-SUA) time series, carried out on the interval 1-30 November 2019, a very clear anomaly of maximum greater than 2.5 SD was detected on November 22, what means a lead time of 4 days before the onset of Mw6.4earthquake. In consequence, all mentioned results could offer opportunities to develop new tools for early detection of geomagnetic anomalies related to major seismic events. 
Towards instrumental catalogs of gravitational instabilities at local and regional scales by a combined seismology and machine learning approach
Authors: Hibert Clement , Malet Jean-Philippe , Radiguet Mathilde , Pillot Quentin , Michéa David , Provost Floriane , Helmstetter Agnès
Published: March 2020

Seismology allows continuous recording of the activity of gravitational instabilities whatever the context, and is therefore able to provide a tool for the study of the spatio-temporal evolution of the activity of gravity instabilities with a unique resolution. Due to the considerable fall in the costs of the means of acquiring seismological data and the increasing densification of global, regional and local networks observed in recent years, the amount of data to be processed is growing exponentially. Thus access to information is more and more complete but in return the volume of data to be processed becomes considerable. To analyze this volume of data and extract relevant information, it is necessary to develop automatic methods of identification of seismic sources and location to quickly build the most complete seismicity catalogs possible.

We present a new machine-learning based method for automatically constructing catalogs of gravitational seismogenic events from continuous seismic data. We have developed a robust and versatile solution, which can be implemented in any context where seismic detection of landslides or other mass movements is relevant. The method is based on spectral detection of seismic signals and the identification of sources with a machine learning algorithm. Spectral detection detects signals with a low signal-to-noise ratio, while the Random Forest algorithm achieves a high rate of positive identification of seismic signals generated by landslides and other seismic sources. The processing chain is implemented to operate in parallel in a high-performance data center, which allows years of continuous seismic data to be explored and a database of events to be rapidly built up. This solution is also deployed for near-real time seismicity catalogs construction in the framework of slow moving landslides monitoring done by the Observatoire Multidisciplinaire des Instabilités de Versants (OMIV). Here we present the preliminary results of the application of this processing chain in different contexts, locally for the monitoring of slow-moving landslides (La Clapière, Super-Sauze, Séchilienne), and at the regional level for the detection of large landslides field (Alaska and Alps).
Lake pushed out by 200 m³ rock avalanche (Zugspitze / Lake Eibsee, D) - New geophysical and sedimentological insights into interactive processes
Authors: Knapp Sibylle , Mamot Philipp , Lempe Bernhard , Krautblatter Michael
Published: March 2020

Rock avalanches destroy and reshape landscapes within only few minutes and are among the most hazardous processes on earth. Water in the travel path may accelerate the rock avalanche, with longer runouts as a result. So far no study has aimed at proving the existence of a paleolake pushed out by a rock avalanche and further analysing the interaction of the moving mass with the former lake. Especially for ancient long-runout mass movements this could be the key to explain exceptional runout lengths.

In this study at the Zugspitze / Eibsee rock avalanche we prove the existence of, and the impact onto a paleolake inside the rock-avalanche trajectories. We assume that there has been a paleo-Lake Eibsee which was displaced by the ~200 mio. m³ rock avalanche. Our approach shows a complementary application of geomorphological mapping (over ~5 km²) and Electrical Resistivity Tomography (ERT) measurements (8 profiles with in total ~9.5 km length), combined with sedimentological analysis in outcrops and drillings. The geoelectrical profiles give us up to ~120 m deep insights into the structure, thickness and distribution of the rock-avalanche deposits, the interactive processes with the lake water and sediments, and the paleotopography. Sediments exposed in outcrops show water-escape structures at the front of the rock avalanche. The data further allow for ERT-calibration at 7 different sites, where it is possible to distinguish materials (rock avalanche, bedrock, lake clay, mixed sediments) and interactive processes of the rock avalanche with the lake and substrate (bulldozing, bulging, overriding of secondary lobes). Here we show how complementary geophysical, geomorphological and sedimentological applications on terrestrial deposits provide detailed insights into multiple effects of impacting of a rock avalanche onto a lake.
A glimpse of the Anthropocene captured by environmental tracers in the groundwater of a fractured aquifer
Authors: Chatton Eliot , Labasque Thierry , Aeschbach Werner , Vergnaud Virginie , Guillou Aurélie , Aquilina Luc
Published: March 2020

The Anthropocene is an epoch in Earth’s history that has been proposed to characterise the global impact of human activities on the Earth's atmosphere, biosphere, hydrosphere, geosphere, i.e. the Critical Zone.

Just as for past climates, the signature of these anthropogenic impacts are recorded by environmental tracers dissolved in groundwater that could provide a better understanding of groundwater flows, residence time and mixing thus providing information on this major water resource both in terms of quantity and quality.

In this study, we use dissolved gases (CFCs, SF6, 4He, 14C, noble gases and VOCs) and groundwater chemical composition as environmental tracers to unveil insights of the Anthropocene in a fractured aquifer in the northwest of France. We analyse the impact of groundwater abstraction on residence time and excess air composition. We evidence the influence of climate change through recharge temperature. We also quantify the appearance of anthropogenic compounds over the last decades.

These observations enable us to define precisely the anthropogenic limits and distribution within groundwater and thus to gain a better picture of the groundwater resource resilience potential in the future.
Subthermocline eddies in the Philippine Sea in 2017 to 2018
Authors: Shin Chang-Woong , Lee Jae Hak
Published: March 2020

In the tropical western Pacific, both of the North and South Equatorial Currents terminate with meeting oceanic continents and form the Equatorial Counter Currents and the Low Latitude Western Boundary Currents (LLWBC). There is the undercurrents that flow opposite direction below the surface currents. The North Equatorial Undercurrents flow eastward having four zonal axis which is related with the LLWBC. Below the southward flowing Mindanao Currents branched from the North Equatorial Currents, there is Mindanao Undercurrents which flow northward that is thought to be a continuation of the New Guinea Coastal Undercurrents passed through the equator. In addition to these complex current systems in the Philippine Sea, eddies exists below the thermocline. Long term current mooring data showed signals of existence of the subthermocline eddies (SE). It is inferred that the SEs are formed by the interaction between the surface currents and the undercurrents and the bottom topography. Although the SE plays an important role in the heat exchange and the intermediate water mixing, it is difficult to observe and there is still much to be revealed. This study was conducted using the CMEMS (COPERNICUS Marine and Environment Monitoring Service) gridded objective analysis fields of temperature and salinity which are produced using profiles from the in-situ real time database of the global in-situ center. The gridded data was rearranged into isopycnal surfaces and analyzed for the distribution and movement of SE. The distributions of the isopycnal layer thicknesses were presented based on the core density of the North Pacific Intermediate Water and Antarctic Intermediate Water and compared to the previous studies.
Variability and changes of the stratospheric large scale circulation and possible consequences for ozone streamer events
Authors: Lisa Küchelbacher , Dominik Laux , Bittner Michael
Published: March 2020

Planetary waves (PW) dominate the meridional Brewer-Dobson circulation in the stratosphere and therewith, the large-scale mass transport of ozone. As PW break, ozone poor air masses are irreversibly mixed into mid-latitudes. Due to the disproportionate warming of the North Pole, an increase in PW activity (PWA) is expected. This should also have consequences for ozone streamer events.

We derived the PWA of ERA 5 and Interim Reanalysis temperature from ground level up the mesosphere. We identify Ozone-streamer events with a statistical based approach on the basis of total column concentration measured by GOME-2. We deconvoluted the time series of the PWA and the ozone-streamer events with the empirical mode decomposition method (EMD). Moreover, we developed a simple spectral model of the meridional wind shear on the basis of PW. This model serves as a measure of the atmospheric instability in the stratosphere.

As we deconvolute the PWA with the EMD we find signatures of QBO, ENSO and solar cycles and quantify their contributions. As PW dominate the circulation in the stratosphere, it appears to be a coherent consequence that ozone streamers are modulated on the same time scales as the PWA.With the spectral model of the meridional wind shear we find regions in the atmosphere, where PW are most likely to break. As a result there is an increased meridional transport of air masses, in particular of ozone. This is why ozone streamers occur most frequently at the transition zones from ocean to continent; strongest from North Atlantic to Europe. Moreover, we find significant long-term trends of the PWA in the stratosphere. Due to the increase of the PWA in the stratosphere, ozone streamer events are likely to occur more often in the future.