bluuebunny/crossref_metadata_2025 huggingface dataset:
Hyperspectral A-band retrievals of cloud droplet number concentration from OCO-2
Authors: Richardson Mark , Lebsock Matthew D. , Stephens Graeme L.
Published: March 2020

NASA’s Orbiting Carbon Observatory-2 (OCO-2) includes a hyperspectral (Dl~0.02 nm) oxygen A-band sensor, and the depth of its absorption features is related to the photon path length. Photon path length increases above a cloud if it is lower (i.e. higher Ptop), and within a cloud if its droplets are farther apart (i.e. lower N­d). This is a novel approach for retrieving Nd that is independent of MODIS-like retrievals, which take an a priori vertical cloud structure and assume that non-adiabatic processes such as precipitation or entrainment affect clouds uniformly. Our last product, OCO2CLD-LIDAR-AUX, used CALIPSO Ptop to help separate the above- and within-cloud path length. Here we show progress in an updated OCO-2 only retrieval of marine boundary layer clouds, including using neural networks for cloud identification and phase classification, additional retrieval of re, and how cloud vertical structure can bias retrieved Ptop and Nd. Successfully addressing this bias would provide a new and independent Nd retrieval that should capture changes due to non-adiabatic processes, and therefore provide a new test of aerosol cloud effects.
Inverting stop-flow leaching experiments and detection of physical and chemical non-equilibria
Authors: Zhou Lian , Lassabatere Laurent , Hanna Khalil
Published: March 2020

Flow heterogeneity strongly impacts mass transport. In particular, the presence of water fractionation into mobile and immobile water fractions may affect pollutant sorption to soil particles. Indeed, before sorbing, the pollutants need to diffuse from mobile water to immobile water fractions. In a previous study, we investigated the possibility of stop-flow experiments for the detection of physical and chemical non-equilibria. A sensitivity analysis proved that it was possible to detect the two types of non-equilibria. The effect of parameters related to physical  (mobile water fraction and solute exchange rate)  and chemical (chemical kinetics) non-equilibria were varied and related impacts on the shape of the breakthrough curves were characterized for stop-flow experiments. However, the feasibility of inverting procedures was not investigated at all. In particular, the estimation of these parameters by fitting the model to real experimental data (with noise) may be feasible but may also bring some uncertainty with biased and non-unique estimates. In this study, using both numerically generated data and experimental data, we characterize the estimate uncertainty and equifinality. This study will help in optimizing the inverting procedure for the design of more robust and less biased estimates and the quantification of physical and chemical non-equilibria parameters.
On the seasonal development of sea-ice microalgal communities and a forecast for downstream effects of ongoing sea-ice decline
Authors: Van Leeuwe Maria , Fenton Mairi , Davey Ee , Annett Amber , Meredith Mike , Stefels Jacqueline
Published: March 2020

The Western Antarctic Peninsula (WAP) is one of the fastest warming oceanic regions on earth, with a recorded increase in winter temperature of 6˚C since 1950. Coinciding with the warming of shelf water the amount of sea ice that is formed over winter shows a general declining trend. The consequences of this decline for biogeochemical processes are poorly understood. Microalgal composition and production was studied in sea ice in four consecutive winters from 2013-2016, at Ryder Bay, located at the southern part of the WAP.

Sea ice was sampled over the period of ice formation in autumn until ice melt in spring. Microalgal composition was studied by means of their pigment signature and microscopy; production capacity was studied by fluorescence analyses and C13-incorporation studies. At the onset of ice formation, the sympagic algal communities consisted of a mixture of species. Over the course of winter, heterotrophic flagellates became dominant. In spring, biomass increased strongly in the bottom layers and reached a maximum concentration of more than 700 µg Chl.a l-1 in December 2014. These communities were mainly diatom-dominated. In spring, algal samples were also taken from under ice and pelagic communities. For the first time, we are able to present data that show essential differences in seeding potential of sea ice for diatom and flagellate species. The downstream effects of predicted changes in sea-ice cover and associated ice-algal communities on biogeochemical exchange processes with the marine ecosystem will be discussed.
Effect of the Ushant SST front on regional weather forecasting in the event of anticyclonic events
Authors: Orain Francoise , Bouin Marie-Noelle , Redelsperger Jean-Luc , Garnier Valérie
Published: March 2020

The representation of the Ushant front in Meteo-France numerical models is not accurate. The aim of this study is to evaluate the impact of a better representation of this front derived from SST satellite observation data on the weather forecast in Brittany.

 

The study consisted in finding and selecting cases from 2016 to 2018 where the Ushant front was present in satellite SST analysis (high spatial and temporal resolution ) with differences in weather pattern between North and South Brittany. Then compare this to the operational Arome model (Meteo France non hydrostatic model).

Situations of disagreement between the model and the observations were selected. Some weather forecast simulations with Mesonh model (very close to Arome) were performed on these cases with a better definition of the Ushant front. We present some results.

 

 
On wind-driven energetics of subtropical gyres
Authors: Dewar William K. , Jamet Quentin , Deremble Bruno , Wienders Nicolas
Published: March 2020

The flow of energy in the wind-driven circulation is examined in a 
combined theoretical and numerical study. Based on a multiple scales 
analysis of the ocean interior, we find the mesoscale field is strongly 
affected by the ventilated thermocline, but no feed back from the eddies 
to the large scale is found.  We then analyze the western boundary 
region arguing that the associated currents divide between coastal jets, 
which conserve mean energy, and open ocean, separated jet extensions
where the mesoscale is energized by the mean field.   It is the 
separated jet zone where the primary loss of general circulation energy 
to the mesoscale occurs.  Connections to the `Thickness Weighted 
Average' form of the primitive equations are made which support the 
differing roles of the eddies in these regions.  These ideas are then 
tested by an analysis of a regional primitive equation 1/12-degree 
numerical model of the North Atlantic. The predictions of the theory are 
generally supported by the numerical results.  The one exception is that 
topographic irregularities in the coastal jet spawn eddies, although 
they contribute modestly to the energy budget.  We therefore conclude 
the primary sink of wind input into the mean circulation is in the 
separated jet, and not the interior.  The analysis also shows
wind forcing is much smaller than the interior energy fluxes. Thus, the 
general circulation is characterized as recirculating energy in the 
manner of a Fofonoff gyre.
The response of Østre Svartisen Icefield, Norway, to 20th/21st century climate change
Authors: Boston Clare M. , Lovell Harold , Weber Paul , Chandler Benjamin M. P. , Barrows Timothy T. , Davies Bethan J.
Published: March 2020

Recently deglaciated forelands contain a wealth of geomorphological and sedimentological data that can provide key information about glacier-climate relationships. Mountain glaciers are particularly important indicators of climate change due to their short response times, which means that their forelands provide a sub-decadal record of changes in glacier size and climate-related dynamics. In this contribution, we examine the glacial geomorphological and sedimentological record at Østre Svartisen, an Arctic plateau icefield in Norway, and discuss temporal variations in glacier dynamics and processes of sediment deposition in response to climate warming since the Little Ice Age (c.1750). We focus specifically on the northeastern sector of the icefield and include two separate cirque/valley glaciers immediately to the north. Differences in landform-sediment assemblages are apparent both within and between forelands relating to changes in topography as well as glacier dynamics. Satellite images and old aerial photographs are also used to investigate differences in the rates of glacier demise across the study area. This evidence enables links to be made between landform generation, bed morphology, glacier dynamics, and glacier response to climate change, which furthers understanding of plateau icefield and outlet glacier behaviour in a warming climate.
The AuScope Geochemistry Laboratory Network
Authors: Prent Alex , McInnes Brent , Gleadow Andy , O'Reilly Suzanne , Boone Samuel , Kohn Barry , Matchan Erin , Rawling Tim
Published: March 2020

AuScope is an Australian consortium of Earth Science institutes cooperating to develop national research infrastructure. AuScope received federal funding in 2019 to establish the AuScope Geochemistry Laboratory Network (AGN), with the objective of coordinating FAIR-based open data initiatives, support user access to laboratory facilities, and strengthen analytical capability on a national scale. 

Activities underway include an assessment of best practices for researchers to register samples using the International Geo Sample Number (IGSN) system in combination with prescribed minima for meta-data collection. Initial activities will focus on testing meta-data schema on high value datasets such as geochronology (SHRIMP U-Pb, Curtin University), geochemistry (Hf-isotopes, Macquarie University) and low-temperature thermochronology analyses (fission track/U-He, University of Melbourne). Collectively, these datasets will lead to a geochemical data repository in the form of an Isotopic Atlas eResearch Platform that is available to the public via the AuScope Discovery Portal. Over time, the repository will aggregate a large volume of publicly funded geochemical data, providing a key resource in quantitatively understanding the evolution of Earth system processes that have shaped the Australian continent and its resources.
Eurovolc Trans National Access service: design and implementation
Authors: Reitano Danilo , Cacciola Lucia , Puglisi Giuseppe , Somataridou Vasiliki , Spampinato Letizia , Zalachori Aspasia
Published: March 2020

Trans-national Access (TA) is the best way to access, for free, to facilities (volcano observatories, laboratories, pool of instruments, etc.) offered in the framework of the EUROVOLC Consortium project. The strategic objective of this activity is to build strong connections between volcanological research infrastructures (providers) and users. Single researchers or research teams can choose facilities located in a different country where they are based. 

In order to achieve this goal, a custom tool built within the EUROVOLC data portal, has been planned and developed. The tool has based on a general design performed in the framework of the EPOS project and according to specific service requirements. It has been used to manage the second open research call offering Trans-national Access organized by the EUROVOLC community.
Interactions between a calcium scaling inhibitor, geothermal fluids, and microorganisms – Results of in situ monitoring in the molasse basin and laboratory experiments
Authors: Otten Christoph , Schulz Beate , Teitz Sebastian , Eichinger Florian , Seibt Andrea , Kuhn Dietmar , Würdemann Hilke
Published: March 2020

The economic and technical efficiency of geothermal plants is often impaired by corrosion, scaling and biological fouling. In Germany, the highly saline fluid of the North German Basin is known to cause severe corrosion. Meanwhile geothermal plants in the southern Molasse Basin, one of the most extensively exploited geothermal regions in Germany, are troubled by carbonate scaling. One possible solution is the employment of a scale inhibitor. A novel scaling inhibitor is evaluated in field- and laboratory tests. This inhibitor consists of a polysaccharide backbone structure and branches of polyacrylic- and maleic acid copolymer.

The laboratory tests with different scaling inhibitor concentrations were designed to observe the biodegradation of the scaling inhibitor in an anaerobic environment similar to the conditions found in heat exchangers of geothermal plants. The concentration of inhibitor was quantified by UV/VIS and liquid chromatography (LC). Molecular biological techniques (PCR, DGGE, Microbiome analysis) were used to characterize the biocenosis on metal surfaces and in fluids of the experiments.

During the experiment the concentration of inhibitor decreased up to  3 % of the initial concentration. The formation of methane and acetate was observed which indicates a biological degradation by acetoclastic methanogenesis. Hydrogen formation was observed in setups containing steel coupons. This implies that hydrogen is primarily formed by corrosion processes and in tests with active microorganisms hydrogen was consumed completely. Various fermentative bacteria classified as Clostridia and Firmicutes as well as methanogenic archaea were identified. In some experiments sulfate reducing bacteria were found. Those are well known to catalyze corrosion processes.

Results of field experiments in a bypass system as well as microbiological monitoring of the inhibitor application in geothermal plant located in the molasse basin will be presented.
VirES for Aeolus - Online visual analysis of Aeolus data
Authors: Santillan Daniel , Schiller Christian , Meringer Markus , Reitebuch Oliver , Weiler Fabian , Huber Dorit
Published: March 2020

VirES (Virtual Workspace for Earth Observation Scientists) is a highly interactive data manipulation and retrieval interface for specific ESA Earth Explorer mission products. It is under evolutionary/operational maintenance by EOX since 2016 for the Swarm geomagnetic mission and starting 2018 it has been extended for ESA's Earth Explorer Aeolus wind profiling mission.

The goal of this service is to provide users with intuitive and easy access to the mission’s level 1B, 2A, 2B and several auxiliary data products.
In order to be able to understand, manage, visualize and analyze the new and complex data produced by the satellite a close collaboration between project partners DLR and DoRIT and EOX as industry partner has been established.

VirES for Aeolus provides means for multi-dimensional visualization, interactive plotting and analysis and stands for a modern concept of extended access to Earth Observation (EO) data. It supports novel ways of data discovery, visualization, filtering, selection, analysis, snapshotting and downloading.

The service was designed with a focus on the following areas of application:
Quality analysis, calibration and validation, scientific exploitation, modeling and prediction.

Specialized solutions have been developed to allow visualization of the complex and large datasets in an interactive and intuitive way. The tool has been further refined and improved since the Aeolus launch August 2018 in close collaboration with its users and project partners. VirES for Aeolus  offers easy access to the mission data through ordinary web browsers  via  without the need for installing any specialized software.
Influence of changing land use/cover and land management on wind erosion potential in southwestern Iran
Authors: Nikseresht Fahime , Rainer Schulin
Published: March 2020

Wind erosion is one of the main factors of soil degradation and air pollution in arid and semiarid regions. In recent years, dust storms have become ever more important sources of air pollution in large areas of Iran. Dust storms previously were confined to the summer season and to western Iran. Nowadays, dust storms occur during eight months of the year and extend to the central regions and the entire south of Iran. This is causing increasing problems for the residents of the affected areas, threatening their health and impairing social, economic and agricultural activities. Ahvaz, the capital of Khuzestan Province, is the city that is most seriously affected by these problems in Iran.

Wind erosion is a multifaceted phenomenon influenced by a variety of factors. One of these factors that has changed considerably in recent time in Iran is land use/cover and land management. To investigate the impact of these changes on wind erosion potential in southwestern Iran we applied an empirical model of the Iran Research Institute of Forest and Rangeland (IRIFR) to remote sensing data extracted from Landsat ETM+ and Landsat 8 imagery of 2010 and 2019. Relationships between changes in wind erosion and land use/cover were determined by cross-tabulation, combining the original spectral bands with synthetic bands and using Maximum Likelihood classification.

The results indicate major changes in wind erosion potential over the last decade in the study area. Interestingly, while areas with a low, medium, and high sediment yield potential decreased, areas with a very high sediment yield potential have increased. Increasing soil erosion potential was primarily related to the conversion of rangeland to agricultural cropland Moreover, the results indicate an increase in desertification in the study area which is also a clear evidence of increasing in soil erosion.
Long time-series of export fluxes in the western Ross Sea (Antarctica)
Authors: Giordano Patrizia , Giglio Federico , Ravaioli Mariangela , Capello Marco , Cutroneo Laura , Dunbar Robert B. , Mucciarone David A. , Smith Walker O. , Manno Clara , Langone Leonardo
Published: March 2020

The export of particulate organic carbon (POC) from the sea surface is an essential part of the biological pump. Export fluxes are the result of what is produced in surface water and how much is consumed during particle sinking in the water column. In the Ross Sea, fluxes of POC and total mass are well correlated implying that particle fluxes are dominated by biogenic debris.

Here, we report new and reference data of vertical particle fluxes to below the productive layer obtained on decadal time scales (1990-2017) by automatic sediment traps tethered to moorings in the western Ross Sea (Antarctica). Compilation of all data available in the Ross Sea (23 sites, >1000 samples) shows that annual POC fluxes to below 200 m average 4.4±3.3 g C m-2  y-1. Particle fluxes are relatively low when primary production is high (spring-summer) followed by enhanced sedimentation in late summer-fall. The high degree of decoupling between production and sedimentation is unusual compared to records of Antarctic Peninsula and may represent low grazing rates. Furthermore, data exhibit a large interannual variability and a decreasing trend over time, with a clear shift after 2000. Do the reduced export fluxes depend on lower biological production, enhanced OM consumption, or other processes (e.g., lateral transfer of biogenic particles outside the study area)?

Satellite observations allow us to reconstruct the seasonal and interannual change of chlorophyll biomass, and sea ice extent and duration. Water temperature recorded at mid-depth is used to monitor the different intrusion over time of CDW, the main driver of temporal variability of Fe supply for the Ross Sea. Time series of particle fluxes, chlorophyll, sea ice cover and mid-depth temperature will be compared in order to test if the recent reduction of downward particle fluxes depend on primary production changes.
Characteristics of induced seismicity during hydraulic stimulations
Authors: Dresen Georg , Bentz Stephan , Kwiatek Grzegorz , Martínez-Garzón Patricia , Bohnhoff Marco
Published: March 2020

Near-realtime seismic monitoring of fluid injection allowed control of induced earthquakes during the stimulation of a 6.1 km deep geothermal well near Helsinki, Finland. The stimulation was monitored in near-real time using a deep seismic borehole array and series of borehole stations. Earthquakes were processed within a few minutes and results informed a Traffic Light System (TLS). Using near-realtime information on induced-earthquake rates, locations, magnitudes, and evolution of seismic and hydraulic energy, pumping was either stopped or varied. This procedure avoided the nucleation of a project-stopping red alert at magnitude M2.1 induced earthquake, a limit set by the TLS and local authorities. Our recent studies show that the majority of EGS stimulation campaigns investigated reveal a clear linear relation between injected fluid volume, hydraulic energy and cumulative seismic moments suggesting extended time-spans during which induced seismicity evolution is pressure-controlled. For most projects studied, the observations are in good agreement with existing physical models that predict a relation between injected fluid volume and maximum seismic moment of induced events. Some EGS stimulations however reveal unbound increase in seismic moment suggesting that for these cases evolution of seismicity is mainly controlled by stress field, the size of tectonic faults and fault connectivity. Transition between the two states may occur at any time during injection, or not at all. Monitoring and traffic-light systems used during stimulations need to account for the possibility of unstable rupture propagation from the very beginning of injection by observing the entire seismicity evolution in near-real-time and at high resolution could possibly provide a successful physics-based approach in reducing seismic hazard from stimulation-induced seismicity in geothermal projects.
A novel method for stable isotope measurement of gaseous elemental mercury
Authors: Irei Satoshi
Published: March 2020

Here, we introduce a new methodology developed for highly precise stable mercury isotope ratio (δHg) analysis: the sampling method collecting sufficient amount of gaseous elemental mercury (GEM) from air within 24 h or less and the extraction method effectively converting the collected GEM to Hg2+ in less than 10 mL of acidified solution.

A big gold-amalgam trap (BAuT), which has approximately 11 times larger inner diameter of the tube and more gold-amalgam granular than a conventional gold-amalgam trap, was designed for quick and effective sampling of GEM in a short time period. A 24-h sampling demonstrated that the collection efficiency was higher than 99.9% under the flow rate of 55 LPM. Prior to the extraction the collected GEM by BAuT was pre-concentrated to a conventional gold-amalgam trap to reduce the dead volume.

The GEM pre-concentrated was transferred into a four side sealed 2L Tedler bag with a PTFE stopcock by heating the gold-amalgam trap to 600 ºC for ~ 4 min under the 0.5 LPM flow of Hg-free air. Prior to this transfer 5mL of 0.5~40% (v/v) reversed aqua resia or RAR (hydrochloric acid: nitric acid = 1:2) was pre-introduced into the bag. The bag with GEM and RAR was left for the conversion of GEM into the stable state in the solution (i.e., Hg2+). The solution recovered was then analyzed by multi collector-ICP-MS for the Hg concentration and δHg.

Results with a standard reference material showed that the recovery from the test with 10% RAR and the extraction duration of 8 days was the highest, 97%, with the 5% of recovery for the residual GEM in the gas-phase. The δHg analysis for five isotope ratios exhibited that the accuracy was between 0.01 and 0.3 ‰. Results from the analytical tests of ambient GEM using this methodology will be discussed.
The Nonlinear Nature of Atmospheric Chemistry
Authors: Prather Michael
Published: March 2020

When scientific or policy-relevant questions involve atmospheric chemistry, one often hears "nonlinear" being invoked to describe the problem in a vague unspecific way.  The precise nature of the nonlinearity is never delineated, and we are left with the fuzzy impression that nonlinear problems are difficult to solve or have no simple answer.  For differentiable systems, nonlinear behavior can be expressed through a Taylor expansion whereby any of the 2nd order terms (x2, y2 or xy) are the first nonlinear parts.  In this lecture we shall explore a range of scientific discoveries or developments in atmospheric chemistry where the nonlinear nature was critical to understanding the problem.  I select a set of problems worked on by many colleagues and myself over the last four decades.  These include:  multiple solutions in stratospheric chemistry; depletion of ozone; numerical methods for tracer transport; our developing understanding of methane; chemical feedbacks and indirect greenhouse gases; and finally the rich heterogeneity of gases that drives tropospheric chemistry. I hope to convince you that by embracing the nonlinear nature of atmospheric chemistry and understanding when it is important and when it is not, we can advance the field.   
Creating Impact through COST Action networks
Authors: Karaca Deniz
Published: March 2020

The European Cooperation in Science and Technology (COST) has a very important role in fostering the establishment of scientific excellence in many fields such as: Geoscience, Planetary and Environment. Over the years, COST Actions have contributed to European competitiveness through their many contributions to standardisation bodies, the small to medium enterprises originating from COST networks and the transfer of results to the European industry.

A series of COST Actions in the field of Meteorology developed global data transfer standards on the basis of infra-networks in collaboration with the World Meteorological Organization advantaging the competitiveness of the industrial participation. Such achievements include harmonisation of UV-index, developing operational programmes, services, networks and phenological responses to climate on a Pan-European Scale and were recognised by the Intergovernmental Panel on Climate Change.  European Centre for Medium-Range Weather Forecasts (ECMWF) is another good example as a result of an Action through its evolution to become an independent intergovernmental organisation with its own structure and headquarters supported by 34 states.

The key findings of COST networks not only contribute to the atmospheric drivers on the impacts of the global change but also increase the understanding of the function of marine ecosystems and its response to climate change. A number of Actions in the field of marine science have developed observing system to integrate the dynamic response of sea-level variations to combine effects of various natural drivers into multi-criteria tools by bringing together oceanographers and meteorologists. These developments urged for an integrated implementation of technology in sea-level monitoring, and for further international agreements on data storage and exchange.

A wide range of disciplines, evaluating the complex interactions between the oceans and the global change, geosciences, natural resources management, environmental monitoring, biogeochemical cycles,  ecology, hydrology, natural disasters, water cycle have well undertaken through COST Action networks. The results were published in high impact journals, guidelines were represented in position papers leading to new research projects on a global scale.  Participation in COST leads to significant results and follow-up in terms of number of proposals submitted for collaborative research in Horizon 2020, with a striking success rate of 33% (the Horizon 2020 average is at 12.2%). By enabling researchers and innovators from all career levels to network, COST connects complementary funding schemes, facilitating the entry of promising young talents into these schemes.

COST is committed to reinforcing its role as the leading networking instrument in the European Research Area (ERA), while creating even higher tangible impact on society.
Numerical Simulation of Debris Flow incurred by Earth Dam Collapse
Authors: Lee Sungsu , Lee Joo Yong , Lee Selugi
Published: March 2020

More than 70% of domestic reservoirs in Korea are earth dams that are more than 50 years old, and until recently, large and small reservoirs have repeatedly collapsed and resulted in damages. However, most of the domestic and foreign techniques of reservoir collapse simulation, which are used as the techniques for damage prediction, are not only based on two-dimensional flow analysis, but are also performed by ignoring the dam collapse process. The dimensional flow, of course, has limitations that do not reflect the effect of the soil mass at the beginning of the collapse. To compensate for the limitations, we used computational fluid dynamics to simulate the collapses of reservoir collapses with three-dimensional Navier-Stokes equations and assumed the multiphase flow technique of soils as three phases of soil, suspension, and air. . In addition, the Herschel-Bulkely fluid was modified to take into account the water content and concentration of the soil, and the coulomb-viscoplastic fluid was introduced to simulate the nonlinear viscosity of the initial soil breakdown by considering the interaction inside the soil. Using 3D simulation techniques, 3D simulation was performed on the assumption of total collapse and partial collapse of the mountain reservoir collapse in 2013. Prediction and comparison of inundation ranges were made and comparison with the inundation area created through previous studies. This research was supported by a grant (2018-MOIS31-009) from Fundamental Technology Development Program for Extreme Disaster Response funded by Korean Ministry of Interior and Safety(MOIS).
Simulations of the Basal Forces Generated by Dam Breaks: Comparison Between Continuous and Discrete Models
Authors: Martin Hugo , Viroulet Sylvain , Peruzzetto Marc , Mangeney Anne
Published: March 2020

Numerical simulations of granular flows have been widely developed and used during the last two decades. Depending on the situation and scale of the simulations, different methods are used, each having specific pros and cons. Among them, three main methods can be distinguished such as; discrete, continuous or depth-averaged approach. At the laboratory scale, discrete approach consists of representing all the grains and contacts. When the amount of grains are important enough to consider the granular medium as an effective fluid, Navier-Stokes simulations can be performed using an appropriate rheology for the fluid, like the -rheology. However, when simulations are performed on geophysical scales none of these two methods can be used because of the enormous computation time required to solve them. To cope up with this issue, the depth-averaged approachs wherein the normal velocities are neglected, considerably reduce the computation time.

Even though all these models have been widely used, it is not clear exactly what information can be extracted about the forces exerted to the ground. These forces represent a new way of visualising a geophysical granular flow. Indeed, very recently, the recorded seismic signals from geophysical granular flows were used to interpret these forces. As a result, seismic data can be used to extract information on the flow dynamics which was missing due to the difficulties of direct observation (ashes, dust, etc…). Being able to compute and interpret the forces generated by a granular flow on
the ground represents a new way for calibrations of numerical methods and is a key point in analysing seismic data generated by granular flows and subsequently in understanding the landslide dynamics at the geophysical scale.

After a quick presentation of the numerical differences between the three models, we present comparisons between discrete, continuous [1] and depth-averaged [2] models. Besides, we put forward this study on the values taken by the forces generated on the ground during the evolution of granular dam breaks. Although, these three methods give relatively the same final deposits, in good agreement with the experiments, we observe they lead to very different dynamics in terms of flow acceleration, forces and histories.

1. http:basilisk.fr.

2. A. Mangeney et al., JGR 112 F02017 (2007)
Interactions of extreme river flows and sea levels for coastal flooding
Authors: Robins Peter , Harrison Lisa , Elnahrawi Mariam , Lewis Matt , Coulthard Tom , Coxon Gemma
Published: March 2020

Coastal flooding worldwide causes the vast majority of natural disasters; for the UK costing £2.2 billion/year. Fluvial and surge-tide extremes can occur synchronously resulting in combination flooding hazards in estuaries, intensifying the flood risk beyond fluvial-only or surge-only events. Worse, this flood risk has the potential to increase further in the future as the frequency and/or intensity of these drivers change, combined with projected sea-level rise. Yet, the sensitivity of contrasting estuaries to combination and compound flooding hazards at sub-daily scales – now and in the future – is unclear. Here, we investigate the dependence between fluvial and surge interactions at sub-daily scales for contrasting catchment and estuary types (Humber vs. Dyfi, UK), using 50+ years of data: 15-min fluvial flows and hourly sea levels. Additionally, we simulate intra-estuary (<50 m resolution) sensitivities to combination flooding hazards based on: (1) realistic extreme events (worst-on-record); (2) realistic events with shifted timings of the drivers to maximise flooding; and (3) modified drivers representing projected climate change.

For well-documented flooding events, we show significant correlation between skew surge and peak fluvial flow, for the Dyfi (small catchment and estuary with a fast fluvial response on the west coast of Britain), with a higher dependence during autumn/winter months. In contrast, we show no dependence for the Humber (large catchment and estuary with a slow fluvial response on the east coast of Britain). Cross-correlation results, however, did show correlation with a time lag (~10 hours). For the Dyfi, flood extent was sensitive to the relative timing of the fluvial and surge-tide drivers. In contrast, the relative timing of these drivers did not affect flooding in the Humber. However, extreme fluvial flows in the Humber actually reduced water levels in the outer estuary, compared with a surge-only event. Projected future changes in these drivers by 2100 are likely to increase combination flooding hazards: sea-level rise scenarios predicted substantial and widespread flooding in both estuaries. However, similar increases in storm surge resulted in a greater seawater influx, altering the character of the flooding. Projected changes in fluvial volumes were the weakest driver of estuarine flooding. On the west coast of Britain containing many small/steep catchments, combination flooding hazards from fluvial and surges extremes occurring together is likely. Moreover, high-resolution data and hydrodynamic modelling are necessary to resolve the impact and inform flood mitigation methodology.
Hydrogeological modelling applied to mineral exploration
Authors: Plagnes Valérie , Quirt David , Benedicto Antonio , Ledru Patrick
Published: March 2020

A multidisciplinary approach combining a groundwater hydrogeochemical survey and a 3D groundwater flow model was applied to unconformity-type U mineralization in the Athabasca Basin (Canada), as a new supplementary guide for uranium exploration. This approach was developed at the McClean Lake Operation site (eastern part of the basin), where several uranium deposits have already been mined and others are not yet mined. The goal of ongoing exploration in this area is to find new deposits in the vicinity of known deposits to facilitate possible future mining.

Groundwater levels were measured in 60 wells and groundwater sampling was carried out in 31 of these wells, some of these wells are screened in bedrock below the unconformity and others in sandstones above the unconformity. Among these wells, we included 4 wells located near a known ore body (SABRE sector) to better evaluate the potential of our approach to identify the presence of U mineralization.

The results show that in this study area, the U concentration and saturation index maps are not good indicators of U mineralization as U concentrations are very low for all samples due to the strong reducing conditions. However, 5 of the wells show remarkable geochemical composition: the highest total dissolved solids, high Cl concentration and strong relationships between Cl and concentrations of Na, K, Mg, Ca, Fe as well as Sr and Ba, suggesting that these ions may have come from a common source. Four of these five samples belong to the deposit of the SABRE sector, but the fifth well is located upstream of this region, far from a known ore body. A 3-D groundwater model was developed for the entire basin and the flow path ending at this well screen was traced to its source by reverse particle tracking. In the structure of the groundwater model, graphite-rich fault zones are considered the main geological structures controlling groundwater flows. The up-gradient geochemical plume deciphered from the backflows allows the identification of new exploration targets. This approach appears to be an appropriate method for prioritizing locations for future exploration drilling.
Drought legacy effects on post-fire vegetation dynamics in a Mediterranean shrubland of Central Spain
Authors: Parra Antonio , Hinojosa María Belén , Torres Iván , Moreno José Manuel
Published: March 2020

Post-fire regeneration often occurs under water scarcity conditions in Mediterranean ecosystems. This fact is likely to be more frequent in the future, as climate change projections for the Mediterranean show increased temperature and decreased rainfall, as well as higher fire weather danger. Therefore, studying how vegetation responds to fire and drought is critical for anticipating vegetation vulnerability to global warming. Here, we present the results of a manipulative field study in a Mediterranean shrubland of Central Spain in which 4 drought treatments were imposed before and after carrying out an experimental burning of the treated plots: natural rainfall, historical rainfall regime (2 months summer drought per year), moderate drought (ca. 25% rainfall reduction from historical records, 5 months drought), and severe drought (ca. 50% rainfall reduction, 7 months drought). We monitored the plant community during the first 4 years after fire under the drought treatments followed by additional 6 years once such treatments had ceased. We found that drought significantly reduced density, cover, and size of seeder species during the first post-fire years under treatment. In contrast, resprouter species were virtually unaffected. As a whole, the changes in woody species dynamics resulted in a community ‘herbalization’, which was richer and more diverse, but probably more prone to a new fire. Moreover, we found that the drought effects on the community, and especially on the seeders, were maintained various years after all plots started receiving natural rainfall. 10 years after the fire, the legacy effect of the drought had been diluted, although some effects on plant density or cover in certain seeder species were still present. Overall, this means that what happens during the first few years after fire is extremely important for vegetation recovery, and that the effects of a long drought can persist over various years, and likely over a whole fire cycle.
Analysis, estimation and prediction criteria for damage from geo-hydrological events: a top-down approach
Authors: Boschini Ilaria , Zambrini Federica , Menduni Givanni , Molinari Daniela , Bignami Daniele
Published: March 2020

A rapid evaluation of flood damage is strategic for the good success of emergency management activities after a natural disaster. A method for the estimation of economic damage is developed considering the impact of hydrogeological phenomena with meteoclimatic forcing over settlements, industrial and rural areas and commercial activities.

Damage estimation is a very current research field, but the available methods are far from being effective in the period immediately following the event. This is due particularly to the intrinsic complexity and variability of the damage process and the lack of reliable and consistent damage measures across areas at least at the regional scale.

This work proposes a national scale first approximation correlation between vulnerated area and expected damage. The relationship, expressed in terms of power law, is calibrated on a huge number of single damage records collected by the Italian government all through the country during flood and landslide events in the last 6 years. Data have been grouped following the type of flood. Records come from official data provided by government commissioners in charge of emergency management, according to the national law. Validation, carried out on an independent data set, is quite encouraging and provides indications for further developments.
Thermal signature of the lithosphere below sedimentary basins in extensional, compressive and transform settings
Authors: Scheck-Wenderoth Magdalena , Bott Judith , Cacace Mauro , Anikiev Denis , Gomez Dacal Maria Laura , Spooner Cameron , Gholamrezaie Ershad
Published: March 2020

The configuration of the lithosphere below sedimentary basins varies in response to the basin-forming mechanism, the lifetime of the causative stress fields and the lithological heterogeneity inherited from pre-basin tectonic events. Accordingly, the deep thermal configuration is a function of the tectonic setting, the time since the thermal disturbance occurred and the internal heat sources within the lithosphere. We compare deep thermal configurations in different settings based on data-constrained 3D lithosphere-scale thermal models that consider both geological and geophysical observations and physical processes of heat transfer. The results presented come from a varied range of tectonic settings including: (1) the extensional settings of the Upper Rhine Graben and the East African Rift System, where we show that rifts can be hot for different reasons; (2) the North and South Atlantic passive margins, demonstrating that magma-rich passive margins can be comparatively hot or cold depending on the thermo-tectonic age; (3) the Alps, where we find that foreland basins are influenced by the conductive properties and heat-producing units of the adjacent orogen; and (4)the Sea of Marmara, along the westernmost sector of the North Anatolian Fault Zone, that suggest strike-slip basins may be thermally segmented.
A framework for causality under data assimilation
Authors: Chakraborty Nachiketa , van Leeuwen Peter Jan , de Caria Michael , Pulido Manuel
Published: March 2020

Time varying processes in nature are often complex with non-linear and non-gaussian components. Complexity of environments and processes make it hard to disentangle different causal mechanisms which drives the observed time-series. It also makes it harder to make forecasts. The standard ways of studying causal relation in the geosciences which includes information theoretic measures of causation as well as predictive framework have deficiencies when applied to non-linear dynamical systems. Here we focus on investigating building a predictive causal framework that allows us to make predictions in simpler systems in a consistent way. We use a Bayesian framework to embed causal measures akin to mutual information from information theory to quantify relations between different random processes in this system. We examine causal relations in toy models and simple systems with a view to eventually applying to the interocean exchange problem in the Indian, the South Atlantic and the Southern Ocean. 
The response of soil enzyme activity to seasonal and microtopographical variations in the sedge peatlands in Changbai Mountain, China
Authors: Wang Ming
Published: March 2020

Hummock-hollow microtopography is a common feature in northern peatlands. It
creates microsites of variable hydrology, vegetation, and soil biogeochemistry, thus affect soil C
cycling in peatlands at the local scale. This study investigated effects of microtopography on soil
enzyme (β-1,4-glucosidase (βG), β-1,4-N-acetylglucosaminidase (NAG), acid phosphatase (AP)
and peroxidase (PER)) activities and environment variables as well as their relationships in a
typical sedge peatland in Changbai Mountain, northeast of China. Our results showed that the
enzyme activities in the sedge peatland significantly varied across seasons and microtopographical
positions. Soil enzyme activities in hummocks exhibited more obvious seasonal variation than
hollows, with the βG, AP and PER activities presented a distinct valley in summer and the
maximum values occurred in Spring or Autumn. Soil hydrolase (βG, NAG and AP) activities in
hummocks were significantly higher compared to hollows, while soil oxidase (PER enzyme)
activity in hollows was higher than hummocks. The NMDS analysis revealed that the influence
degree of microtopography on the enzyme activities was higher than that of seasonal variation.
Redundancy analysis (RDA) indicated that the variations of soil enzyme activities in the peatland
were related to environmental variables, especially to water table depth (WTD), soil temperature
(ST), SOC, N availability and P availability. Furthermore, correlation analysis showed that the
three hydrolase (BG, NAG and AP) activities were positively correlated with soil TN, SOC and
C/N, and negatively correlated with WTD and TP. On the contrast, the PER activities were
positively correlated with TP, and negatively correlated with ST, SOC and C/N. The present
study demonstrated that small scale topographic heterogeneity created by hummock cause habitat
heterogeneity and thus lead to significant difference of soil enzyme activity between hummock
and hollow in the sedge peatlands. This finding provides further evidence of the importance of
peatland microtopography to C cycling and has direct implications for scaling biogeochemical
processes to the ecosystem level.