bluuebunny/crossref_metadata_2025 huggingface dataset:
Unsupervised delineation of landfill geometries based on geophysical imaging results
Authors: Steiner Matthias , Chwatal Werner , Freudenthaler Andreas , Flores Orozco Adrian
Published: March 2020

 Environmental aspects and the growing interest in the economical exploitation of landfills urges the need for cost-efficient workflows providing information with high spatial resolution. Especially for landfill mining, a detailed characterization of the landfill geometry and the waste composition is critical to assess the economic potential. Geophysical methods have proven to fulfill these requirements since they permit to collect data in a quasi-continuous manner. However, the subjective perception of the geophysical imaging results might bias the interpretation, e.g. the characterization of the landfill boundaries and the estimation of waste volumes. To overcome such shortcomings, we present here an unsupervised method for the post-processing of geophysical imaging to identify subsurface interfaces associated to e.g. landfill geometries, waste variation etc. Our methodology is applicable for results obtained with a single method, or the combination of different geophysical methods, e.g. refraction seismic tomography (RST), electrical resistivity tomography (ERT) or induced polarization (IP). Assuming strong contrasts in the retrieved physical properties associated to interfaces, our method computes the magnitude of the gradient vector for each point in the resolved model. In the next step, a random walker algorithm converts the gradient magnitude image into a binary image permitting to obtain the contours of subsurface regions characterized by high gradients. Originating from the centroid for such a region further base points are determined and used in the final step to compute shape and location of the corresponding interface. To demonstrate the applicability of our method we present here results obtained for a landfill located in Upper Austria, where RST, ERT and IP data were collected along several transects. Our results demonstrate that the method proposed here has the potential to enhance geophysical investigations of landfills by permitting an improved interpretation of the imaging results, as required, for instance to estimate waste volume.
Low-frequency Sea Level Variability and Impact of Recent Sea Ice Decline on the Sea Level Trend in the Arctic Ocean from a High-Resolution Simulation
Authors: Chen Meixiang , Xiao Kai , Wang Qiang , Wang Xuezhu , Zhang Wenhao
Published: March 2020

The Arctic Ocean is undergoing significant changes, with rapid sea ice decline, unprecedented freshwater accumulation and pronounced regional sea level rise. In this work we analyzed the sea level variation in the Arctic Ocean based on a global simulation with 4.5 km resolution in the Arctic Ocean using the multi-resolution Finite Element Sea ice-Ocean Model (FESOM). The simulation reasonably reproduces both the main spatial features of the sea surface height (SSH) and its temporal evolution in the Arctic Ocean in comparison to tide gauge and satellite data. Using the model results we investigated the low-frequency variability of the Arctic SSH. The decadal variability is the dominant mode of the annual-mean SSH evolution in the Arctic Ocean, which can be mainly attributed to the variability of the halosteric height. The atmospheric circulation associated with the Arctic Oscillation drives the accumulation and release of freshwater in the Arctic deep basin, thus leading to the decadal variability of the SSH. The associated redistribution of water mass changes the ocean mass over the continental shelf, so the change in SSH is opposite between the shelf seas and the deep basin. By using a dedicated sensitivity simulation in which the recent sea ice decline is eliminated, we find that the sea ice decline contributed considerably to the observed sea level rise in the Amerasian Basin in the recent decades. Although the sea ice decline did not change the mean SSH averaged over the Arctic Ocean, it significantly changed the spatial pattern of the SSH trend. Our finding indicates that both the wind regime and on-going sea ice decline should be considered to better understand and predict the changes in regional sea level in the Arctic Ocean.
Petrology of the April 2015 eruption of Calbuco volcano, southern Chile
Authors: Namur Olivier , Bolle Olivier , Vander Auwera Jacqueline
Published: March 2020

Understanding the origin of intermediate magmas that commonly erupt from subduction zone volcanoes is important to better constrain the mechanisms of continental crust formation. We carried out a detailed mineralogical and petrological study of the eruptive products from the last eruption of Calbuco volcano, Chile. In April 2015, Calbuco produced a 3 phase sub-Plinian eruption with pyroclastic fallouts and flows of andesitic composition. Rocks from Calbuco are made up of a glass phase and a high but variable proportion of minerals dominated by plagioclase, clinopyroxene, orthopyroxene and minor olivine, amphibole and magnetite. Plagioclase is very strongly zoned with highly anorthitic cores surrounded by more albitic rims. Based on thermodynamic calculations and using published experimental data, we estimate that the anorthitic cores crystallized from a basaltic andesite containing 3.5-4.5 wt.% H2O. Using geochemical modelling, we also estimate that the bulk-rock major and trace element variability of Calbuco is best explained by accumulation of minerals in proportion plagioclase/pyroxene 72/28 in a dacitic melt. Such minerals most likely formed in the crystal mush zone of a magma chamber which, according to pyroxene and amphibole compositions, may have formed at a pressure of 2-3 kbar, corresponding to a depth of 8-11 km. A few weeks to months before the eruption, the crystal mush disaggregated, perhaps due to magmatic underplating, and a crystal-bearing dacitic melt moved upwards into a sub-surface storage region where the anorthite-poor rims formed. The 2015 eruption was probably internally triggered by over-pressurization in the shallow magma chamber.
Managing collaborative research data for integrated, interdisciplinary environmental research
Authors: Finkel Michael , Baur Albrecht , Weber Tobias K.D. , Osenbrück Karsten , Rügner Hermann , Leven Carsten , Schwientek Marc , Schlögl Johanna , Hahn Ulrich , Streck Thilo , Cirpka Olaf A. , Walter Thomas , Grathwohl Peter
Published: March 2020

The consistent management of research data is crucial for the success of long-term and large-scale collaborative research. Research data management is the basis for efficiency, continuity, and quality of the research, as well as for maximum impact and outreach, including the long-term publication of data and their accessibility. Both funding agencies and publishers increasingly require this long term and open access to research data. Joint environmental studies typically take place in a fragmented research landscape of diverse disciplines; researchers involved typically show a variety of attitudes towards and previous experiences with common data policies, and the extensive variety of data types in interdisciplinary research poses particular challenges for collaborative data management.We present organizational measures, data and metadata management concepts, and technical solutions to form a flexible research data management framework that allows for efficiently sharing the full range of data and metadata among all researchers of the project, and smooth publishing of selected data and data streams to publicly accessible sites. The concept is built upon data type-specific and hierarchical metadata using a common taxonomy agreed upon by all researchers of the project. The framework’s concept has been developed along the needs and demands of the scientists involved, and aims to minimize their effort in data management, which we illustrate from the researchers’ perspective describing their typical workflow from the generation and preparation of data and metadata to the long-term preservation of data including their metadata.
A closer look at factors governing landslide recovery time in post-seismic periods
Authors: Tanyas Hakan , Kirschbaum Dalia , Lombardo Luigi , Gorum Tolga
Published: March 2020

Various mechanisms are proposed to explain landslide recovery time in the time following major earthquakes. However, research on prescribing possible recovery times following an earthquake is still relatively new. This paper provides an insight into factors governing landslide recovery time, which could be considered as a step forward in predictive modeling for landslide recovery time. To accomplish this, we examined 11 earthquake-affected areas based on the characteristics of both landslide events and landslide sites associated with diverse morphologic and climatic conditions. Our analyses indicate that the dominant characteristics of post-seismic landslide mechanisms determine the recovery time. The characteristics can be identified based on: (i) the fraction of area affected by landslides (%), (ii) mean relief and its standard deviation (m), (iii) average daily accumulated precipitation (mm) and (iv) rainfall seasonality index. If there are not enough co-seismic landslide deposits or not enough relief to trigger large deposits on hillslopes, then the recovery processes are mostly controlled by new landslides caused by a strength reduction of hillslope materials. In most of the cases, this brings a relatively quick recovery process in which the majority of post-seismic landslides may happen within a year or even in a month if sufficient intense rainfalls occur soon after the earthquake. If the predisposing factors create large co-seismic landslide deposits, then remobilization of material takes the role of the dominant mechanism and recovery may take years. Overall, our analyses show that the recovery takes relatively longer if a large amount of co-seismic landslide material is deposited within a high-relief mountainous environment where precipitation rate is low and not persistent.
Variability of the North Atlantic response to sudden stratospheric warming events in a simplified atmospheric model
Authors: Afargan-Gerstman Hilla , Jiménez-Esteve Bernat , Domeisen Daniela I.V.
Published: March 2020

Sudden stratospheric warming (SSW) events are often followed by a surface impact, most commonly by a negative phase of the North Atlantic Oscillation (NAO). Recent work has emphasized the large variability among the tropospheric response after these events, showing that only about two thirds of the SSWs are dominated by this canonical negative NAO response. In this study, we use an idealized atmospheric model forced with seasonally varying sea surface temperatures to examine the influence of the pre-existing tropospheric conditions on the North Atlantic response to stratospheric forcing. In the model, the negative phase of the NAO is found to be the most common response to SSWs, occurring after ~85% of the SSWs (under climatological SST forcing).  For the remaining ~15% of the SSW events, the response is associated with a positive phase of the NAO. In the search for the origin of the different tropospheric response in the North Atlantic, the role of synoptic wave propagation from the eastern Pacific on the downward response to SSWs is investigated. By systematically varying the strength of the North Pacific circulation, we are able to assess the sensitivity of the downward response to tropospheric variability in the Pacific, and shed light on its contribution to the persistence of the downward impact of SSWs in the idealized model.
From science to policy: how can research community contribute to the reporting and verification needs under the Paris Agreement?
Authors: Perugini Lucia , Pellis Guido , Grassi Giacomo , Ciais Philippe , Dolman Han , House Joanna I. , Peters Glen , Smith Pete , Günter Dirk , Peylin Philippe
Published: March 2020

The time for action on the Paris Agreement is upon us, requiring all signatory countries to have a robust reporting and accounting system that is transparent, accurate, complete, consistent and comparable (through the Enhanced Transparency Framework), with a periodical review of the collective achievement of the 2°C temperature goal (the Global Stocktake). The research community is therefore called to reinforce databases and methodologies to improve national greenhouse gas inventory estimates, especially for developing countries that are subject to new reporting obligations, but also to define a comparable scientific “benchmark" to assess the achievement of the Paris Agreement goal.

Despite the key role of science in the process, often research communities working on emission statistics have approached the problem of climate change through different angles and by using terminologies, metrics, rules and approaches (e.g. spatial and temporal scales) that do not always match with those used by the inventory communities. Within the VERIFY project (Horizon 2020, grant agreement No 776810) a networking between the two communities (research and inventory) has been established. The discussion between them highlighted the importance of a continue exchange to increase the mutual understanding of needs, terms, rules, procedures and guidelines in use, especially those adopted under the UNFCCC and Paris Agreement process.

The presentation will therefore guide the researchers through the monitoring, reporting and verification frameworks under the UNFCCC and Paris Agreement, identifying how and where science production can assist the inventory communities in improving greenhouse gasses estimations and verification systems. Land Use, Land-Use Change and Forestry is the most complicate sector to deal with because of intricacy of flux attribution (that can be both anthropogenic and non-anthropogenic) and methodological complexity, affected also by common misunderstandings in the use of terminologies and different definitions. 

On the basis of the available literature and the outcomes of the work undertaken under VERIFY project, we provide an analysis on the possible critical issues and main misunderstanding that could arise, identifying options on how to solve them.
Morphology of scallop patterns in erosion by dissolution
Authors: Berhanu Michael , Dubourg Raphael , Walbecq Arthur , Ozouf Cyril , Guerin Adrien , Derr Julien , Courrech du Pont Sylvain
Published: March 2020

Erosion by dissolution is a decisive process shaping small-scale landscape morphology [1]. For fast dissolving minerals, the erosion rate is controlled by the solute transport [2] and characteristic erosion patterns can appear due to hydrodynamics mechanisms. Among the diversity of the dissolution patterns, the scallops are small depressions in a dissolving wall, appearing as cups with sharp edges. Their size varies from few millimeters to around ten centimeters. The scallops occur typically as the final steady form of ripple patterns created by the action of a turbulent flow on a dissolving surface [3,4]. Moreover, very similar shapes are also met, without imposed external flow, when the fluid motion results from the solutal convection induced by the dissolution [2,5,6]. Finally, scallop patterns resulting from similar mechanisms appear also on ice surfaces by melting in presence of a turbulent flow [7] or a convection flow [6].
Using three-dimensional surface reconstruction, we characterize quantitatively the scallop patterns mainly for experimental samples patterned by solutal convection. The temporal evolution of the scallop shape, of their spatial distribution and of the induced roughness are specifically investigated, in order to determine mechanisms explaining the generic aspects of dissolution patterns.

[1] P. Meakin and B. Jamtveit, Geological pattern formation by growth and dissolution in aqueous systems, Proc. R. Soc. A 466 659-694 (2010)

[2] J. Philippi, M. Berhanu, J. Derr and S. Courrech du Pont, Solutal convection induced by dissolution, Phys. Rev. Fluids, 4, 103801 (2019)

[3] P.N. Blumberg and R.L. Curl, Experimental and theoretical studies of dissolution roughness,  J. Fluid Mech. 65, 735 (1974)

[4] P. Claudin, O. Durán and B. Andreotti, Dissolution instability and roughening transition,  J. Fluid Mech. 832, R2  (1974)

[5] T.S. Sullivan, Y. Liu and R. E. Ecke, Turbulent solutal convection and surface patterning in solid dissolution, Phys. Rev. E 54, (1) 486, (1996)

[6] C. Cohen, M. Berhanu, J. Derr and S. Courrech du Pont, Erosion patterns on dissolving and melting bodies (2015 Gallery of Fluid motion), Phys. Rev. Fluids, 1, 050508 (2016)

[7] M. Bushuk, D. M. Holland, T. P. Stanton, A. Stern and C. Gray. Ice scallops: a laboratory investigation of the Ice-water interface, J. Fluid Mech. 873, 942 (2019)
Gravity and magnetic data analysis based on Poisson wavelet-transforms
Authors: Kuznetsov Kirill , Andrey Bulychev , Lygin Ivan
Published: March 2020

Studies of the Earth’s interior structure are one of the most complex topics in modern science. Integration of different geophysical methods plays a key role in effectively tackling the problem. In the last decade capabilities of potential field geophysical methods have been increasing due to development of advanced digital technologies. Improved resolution and accuracy of gravity and magnetic fields measurements made by modern equipment makes it possible to build more detailed geological models. Different tectonic and structural elements being interpreted in such models produce potential field signals with different spectral characteristics. Like any geophysical signals, potential fields can be described as a spatially non-stationary signal. This means its frequency content may change depending on a given signal sample, in particular with different spatial location of a sample. In this case, approaches of gravity and magnetic fields analysis based on Fourier transform or signal decomposition into a number of harmonic functions can lead to incorrect results. One of the ways to solve this challenge involves using wavelet transform based algorithms, since these transforms do not assume stationary signals and each function of a wavelet-based basis is localized in space domain.

In gravity and magnetic data analysis it is beneficial to use wavelets based on partial derivatives of the Poisson kernel, which correspond to derivatives of a point source gravity potential. Application of Poisson wavelets in potential field data analysis has begun in the 1990's and is predominantly aimed at studying gravity and magnetic fields singularity points during data interpretation.

Similar to Fourier-based potential field techniques, it is possible to construct a number of data filtering algorithms based on Poisson wavelets. Current work demonstrates that it is possible to construct algorithms based on Poisson wavelets for transforming profile and spatially gridded gravity and magnetic data, e.g. for calculation of equivalent density and magnetization distributions, upward and downward continuations, reduction to pole and many other filters that take into account spatial distribution of the signal.

Wavelet-transforms allow to account for spatially non-stationary nature of geophysical signals. Use of wavelet based techniques allows to effectively carry out potential field data interpretation in a variety of different geologic and tectonic settings in a consistent fashion.
Will post-processing always improve my forecasts?
Authors: Skøien Jon Olav , Salamon Peter , Wetterhall Fredrik
Published: March 2020

Different statistical techniques are frequently employed to post-process the outcome of ensemble forecasting models. The main reason is to compensate for biases due to errors in model structure or initial conditions, and as a correction for under- or overdispersed ensembles.

Here we present analyses of the results from one these methods. We use the Ensemble Model Output Statistics method (EMOS; Gneiting et al., 2005) to post-process the ensemble output from a continental scale hydrological model - LISFLOOD (Van Der Knijff et al., 2010; De Roo et al., 2000). The model was calibrated at approximately 700 stations based on long term observations of runoff and meteorological variables. We use the same locations for calibration and verification of the 1-10 days forecasts of the model, based on ensemble and deterministic meteorological forecasts from ECMWF (51 ensemble members + 1 high-resolution), DWD (1 member) and COMSO-LEPS (16 ensemble members).

We calibrated the EMOS-parameters using the Continuous ranked probability score (CRPS). Whereas the post-processing improved the results for the first 1-2 days lead time, the improvement was less for increasing lead times of the verification period. As the post-processing is based on assumptions about the forecast errors, we will here present analyses of the ensemble output that can give some indications of what to expect from the post-processing.

 

Gneiting, T., Raftery, A. E., Westveld, A. H. and Goldman, T.: Calibrated Probabilistic Forecasting Using Ensemble Model Output Statistics and Minimum CRPS Estimation, Mon. Weather Rev., 133(5), 1098–1118, doi:10.1175/MWR2904.1, 2005.

Van Der Knijff, J. M., Younis, J. and De Roo, A. P. J.: LISFLOOD: a GIS‐based distributed model for river basin scale water balance and flood simulation, Int. J. Geogr. Inf. Sci., 24(2), 189–212, doi:10.1080/13658810802549154, 2010.

De Roo, A. P. J., Wesseling, C. G. and Van Deursen, W. P. A.: Physically based river basin modelling within a GIS: The LISFLOOD model, in Hydrological Processes, vol. 14, pp. 1981–1992, John Wiley & Sons Ltd. [online] Available from: http://www.scopus.com/inward/record.url?eid=2-s2.0-0034254644&partnerID=tZOtx3y1, 2000.

 
Optimizing barrier placement for lava flow hazard and risk mitigation
Authors: Bilotta Giuseppe , Cappello Annalisa , Centorrino Veronica , Corradino Claudia , Ganci Gaetana , Del Negro Ciro
Published: March 2020

Mitigating hazards when lava flows threaten infrastructure is one of the most challenging fields of volcanology, and has an immediate and practical impact on society. Lava flow hazard is determined by the probability of inundation, and essentially controlled by the topography of the area of interest. The most common actions of intervention for lava flow hazard mitigation are therefore the construction of artificial barriers and ditches that can control the flow direction and advancement speed. Estimating the effect a barrier or ditch can have on lava flow paths is non-trivial, but numerical modelling can provide a powerful tool by simulating the eruptive scenario and thus assess the effectiveness of the mitigation action. We present a numerical method for the design of optimal artificial barriers, in terms of location and geometric features, aimed at minimizing the impact of lava flows based on the spatial distribution of exposed elements. First, an exposure analysis collects information about elements at risk from different datasets: population per municipality, distribution of buildings, infrastructure, routes, gas and electricity networks, and land use; numerical simulations are used to compute the probability for these elements to be inundated by lava flows from a number of possible eruptive scenarios  (hazard assessment) and computing the associated economic loss and potential destruction of key facilities (risk assessment). We then generate several intervention scenarios, defined by the location, orientation and geometry (width, length, thickness and even shape) of multiple barriers, and compute the corresponding variation in economic loss. Optimality of the barrier placement is thus considered as a minimization problem for the economic loss, controlled by the barrier placement and constrained by the associated costs. We demonstrate the operation of this system by using a retrospective analysis of some recent effusive eruptions at Mount Etna, Sicily.
Do olivine crystallisation temperatures faithfully record mantle temperature variability?
Authors: Matthews Simon , Wong Kevin , Shorttle Oliver , Edmonds Marie , Maclennan John
Published: March 2020

Crystallisation temperatures of primitive olivine crystals have been widely used as both a proxy for, or an intermediate step in calculating, mantle temperatures. The olivine-spinel aluminium-exchange thermometer has been applied to many samples from mid-ocean ridges, ocean islands and large igneous provinces, yielding considerable variability in primitive olivine crystallisation temperatures. We supplement the existing data with new crystallisation temperature estimates for Hawaii, in the range 1282±21 - 1375±19°C.

Magmatic temperatures may be linked to mantle temperatures if the thermal changes during melting can be quantified. Melting lowers the temperature of co-existing magma and solid mantle, owing to the latent heat of melting. The magnitude of this cooling depends on melt fraction, itself controlled by mantle temperature, mantle lithology and lithosphere thickness. All of these parameters are likely to vary both spatially and temporally. For robust quantification of mantle temperature variability, the controls of lithosphere thickness and mantle lithology on crystallisation temperatures must be isolated.

We develop a multi-lithology melting model that can predict crystallisation temperature. The model allows mantle temperature, lithospheric thickness, and fractions of mantle lherzolite, pyroxenite and harzburgite to be varied. Inverting the model using a Bayesian Monte Carlo routine enables assessment of the extent to which crystallisation temperatures require variations in mantle temperature. We find that the high crystallisation temperatures seen at mantle plume localities do require high mantle temperatures. However, in the absence of further constraints on mantle lithology or melt productivity, we cannot robustly infer variable plume temperatures in either the present-day or throughout the phanerozoic. This work demonstrates the limit of petrological thermometers when other geodynamic parameters are poorly known.
Comparison of bioaccumulation potential of eleven pine species in low polluted ecosystem
Authors: Jonczak Jerzy , Sut-Lohmann Magdalena , Polláková Nora , Parzych Agnieszka , Šimanský Vladimír , Donovan Sally , Medinski Tetiana
Published: March 2020

Forests play a pivotal role in sustaining ecosystem services. Continuous human modification of the biogeochemical cycling of potentially toxic metals, together with constant growing release, often lead to mutagenic or directly lethal health effects. Bioindicating organisms are commonly used to assess metal contamination in soil. However, there is a big gap in knowledge regarding reference stands (low polluted ecosystems), which is crucial to determine relationships between mineralogy and spatial distribution of potentially toxic metals in soil and forest stands. We evaluated bioaccumulation intensity of Cr, Cu, Mn, Ni and Zn in the 1 and 2-year old needles of eleven pine species growing in the Arboretum Mlyňany, located in an uncontaminated area of south-western Slovakia. The results were evaluated using Ward method, Euclidean distance and Kruskal-Wallis test. The results presented in our study point to a specific bioaccumulation behavior of 11 pine species under low soil pollution levels.
Evaluation of pond/aquifer flow exchanges using local discretization and contrasting different boundary condition in MODFLOW. Case of Santa Olalla pond (SW Spain)
Authors: Serrano-Hidalgo Carmen , Heredia Díaz Javier , Guardiola-Albert Carolina , Elorza Tenreiro Francisco Javier
Published: March 2020

Almonte-Marismas is a coastal aquifer situated in Doñana Natural Park (Southwestern of Spain, Huelva). It supports one of the most important wetland areas in Europe due to its biodiversity, size and strategic location. Nowadays, the aquifer suffers serious threats due to the large amount of water extraction that takes place in the area due to the high demand for water that exists for the supply of tourism and irrigation.

There is a flow model of the regional aquifer which is used to support the water management Administration. However, this model does not take into account groundwater interactions with local ponds. Santa Olalla pond is a hypogenic wetland that, on a regional scale, it receives the discharge of the Almonte-Marismas aquifer. This fact allows it to maintain a permanent water regime without suffering a reduction in its volume of water. Despite of that, the intense pumping in the zone could affect it and be a risk in the future.

The objective of this study is the identification of an appropriate model structure to characterize and implement the Santa Olalla Pond in the current steady-state model of the regional aquifer of Doñana employing ModelMuse interface. For this purpose, different boundary conditions (LAKE and DRAIN packages) were contrasted to represent the pond, combined with different local grid refinement (LGR2 package). The contrast criteria to assess the goodness of the numerical representation have been the piezometric heads in the wells situated in the surroundings of the pond and the stage levels and water balance of the pond.
Anisotropic turbulent diffusivities and rotating magnetoconvection problems
Authors: Filippi Enrico , Brestenský Jozef
Published: March 2020

Earth’s core Physics inspires the magnetoconvection models. Turbulent state of the core can increase the viscosity, the thermal diffusivity and also the magnetic diffusivity. The change of magnetic diffusivity is also called β-effect and it is important in dynamo mechanisms. Moreover, the turbulence suggests that the dynamics can be more complicated than it is usually presented. For instance, due to turbulence the diffusivity coefficients could be anisotropic as it was described in some recent studies, which stress how anisotropy in many cases facilitate convection and in other cases inhibits it. For example, if there is anisotropy some types of convection can occur also with very small values of Ekman numbers, which are usual for the Earth’s core. This is important because the convection can be the main cause of dynamo action. We present several rotating magnetoconvection models in horizontal plane layer with gravity and rotation axis in vertical direction and homogeneous magnetic field in horizontal direction. Different models correspond to different cases of anisotropic diffusivities. In other words, we consider several anisotropic models: one with anisotropy in all diffusivities and other models with various combinations of anisotropic and isotropic diffusivities. Comparisons with other former models (e.g. with isotropic case, p-case, partial anisotropy case when only magnetic diffusivity is isotropic, and f-case, full anisotropy case with all diffusivities anisotropic) are thoroughly performed. In all models we consider two distinct kinds of anisotropy, Stratification Anisotropy – SA, determined by direction of single gravity (buoyancy) force and Braginsky-Meytlis one – BM, determined by directions of magnetic field and rotation axis. All systems described by these models are prone to instabilities, so analysis in term of normal modes and search for preferred modes are very useful to study such systems. We focus our attention on stationary modes and SA anisotropies. Furthermore, we distinguish two sub-cases of SA anisotropy: atmospheric – Sa, if the diffusion in the vertical direction is greater than in the horizontal ones and oceanic – So, if opposite holds. In Sa (So) anisotropy the convection is in major cases facilitated (inhibited). This fact suggests that it is important to study Sa as well as So anisotropies in the Earth’s core. Our main results concern cases of anisotropic diffusivities, when preferred modes give new dynamics (unexpected in isotropic case) in the system in which geodynamo can work. 
Economic Landslide Susceptibility under a socio-economic perspective: an application to Umbria Region (Central Italy)
Authors: Donnini Marco , Modica Marco , Salvati Paola , Marchesini Ivan , Rossi Mauro , Guzzetti Fausto , Zoboli Roberto
Published: March 2020

An accurate understanding of physical and economic effects of landslides is fundamental to develop more refined risk management, mitigation strategies and land use policies. We develop a measure to consider the interconnection between physical and economic exposure, e.g. what we call the economic landslide susceptibility, namely the probability of landslide occurrence in an area weighted for its socio-economic exposure. The economic landslide susceptibility is estimated trough a pixel-based method designed for large areas. The method makes use of landslide susceptibility maps and a real estate market value maps for any given areas under analysis. We apply this methodology to the Umbria Region (Central Italy). The innovative concept of economic landslide susceptibility (that is de facto an ex ante landslide cost assessment) may be interpreted as the potential loss that an area might suffer in terms of its propensity for landslides. Useful applications of the proposed method lie in a better territorial management and in the land use planning.
Rogue-wave-energy: wave-to-wire mathematical modelling
Authors: Bokhove Onno
Published: March 2020

A novel wave-energy device design [1,2] will be presented based on the following features: (i) an electro-magnetic generator based on cylindrical magnets moving through induction wires around a cylindrical tube, like in the IP wave-buoy, (ii) a convergence in a breakwater to amplify the incoming waves, like in the TapChan device, and (iii) a wave-activated buoy with magnets attached, like in the Berkeley wedge, constrained to move in a slight arc or in a rectilinear manner. Its workings will be demonstrated in a first, operating proof-of-principle. A monolithic mathematical model is established by coupling the three variational principles for the hydro-dynamic wave motion, using the potential-flow approximation, the constrained wave-activated buoy motion, and the electro-magnetic generator together into one grand variational principle. The resistive losses in the electrical circuit and the energy harvested in the (parallel LED) loads are subsequently added to the dynamics. After linearisation of the resulting full 3D nonlinear model around a state of rest and application of the shallow-water approximation, we discretize the linear dynamics in a compatible, i.e. geometrically consistent, manner using a finite-element approach in space and symplectic integrators in time. Preliminary numerical modelling and simple optimization will be shown and these are promising. Finally, further optimisation of the device for different geometries and for a given wave-climate as well as alternative designs will be discussed.

References
[1] O. Bokhove, A. Kalogirou, W. Zweers 2019: From bore-soliton-splash to a new wave-to-wire wave-energy model. Water Waves 1.
[2] O. Bokhove, A. Kalgirou, D. Henry, G. Thomas 2019: A novel rogue-wave-energy device with wave amplification and induction actuator. In: 13th European Wave and Tidal Energy Conference 2019, Napoli, Italy.
The Zhidoy massif of ultrabasic-alkaline rocks and carbonatites: its geochemical features, sources and ore potential.
Authors: Vladykin Nikolai , Alymova Natalia
Published: March 2020

 The article describes geological structure of Jidoi massif and its age. The scheme of the massif magmatism has been constructed. Double correlation plots of petrogenic elements of rocks of the massif in which the unified trend of rock structures is observed, are given for verification of correctness of the scheme of magmatism. Spectra of TR and spider diagrams of concentrations of rare elements in rocks of the massif are given. Piroxenites, early rocks of the massif are ores on titanium. Titanium concentrates in three minerals: titanomagnetite, ilmenite and perovskite. The main type of titanium ores is perovskitic type, it is known only in Jidoi massif. Mantle sources of primary magma of the massif is concluded on the basic of geochemistry of isotopes of Sr and Nd. 
Purification of Organic Compounds Using Microsublimation for 14C Analysis
Authors: Heusser Christian , Welte Caroline , Hattendorf Bodo , Montluçon Daniel , Günther Detlef , Eglinton Timothy Ian
Published: March 2020

The decrease in required sample sizes for radiocarbon (14C) analysis by accelerator mass spectrometry (AMS), which now is on the order of ten micrograms carbon or less provides the opportunity for precise dating of single specific compounds. However, background contamination associated with sample purification presents a major limitation to precise 14C dating at these low sample sizes. Many key target compounds are amenable to isolation using preparative chromatographic methods. Using preparative GC, for example, column bleed has been reported as the main contamination source. Although this contamination may be at sub-microgram levels[1], removal is favorable for accurate dating of ultra-small samples. In synthetic and analytical chemistry, sublimation is a well-established approach for purification of semi-volatile compounds, and here we test it as an approach for purification of selected compounds for microgram-level 14C analysis. As commercial sublimation equipment usually is not designed for such small sample sizes, a custom-built micro-sublimation apparatus has been developed and tested for the purification of organic compounds in the sub-milligram range. The design of the microsublimation apparatus, which has been optimized to enable a streamlined protocol that minimizes contamination risks, will be presented. Experiments were performed with a range of different compound types, including fatty alcohols, alkanes and vanillin. Reproducibility with yields of up to 90% have been achieved. Stability of isotopic measurements and contamination sources will be discussed along with possible other application areas in the future.

 

[1]      E. Casanova, T. D. J. Knowles, C. Williams, M. P. Crump, R. P. Evershed, Anal. Chem. 2017, 89, 7090–7098.
Decoupling primary productivity from silicate weathering – how ecosystems regulate nutrient uptake along a climate and vegetation gradient
Authors: Oeser Ralf , von Blanckenburg Friedhelm
Published: March 2020

Water flow as well as the presence and growth rate of land plants are commonly thought to present drivers of rock weathering. While plants are indeed key players in weathering, the quantitative evaluation of biota on total abiotic and biotic weathering processes remains vague.

Here, we report on weathering rates and nutrient uptake along the “EarthShape” climate and vegetation gradient in the Chilean Coastal Cordillera. The hypothesis we evaluated is whether weathering rate and degree does increase from north to south along the EarthShape climate gradient and whether the increase in biomass growth rate along this gradient is accommodated by additional nutrient-supply induced through weathering. We quantified the bio-available fraction of nutritive elements in regolith and we measured 87Sr/86Sr isotope ratios in the different compartments of the Earth’s Critical Zone (bedrock, regolith, bio-available fraction in saprolite and soil, and vegetation) to identify the sources of mineral nutrients to plants. We were thus quantified gains and losses of nutritive elements in and out of these ecosystems and to quantify nutrient recycling.

We find that despite the increase in biomass growth the weathering rate is relatively uniform along the gradient. Instead of accelerating biogenic weathering ecosystems with high productivity rely on efficient recycling between plants and soil to sustain their nutrition. Thus, the organic nutrient pathway (between plants and litter on the foerst floor) intensifies, whereas the geogenic nutrient pathway (from minerals to plant) remains steady despite increasing precipitation and primary productivity. We further speculate that the presence of plants might compensate weathering downward by regulating the hydrological cycle, fostering secondary-mineral formation, and a microbial community specializing on nutrient-recycling rather than nutrient-acquisition through weathering.
Do we need to new set of soil principles to guide the cross-sector engagement of soil education
Authors: Field Damien
Published: March 2020

The importance of and role that soil plays in ensuring the future sustainability of human and planetary health is well established and the emerging soil security concept clearly identifies that education is a crucial component to ensure the securing soil to be fit for this purpose. Traditionally education in soil science has been limited to developing expertise in the discipline. To be truly effective we need to go beyond the boundaries of the discipline, and even its natural home of academia, and begin to explore the types of learning that can be developed to engage the whole community and raise our collective connectivity with soil.

Previously theoretical frameworks based around the dimensions of to ‘know’, ‘know of’ and ‘be aware’ of soil have been accepted by the education community as well as experiential learning practices framed by the teaching-research-Industry-learning (TRIL) models. There is now the emerging question of the need for a set of newly proposed set of principles, in the same way as a set of elementary assumptions have been developed for disciplines in biology and geology, which will impact the design of learning and its engagement within the disciplinary and broader community. Starting with the Pedon this elementary level will ensure awareness of soil. Coupled with outward focused responsibility of providing salient knowledge together with the social intelligence will use the second principle of Processes to provide resolution to soil related problems. Traditionally, this knowledge is often used to tackle well know threats, but more recently the advances in digital soil mapping and decreasing soil modelling have enabled greater interdisciplinary opportunities to solve soil knowledge based around the principles of variation and ultimately forecasting soil change.

This paper will align the set of principles against the current soil science education practices and how these can be used to engage with the broader community outside of academia.  
Plasmoid releases in the Saturn's magnetosphere
Authors: Chané Emmanuel
Published: March 2020

In this work, the interactions between the solar wind and the magnetosphere of Saturn are studied via state-of-the-art global MHD simulations, focusing on the release of plasmoids in the magnetotail. We analyze in detail the occurrence rate, the size, the speed and the evolution of the plasmoids in the simulations and compare the results with in-situ measurements. In our simulations, the multi-species three-dimensional MHD equations are solved with the code MPI-AMRVAC on a spherical non-uniform mesh ranging from 3 Rs (inner boundary) to 200 Rs (outer boundary). In order to simulate the magnetosphere-ionosphere coupling, to accelerate the ionospheric plasma up to rigid corotation and to close the electrical current systems, ion-neutral collisions are introduced in the MHD equations in the ionospheric region near the inner boundary. The strong mass-loading associated with the moon Enceladus is also included as an axisymmetric torus centered at 5.5 Rs.
A European multi-hazard assessment for Nuclear Power Plants with applications to other infrastructure types with operational time windows
Authors: Daniell James , Schaefer Andreas , Winter Hugo , Gehl Pierre , Vardon Phil , Mohan Varenya , Molenaar Cor , Natarajan Venkat , Foerster Evelyne , Ragon Florence
Published: March 2020

Within the course of the EU project NARSIS (New Approach to Reactor Safety ImprovementS), sites of decommissioned nuclear power plants (NPPs) were investigated for external hazards using a multi-hazard approach.

The starting point was a review of existing multi-hazard frameworks, as well as their application to real world locations. From this knowledge, after significant screening, external hazards were analysed at different site locations in Europe using stochastic event sets for earthquake, flood, lightning, tornadoes, tsunami, hail and other perils in order to identify key scenarios along the hazard curves. These were built from existing national and supranational stochastic event sets.

The joint probability at each site of certain threshold events occurring was calculated, and relevant risk scenarios were chosen based on these hazard thresholds. Most importantly, the concept of joint operational time windows was investigated. Because the overall hazard for events is generally low, the chance of two low probability events is often screened out. However, during the damage and recovery window of these events (the operational time), the joint probabilities are much higher, thus affecting the infrastructure. Including the cascading effects, aftershocks, secondary effects and associated event sequences, provides a new insight into the probabilities of multi-hazard events and the implications for multi-risk.

Historical events from the loss database CATDAT and other records are chosen where joint operational time windows have occurred to show empirical examples of joint occurrences and cascades in the past for European and international examples.

Joint probabilities for significant events at decommissioned NPPs are presented within the NARSIS project and the application to multi-risk within Probabilistic Safety Assessments (PSA), however it is the application to other industrial types and infrastructure which shows the need for integration of multi-hazard (coinciding or cascading) events into operational management plans as well as important thought processes for building standards and use.
Capability of existing drought indices in reflecting agricultural drought in China
Authors: Zhao Zhe , Wang Kaicun
Published: March 2020

A variety of drought indices have been constructed to monitor agricultural drought using ground and satellite data. Our study aimed to evaluate the performance of drought indices to indicate agricultural drought in China. Seven drought indices of four types were selected over the main agricultural regions of China: indices based on regular meteorological data (DImet), indices based on vegetation index (DIvi), indices based on soil moisture (DIsm), and synthesized indices (DIsyn). The independent reference data used here included three aspects: soil moisture, vegetation photosynthesis and crop yield data. The latter two reference datasets were selected to check drought impact on agriculture. Drought indices with short timescales are more sensitive to topsoil moisture. Drought indices have different abilities to capture vegetation photosynthesis condition during the growing season. Expect for the Yangtze region and North China region during the wheat growing season, the DImet and DIsyn show significant positive correlations with the sun-induced chlorophyll fluorescence (SIF), while the other drought indices have weaker or no correlations. For crop yield, the prediction ability of the drought indices show a similar pattern with the results for vegetation photosynthesis but with relatively large uncertainty. Generally, our study show that DImet have better or equivalent performance than that of the other types of drought indices, and DIsyn show the widest applicability. Our study may shed light on agricultural drought research in the future.