bluuebunny/crossref_metadata_2025 huggingface dataset:
An open-source database and collections management system for fish scale and otolith archives
Authors: Tray Elizabeth , Leadbetter Adam , Meaney Will , Conway Andrew , Kelly Caoimhín , O’Maoileidigh Niall , De Eyto Elvira , Moran Siobhan , Brophy Deirdre
Published: March 2020

Scales and otoliths (ear stones) from fish are routinely sampled for age estimation and stock management purposes. Growth records from scales and otoliths can be used to generate long-term time series data, and in combination with environmental data, can reveal species specific population responses to a changing climate. Additionally, scale and otolith microchemical data can be utilized to investigate fish habitat usage and migration patters. A common problem associated with biological collections, is that while sample intake grows, long-term digital and physical storage is rarely a priority. Material is often collected to meet short-term objectives and resources are seldom committed to maintaining and archiving collections. As a consequence, precious samples are frequently stored in many different and unsuitable locations, and may become lost or separated from associated metadata. The Marine Institute’s ecological research station in Newport, Ireland, holds a multi-decadal (1928-2020) collection of scales and otoliths from various fish species, gathered from many geographic locations. Here we present an open-source database and archiving system to consolidate and digitize this collection, and show how this case study infrastructure could be used for other biological sample collections. The system utilizes the FAIR (Findable Accessible Interoperable and Reusable) open data principals, and includes a physical repository, sample metadata catalogue, and image library.
Swelling clayey soils promote slope instability in the Muhunguzi watershed, western Burundi
Authors: Delvaux Bruno , Kankurize Clairia , Rufyikiri Gervais
Published: March 2020

In Burundi, landslides are frequent on the western slope of the Congo-Nile ridge. Unfortunately, they are poorly studied and understood despite their deadly consequences. Previous reports have suggested that slope steepness, lithology and clay soils expose this slope to landslides, while heavy and intense rainfall is a trigger. However, the role of soil in the vulnerability of this specific slope to landslides is unknown. Here we investigate on soil characteristics involved in land sliding in this area.

We selected and sampled black and red soils in two Muhunguzi landslides. We determined the soil plasticity from Atterberg limits as well as the particle size distribution. In addition, we measured the soil weathering stage, and further identified the clay minerals from measuring the cation exchange capacity of the clay fraction and analyzing clay samples with X-ray diffraction (XRD).

Both the black and red soils are moderately weathered since TRB values in the B horizons range between 330 and 425 cmol(+) kg-1. The soils are loamy clayey to clayey (% clay: 33-55%), and contain high charge clay minerals. They do not differ in their Atterberg limits, which classify the soils as medium plasticity soils in the Casagrande plasticity diagram. Our data further show that both soils have a medium swelling potential. XRD show that the clay fraction consists of kaolinite and smectite and/or vermiculite. The latter 2:1 clay minerals are expandable and swelling clays, respectively. They give these two soils their plasticity and swelling properties. These two properties play an important role in the mechanical behavior of water-saturated soils. Indeed, swelling reduces soil cohesion while the plasticity index and the liquidity limit vary inversely with the internal angle of friction of the soil; cohesion and internal angle of friction being the fundamental parameters of the soil shear resistance. In addition, the soil mantle covers a hard schistose rock whose declivity is parallel to the soil surface slope. Thus, after intense rainfall during the wet season, the water-saturated soil reaches a level of liquidity sufficient to favor a landslide, all the more easily if the slope of the hard rock is inclined in the direction of the gravity flow.gru
Do conservation practices contribute to the sustainability of soils in row crop agriculture?
Authors: Locke Martin
Published: March 2020

Do conservation practices contribute to the sustainability of soils in row crop agriculture?

Martin A. Locke

In row crop agriculture in the United States, so called conservation practices such as reduced tillage and cover crops are promoted as a means to improve the condition of soil (i.e., soil health, soil quality, soil sustainability).  In a series of studies conducted in the alluvial plain of the Mississippi River, various conservation practices were implemented, and several parameters were measured to determine how these practices influenced soil conditions.  Conservation management practices in corn or cotton production systems included reduced tillage, cover crops, and a government sponsored called Conservation Reserve Program, or CRP, where land is removed from agricultural production and replanted with native species as a fallow or buffer area.  Synthesized conclusions from the reduced tillage and cover crop studies showed that: (a) Cover crop and reduced tillage resulted in modest increases in soil organic carbon and nitrogen; (b) Soil biological activity was enhanced by cover crops (e.g., enzymes, mycorrhizae); (c) Runoff losses of solids was reduced with no-tillage and cover crop; (d) The phosphorus and nitrogen associated with runoff solids were reduced with cover crop and no-tillage; (e) Soluble phosphorus and nitrogen in runoff was variable; at times higher with cover crop and no-tillage; (f) cotton and corn grain production in cover crop and reduced tillage systems did not differ from that of conventional systems.  Three years after implementing CRP, microbial biomass, enzyme activities (phosphatase, glucosidase, and N-acetylglucosaminidase), and soil carbon and nitrogen in the surface of CRP soils were higher than in adjacent row crop soils.  Loss of some nutrients in runoff from the CRP was lower than that of row crop areas.  These two studies indicate that conservation practices can improve some environmental parameters related to soil sustainability.  Economics needs to be evaluated to determine the sustainability of maintaining these systems.
Statistical mechanics-based forecasting of induced seismicity within the Groningen gas field
Authors: Bourne Stephen , Oates Steve
Published: March 2020

Geological faults may fail and produce earthquakes due to external stresses induced by hydrocarbon recovery, geothermal extraction, CO2 storage or subsurface energy storage. The associated hazard and risk critically depend on the spatiotemporal and size distribution of any induced seismicity. The observed statistics of induced seismicity within the Groningen gas field evolve as non-linear functions of the poroelastic stresses generated by pore pressure depletion since 1965. The rate of earthquake initiation per unit stress has systematically increased as an exponential-like function of cumulative incremental stress over at least the last 25 years of gas production. The expected size of these earthquakes also increased in a manner consistent with a stress-dependent tapering of the seismic moment power-law distribution. Aftershocks of these induced earthquakes are also observed, although evidence for any stress-dependent aftershock productivity or spatiotemporal clustering is inconclusive.

These observations are consistent with the reactivation of a mechanically disordered fault system characterized by a large, stochastic prestress distribution. If this prestress variability significantly exceeds the induced stress loads, as well as the earthquake stress drops, then the space-time-size distribution of induced earthquakes may be described by mean field theories within statistical fracture mechanics. A probabilistic seismological model based on these theories matches the history of induced seismicity within the Groningen region and correctly forecasts the seismicity response to reduced gas production rates designed to lower the associated seismic hazard and risk.
Pedotransfer functions to mapping total and adsorbed phosphate using Vis-NIR (DRS)
Authors: Marques Júnior José , Gomes Romário Pimenta , da Silva Luis Fernando Vieira , Silva João de Deus Ferreira , Silva Laércio Santos
Published: March 2020

Pedotransfer functions to mapping total and adsorbed phosphate using Vis-NIR (DRS)

José Marques Júnior a, Romário Pimenta Gomes a, Luis Fernando Vieira da Silva a, João de Deus Ferreira e Silva a & Laércio Santos Silva a

Department of Soils and Fertilizers, Research Group CSME - Soil Characterization for Specific Management, State University of São Paulo (UNESP), Via de Acesso Prof. Paulo Donato Castellane s/n, 14883-292 Jaboticabal, São Paulo, Brazil

 

Soil oxides-Fe can be an excellent predictor of spatial variability of total and adsorbed P, contributing to rapid mapping, low cost and differentiation of minimum areas of phosphate fertilizer management. In the Western Paulista Plateau (Brazil) were collected 300 soil samples representing the lithological (sandstone and basalt) and geomorphic variability (less, moderately and highly dissected), at a depth of 0.0 – 0.2 m. The total (Ptotal) and adsorbed phosphorus (Pads) determined by conventional methods and hematite and goethite by X-ray diffraction (XRD). By partial least squares regression (PLS) and chemometric calibration, internal validation and external calibration, the Ptotal and Pads were estimated by diffuse reflectance spectroscopy (Vis-NIR-DRS), using hematite (Hm) and goethite (Gt) as a predictor. Then, the spatial pattern was obtained by geostatitic analysis. Phosphorus ware influenced by geology and dissection of the landscape and is a covariate of Hm and Gt, important indicators of environments with high or low P adsorption and content potential. Partial least squares (PLS) regression analysis of the spectral data demonstrated the influence of iron oxides on Ptotal and Pads, whereby Hm affects the former and Gt the latter. The lower maximum phosphorus adsorption capacity indicates the scarcity of P minerals and Fe oxides from sandstone sediments, with severe risk of phosphate loss and environmental damage. Significant correlation between Ptotal and Hm and Pads and Gt in Vis-NIR-DRS indicates the potential of this study in mapping large areas based on iron oxides, which can be used to develop soil P inventories as well as monitor and estimate the future impacts of land use, considering the complex relations between soil and landscape.

Keywords: Diffuse reflectance spectroscopy, goethite, hematite, geostatistics.
Nature 4.0 – Intelligent networked systems for ecosystem monitoring
Authors: Friess Nicolas , Ludwig Marvin , Reudenbach Christoph , Nauss Thomas ,   Nature 4.0-Team
Published: March 2020

Successful conservation strategies and adaptive management require frequent observations and assessments of ecosystems. Depending on the conservation target this is commonly achieved by monitoring schemes carried out locally by experts. In general, these expert surveys provide a high level of detail which however is traded-off against the limited spatial coverage and repetition with which they are commonly executed. Thus, it is common practice to spatially expand these observations by remote sensing techniques. For a resilient monitoring both the expert observations and the spatio-temporal upscaling have to be extended by automated measurements and reproducible modelling.  Therefore, Nature 4.0 is developing a prototype of a modular environmental monitoring system for spatially and temporally high-resolution observations of species, habitats and key processes.  This prototype system is being developed in the Marburg Open Forest, an open research, education and development platform for environmental observation methods. Here, we present the experiences and challenges of the first year with a focus on the conceptual design and the first implementation of the core observation subsystems and their comparison with the data collected by classical field surveys and remote sensing. The spatially distributed acquisition of abiotic and biotic environmental parameters is based on self-developed as well as third party sensor technology.  This includes an automated area-wide radiotracking system of bats and birds and sensor units for measurements of microclimatic conditions and tree sap flow as well as spectral imaging and soundscape recording. The backbone of the automated data collection and transmission is an autonomous LoRa and WiFi mesh network, which is connected to the internet via radio relay. By utilizing powerful data integration and analysis methods, the system will enable researchers, conservationists and the public to effectively observe landscapes through a set of diverse lenses. Here, we present first results as well as an outlook for future developments of intelligent networked systems for ecosystem monitoring.
Digital Elevation Models (DEM) for the Analysis of the paved surface of Linear Infrastructures
Authors: Fiani Margherita , Di Benedetto Alessandro
Published: March 2020

The proposed study aims at analyzing effective surveying techniques and methodologies to acquire more detailed metric data and to support traditional surveying techniques on linear infrastructures.

In particular, from measurements acquired with LiDAR technique, it is possible to obtain an accurate 3D model of the infrastructure surface, which can be used to have complete information on its distress conditions.

The particular plano-altimetric development of the road belt makes the classic methods used for DEM extraction unsuitable, on which most modelling software is based, which reconstruct the trend of a given variable according to a regular grid of nodes starting from discrete measured and irregularly distributed values. This is done by means of interpolation techniques with which we arrive at a statistical or deterministic surface, usually in matrix format with a resolution chosen by the user; each element of the matrix corresponds to an elevation value. However, it is evident that a grid structure oriented according to the North-South cartographic grid is not effective to represent the curvilinear development of a road infrastructure.

Therefore, we want to introduce a first methodology to generate a particular curvilinear abscissa DEM, called DEMc, suitable for road pavements, which optimizes not only the computational effort but also the organization and extraction of profiles (longitudinal and transversal) and the plano-altimetric analysis. The construction of this model, represented by a ‘raster’ matrix, is semi-automatic. The elevation value of each single node of the two-dimensional grid is estimated through specially modified spatial and local interpolation processes. The process has been implemented in a Matlab environment.

A more advanced example of the digital paving model was based on the study of the deviation of the paved surface from a reference plane. The process involves the creation of a two-pitched flat surface constructed so as to lay on the real surface (theoretically, a road cross-section is represented by a double pitch to allow water flow). The building of the planes is carried out on road sections as wide as the entire carriageway and between 3 and 5 m long. To ensure that the pitch lays on the surface, an iterative algorithm has been implemented; at each iteration the algorithm excludes the points below the plane obtained by previous interpolation. In this way, in the next cycle, the new plane will be built by interpolation on the basis only of the data that were above the plane at the previous iteration; this method makes the plane orient itself according to the number of points remaining at each iterative cycle. The adjacent pitches, in the direction of travel, are built in such a way as to be mutually joined. This process has been implemented in the Matlab environment as well.
Flood-based Farming as Affected by Hydrological Deficit in the Semiarid Lowlands of Northern Ethiopia
Authors: Negash Emnet , Nyssen Jan , Gebresamuel Girmay , Embaye Tesfa-alem , Nguvulu Alick , Meaza Hailemariam , Gebrehiwot Misgina , Demisse Biadglign , Gebreyohannes Tesfaalem , Zenebe Amanuel
Published: March 2020

Agriculture remains the dominant source of food production and the livelihood foundation for majority of the rural poor in the sub-Saharan Africa, including Ethiopia. Access to agricultural-water is, however, a limitation hindering crop productivity and end food insecurity in the drylands. In rain-deficit lowlands such as in the Raya-valley, flood-based farming is a means of improving crop production. Such spate irrigation systems grow in importance; though the effects of headwater hydrological deficit on flood-farming systems are lacking evidence. The present work investigates the impacts of headwater hydrological deficit on spate-irrigated agriculture in Tsge’a spate systems. Canal length and area of spate-irrigated agriculture along Guguf river for the 1980s and 2010s were tracked using Global Positioning System; while runoff trend analysed using linear regression. Annual volume of flash-flood shrunk by 7.36x106 m3. This is mainly due to changing climate and increasing water retention by the soil and humans at the escarpment. As a result, length of canals and area of spate-based farms downstream declined by 1.37 km (35%) and 1540 ha (57.5%), respectively, only in three decades time. This corresponds to an average withdrawal of -44 ha yr-1. A 1x106 m3 decline in flash-flood caused a 366.4 ha decline in spate-based farms. Moreover, farm fields located next to the river course are less affected, as compared to farms on the tail of the scheme. If the current trend continues, there is likely a high risk that the remaining farms currently receiving flood may run out of spate systems. Therefore, flood management technologies are needed to optimize the efficiency of soil moisture in the spate system.

The abstract is based on Negash, E., Gebresamuel, G., Embaye, T., Nguvulu, A., Meaza, H., Gebrehiwot, M., Demisse, B., Gebreyohannes, T., Nyssen, J., & Zenebe, A. (2020). Impact of headwater hydrological deficit on the downstream flood-based farming system in northern Ethiopia. Irrigation and Drainage, In Press.
Characteristics of precipitation and temperature in the Daqing River Basin
Authors: Jiao Yufei , Liu Jia , Li Chuanzhe , Qiu Qingtai , Wang Wei
Published: March 2020

The statistical characteristics of precipitation and temperature in the Daqing River Basin from 1980 to 2015 are analyzed, including the analysis of the homogeneity, trend, mutation and periodicity. Among them, the analysis of homogeneity is based on the method of cumulative value. The trend analysis adopts the methods of moving average, M-K test and R/S. M-K test is also used for the mutation analysis. The wavelet transform is used in the periodic analysis to draw the contour of real part and modulus of precipitation and temperature, as well as the map of the wavelet variance and the main period trend. The results show that the precipitation in the Daqing River Basin from 1980 to 2015 is uniform and has a significant upward trend, and has a sudden change in 2008. As for the periodicity, there are three kinds of periodic changes in 22-32 years, 8-16 years and 3-7 years. In the 22-32 year scale, there are two quasi oscillations of the dry and wet alternation, and four quasi oscillations in the 8-16 year scale. In the graph of the wavelet variance, the peak corresponds to the time scale of 28 years, which indicates that the oscillation of 28 years is the strongest, which is the first main period of precipitation change. From 1980 to 2015, the temperature in the Daqing River Basin is also uniform, and has an obvious upward trend, and has a sudden change in 1992. As for the periodicity, there are three kinds of periodic change, 5-10 years, 14-20 years and 25-32 years, respectively. In the 25-32 year scale, there are two quasi oscillations of dry and wet alternation, and three quasi oscillations in the 14-20 year scale. There are three obvious peaks in the map of wavelet variance, which correspond to the time scales of 28 years, 18 years and 8 years in turn.
Etch pit distribution on calcite cleavage surfaces – experiments and simulation
Authors: Rohlfs Ricarda D. , Trindade Pedrosa Elisabete , Kurganskaya Inna , Fischer Cornelius , Luttge Andreas
Published: March 2020

During the dissolution at a calcite cleavage face, etch pits open around defects. Atomic steps moving outwards from these pit centres are currently considered the general driving mechanism of this dissolution process that results in heterogeneous material flux from the surface. This means that the defects that generate the etch pits are crucial for the surface evolution. Recent kinetic Monte Carlo (kMC) simulation results indicate that not only the density but also the spatial distribution of defects is critical for the influence on dissolution.

In kMC simulations used for crystal dissolution, defect positions are input and can be defined in various ways, e.g., at pre-defined coordinates or randomly drawn from a distribution. The user is free in defining the defects, although it can generally be considered reasonable to choose defect densities and distributions as close as possible to what is expected to occur in nature and technical systems.

The actual spatial distribution of screw dislocations in calcite and their influence on rate variability are still not entirely known. To make the calcite kMC simulations comparable with experimental results, we experimentally determined the etch pit distributions, analyzed them and subsequently used them as input for further kMC studies.

While the direct measurement of defects in the crystal structure is extremely difficult, the indirect approach of measuring etch pits that have formed around defect outcrops during the beginning of dissolution is more feasible. For this, cleaved calcite single crystals were etched using ultra-pure water for 3 to 4 hours to obtain a significant amount of etch pits on the surface. The topography of the crystal surfaces was analysed using Vertical Scanning Interferometry (VSI). The resulting topography maps were stitched to gain a larger area for better statistics, and the centres of visible etch pits marked. This generates two-dimensional point patterns that describe the actual defect distribution more accurately than purely randomly generated coordinates without further constraints.

Based on data analysis of the experiments, we will show the resulting point distributions and synthetic patterns with similar underlying statistics. Using these as input for modelling, we then calculate kMC simulations and geometrical models of a system close to the calcite single crystal from our experiment, and compare them also to simulations using different defect positions as input.
Running a temporary mobile Infrasound Array in Austria: Challenges and Detections
Authors: Mitterbauer Ulrike
Published: March 2020

The mobile Infrasound Array of the Austrian National Data Centerwhich is a part of the Central and Eastern European Infrasound Network (CEEIN) was installed in a location south of Vienna in April 2019. There data will be collected till April 2020 and the analysis will be conducted using dtkGPMCC-Software which is included in the NDC-in-a-Box-Paketand provided by the Comprehensive Treaty Test Ban Organisation (CTBTO). Several challenges occurred due to the power supply with a fuel cell. After constant problems an upgrade was initialized in July 2019. Results of the analysis since beginning of deployment will be shown in the presentation. Detected signals will be compared both with ground truth information and with observations collected by other Infrasound-stations of CEEIN and IMS-station IS26 located in Germany. 

 
Characterization of drought over Botswana: Towards a multivariate approach of drought prediction
Authors: Keitumetse Onneile Nomsa , Mengistu Tsidu Gizaw
Published: March 2020

Recently there has been an increased water scarcity around the world due to high water demand, which is worsened by the recurrent drought characterized by long duration and high severity. However, these characteristics are important in drought monitoring and decision-making for reliable disaster early warning system, water resources planning and management. Semi-arid environments, of which Botswana is known for, exhibit high variability in climate leading to recurring droughts. Hence there is a need to conduct a study to understand the spatio-temporal variability of droughts over Botswana. The Standardized Precipitation Index (SPI) and the Standardized Evapotranspiration Index (SPEI) were used for analysing drought based on gridded rain gauge and evapotranspiration data referred to as Climatic Research Unit (CRU) covering a period of 1901-2018 at a time scale of 12 months. Both SPI and SPEI were able to detect the spatial and temporal variation of drought events. But SPEI was able to identify more droughts in the severe to moderate categories over a wider areas in the country than SPI does. The temporal trends of droughts mostly showed a significant drying trends. The conditional return period of drought of different categories was also determined in a multivariate context by coupling duration, severity, inter-arrival time of drought based on copula distribution and cumulative density functions. Drought events with high intensities had a low probability of occurrence while lower intensities had a high chance of occurrence within 5 to 10 years. Such information on the drought conditional probabilities can be useful in evaluating the water-supply capability and the needed supplementary water resources during severe droughts for a specific water-supply system. In particular, it is generally suitable for the long term planning and management of water resources systems over the country.
NDACC Lidar Validation Activities in Europe
Authors: Wing Robin , Steinbrecht Wolfgang , Godin-Beekmann Sophie , McGee Thomas J. , Sullivan John , Sumnicht Grant , Ancellet Gérard , Hauchecorne Alain , Khaykin Sergey , Keckhut Philippe
Published: March 2020

Recent intercomparison exercises have been conducted at two European NDACC lidar sites.  The mobile NASA Stratospheric Ozone Lidar (NASA STROZ) was present for a two part validation campaign at the Observatoire de Haute-Provence (43.93 N, 5.71 E) in July 2017 and March 2018 and at the Hohenpeißenberg Meteorological Observatory (47.80 N, 11.00 E) in March 2019.  Lidar profiles of ozone and temperature were compared with local radiosondes and ozonesondes; satellite profiles from local overpasses of Sounding of the Atmosphere by Broadband Emission Radiometry instrument (SABER) and Microwave Limb Sounder (MLS); and NCEP reanalysis. There is overall good agreement between all the lidar instruments and the balloon measurements, particularly in the reproduction of small scale features, during all three phases of the European campaign.  

We have conducted a detailed correlational study of all instruments involved in the campaign and have rigorously evaluated the uncertainty budget of each instrument.  We will discuss the strengths and drawbacks of different statistical techniques for evaluating coincident ozone and temperature measurements and compare how our estimates of instrument uncertainty compare to the observed variance in the data.
The World Digital Magnetic Anomaly Map: version 2.1
Authors: Dyment Jerome , Choi Yujin , Lesur Vincent , Garcia-Reyes Andreina , Catalan Manuel , Ishihara Takemi , Litvinova Tamara , Hamoudi Mohamed
Published: March 2020

The World Digital Magnetic Anomaly Map (WDMAM) is an initiative of the IAGA (International Association of Geomagnetism and Aeronomy) supported by the CGMW (Commission for the Geological Map of the World) of UNESCO. The second version was released in 2015 (Dyment et al., 2015; Lesur et al., 2016), and mandate was given to the authors to update this version 2.0 using the same methodology as often as newly available data would make it necessary. Five better datasets justify the preparation and release of version 2.1: (1) the complete digital aeromagnetic map of Brasil made available to CGMW by Agência Nacional do Petróleo, Gás Natural e Biocombustíveis; (2) an improved version of the aeromagnetic map of Russia prepared at VSEGEI; (3) the second version of the Antarctic Digital Magnetic Anomaly maP (ADMAP; Golynsky et al., 2018) which construction results from a remarkable international effort during and after the Second International Polar Year; (4) a new map of the Caribbean plate and Gulf of Mexico resulting from the compilation and re-processing of existing marine and aeromagnetic data in the area (Garcia, 2018); and (5) a new compilation of marine magnetic data worldwide. The new map shows significant improvements over the previous versions and will be shortly available at wdmam.org.
Direct inversion of 3-D shear wave speed azimuthal and radial anisotropy from surface-wave traveltime data: methodology and applications
Authors: Huajian Yao , Chuanming Liu , Shaoqian Hu
Published: March 2020

Seismic anisotropy plays a key role in understanding deformation patterns of Earth’s material.  Surface wave dispersion data have been widely used to invert for azimuthal and radial anisotropy of shear wave speeds in the crust and upper mantle typically based on a 1-D pointwise inversion scheme. Here we present new methods of inverting for 3-D shear wave speed azimuthal and radial anisotropy directly from surface-wave traveltime data with the consideration of period-dependent surface wave raytracing. For the inversion of 3-D azimuthal anisotropy, our new method includes two steps: (1) inversion for the 3-D isotropic Vsv model directly from Rayleigh wave traveltime data (DSurfTomo; Fang et al., 2015, GJI); (2) joint inversion for both 3-D Vsv azimuthal anisotropy and additional 3-D isotropic Vsv perturbation. The joint inversion can significantly mitigatethe trade-off between the strong heterogeneity and azimuthal anisotropy. We apply the new method (DAzimSurfTomo) (Liu et al., 2019, JGR)to a regional array in Yunnan, southwestern China using the Rayleigh-wave phase velocity dispersion data in the period band of 5-40 s extracted from ambient noise interferometry. The obtained 3-D model of shear wave speed and azimuthal anisotropy indicates differentdeformation styles between the crust and upper mantle insouthern Yunnan. For the inversion of 3-D radial anisotropy, we presented a new inversion matrix that directly inverts Rayleigh and Love wave traveltime data jointly for 3-D Vsv and radial anisotropy parameters (Vsh/Vsv) simultaneously without intermediate steps (Hu et al., submitted to JGR).  The new approach allows for adding the smoothing or model regularization terms directly on the radial anisotropy parameters, which helps to obtain more reliable radial anisotropy structures compared to the previous division approach (Vsh/Vsv) from separate inversion of Vsv and Vsh structures. We apply this new approach (DRadiSurfTomo) to the region around the eastern Himalayan syntaxis using ambient noise dispersion data (5-40s). The obtained 3-D Vs and radial anisotropy models reveals complex distribution of crustal low velocity zones and spatial variation of deformation patterns around the eastern syntaxis region.
Developing new approaches and strategies for teaching Physical Geography and Geomorphology: the role of AIGeo (Italian Association of Physical Geography and Geomorphology)
Authors: Bollati Irene Maria
Published: March 2020

The researches carried out by the AIGeo (Italian Association of Physical Geography and Geomorphology) members, also in collaboration with other researchers, cover various important topics of the Environmental and Earth Sciences. Geomorphology is central, also in the framework of dissemination strategies that are implemented and elaborated. A particular focus is, in fact, addressed to the development of educational strategies and applications focusing on landscape evolution through space and time having as target both students and teachers. The proposed strategies include fieldworks, multimedia activities and multidisciplinary approaches addressed mainly to secondary schools. In the Italian framework, the Ministerial National Guidelines provide indications about teaching these topics in the secondary schools. The guidelines indicate specifically, for the secondary schools of 2nd level, the topics and novelties concerning Physical Geography and Geomorphology. Among the general goals referred to the secondary school of 1st level, the landscape observation and the related natural phenomena are approached by the Geography teachers and by the Science teachers. Herein, we present an overview on the AIGeo activities regarding education in Physical Geography and Geomorphology. Some examples of the most recent researches planned and tested for the secondary school (1st and 2nd level) will be outlined. Moreover, the initiatives addressed specifically to present and future teachers will be illustrated too.
Evaluating the signature of oceanic striations on the distribution of biogeochemical properties in the Eastern Pacific Ocean off Chile
Authors: Auger Pierre-Amaël , Villegas Valerie , Belmadani Ali , Donoso David , Berger Tomas , Hormazabal Samuel
Published: March 2020

In recent years, quasi-zonal mesoscale jet-like features, also called “striations”, have been ubiquitously detected in the time-mean circulation of the world ocean using satellite altimetry and in situ data. These alternating bands of eastward/westward flow are able to advect and mix physical properties. Yet, their impact on biogeochemistry, and potentially marine ecosystems, has not been assessed yet.

In eastern boundary upwelling systems, a mesoscale structuration of biogeochemical properties may be associated to striations through the interaction of zonal flows with sharp coastal-offshore background gradients (stirring). Transport patterns by mesoscale eddies (trapping) may also be involved as striations were noticeably suggested to result from the organization of the mesoscale eddy field as preferred eddy tracks in the eastern South Pacific upwelling system (off central Chile).

In this region, we evaluate the expression of striations in satellite records of ocean color and in a set of numerically simulated biogeochemical tracers (chlorophyll, carbon, primary production, oxygen, nutrients). A multi-decadal hindcast simulation of the physical-biogeochemical dynamics was run over the period 1984-2013 using the ROMS-PISCES (for Regional Oceanic Modeling System - Pelagic Interactions Scheme for Carbon and Ecosystem Studies) platform at an eddy-resolving resolution. High-pass spatial filtering is used to remove the large-scale signal in time-averaged satellite data and model outputs, and subsequently evaluate the match between striations and biogeochemical tracer anomalies in the model and observations. The relation between striations and the shape of the coastal-offshore gradient of the phytoplankton biomass and the oxygen-minimum zone is then deduced in the CTZ, and further in the open ocean region. The fraction of tracer anomalies associated to striations is quantified, and the respective potential role of stirring and eddy trapping is explored by matching quasi-zonal bands of sea level anomaly, geostrophic currents and biogeochemical tracers on moving frames of variable widths from 3 months to several years. The role played by eddy trapping is then confirmed by a composite analysis based upon automated eddy tracking.
A particle method strategy to estimate subsidence induced by a high-dimensional disc-strain model for reservoir compaction.
Authors: Kim Samantha , Vossepoel Femke , Hanssen Ramon F. , Wouters Marius , Govers Rob , Stouthamer Esther
Published: March 2020

This work is part of the "Subsidence" DeepNL project which aims to identify subsurface drivers of subsidence above the Groningen (the Netherlands) gas field and to forecast future subsidence. The hydrocarbon extraction in Groningen induces a pressure reduction in the gas reservoir which triggers compaction and land subsidence. This deep-subsurface process is modeled by a disc-shaped reservoir model, which is a superposition of individual nuclei of strain based on the Geertsma's approach. We estimate the surface deformation and the strength of the disc strain using a particle method. We apply the method to one single nucleus of strain at 3 km depth and extend to a disc-shape geometry. Synthetic experiments with a single nucleus of strain and with discs of varying sizes, 2.2 km to 13.3 km diameter, at 3 km depth are performed to assess the performance of the method for an increasing degree of complexity. Sequential Importance Resampling prevents the sample degeneracy when the number of nuclei increases. Adding a jitter noise in the resampling step avoids an impoverishment of the ensemble values. The results indicate that the method estimates the surface deformation and the strength for a large number of sources and for a relatively small effective ensemble size. In further investigations, localization can provide an additional means to deal with increasing dimensions and a relatively small ensemble size.
The role of coordination number and pore size distribution on flow organization in porous media
Authors: Puyguiraud Alexandre , Uszes Pierre , Dentz Marco
Published: March 2020

Understanding and computing fluid flow in porous media is relevant for many environmental and industrial applications. However, directly computing the flow on complex and large geometries is limited by computational capacities. To tackle this issue, many studies have aimed at relating flow distributions to the geometrical properties of the domain. However, understanding the relation between the the pore-scale structure and the experienced velocity distribution is still a challenge.
To improve this understanding we study well defined pore network models in 2D and 3D. We vary three main parameters: the coordination number that determine the amount of connections that a pore body has, the distribution of pore sizes, and geometric disorder.

We focus on the impact of these parameters on the flow organization in term of the distribution of flow speeds and local pressure gradients. We conclude that distribution of pore sizes and the coordination number are the main geometrical features that control the Eulerian speed distribution. 
The magnetic field quantization in pulsar
Authors: Rozina Chaudhary , LevanNodar Tsintsadze , Tsintsadze Nodar
Published: March 2020

Magnetic field quantization is an important issue for degenerate environments such as neutron star, radio pulsars and magnetars etc., due to the fact that these stars have magnetic field even more than the quantum critical field strength of the order of 4.4×10¹³G, accordingly the cyclotron energy may be equal or even much more than the Fermi energy of degenerate particles. We shall formulate here the exotic physics of strongly magnetized neutron star. The effect of quantized anisotropic magnetic pressure, arising due to a strong magnetic ﬁeld is studied on the growth rate of Jeans instability of quantum electron–ion and classical dusty plasma.  Here we shall formulate the dispersion equations to govern the propagation of the gravitational waves both in perpendicular and parallel directions to the magnetic ﬁeld, respectively.  We will depict here that the quantized magnetic field will result in Jeans anisotropic instability such that for perpendicular propagation, the quantized magnetic pressure will stabilize Jeans instability, whereas for the parallel propagation the plasma become more unstable.  We also intend to calculate the corresponding Jeans wave number in the absence of tunneling. The Madelung term leads to the inhomogeneity of the plasma medium. Numerical results are presented to show the effect of the anisotropic magnetic pressure on the Jeans instability.
A global synthesis of dual nitrate isotope values in rivers and groundwaters
Authors: Matiatos Ioannis ,   IAEA Coordinated Research Project on Isotopes to study nitrogen pollution and eutrophication of rivers and lakes
Published: March 2020

Exponential human population growth and the rapid co-development of agricultural and industrial sectors have caused a sharp increase of nitrogen loading to rivers and groundwaters worldwide since the 1950s. Reactive nitrogen species (e.g., nitrate, ammonium) are widely distributed compounds in rivers and groundwaters primarily as a result of diverse agricultural activities utilizing N-containing fertilizers and anthropogenic non-point sources, such as the disposal of sewage by centralized and individual systems, animal feeding operations, and elevated atmospheric N deposition. Systematic efforts to identify global patterns in nitrogen loss processes using nitrogen isotopes have mostly targeted soil and plant systems but remain rather limited for surface and/or groundwater systems. Here, synthesized published (4,492) and new data (425) for nitrogen and oxygen isotopes of nitrate in rivers and groundwater generated under an IAEA Coordinated Research Project, which aimed to utilize the application of nitrogen isotope techniques to assess nitrogen pollution in rivers and groundwaters, are presented. Among the two water types, we found that groundwater had higher average nitrate concentrations (~5.0 mg L-1 NO3-N) versus rivers (~2.0 mg L-1 NO3-N), slightly higher δ15N and much higher δ18O (+7.6 ‰ and +4.3 ‰, respectively) compared to rivers (+7.0 ‰ and +1.8 ‰, respectively). Seasonal variations in the concentrations and the isotopic compositions of N-species were found to be temperature related, given that biological activity increases with water temperature. Across a range of Köppen climate types, we found the δ15N and δ18O of NO3 in rivers systematically increased when moving from temperate to tropical climates, following the increase of the average air temperature.
Criticality in Tropical Rainfall: A Simple Water Budget Model
Authors: Svendsen Mikkel
Published: March 2020

Deep convective rain events in the tropics represent an essential ingredient of Earth's climate system, acting as a driver of large-scale circulation which distributes energy and moisture. Understanding how they organize remains a challenge. Observational studies indicate that tropical convection may be understood as an instance of self-organized criticality (SOC) [1]:
(i) Rain rate vs. column water vapor follows a clear "pickup curve": Essentially no rain is observed in dry areas, while at column moistures above a critical value the rain rate increases sharply.
(ii) Rain events and clusters, defined as groups of contiguous rainy points in space and/or time, have size distributions well described by power laws.
The first result indicates that the atmosphere undergoes a phase transition, separating a non-raining "inactive" phase from a rainy "active" one. The second result suggests that the system is found close to the critical transition point, where "scale-free" power law distributions are expected. Indeed, observations find typical moisture values to be close to the critical moisture value. 

SOC theory would suggest that the observational results are an emergent phenomenon, caused by simple local interactions that carry over to larger scales. However, to our knowledge, no simple SOC model linking moisture and rainfall has been suggested that explains how criticality arises from convective processes while also predicting the observed rain cluster sizes. A more complete theory, especially on spatial aspects, is lacking.
We therefore present a simple spatiotemporal model of the atmospheric water budget, exploring whether a fuller picture including spatial information can be developed. Each site of the model represents an atmospheric column, where water can enter through surface evaporation, leave as surface rain, or get redistributed among neighboring sites due to convective in- and outflows. We analyse a cloud resolving model simulation in radiative-convective equilibrium, by grouping grid points into three categories: rainy points (convectively active), neighbors of rainy points and others (convectively passive). Tendencies, evolutions and transitions are examined to identify local "rules" to inform the interactions and parameters in our model.
Hence, in this project we use a simple model approach to find whether local convection mechanisms of water rearrangements can explain why tropical rainfall seems to show critical characteristics. In addition, this might aid development of convective parameterizations for climate models: Including a few key convective scale interactions, suggested by our model, might help to better capture important effects of subgrid correlations in a simple way.
 
[1] Peters, O., and J. D. Neelin (2006), Critical phenomena in atmospheric precipitation, Nat. Phys., 2(6), 393-396, doi:10.1038/nphys314.
Ambient seismic noise suppression in COST action G2Net
Authors: Ilić Velimir , Bertolini Alessandro , Bonsignorio Fabio , Jozinović Dario , Bulik Tomasz , Štajduhar Ivan , Secrieru Iulian , Koley Soumen
Published: March 2020

The analysis of low-frequency gravitational waves (GW) data is a crucial mission of GW science and the performance of Earth-based GW detectors is largely influenced by ability of combating the low-frequency ambient seismic noise and other seismic influences. This tasks require multidisciplinary research in the fields of seismic sensing, signal processing, robotics, machine learning and mathematical modeling.

In practice, this kind of research is conducted by large teams of researchers with different expertise, so that project management emerges as an important real life challenge in the projects for acquisition, processing and interpretation of seismic data from GW detector site. A prominent example that successfully deals with this aspect could be observed in the COST Action G2Net (CA17137 - A network for Gravitational Waves, Geophysics and Machine Learning) and its seismic research group, which counts more than 30 members. 

In this talk we will review the structure of the group, present the goals and recent activities of the group, and present new methods for combating the seismic influences at GW detector site that will be developed and applied within this collaboration.

 

This publication is based upon work from CA17137 - A network for Gravitational Waves, Geophysics and Machine Learning, supported by COST (European Cooperation in Science and Technology).