bluuebunny/crossref_metadata_2025 huggingface dataset:
Global water soil erosion risk associated with climate change
Authors: Xiong Muqi
Published: March 2020

Water-driven soil erosion is the most widespread form of soil degradation worldwide, which threatens to the sustainability of agriculture. Climate change may aggravate the threat of erosion. On the basis of the Revised Universal Soil Loss Equation, combined with Geographic Information Systems (GIS), we assessed spatiotemporal variances in global water erosion risk trends during the period 1992–2015 using the linear regression model. The research objective was to explore the spatial pattern of global water erosion risk change in recent decades and to identify the driving factors. The results show that the global water erosion risk increased over 54% of the surface during 1992–2015, with an average rate of 0.17 t·ha-1·yr-2. The lands with significant increasing trends (p < 0.05) accounted for 12% of global lands, with an average rate of 0.27 t·ha-1·yr-2. In which, over 75% regions with significant increasing trends were croplands and forest lands in the cold climate zone as the rainfall intensity increased. However, the increasing rates of soil erosion risk on bare lands and croplands were extremely larger than that on lands with natural vegetation, which means that water erosion on natural lands had much lower sensitive to rainfall changes. These results suggest that improving vegetation conditions in the region with sensitive climate change could reduce the erosion threat.
Soil heterotrophic respiration as a function of water content and temperature in a mechanistic pore-scale model
Authors: Gharasoo Mehdi , Fairbairn Linden , Rezanezhad Fereidoun , Van Cappellen Philippe
Published: March 2020

Soil heterotrophic respiration has been considered as a key source of CO2 flux into the atmosphere and thus plays an important role in global warming. Although the relationship between soil heterotrophic respiration and soil water content has been frequently studied both theoretically and experimentally, model development has thus far been empirically based. Empirical models are often limited to the specific condition of their case studies and cannot be used as a general platform for modeling. Moreover, it is difficult to extend the empirical models by theoretically defined affinities to any desired degree of accuracy. As a result, it is of high priority to develop process-based models that are able to describe the mechanisms behind this phenomenon with more deterministic terms.

Here we present a mechanistic, mathematically-driven model that is based on the common geometry of a pore in porous media. Assuming that the aerobic respiration of bacteria requires oxygen as an electron acceptor and dissolved organic carbon (DOC) as a substrate, the CO2 fluxes are considered a function of the bioavailable fraction of both DOC and oxygen. In this modeling approach, the availability of oxygen is controlled by its penetration into the aquatic phase through the interface between air and water. DOC on the other hand is only available to a section of the soil that is in contact with water. As the water saturation in the pore changes, it dynamically and kinematically impacts these interfaces through which the mass transfer of nutrients occurs, and therefore the CO2 fluxes are directly controlled by water content. We showcased the model applicability on several case studies and illustrated the model capability in simulating the observed microbial respiration rates versus the soil water contents. Furthermore, we showed the model potential to accept additional physically-motivated parameters in order to explain respiration rates in frozen soils or at different temperatures.
The evolution and distribution of recycled oceanic crust in the Earth’s mantle: Insight from geodynamic models
Authors: Yan Jun , D. Ballmer Maxim , J. Tackley Paul
Published: March 2020

A better understanding of the Earth’s compositional structure is needed to place the geochemical record of surface rocks into the context of Earth accretion and evolution. Cosmochemical constraints imply that lower-mantle rocks may be enriched in silica relative to upper-mantle pyrolite, whereas geophysical observations support whole-mantle convection and mixing. To resolve this discrepancy, it has been suggested that subducted mid-ocean ridge basalt (MORB) segregates from subducted harzburgite to accumulate in the mantle transition zone (MTZ) and/or the lower mantle. However, the key parameters that control basalt segregation and accumulation remain poorly constrained. Here, we use global-scale 2D thermochemical convection models to investigate the influence of mantle-viscosity profile, planetary-tectonic style and bulk composition on the evolution and distribution of mantle heterogeneity. Our models robustly predict that, for all cases with Earth-like tectonics, a basalt-enriched reservoir is formed in the MTZ, and a harzburgite-enriched reservoir is sustained at 660~800 km depth, despite ongoing whole-mantle circulation. The enhancement of basalt and harzburgite in and beneath the MTZ, respectively, are laterally variable, ranging from ~30% to 50% basalt fraction, and from ~40% to 80% harzburgite enrichment relative to pyrolite. Models also predict an accumulation of basalt near the core mantle boundary (CMB) as thermochemical piles, as well as moderate enhancement of most of the lower mantle by basalt. While the accumulation of basalt in the MTZ does not strongly depend on the mantle-viscosity profile (explained by a balance between basalt delivery by plumes and removal by slabs at the given MTZ capacity), that of the lowermost mantle does: lower-mantle viscosity directly controls the efficiency of basalt segregation (and entrainment) near the CMB; upper-mantle viscosity has an indirect effect through controlling slab thickness. Finally, the composition of the bulk-silicate Earth may be shifted relative to that of upper-mantle pyrolite, if indeed significant reservoirs of basalt exist in the MTZ and lower mantle.
Canadian Air Quality Forecasting and Information Systems
Authors: Pavlovic Radenko , Racine Jacinthe , Egyed Marika , Lamy Serge , Boucher Pierre
Published: March 2020

Canadian Air Quality Forecasting and Information Systems

Environment and Climate Change Canada (ECCC) has been in charge of the national air quality program for more than 20 years. As of today, air pollution remains one of the most important environmental risk factors to health, in addition to hazardous effects on climate change, ecosystems, properties, and food and water chain.

Currently, Canadian air quality forecasting and information systems with observational and modeling components are a key element for policy and mitigation measures, which are used to reduce the negative impacts of air pollution. The operational ECCC’s air quality program provides immediate adaptive measures based on early warning services. In addition to this operational service, the air quality scenario and policy modelling is essential for implementing cost-effective emission reduction strategies and local planning to ensure compliance with air quality standards.

Canadian air quality forecasting and information systems also enable access to air quality data at different temporal and spatial scales. This is done through coordination of national activities to facilitate seamless provision of atmospheric composition information at various scales. This work will present Canadian air quality forecasting and information systems, components, collaboration, application and data streaming, as an example that can be helpful in building the WMO GAFIS initiative.
Integrating water desalination plants in renewable energy systems for isolated areas
Authors: Ntrizai Argyris , Dimitriadis Panayiotis , Iliopoulou Theano , Mamassis Nikos , Koutsoyiannis Demetris
Published: March 2020

Isolated areas may face difficulties regarding both energy security and water supply as they are often not connected to the energy and water network of the mainland. In this respect, we investigate the integration of a desalination plant in the planning of a hybrid renewable energy system for an isolated area, in order to satisfy energy and freshwater needs. We examine the major desalination technologies (thermal, membrane) and we compare their advantages, limitations and potential for water production, in a small Aegean island. Using stochastic approaches for the energy and water demand and production, the reliability and feasibility of such a renewable energy-based desalination plant are investigated.

Acknowledgement: This research is conducted within the frame of the undergraduate course "Stochastic Methods" of the National Technical University of Athens (NTUA). The School of Civil Engineering of NTUA provided moral support for the participation of the students in the Assembly.
Spatiotemporal analysis of extreme temperature and humidity in the Mississippi River Basin, USA
Authors: Tavakol Ameneh , Rahmani Vahid
Published: March 2020

Impacts of climate change on water resources will rise from the co‐occurrence of extreme hot and humid conditions. In this study, changes in the daytime and nighttime hot and humid conditions were analyzed in the Mississippi River Basin, USA covering large semi-arid regions. Results indicated that humid nights and days have increased over 1948-2017 in at least 93% of the basin. Concurrent hot and humid events were increased during both nights and days with more significant trends for nighttime events. A change-point analysis was completed and more significant upward trends were observed after the 1980s and 1990s for extreme temperature, humidity, and hot-humid events. Results suggested a higher risk of receiving extreme hot and humid conditions for the central and southern Mississippi River Basin. The findings can help improve water resources management and allocation in the semi-arid regions of the watershed where access to surface water resources is limited.
Integrated geophysical data for investigating the tectonic structures in eastern Taiwan
Authors: Kuo-Chen Hao , Guan Zhuo-Kang , Sun Wei-Fang , Chen Chun-Rong
Published: March 2020

The Taiwan orogeny is forming along a complex plate boundary in which the Eurasian Plate (EUP) is subducting eastward beneath the Philippine Sea Plate (PSP). This complex plate boundary is situated in eastern Taiwan and results in large earthquakes occurred frequently in this region. For instance, in 1951, 1972, 1986, 2003, 2006, 2013, 2018, and 2019, earthquakes with magnitude greater than 6 occurred near or along the plate boundary and most of them caused serious damages. However, due to the complexity of the plate boundary from south to north of eastern Taiwan, the seismogenic structures for those events are very different. In order to understand the tectonic structures thoroughly in eastern Taiwan, we planned a integrated geophysical experiment, including seismic reflection, dense seismic array deployments, and magnetic survey from 2016 to 2020. There are 8 seismic reflection profiles along the Longitudinal valley from north to south. As a result, the seismic images show that the sedimentary deposits can reach ~1 km thickness in the northern part and is shallower toward to the southern part. The rocks below the sedimentary deposits are from the east flank of the Longitudinal valley, which belongs to the Eurasian plate. The dense array deployments from 2016-2019 around eastern Taiwan with 1-5 km spacing and totally more than 300 short-period stations deployed. During the deployments, we have captured two aftershock sequences in the north of eastern Taiwan in 2018 and 2019. The seismogenic zones with high-resolution tomography from dense seismic array data sets reveal that the plate interaction between the EUP and PSP. The physical behaviors of the seismogenic zones are related to the collision to subduction along the plate boundary from south to north. Also, the results of the magnetic survey in eastern Taiwan show that the high magnetic anomalies only sparsely distribute, which indicates the volcanic arc may not widely occupy than previous geological investigation. The results of this experiment provide a new thought of the tectonic processes along the plate boundary in eastern Taiwan.
Modeling directional anisotropies of forest emissions using a thermal FRT model
Authors: Bian Zunjian , Cao Biao , Li Hua , Du Yongming , Xiao Qing , Liu Qinhuo
Published: March 2020

Land surface temperature (LST) is an essential indicator of forest growth conditions, drought and fire. However, retrieved LSTs from satellite-based thermal infrared (TIR) observations prone to directional anisotropies, and a pixel-averaging temperature, that is usually aggregated by different components such as overstory canopy, tree trunk, understory vegetation and bottom soil, cannot directly reflect the temperature distribution inside a forest. Currently, existing analytical thermal radiative transfer models (RTM) can hardly fill this gap due to complicated structural and thermal variations in a forest stand. In this paper, a famous visible and near-infrared (VNIR) RTM, FRT, was introduced to the TIR domain, in which a themral emission term of components was added. Moreover, the effect of vertical heterogeneity of leaves’ temperatures on top-of-canopy (TOC) brightness temperatures (BTs) was also considered. Based on a simulated dataset, the effect of the tree trunk and understory vegetation on TOC BTs was found significant, and the temperature profile of leaves can increase the directional anisotropy of TOC BTs. An inter-comparison with a three-dimensional radiosity model indicated a stable performance of the modified thermal FRT model. The thermal FRT model was also validated using a measured dataset from an airborne sensor, and the evaluation result revealed a satisfactory performance with root mean squared error and coefficient of determination of 0.55°C and 0.74 in the solar principal plane (SPP), respectively, and the corresponding values were 0.21°C and 0.90 in cross-SPP. The thermal FRT model has capable of acting as not only a tool to link satellite TIR observations and component temperatures for a further sub-pixel inversion and an angular normalization study of LSTs, but also a supplement for combined applications using both VNIR and TIR remotely sensed observations.
Chemical composition of summertime High Arctic aerosols using chemical ionization mass spectrometry
Authors: Siegel Karolina , Zieger Paul , Salter Matthew , Riipinen Ilona , Ekman Annica M.L. , Mohr Claudia
Published: March 2020

Low-level clouds and fogs play a key role in the radiative balance over the Arctic pack ice by regulating surface energy fluxes. The radiative features of clouds are dependent on the amount of airborne aerosol particles and their properties, since the particles can act as CCN (cloud condensation nuclei) and INP (ice nucleating particles). As the Arctic climate is currently warming, the local emissions and formation mechanisms of aerosols are expected to change, possibly leading to altered cloud properties.

We measured aerosol chemical composition using FIGAERO-CIMS (Chemical Ionization Mass Spectrometer coupled to a Filter Inlet for Gases and AEROsols) analysis of samples collected during the MOCCHA campaign (Microbiology-Ocean-Cloud-Coupling in the High Arctic) close to the North Pole in 2018. The goal of the campaign was to investigate natural aerosol emissions from the ocean to the atmosphere during summertime in terms of local sources and potential contribution to cloud formation. The sampling period was therefore around the seasonal sea ice minimum in September. With our CIMS setup, the sample molecules are ionised by iodide ions (I-). The negatively charged adducts are then separated by mass, allowing for characterisation on a molecular level. This is the first time aerosol chemical composition of High Arctic aerosols has been measured using this technique. As the current knowledge about the atmospheric composition in this region is low, our results suggest a potential for using this method for further aerosol chemical characterisation in the pristine Arctic environment.

Our analysis shows that sulphur-containing compounds were most abundant in the aerosol samples, including sulphuric acid, sulphur trioxide, methanesulphonic acid (MSA) and dimethyl sulphoxide (DMSO). MSA and DMSO are oxidation products of dimethyl sulphide (DMS), which is released by marine phytoplankton to the atmosphere under ice-free conditions. Non-sea-salt sulphate (nss-SO42-) aerosols are known to be efficient CCN. The results will be compared to aerosol samples from the NASCENT campaign (Ny-Ålesund Aerosol and Cloud Experiment), analysed using the same CIMS technique. The campaign runs for a year during 2019-2020 at the Zeppelin station in Svalbard. Our findings are expected to contribute to better understanding of the connection between aerosols and cloud formation in the polar regions and the effects on the ocean and pack ice.
Evolution of Turbulence in the Kelvin–Helmholtz Instability mediated by the Magnetopause and its Boundary Layer
Authors: Di Mare Francesca , Sorriso-Valvo Luca , Retino' Alessandro , Malara Francesco , Hasegawa Hiroshi
Published: March 2020

The turbulence at the interface between the solar wind and the Earth’s magnetosphere, mediated by the magnetopause and its boundary layer are investigated by using Geotail and THEMIS spacecraft data during ongoing Kelvin-Helmholtz instability (KHI). The efficient transfer of energy across scales for which the turbulence is responsible, achieves the connection between the macroscopic flow and the microscopic dissipation of this energy. This boundary layer is thought to be the result of the observed plasma transfer, driven by the development of the KHI, originating from the velocity shear between the solar wind and the almost static near-Earth plasma. A collection of 20 events spatially located on the tail-flank magnetopause, selected from previously studied by Hasegawa et al. 2006 and Lin et al. 2014, have been tested against standard diagnostics for intermittent turbulence. In light of the results obtained, we have investigated the behaviour of several parameters as a function of the progressive departure along the Geocentric Solar Magnetosphere coordinates, which roughly represent the direction in which we expect the KHI vortices to evolve towards fully developed turbulence. It appears that a fluctuating behaviour of the parameters exist, visible as a decreasing, quasi-periodic modulation with an associated periodicity, estimated to correspond to approximately 6.4 Earth Radii. Such observed wavelength is consistent with the estimated vortices roll-up wavelength reported in the literature for these events. If the turbulence is pre-existent, it is possible that the KHI modulates its properties along the magnetosheath, as we observed. On the other hand, if we assume that the KHI has been initiated near the magnetospheric nose and develops along the flanks, then the different intervals we study may be sampling the plasma at different stages of evolution of the KH-generated turbulence, after the instability has injected energy in a cascading process as large-scale structures.
Interannual variability of the seesaw mode of the interface between the Indian and East Asian summer monsoons
Authors: Yang Ruo Wen , Wang Jian
Published: March 2020

The relation between the seesaw mode of the Interface between the Indian summer monsoon and East Asian summer monsoon (IIE) and the South China Sea summer monsoon trough (SCSSMT) and the Indian summer monsoon trough (ISMT) is investigated using two atmospheric reanalyses together with outgoing longwave radiation, sea surface temperature (SST), and gridded precipitation datasets. Canonical correlation analysis combined with empirical orthogonal functions, correlation, and composite analysis are employed. Results indicate that a stronger ISMT and SCSSMT resulting from colder SST over the tropical Indian Ocean and tropical east-central Pacific cause the IIE to deviate from its normal position in an anticlockwise direction, with a node at around 22°N. This leads to heavier than normal summer rainfall over the north-central Indian subcontinent and South China Sea, but weaker than normal from the low and middle reaches of the Yangtze River and South Korea to central Japan. A weaker ISMT and SCSSMT resulting from warmer SST over the tropical Indian Ocean and tropical east-central Pacific causes the IIE to deviate from its normal position in a clockwise direction, and the anomalous summer rainfall pattern is the opposite of that for the stronger troughs. Further analysis indicates that the SCSSMT plays a crucial role in the evolution of the IIE seesaw mode. The latitudinal difference between the IMST and SCSSMT may be one of the most important reasons for the formation of the IIE seesaw mode.
Estimation of the annual runoff frequency distribution under a non-stationarity condition within the Budyko framework
Authors: Yang Hanbo , Liu Ziwei
Published: March 2020

In the past decades, climate change has been leading to non-stationarity in hydrological variables. Therefore, a simple framework within the Budyko framework is proposed to estimate the annual runoff frequency distribution and provide a new method for hydrological design under non-stationarity conditions. In this framework, the mean and standard deviation of annual runoff are derived by the Choudhury-Yang equation. Furthermore, the P-Ш type frequency curve is selected to calculate the annual runoff on a design return period. Based on this framework, the change in water resources in 207 three-level basins across China during 2020-2050 are estimated according to the Coupled Model Inter-comparison Project Phase 5. The results show that the mean annual runoff will decrease by 2.7% for all basins, and the regional difference will decline, i.e., the mean annual runoff will increase in the north of China and decrease in the south of China. However, the inter-annual variability of annual runoff will increase in more than 70% of basins. Additionally, in the wet year, approximately half of the total basins show decreased runoff change, and in the dry year, decreased change appears in ~65% basins. These findings offer a simple and effective way to re-examine the effects of non-stationarity in hydrological design.
Future climate change risk to forests in China responding to intensified dryness
Authors: Yin Yunhe , Ma Danyang , Wu Shaohong
Published: March 2020

Variations in forest net primary productivity (NPP) reflects the combined effects of key climate variables on ecosystem structure and function, especially on the carbon cycle. We performed risk analysis indicated by the magnitude of future negative anomalies in NPP in comparison with the natural interannual variability to investigate the impact of future climatic projections on forests in China. The analysis was conducted mainly based on modifying the Lund–Potsdam–Jena Dynamic Global Vegetation Model, which was driven by five general circulation models (GCMs) simulations. Results from the multi-model ensemble showed that climate change risk of decreases in forest NPP would be more significant in higher emission scenario in China. Under relatively low emission scenarios, the total area of risk was predicted to decline, while for RCP8.5, it was predicted to first decrease and then increase after the middle of 21st century. The rapid temperature increases predicted under the RCP8.5 scenario would be probably unfavorable for forest vegetation growth in the long term. High-level risk area was likely to increase except RCP2.6. The percentage area at high risk was predicted to increase from 5.39% (2021–2050) to 27.62% (2071–2099) under RCP8.5. Climate change risk to forests was mostly concentrated in southern subtropical and tropical regions, generally significant under high emission scenario of RCP8.5, which was mainly attributed to the intensified dryness in south China.
A meta-model assisted framework of optimization of the Hydrological model parameters for accurate calibration
Authors: Nusrat Ammara , Farooq Gabriel Hamza , Haider Sajjad , Shahid Muhammad
Published: March 2020

 Increase in frequency of the floods is one of the noticeable climate change impacts. The efficient and optimized flood analysis system needs to be used for the reliable flood forecasting. The credibility and the reliability of the flood forecasting system is depending upon the framework used for its parameter optimization. Comprehensive framework has been presented to optimize the input parameters of the computationally extensive distributed hydrological model. A large river basin has the high spatio-temporal heterogeneity of aquifer and surface properties.  Estimating the parameters in fully distributed hydrological model is a challenging task. The parameter optimization becomes computationally more demanding when the model input parameters (30 to 100 even greater) have multi-dimensional parameter space, many output parameters which make the optimization problem multi-objective and large number of model simulations requirement for the optimization. Aforementioned challenges are met by introducing the methodology to optimize the input parameters of fully distributed hydrological model, following steps are included (1) screening of the parameters through Morris sensitivity analysis method in different flow periods, so that optimization would be performed for sensitive parameters, different scalar output functions are used in this regard (2) to emulate the hydrologic response of the dynamic model, surrogate models or meta-models are used (3) sampling of parameters values using the optimized ranges obtained from the meta-models; the results are evident that the parameter optimization using the proposed framework is efficient can be effectively performed.  The effectiveness and efficiency of the proposed framework has been demonstrated through the accurate calibration of the model with fewer model runs. This study also demonstrates the importance and use of scalar functions in calculating sensitivity indices, when the model output is temporally variable. In addition, the parameter optimization using the proposed framework is efficient and present study can be used as reference for optimization of distributed hydrological model. 

 

Keywords: Calibration, parameter ranking, Sensitivity analysis, Hydrological modeling, optimization
PPP RAIM Algorithm of based on Fuzzy Clustering Analysis
Authors: Gu Shouzhou
Published: March 2020

With the development of various navigation systems, there is a sharp increase in the number of visible satellites. Accordingly, the probability of multiply gross measurements will increase. However, the conventional RAIM methods are difficult to meet the demands of the navigation system. In order to solve the problem of checking and identify multiple gross errors of  receiver autonomous integrity monitoring (RAIM), this paper designed full matrix of single point positioning by QR decomposition, and proposed a new RAIM algorithm based on fuzzy clustering analysis with fuzzy c-means(FCM). And on the condition of single or two gross errors, the performance of hard or fuzzy clustering analysis were compared. As the results of the experiments, the fuzzy clustering method based on FCM principle could detect multiple gross error effectively, also achieved the quality control of precision point positioning and ensured better reliability results.
Evapotranspiration partitioning in a semiarid shrubland and its relation to spring precipitation
Authors: Chen Lajiao , Hu Hongchang , Tudaji Maihemuti , Ma Yan , Zhao Lingjun
Published: March 2020

ET partitioning is crucial to examine how water and carbon cycles are coupled and to understand the impact of climate change and human activities on ecosystems and water resources. In this study, an optimality-based ecohydrological model is validated and applied for ET partitioning in a Chihuahuan Desert shrubland site in south-eastern Arizona, USA. The ratio of transpiration to evapotranspiration is 49% for the whole period. Evaporation and plant transpiration mainly occur in growing season following the precipitation events. Evaporation responds immediately to rainfall events, while transpiration shows a lagged response of several days to those events. T/ET ratio dynamic in growing season demonstrates different patterns. Some years show low T/ET ratio at the beginning of the growing season. The peak of the T/ET ratio lags behind the rain events. Other years demonstrate stable and relatively high T/ET ratio T/ET ratio is higher than 60% during monsoon when vegetation is active. We find out that spring precipitation especially the size of the precipitation have a significant influence on shrub growth and the T/ET ratio in growing season. These years have dry spring with extremely low spring precipitation, shrubs remain inactive and there is no evident CO2 uptake during the spring. Under such circumstance, when summer rainfall event happens, shrub has not grown yet, so the most rains are consumed by soil evaporation. In contrast, these years with high T/ET during the growing season all have high amount of spring precipitation. As a consequence, shrubs have developed a certain number of roots and leaves in spring, shrubs recover quickly after the first rain event during the growing season.

Keywords: evapotranspiration partitioning; evaoration; transpiration; spring precipitation; semiarid shrubland; Chihuahuan Desert.
New tools for 2D full-waveform inversion: applications on Brazilian Pre-Salt velocity model from Santos Basin
Authors: Santos Henrique , Eikmeier Claus , Volpe Ernani
Published: March 2020

In this work, we present full-waveform inversion (FWI) results of a typical Brazilian Pre-Salt model (Santos Basin) using new open-source tools. The large accumulations of oil with excellent quality and high commercial value discovered in the pre-salt carbonates of southeastern Brazil, especially in the Santos Basin, have made this province one of the most prospective in the world. Velocity model building in areas of highly complex geology (like the Santos Basin) remains a challenging step in seismic processing. FWI proved to be an efficient tool for the determination of high-resolution details in multiparameter models of complex subsurface structures, and it has been applied in different geophysical problem scales. However, since FWI is a computationally and mathematically challenging problem, many issues remain open, such as more efficient ways to deal with multiparameter inversion problems such crosstalk and different orders of magnitude in the seismic signal for different classes of parameters. Inversions for more than one class of parameters are of particular importance in the estimation of the physical properties of rocks (poroacoustic or poroelastic applications), for example, to monitoring oil and gas reservoirs and for monitoring the injection of carbon dioxide into geological structures. Also, programming complex numerical algorithms for each application is time-consuming and often evades the expertise of researchers from the geoscientific community. In this sense, a high-level computational tool for simulations and inversions would greatly improve the working time for researchers. Existing finite difference based FWI tools such as Devito, and finite elements based partial differential equations (PDE) solvers tools such as FEniCS and Firedrake are being explored and used for these purposes. In this work, we initially present an FWI acoustic isotropic inversion test (velocity inversion only), performed with the Devito software while a particular code is being developed in FEniCS and Firedrake computer programs. Devito is also a new and under development software and therefore must be tested under different conditions. Our first numerical results indicate the potential of using freely available computational programs in a real case scenario.
Geostatistical interpolation and simulation of geological properties considering regional deformation
Authors: von Harten Jan , de la Varga Miguel , Wellmann Florian
Published: March 2020

Kriging is a widely used geostatistical tool to estimate the value of a spatially correlated property at a certain location based on sampled data in the surrounding domain. It creates a weighted average of this data based on the distances to the point that is to be predicted. Interpolated maps and simulated stationary fields play an important role in various geological fields like flow simulation and resource estimation.

Distances between locations in a specified domain thus play an important role in the kriging process and are traditionally measured as straight-line distances. In this work we develop an alternative distance metric to these Euclidian distances normally used in the geostatistical worklflow.

The metric is based on a scalar field that is calculated for 3-D geologic models that are interpolated based on a potential field method implemented in the open-source, implicit geologic modeling tool GemPy.

The measure follows the curvature of the deformation of stratigraphic units, which is relevant when modeling the distribution of a property that developed before deformation. As an undeformed state of the domain is represented by these distances, authorized variogram and covariance models are still valid with the introduced distance metric.

In addition, anisotropies can be modeled in relation to the deformation of a layer by manipulating the new distance metric. The kriging calculations and distance measurements are combined in a Sequential Gaussian Simulation to estimate an entire domain, while adequately modeling the underlying variance. We show first promising results of our work using the newly developed distance metric in different geological settings, including folded and faulted domains.
One-Km of Subduction-Induced Subsidence of the Eastern Side of the Southern Andes at 10 Ma, as Measured Using Hydrogen Isotopes in Hydrated Volcanic Glass
Authors: Brandon Mark , Fennell Lucas , Hren Michael , Hu Jiashun , Liu Lijun
Published: March 2020

We report new results for the topographic evolution of the eastern flank of the South-Central Andes at ~35 S latitude. Our work is based on a piggy-back basin near Malargüe, Argentina, which provides a continuous stratigraphic record from 55 to 10 Ma. We have separated volcanic glass and measured hydrogen isotopes (δD) from 107 samples. Studies over the last several decades show that volcanic glass will take up precipitation water by hydration on a 1 to 10 ka time scale. This reaction is irreversible, and later diffusive exchange is too slow to alter the initial isotopic composition. Thus, we conclude that our data provide a record of the isotopic composition of precipitation for most of the Cenozoic. Empirical and theoretical work indicate that the isotopic composition of precipitation decreases in a linear fashion with increasing orographic lifting. We have calibrated this relationship by isotopic modeling of modern water isotopes (152 samples) at 35 S across Chile and Argentina, and that work indicates a lifting relationship for precipitation δD ~20‰/km.

Our glass isotope record shows a steady decrease in δD through the Cenozoic, which matches well with the isotopic response predicted for global cooling at that time. After correction for this climate effect, our glass isotope record indicates that the Marlargüe region had a steady elevation from 55 to 20 Ma, and then was subjected to a cycle of 1 km of subsidence and an equivalent amount of rebound, between 20 to 0 Ma. 

Ongoing geodynamic modeling provides independent evidence of a large subsidence event in this region of South America as determined from the history of slab age and subduction velocity, both constrained by plate kinematics. This dynamic subsidence would have affected both the Andes and the eastern “retroarc” basin. Previous workers have viewed the subsidence history of the retroarc basin as providing a diagnostic record of the growth and decay of orogenic topography, but our work shows that subduction-induced dynamic topography can produce effects of similar magnitude.
Quantifying and attributing changes in tropospheric ozone from a combination of satellite measurements and models
Authors: Neu Jessica , Miyazaki Kazuyuki , Bowman Kevin , Osterman Gregory
Published: March 2020

Given the importance of tropospheric ozone as a greenhouse gas and a hazardous pollutant that impacts human health and ecosystems, it is critical to quantify and understand long-term changes in its abundance.  Satellite records are beginning to approach the length needed to assess variability and trends in tropospheric ozone, yet an intercomparison of time series from different instruments shows substantial differences in the net change in ozone over the past decade.  We discuss our efforts to produce Earth Science Data Records of tropospheric ozone and quantify uncertainties and biases in these records.  We also discuss the role of changes in the magnitude and distribution of precursor emissions and in downward transport of ozone from the stratosphere in determining tropospheric ozone abundances over the past 15 years.
Combination of subsurface organic fertilization and film mulching could effectively optimize soil structure in saline alkali soil
Authors: Zhang Hongyuan , Pang Huancheng , Lu Chuang , Wang Jing , Wang Guoli , Chang Fangdi , Li Yuyi
Published: March 2020

Abstract：Saline soil has a serious negative effect on crop growth in the world, subsurface organic fertilizationcombined with plastic film mulching (OMP) is one of the effective measures to solve this issue, which could alleviate salt stress, increase nutrient content and microflora diversity, then furtherly improve crop productivity. However, its impact on soil structure especially soil pore structure has not well documented, so a three-year experiment was conducted to analysis effect of OMP on aggregate distribution and stability, aggregate organic carbon distribution and pore size distribution, during 2015-2017 in Wuyuan Country, Inner Mongolia, China. Four treatments were set in the experiment, including plowing without plastic mulching (CK), plowing plus plastic mulching (PM), subsurface (10–30 cm) treatment with organic manure (OM), and OM plus plastic mulching (OMP). The results showed that in condition of no mulching OM significantly increased the 0.25-2mm aggregates content (18.09%) in 10-30cm soil layer, and significantly increased the organic carbon content of > 2mm (30.79-158.76%) and 0.25-2mm aggregates (161.27-290.94%) in each soil layer compared with CK.In condition of mulching, only OMP can significantly increase the average weight diameter (21.58% for 0-10 cm and 55.95% for 10-30 cm) and the organic carbon content (2.44-94.35% for 0-10 cm and 23.23-215.29% for 10-30 cm) of soil aggregates compared with CK.  Under the condition of subsurface organic fertilization (OM, OMP), the dominant particle size of each soil layer changed from < 0.053 mm aggregate to 0.25-2 mm aggregate, which increased the content of large aggregate and water stability.Compared with OM, the average weight diameter of soil aggregates in 0-10cm and 10-30cm soil layers of OMP increased by 21.58% and 14.36% respectively, but the content of organic carbon in each particle size aggregate in 0-10cm and 10-30cm soil of OMP decreased by 4.24-24.89% and 19.35-40.26% respectively. Furtherly, the large porosity (greater than 30 μm) of 10-30cm and 30-40cm soil layers of OMP increased by 10.52% and 0.71% than that of CK, and the porosity of each equivalent pore size range also increased significantly. Therefore, combination of subsurface organic fertilization and film mulching could effectively optimize soil physical structure by increasing the stability of soil aggregates, maintaining higher organic carbon content, enhancing soil respiration and improving soil pore structure.

Key words：Saline alkali soil; organic fertilizer; soil aggregate; soil pore structure; micro CT
Mafic alkaline ring Yllymakh massif , Aldan shield, Yuakutia, geochemistry and geochronology
Authors: Vasyukova Elena , Medvedev Nikolai
Published: March 2020

The Yllymakh massif belongs to a number of ring massifs of the Mesozoic age typical for the Aldan shield. Being formed in an intraplate environment, the Yllymakh massif is characterized by specific features of intraplate rocks in general and a number of coeval intrusions of the Aldan magmatic province in particular. These include a potassium-sodium slope, an extremely low eNd value (-13--14), a specific distribution of rare-earth elements with almost or with a weakly developed Eu minimum.

The range of rocks composing the Yllymakh massif is very wide. It consists of up to 20 species of rocks. The most melanocratic are olivine schonkinites. The most widespread and diverse are the rocks average in SiO2 content. These include feldsparless syenites, feldspar syenites with nepheline, feldspar syenites with quartz, syenites with phoid (nepheline or leucite) in various quantities, alkaline granites. Of course, the question arises of the processes that led to such diversity.

Previous geochronological studies of the Ar-Ar method [Vasyukova et al, 2020] three stages of the massif formation were determined: 140 ± 1.9 Ma, 130 ± 1.9 - 131 ± 2.4 Ma and 125 ± 1.9 Ma. And geochemical studies showed that the Yllymakh massif was formed in several stages due to the pulsed introduction of successive portions of magma.

The analysis of petrochemical and geochemical diagrams showed the impossibility of the formation of the rock spectrum by fractionation of the melt. The critical fractionating phases were different: pyroxene in first and plagioclase in the second group. So they gave different trends in the coordinates CaO-, Na2O-, Al2O3-SiO2 and MgO-, Fe2O3-SiO2. apatite also plays an important role in the formation of the spectrum of rocks, as can be seen in P2O5-SiO2. However, it is not a rock-forming mineral, but it is a good marker of the fluid and geochemical conditions of the melt.

The isotopic composition of oxygen showed the predominance of mantle material in the source. The Nd and Sr isotopic data show that the rocks of the Yllymakh massif were formed in an enriched source. Sharply negative values of the eNd of the studied rocks fit into the overall picture of the region – similar characteristics are determined for other objects of similar age (Inagli, Ryabinovy, etc.).

Supported by RFBR grant 19-05-00788

Vasyukova E.A., Ponomarchuk V.A, Doroshkevich A.G. Petrology and age boundaries of Yllymakh massif. Russian Geology and Geophysics, 2020 in press
Long turnover time and large sequestration potentials in a dry pine forest based on 15-year flux and inventory records
Authors: Qubaja Rafat , Grünzweig Jose , Rotenberg Eyal , Yakir Dan
Published: March 2020

A large terrestrial carbon sink significantly influences the rate of change in atmospheric CO2 concentrations, but uncertainties associated with its estimate are considerable. Here we combined carbon stock (CS) and eddy covariance (EC) flux measurements that were collected over a period of 15 years (2001-2016) in a 55-year-old 30 km2 pine forest growing at the semi-arid timberline (with no irrigating or fertilization). The objective was to constrain estimates of the carbon (C) storage potential in forest plantations in such semi-arid lands, which cover ~18 % of the global land area. Annual integrated carbon accumulation was 145-160 g C m-2 y-1 over the study period based on the EC and CS approaches, with a mean value of 152.5 ± 30.1 g C m-2 y-1 indicating 20 % uncertainty in carbon uptake estimates. This carbon uptake reflect high carbon use efficiency NEP/GPP of 29 compared to ~21 in temperate forests, leading to the current ecosystem stocks of 7943 ± 323 g carbon m-2 and 372 g nitrogen m-2. In addition, carbon is mostly stored in the soil (~71 % of the current ecosystem C stock), with a long C turnover time of 59 ± 4 y (compared to mean value of 18 years in temperate forests). It is also estimated that soil carbon at the study site constitutes only ~25 % of the estimated soil saturation capacity. Irrespective of un-expected disturbances beyond those observed at the study site, the results support considerable C sink potential in semi-arid soils and forest plantations, and imply that afforestation of even 10 % of semi-arid land area under conditions similar to that of the study site, could sequester ~0.4 Pg C y-1 over several decades.
Romanian-Hungarian cooperation in the field of reduction of seismic risk to infrastructures
Authors: Bostenaru Dan Maria , Gociman Cristina Olga , Anghelache Mirela Adriana , Kegyes-Brassai Orsolya
Published: March 2020

Between the Ion Mincu University of Architecture and Urbanism in Bucharest, Romania and the Szechenyi Istvan University in Gyor, Hungary a cooperation agreement was concluded between the first and fourth author regarding disaster management. A first step was taken in January 2020 starting the reciprocical visits by a visit of the third author to the Romanian university. Exchange encompassed participation to master level courses at the Master Urban Design (urban prospective: urban vulnerability and protection of localities against risks, the later taught by the second author, who is also a titular member of the doctoral school) and a lecture at the doctoral school with discussions moderated by the first and third authors. The conclusions were discussed with the master students as well. The innovative in the cooperation is that it regards how urban planners can contribute to disaster management and infrastructures in a field where they can best plan. Master students learn how to design urban projects while doctoral candidates do research in this, and are thereof complementary. Cooperation will continue by various national and bilateral schemes. This contribution shows the conclusions of the discussions.
Postagrogenic differentiation of the old-arable horizon of different-aged fallow soils
Authors: Fattakhova Leysan , Kuzina Dilyara
Published: March 2020

The study of different-aged fallow soils seems to be interesting from the point of view of changes in their conditions of genesis and functioning because a radical change of pedogenesis nature in time the removal of arable land to fallow leads to soil evolution. If the climax stages of postagrogenic successions are quite achievable, then the process of restoring the original climax vegetation should be associated with a reversible return of the soil to its original state. But pedogenesis is not limited only to the processes of converting organic residues into soil humus, binding it to mineral surfaces, humus, and biophilic elements accumulation. It also includes a slow chemical transformation of the parent rocks, due to the course of a number of reactions that rarely reach chemical equilibrium. And for soils that were once plowed, we can state with confidence that there is no identity between the component and phase compositions of fine mineral phases at the stages of involving virgin soil to cultivation and removing arable soil to fallow. Accordingly, the once homogeneous old-arable layer can be considered as a lithologically homogeneous soil-forming rock for the magnetic subprofile that is formed on it in the process of successional restoration of ecosystems. Therefore, the study of the magnetic properties of the upper part of the profile of different-aged fallow soils is appropriate in the aspect of the kinetic parameters of postagrogenic differentiation of the old-arable horizon. This work is devoted to studying magnetic properties of different-aged light-gray forest (30-35 years), dark grey forest (10-15 years) and sod-podzolic (12-17 years) fallow forest-steppe soils of the Republic of Tatarstan for the diagnosis of postagrogenic signs of differentiation of the old-arable horizon.

The work is performed according to the Russian Government Program of Competitive Growth of Kazan Federal University and with the support of the RFBR in the framework of the scientific project No. 19-35-50040.