bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness Analysis of Multi-purpose Dam: Socio-hydrology Modeling Approach
Authors: Lee Sleemin , Kang Doosun
Published: March 2020

Water resources are essential for human life and closely related to various social and economic factors (e.g. land use, population, economic development, environment, etc). Also, such human activities affect hydrological environment conversely. Thus, socio-hydrology interdisciplinary studies that consider both hydro-engineering and socio-economic behavior are needed. Multi-purpose dam is a large water infrastructure mitigating water-related disasters by flood control and stable water supply. However, the effectiveness of multi-purpose dam besides the disaster mitigation has not been well analyzed, such as the social and economic influence to downstream area. This study aims to understand the relationship between the socio- and hydrology-sectors and quantitatively analyze the effects of the multi-purpose dam in target area. The representative components of socio-sector are population, land use, GRDP (gross regional domestic product), and flood/drought damages, and the hydrology-sector includes dam inflow/outflow, precipitation, and water demand. A causal loop was developed to identify the causal relationship between the socio- and hydrology-components, and a socio-hydrology system model was constructed using a system-dynamics technique. Various climate and socio-economic scenarios were applied to analyze the future effects of the multi-purpose dam on the population, regional economy, water supply, and flood damage prevention of the target area. The constructed socio-hydrology model can be used in decision-making for efficient water management and water facility planning.

 

Keywords: Climate change, Multi-purpose dam, Socio-hydrology, System-dynamics modeling

                                                                 

Acknowledgment: This study is supported by Korea Ministry of Environment (MOE) as “Graduate School specialized in Climate Change”.
Crustal and uppermost mantle velocity structure beneath the Mid-lower Yangtze metallogenic belt and its adjacent regions from joint inversion of receiver function and surface wave
Authors: Li Jiapeng
Published: March 2020

    The Middle-Lower Yangtze River Metallogenic Belt, known as the eastern “industrial corridor”, is an important polymetallic mineral resource base in eastern China. It has a significant influence on economic development in eastern China and its deep dynamic process has been the focus of debate for deposit scientists.

    Why does such a narrow zone contain so rich mineral resources? What is the deep dynamics? Many scholars put forward different explanations, such as “ continental extension mode ”, “ subduction mode ” and “ reverse L-shaped collision mode ”. Although these views reach a consensus in some aspects, they are different essentially. Thus, the deep structure information has become the key to distinguish such different views.

    In this study, we conduct teleseismic P wave receiver function, ambient noise tomography and teleseismic two-plane-wave tomography to probe the crustal and uppermost mantle structures in the Middle-Lower Yangtze River region. The data include (1) continuous seismic data from June 2012 to July 2013 recorded from Chinese provincial networks; (2) seismic event data from 2010 to 2011 recorded from Chinese provincial networks; (3) continuous seismic data from November 2009 to August 2010 deployed by Chinese Academy of Geological Sciences; (4) continuous seismic data from June 2012 to July 2013, from August 2014 to June 2015 and from July 2015 to November 2015 deployed by China University of Geosciences(Beijing). First, we apply receiver function to get the Moho depth below 191 seismic stations and the results are in good accordance with previous researches. We then conduct joint inversion of receiver function and surface wave dispersion to generate shear wave velocity structures below 191 seismic stations. The result shows that in the upper crust, the basin regions, including the JiangHan, HeHuai, SuBei, HeFei and NanYang basin, are all featured with low velocities, and the mountain regions with high velocities. In the northeastern of the Middle-Lower Yangtze River Metallogenic Belt, the result shows ore districts are clearly characterized with the strongest low velocity anomaly in the uppermost mantle at ~70km depth. The depth extent of the low-velocity zone becomes shallower and the amplitude of low velocity anomaly becomes larger from the northeast to southwest.
PKU Energetic Particle Instrument
Authors: Yang Liu , Wang Linghua , Zong Qiugang , Yu Xiangqian , Wang Yongfu , Shi Weighing , Wimmer-Schweingruber Robert
Published: March 2020

The PKU energetic particle instrument (EPI) is designed to make measurements of the three-dimensional distribution of suprathermal electrons and ions with good time, energy and angular resolutions in the interplanetary space, respectively, at energies from 20 keV to 1 MeV and from 20 keV to 11 MeV.  The EPI consists of four dual-double-ended foil/magnet semi-conductor telescopes, which cleanly separate electrons in the energy range of 20–400 keV and ions from 20 keV–6 MeV. The output of front detectors is taken in anti-coincidence with center detectors, to achieve the low background. The magnet telescopes also employ the well-established dE/dx vs. total energy approach to determine the nuclear charge and mass of some ion species.
Glacio-hydrological modelling of partially debris-covered Dokriani Glacier in monsoon-dominated Garhwal Himalaya (India)
Authors: Azam Mohd Farooq , Srivastava Smriti
Published: March 2020

Glacier-wide mass balances and catchment-wide runoffs are reconstructed over 1979-2018 for Dokriani Glacier catchment in the Garhwal Himalaya (India). A glacio-hydrological model including temperature-index, accumulation, rain and evapotranspiration modules is used for the reconstruction using daily air-temperature and precipitation fields from ERA5 data. Model is calibrated using 6 years of observed annual glacier-wide mass balances (1993-1995 and 1998-2000) and observed summer mean monthly runoff (1994, 1998-2000) data. Modelled mass wastage on Dokriani Glacier is moderate with annual loss of −0.28±0.38 m w.e. a–1 over 1979-2018. The mean winter glacier-wide mass balance is 0.62±0.38 m w.e. a–1 while mean summer glacier-wide mass balance is −0.91±0.38 m w.e. a–1 over 1979-2018. The mean annual catchment-wide runoff is 1.38±0.11 m3 s–1 over 1979-2018. Maximum runoff is produced during summer-monsoon months with a peak in August (5.35 m3 s−1). Rainfall contributes the maximum to the total mean annual runoff with 44% share while snow melt and ice melt contribute 35% and 22%, respectively. The loss through evapotranspiration is only around 2% of the total runoff. The heterogeneous debris-cover distribution over lower ablation area (<5000 m a.s.l.) protects the glacier for higher melting. Decadal mass balances suggest that Dokriani Glacier was close to steady-state conditions over 1989-1997 because of negative temperature anomaly and positive precipitation anomaly over this period. Mass balance and runoff are the most sensitive for threshold temperature for melt with sensitivities of −0.71 m w.e. a–1oC–1 and 0.18 m3 s–1 oC–1, respectively.
A simple transport rate relation that unifies aeolian and fluvial nonsuspended sediment transport
Authors: Pähtz Thomas , Duran Orencio
Published: March 2020

Nonsuspended sediment transport driven by streams of liquid or air is an important driver of the morphodynamics of planetary landscapes, seascapes, and riverscapes. Laboratory and field measurements of the sediment transport rate as a function of the fluid shear stress have enabled us to predict such processes with reasonable accuracy on Earth. However, sediment transport is also ubiquitous in extraterrestrial environments, such as on Venus, Mars, Titan, and occurs possibly even on Pluto. This raises the question of whether we can extrapolate transport rate expressions validated with measurements on Earth to extraterrestrial environments. The answer is probably, yes, but only if the used expressions capture the essential physics. Here, using coupled DEM/RANS numerical sediment transport simulations, we show that nonsuspended sediment transport in a large range of aeolian and fluvial environments has a conceptually simple common physical underpinning that allows treating these different transport regimes in a universal manner. That is, a conceptually simple universal model captures simulated and measured transport thresholds and transport rates. In particular, when the transport layer thickness substantially exceeds the viscous sublayer thickness (true for many environments), this model yields a mathematically simple transport rate expression that agrees, simultaneously, with existing measurements in air and water.
Higher climate sensitivity and cloud feedback in ECHAM6.3 with a prognostic cloud cover scheme due to changes in sub-grid scale dynamics
Authors: Muench Steffen , Lohmann Ulrike
Published: March 2020
The role of phlogopite in the deep Earth’s water and fluorine cycles
Authors: Sun Jiaqi , Yang Yan , Xia Qunke
Published: March 2020

    Knowledge of the volatiles cycles is vital to understand the evolution of the planet Earth and the life it supports. Although it is gradually accepted that water and other volatiles are recycled into the mantle through subduction, it is still not unclear how these volatiles are transported down into the deep Earth. Phlogopite is an accessory mineral frequently observed in samples from the upper mantle, thereby acting as an important carrier of fluorine and water down to >200 km depth. Previous experimental studies and textural relationships of natural samples have indicated that fluorine-rich phlogopite can be stable under ultra-high-temperature conditions. To further investigate effects of fluorine on the stability of phlogopite, here, we present an atomic level research of effects of fluorine on the structural stability using in situ high temperature infrared spectroscopy, Raman spectroscopy, and X-ray powder diffraction. Both X-ray powder diffraction and Raman spectroscopy suggests that fluorine-poor phlogopite decomposes earlier than the fluorine-rich phlogopite. Moreover, the O-H bonds and lattice modes are stiffer for the fluorine-rich phlogopite than the fluorine-poor phlogopite, which is well responsible for the mechanism of fluorine stabilizing phlogopite. Based on our studies, we propose that fluorine-rich phlogopite can effectively transport water and fluorine to the deep Earth.
Quantifying baseline length and height-difference dependent errors from commercially available software
Authors: Erol Tuna , Sanli D.Ugur
Published: March 2020

Commercial software are usually refered to in national surveying practice and local deformation studies. Since their working environment is user friendly and implementation is easy, they could be prefered by many surveying practitioners or even researchers. However their usage is usually limited to 20-30 km due mainly to their crude ambiguity resolution algorithms and  the fact that they usually use broadcast ephemeris and standard troposphere models.  Since usualy the tropospheric zenith delay is not estimated but obtained from a standard troposphere model, the accuracy of the vertical component would be affected as the height difference between baseline points grows. As the baseline length becomes >20-30 km the tropospheric error would be coupled with orbital errors. Results based on large height difference would affect positioning solutions as well as local geoid determination studies. Monitoring local deformation such as landslides would also be affected if there is large height difference between the crown and the toe. The level of baseline dependent error is usually well covered in surveying standards manual however the effect of large height difference is generally ignored. In this study, we made an attempt to quantify vertical positioning error levels both considering large height difference between baseline points and longer baseline lengths. We used the data of CORS stations in the western US for the simulation of the observing session duration. TOPCON’s software MAGNET (Ver 4.0.1) was used to process the GNSS data. It appears that every 10 km increase in the baseline length and every 100 m increase in the height difference would cause 2.59mm and 1.24 mm vertical positioning error respectively. 
Detection of drought-related human migration and population change on the North American Great Plains
Authors: McLeman Robert , Grieg Clara , Heath George , Fontanella Francesca
Published: March 2020

Rural migration responses to drought are complex, context specific, and multi-directional. Migration is one of many possible adaptive responses to drought, and is typically initiated only after other, less disruptive strategies have been attempted. The potential for drought to stimulate migration or displacement is inversely related to the range of alternative adaptation options available to households, and is lowered through coordinated vulnerability-reduction mechanisms such as institutional water-management regimes and crop insurance programs. When drought-related migration does occur, it tends to flow along pre-existing social networks to known destinations, which are usually urban centres within the same state/country or in contiguous ones. Using a mixed-methods approach that combines geospatial tools, quantitative methods (i.e. random forest and spatial regression) and qualitative data gathered through archival research and local interviews, we have generated detailed models of the changing influence over time of drought on rural population patterns on the North American Great Plains. In this presentation we highlight key findings from our work, describe data needs and limitations, discuss the predictive power of various quantitative methods, identify non-climatic variables that mediate migration outcomes, and emphasize the importance of mixed-methods approaches.
Predicting the morphology of ice particles in deep convection using the super-droplet method
Authors: Shima Shin-ichiro , Sato Yousuke , Hashimoto Akihiro , Misumi Ryohei
Published: March 2020

In this presentation, we summarize the main results of Shima et al. (2019). The super-droplet method (SDM) is a particle-based numerical algorithm that enables accurate cloud microphysics simulation with lower computational demand than multi-dimensional bin schemes. Using SDM, we developed a detailed numerical model of mixed-phase clouds in which ice morphologies are explicitly predicted without assuming ice categories or mass-dimension relationships. Ice particles are approximated as porous spheroids. The elementary cloud microphysics processes considered are advection and sedimentation; immersion/condensation and homogeneous freezing; melting; condensation and evaporation including cloud condensation nuclei activation and deactivation; deposition and sublimation; collision-coalescence, -riming, and -aggregation. To evaluate the model's performance, we conducted a 2D large-eddy simulation of a cumulonimbus. The results well capture characteristics of a real cumulonimbus. The mass-dimension and velocity-dimension relationships the model predicted show a reasonable agreement with existing formulas. Numerical convergence is achieved at a super-particle number concentration as low as 128/cell, which consumes 30 times more computational time than a two-moment bulk model. Although the model still has room for improvement, these results strongly support the efficacy of the particle-based modeling methodology to simulate mixed-phase clouds. 

Shima, S., Sato, Y., Hashimoto, A., and Misumi, R.: Predicting the morphology of ice particles in deep convection using the super-droplet method: development and evaluation of SCALE-SDM 0.2.5-2.2.0/2.2.1, Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2019-294, 1-83, 2019.
What plausible urban coastal futures may look like? Spatially explicit urbanization projections for 10 Mediterranean countries.
Authors: Wolff Claudia , Nikoletopoulos Theodore , Hinkel Jochen , Vafeidis Athanasios
Published: March 2020

The urban extent in the Low Elevation Coastal Zone (LECZ) is increasing faster than in the surrounding regions, which will lead to increased exposure to climate change-related hazards. Societies’ risk to these hazards will, therefore, depend on the rate and pattern of urban expansion and in what ways decision-makers will drive future urban development. One opportunity to investigate how urban development influences potential future coastal flood risk is to combine impact assessments with spatiotemporal urban land cover analysis and spatially explicit future urban projection. In this study, we have developed spatially explicit urban extent scenarios for 10 countries in the Mediterranean. The urban extent scenarios are quantitatively and qualitatively consistent with the assumptions of the global Shared Socioeconomic Pathways (SSPs). We employ a machine learning approach, namely Artificial Neural Networks (Multi-Layer Perceptron - MLP), to develop an Urban Change Model. The MLP model employs simple inputs as proxies for processes that drive urban development on a regional scale and estimates the likelihood of urban transformation for every grid cell between 2000 and 2012. In a next step, we calculate, for each SSP, the future urban land demand in 5-year time steps until 2100 and classify the ANN model outputs accordingly. These projections are then employed for calculating future exposure to coastal flooding.

The urban change models are able to reproduce the observed patterns of urban development with an overall accuracy of approximately 99% in all countries. The future projections indicate that accounting for the spatial patterns of coastal development can lead to significant differences in exposure. The increase in urban extent in the extended LECZ (below 20m) until 2100 varies, for instance,  by 67% (2075km²) for Italy, 104% (2331km²) for France (Mediterranean coast only) and 86% (691km²) in Greece depending on the urban development scenario chosen. This highlights that accounting for urban development in long-term adaptation planning, e.g. in the form of land-use planning is a very effective measure for reducing future coastal flood risk on a regional scale.
Perliminary thermal metamorphic constraints on tectonic evolution in the eastern margin of Tibetan Plateau: lessons from the slate belt of Taiwan?
Authors: Chang-Chien Wan-Ching , Chen Chih-Tung , Tan Xi-Bin
Published: March 2020

      The Tibetan Plateau, resulting from the active Eurasian-India collision, presents a major scientific challenge in understanding its growth and propagation. One key region is the Longmen Shan mountain belt in western Sichuan, which forms the steepest margin of the plateau and has been active as demonstrated by the Mw 7.9 Wenchuan (2008) and Mw 6.6 Lushan (2013) earthquakes. Tectonic history of the Longmen Shan belt and the neighboring Songpan-Garze terrane, however, began in the Triassic Indosinian orogenesis, which complicates the geologic records. But the major thickening of Tibet was formed in Himalayan orogenesis. Therefore, quantitative constraints on the pre-Tertiary tectonic evolution of the region are crucial in delineating Himalayan geodynamics. In this study, the raman spectroscopy of carbonaceous material (RSCM) geothermometer is applied to the metasediments of the Longmen Shan and Sonpan-Garze terrane to obtain their peak metamorphic states. Combining existing metamorphic, geochronologic and thermochronologic data, better rock thermal histories may be reconstructed, providing insights to the structure and development of the orogenic system.

      In this study, 50 samples were collected in eastern margin of Tibetan Plateau along several transects in NW-SE direction, perpendicular to the structural grain of the Longmen Shan and into the Songpan-Garze terrane. Together with existing data, distribution of the peak temperatures from RSCM analyses is not correlated to later igneous intrusions, ruling out significant contact metamorphism overprint. Along the WenChuan Fault, the Songpan-Garze terrane is of higher grade than the Longmen Shan, indicating it is a major reverse shear zone. The rather high RSCM temperatures (over 500 °C) acquired from Songpan-Garze metasediments are inconsistent with past models as remnants of a classical accretionary prism; the complex wedge kinematics involving significant basal accretion observed in the slate belt of Taiwan orogen may give clues in reconstructing the structure and evolution of eastern Tibetan Plateau.

Keywords: Tibetan Plateau; Longmen Shan; RSCM geothermometer
Surface Topography Anomalies Induced by Geodynamic Processes in the Southeast Carpathians
Authors: Şengül Uluocak Ebru , Pysklywec Russell N. , Göğüş Oğuz H. , Ulugergerli Emin
Published: March 2020

Southeast Carpathians with deep basins (e.g., Transylvania and Focsani) and the mountain chain (SE Carpathians Mountain with ~1.5 km elevation) are characterized by unique morphological features.  The highly-variable subsurface structures (e.g., Vrancea slab) related to post-collisional tectonics are imaged by geophysical studies. Numerical modeling studies are performed to understand the deformation linked with active geodynamic processes developing in the east part of the region. Here, we present our multi-dimensional (2D-3D) thermo-mechanical modeling results with varying temperatures and crustal configurations. We analyze modeling results together with the observations in terms of possible mantle flow components of the surface topography in Southeast Carpathians. In addition to residual topography calculations, non-isostatic compensation of the elevation is interpreted based on admittance functions between free-air gravity and topography. Our results indicate that mantle flow induced dynamic forces beneath the region modify the elevation with positive amplitudes over the Transylvania Basin (0.8-1 km) and the high SE Carpathian Mountains (~ 1 km) and subsidence of the Focsani Basin (0.5-1 km).
Interplay of bubble injections in the plasma sheet dynamics as inferred from RCM-I simulations
Authors: Sadeghzadeh Sina , Yang Jian
Published: March 2020

Understanding the transport of hot plasma from tail towards the inner magnetosphere is of great importance to improve our perception of the near-Earth space environment. In accordance with the recent observations, the contribution of bursty bulk flows (BBFs)/bubbles in the inner plasma sheet especially in the storm-time ring current formation is nonnegligible. These high-speed plasma flows with depleted flux tube/entropy are likely formed in the mid tail due to magnetic reconnection and injected earthward as a result of interchange instability. In this presentation, we investigate the interplay of these meso-scale structures on the average magnetic field and plasma distribution in various regions of the plasma sheet, using the Inertialized Rice Convection Model (RCM-I). We will discuss the comparison of our simulation results with the observational statistics and data-based empirical models.
GPP and NEE estimation for global forests based on a deep convolutional neural network
Authors: Wu Wenjin
Published: March 2020

To generate FluxNet-consistent annual forest GPP and NEE, we have developed a deep neural network that can retrieve estimations globally. Seven parameters considering different aspects of forest ecological and climatic features which include the Normalized Difference Vegetation Index (NDVI), the Enhanced Vegetation Index (EVI), Evapotranspiration (ET), Land Surface Temperature during Daytime (LSTD), Land Surface Temperature at Night (LSTN), precipitation, and forest type were selected as the input. All these datasets can be acquired from the Google earth engine platform to ensure rapid large-scale analysis. The model has three favorable traits: (1) Based on a multidimensional convolutional block, this model arranges all temporal variables into a two-dimensional feature map to consider phenology and inter-parameter relationships. The model can thus obtain the estimation with encoded meaningful patterns instead of raw input variables. (2) In contrast to filling data gaps with historical values or smoothing methods, the new model is developed and trained to catch signals with certain levels of occlusions; therefore, it can tolerate a relativly large portion of missing data. (3) The model is data-driven and interpretable. Therefore, it can potentially discover unknown mechanisms of forest carbon absorption by showing us how these mechanisms work to make correct estimations. The model was compared to three traditional machine learning models and presented superior performances. With this new model, global forest GPP and NEE in 2003 and 2018 were obtained. Variations of the carbon flux during the 16 years in between were analyzed.
Adopting soil properties of compacted tramlines into soil erosion modelling: A field-scale approach
Authors: Saggau Philipp , Kuhwald Michael , Duttmann Rainer
Published: March 2020

Soil erosion by water is recognized as the most threatening land degradation process worldwide, reducing natural soil fertility and productivity especially on arable land. Despite advances in soil erosion modelling, one major process, which is rarely investigated, is the effect of soil compaction from field management induced wheel tracks. However, tramlines noticeably contribute to the amount of soil eroded inside a field. To quantify these effects we incorporate high-resolution spatial tramline data into modelling. For simulation, we used the process-based soil erosion model EROSION3D, which has been applied on different fields for a single rainfall event. Model results were compared against measured soil loss. Our investigation showed that i) grid-based models like E3D are able to integrate tramlines, ii) the share of measured erosion between tramline and cultivated areas fits well with measurements for resolution ≤ 1 m, iii) tramline erosion showed a high dependency to the slope angle and iv) soil loss and runoff are generated quicker within tramlines during the erosion event. The results indicate that the integration of tramlines in soil erosion modelling improves the spatial prediction accuracy, and therefore, can be important for soil conservation planning.
Non-CO2 forcing changes will likely decrease the remaining carbon budget for 1.5°C
Authors: Mengis Nadine , Matthews H. Damon
Published: March 2020

Estimates of the 1.5°C carbon budget vary widely among recent studies. One key contribution to this range is the non-CO2 climate forcing scenario uncertainty. Based on a partitioning of historical non-CO2 forcing, we show that there is currently a net negative non-CO2 forcing from fossil fuel combustion (FFC) mainly due to the co-emission of aerosols, and a net positive non-CO2 climate forcing from land-use change (LUC) and agricultural activities. We then perform a set of future simulations in which we prescribed a 1.5°C temperature stabilization trajectory, and diagnosed the resulting 1.5°C carbon budgets. Using the results of our historical partitioning, we prescribed changing non-CO2 forcing scenarios that are consistent with our model’s simulated decrease in FFC CO2 emissions. We compared the diagnosed carbon budgets from these idealized scenarios to those resulting from the default RCP scenario non-CO2 forcing, as well as from a scenario in which we assumed proportionality between future CO2 and non-CO2 forcing. We find a large range of carbon budget estimates across scenarios, with the largest budget emerging from the scenario with assumed proportionality of CO2 and non-CO2 forcing. Furthermore, our adjusted-RCP scenarios, in which the non-CO2 forcing is consistent with model-diagnosed FFC CO2 emissions, produced carbon budgets that are smaller than the corresponding default RCP scenarios. Our results suggest that ambitious mitigation scenarios will likely be characterized by an increasing contribution of non-CO2 forcing, and that an assumption of continued proportionality between CO2 and non-CO2 forcing would lead to an overestimate of the remaining carbon budget required to avoid low-temperature targets. Maintaining such proportionality under ambitious fossil fuel mitigation would require mitigation of non-CO2 emissions from agriculture and other non-FFC sources at a rate that is substantially faster than is found in the standard RCP scenarios.
Magnitude Scaling of Regional-phase Amplitudes from the DPRK Announced Nuclear Tests
Authors: Peacock Sheila , Bowers David , Selby Neil
Published: March 2020

At regional distances (<~1700 km) the phases Pn, Pg and Lg are generally the most prominent arrivals from a crustal seismic source.  Amplitude ratios of Pn or Pg to Lg have been investigated by several authors (e.g. Hartse et al. 1997 Bull. Seism. Soc. Am.) as earthquake/explosion discriminators.  Theory and observation show that explosions generate shear phases less efficiently than earthquakes, hence the amplitude ratio of Pn and Pg to Lg is expected to be higher for explosions, especially at frequencies above ~2 Hz.  Walter et al. (2108 Seismol. Res. Lett. DOI 10.1785/0220180128) showed that amplitude ratios Pg/Lg and Pn/Lg at 2-4 Hz were clear discriminants between the six announced nuclear tests of the Democratic People's Republic of Korea (DPRK) and a population of earthquakes.  We investigate regional-phase amplitudes for stations MDJ (distance ~376 km) and USRK (~406 km). Walter et al. found a weak dependence of Pg/Lg in the 2-4 Hz band at MDJ on the magnitude Mw of the explosion. We find this dependence at USRK also.  We also explore the regional amplitude behaviour at a range of frequencies, and dependence on different magnitude measures, such as network body-wave and surface-wave magnitudes.

© British Crown Owned Copyright 2019/AWE

This work is distributed under the Creative Commons Attribution 4.0 License. This licence does not affect the Crown copyright work, which is re-usable under the Open Government Licence (OGL). The Creative Commons Attribution 4.0 License and the OGL are interoperable and do not conflict with, reduce or limit each other.
Quantitative assessment of gully erosion dynamics using a GIS implementation of Sidorchuks' DYNGUL model in Southern KwaZulu-Natal, South Africa
Authors: omran adel , Schroeder Dietrich , Sommer Christian , Hochschild Volker , Sidorchuk Aleksey , Maerker Michael
Published: March 2020

Soil erosion is considered as one of the main threats affecting both rural and urban areas in many different parts all over the world. Therefore, increasing attention has been attributed to soil erosion in the last decades. This can also be documented by an increasing number of studies targeting soil erosion assessment using qualitative and quantitative models. However, gully erosion phenomena have been widely neglected in erosion modelling due to the nature and complexity of the related processes and hence, it is also more difficult to simulate, predict and to visualize its effects. Sidorchuk (1999) established a Fortran based dynamic erosion model called DYNGUL to describe the first quick stage of gully development, coinciding with the main changes in gully morphology; like changes in volume, area and elevation of the longitudinal profile. The DYNGUL model is based on the solution of the equations of mass conservation and gully bed deformation. The model of straight slope stability was used to predict gully side wall inclination and of the finite morphology of the gully. The objective of this contribution is to establish a GIS tool for a quantitative gully erosion assessment and to predict gully evolution over time. The tool will help: i) to cope with or mitigate gully erosion processes and ii) to plan measures to stabilize the landscape affected by gully erosion. Therefore, we developed a Python-based tool that can be applied in a GIS environment. The model was tested its performance and the sensitivity of physical parameters with data from a gully in the Drakensberg Mountains, KwaZulu-Natal, South Africa. The results of the gully erosion model showed that their sensitivity to lithological and hydrological factors is rather high.
Post-fire impact on the water quality of a reservoir: an integrated watershed-reservoir modeling approach
Authors: Basso Marta , Mateus Marcos , Ramos Tiago , Vieira Diana
Published: March 2020

Wildfires are an increasing threat in the Mediterranean area causing the loss of goods and frequently on the loss of human lives. Not only forest fires are worrisome for their first and visible impacts on vegetation and soil, but also for the secondary impacts on the quality of surface water bodies. Approximately one third of the world’s largest cities obtain their drinking water from forest catchments. The removal of vegetation and consequent increase in runoff with high concentration in sediments often leads to increased nutrients and sediment loads to water reservoirs damaging the aquatic ecosystem and human health.

In Portugal, the catastrophic events of Portuguese territory in 2017 occurred in strategic catchments from the water supply point of view. The Castelo de Bode reservoir, located in that area, with a total capacity of 1095 hm3, supplies the city of Lisbon and surrounding areas (2,000,000 inhabitants). During 2017, more than one hundred thousand hectares of land in the upstream watershed were burned, making it one of the most affected areas in Portugal.

This study focuses on the impacts of the fires on the water quality of Castelo de Bode reservoir. The Soil Water Assessment Tool (SWAT) was first calibrated and validated for simulating streamflow, sediments and nutrients transport. The post-fire impacts were implemented by adjusting land use characteristics (curve number, crop vegetation management factor), and soil properties (soil erodibility), taking into account the different impacts from fire (low, medium, and high severity). The output from this model was then used as input to CE-QUAL-W2 reservoir model. During the calibration phase, it was possible to observe that CE-QUAL-W2 presented some limitations in reproducing water quality parameters, according to the available field measurements in such large reservoir . Therefore, the parameters with the best fit to the measurements at the dam wall were chosen as water quality indicators in the post-fire.

Preliminary results indicated an increase in nutrients and algae concentrations in the year following the 2017 fire events, characterized also by a decrease in the water level due to the base flow reduction at the watershed scale. Although high concentrations of nutrients characterized the reservoir inlet, only phosphate concentration slightly overcame the thresholds limits foreseen in legislation for drinking water close to the dam wall, likely due to the large volume of the reservoir which diluted the inflow concentrations.
Predicting Cs-137 Distribution Patterns from Soil Samples - The Relationships Between Topographic Parameters, Soil Properties, and Cs-137 Concentration Levels
Authors: Yasumiishi Misa , Nishimura Taku , Bittner Thomas , Aldstadt Jared , Bennett Sean
Published: March 2020

Forests provide valuable water and nutrient resources to farming activities as well as places for various leisure activities. However, decontaminating forests in the aftermath of a massive radionuclide contamination event presents challenges because of the topography and the difficulty of collecting a large number of field samples. Achieving accurate remote measurements also can be hindered by the canopy cover. In Fukushima, Japan, where elevated radioactive fallout occurred following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in March 2011, about 70 percent of the land is covered with forests. Soil samples collected in a forest in Iitate Village, Fukushima, beginning in 2016 through 2018 still contained an average 98200 Bq/kg of Cs-137 in the top 4 cm depth (std. dev. 114100 Bq/kg). Thus, decontamination and identification of Cs-137 distribution patterns in those forests is still a pressing issue. However, soil types in that region, 1000 mm annual precipitation with intense rain during typhoons, and microtopography have presented challenges to understanding how Cs-137 behaves in those forests.  In this study, six topographic parameters were computed from 1-m and 10-m resolution DEMs and the relationships between those parameters and soil water content and bulk density were systematically analyzed for their effects on Cs-137 concentration levels. As the first analytical step, correlation indices and the generalized additive models (GAM) analysis were conducted on those parameters. The results show that not all topographic effects are apparent in the correlation analysis, yet the results can be improved when mixed with other parameters in GAM models. Overall the effect of topographic parameters on Cs-137 levels is DEM resolution-dependent while individual soil properties indicate a strong relationship. Also, it was found that depending on the analysis depth, correlation levels and significance of those parameters in GAM models fluctuate. As the second step, Cs-137 levels were extrapolated to a larger area in the study site to understand further the connections between topography and soil properties. The results, including the limitations and proposals for future forest decontamination, will be presented in the session. Understanding how Cs-137 moves and accumulates in forests, especially immediately after contamination, is critical to avoiding the negative impacts on the environment by decontamination measures and to protecting lowlands from harmful radioactivity levels. This study contributes to the radionuclide research field by presenting an example of data analysis processes using field sampled data.
Retrieval of Arctic sea ice freeboard from passive microwave data using deep neural network
Authors: Chi Junhwa , Kim Hyun-Cheol , Lee Sung Jae
Published: March 2020

Changes in Arctic sea ice cover represent one of the most visible indicators of climate change. While changes in sea ice extent affect the albedo, changes in sea ice volume explain changes in the heat budget and the exchange of fresh water between ice and the ocean. Global climate simulations predict that Arctic sea ice will exhibit a more significant change in volume than extent. Satellite observations show a long-term negative trend in Arctic sea ice  during all seasons, particularly in summer. Sea ice volume has been estimated by ICESat and CryoSat-2 satellites, and then NASA’s second-generation spaceborne lidar mission, ICESat-2 has successfully been launched in 2018.  Although these sensors can measure sea ice freeboard precisely, long revisit cycles and narrow swaths are problematic for monitoring of the freeboard in the entire of Arctic ocean effectively. Passive microwave sensors are widely used in retrieval of sea ice concentration. Because of the capability of high temporal resolution and wider swaths, these sensors enable to produce daily sea ice concentration maps over the entire Arctic ocean. Brightness temperatures from passive microwave sensors are often used to estimate sea ice freeboard for first-year ice, but it is difficult to associate with physical characteristics related to sea ice height of multi-year ice. In machine learning community, deep learning has gained attention and notable success in addressing more complicated decision making using multiple hidden layers. In this study, we propose a deep learning based Arctic sea ice freeboard retrieval algorithm incorporating the brightness temperature data from the AMSR2 passive microwave data and sea ice freeboard data from the ICESat-2. The proposed retrieval algorithm enables to estimate daily freeboard for both first- and multi-year ice over the entire Arctic ocean. The estimated freeboard values from the AMSR2 are then quantitatively and qualitatively compared with other sea ice freeboard or thickness products.  
What if a larger earthquake would occur at the causative fault of the Gyeongju earthquake with ML 5.8 on September 11, 2016 in South Korea?
Authors: Choi Hoseon
Published: March 2020

A seismic source can be a capable tectonic source or a seismogenic source. A capable tectonic source is a tectonic structure that can generate both vibratory ground motion and tectonic surface deformation at or near the earth's surface in the present seismotectonic regime. On the other hand, A seismogenic source generates vibratory ground motion but is assumed to not cause surface displacement, covering wide range of seismotectonic conditions, from a well-defined tectonic structure to simply a large region of diffuse seismicity.

The ML 5.8 Gyeongju earthquake on September 11, 2016 in South Korea is the largest instrumental one since 1978 that occurred in buried fault not exposed to the surface area. So to speak, there is no evidence of surface faulting till now. On the other hand, the geometry of the causative fault of the Gyeongju earthquake was revealed in detail from the distribution of foreshocks and aftershocks. Therefore, the causative fault of the Gyeongju earthquake can be treated as a seismogenic source corresponding to a well-defined tectonic structure as mentioned above.

What level of ground motions would occur at the site of interest if a larger earthquake would occur at the causative fault of the Gyeongju earthquake? To make a rough estimate of that question, we carried out a simple study of modeling the causative fault with the data available, and simulating strong ground motions with the stochastic and empirical Green’s function techniques. The magnitude of the maximum earthquake potential on the causative fault is in the range of 6.0 to 7.0 and increased by 0.5. We do not claim the possibility of such a large earthquake in the region, but have a goal to evaluate the seismic safety evaluation of the site of interest from such an earthquake potential. This type of study may help us elucidate the seismic hazard in a low seismicity area such as South Korea and review the seismic safety of the site of interest.
Based on Artificial Intelligence Simulation Study on the Impact of Land Use on Coastal Ecological Security in China's Coastal Zone
Authors: Xu Yuelei
Published: March 2020

As a transitional area between land and ocean system, coastal zone is a sensitive area of global change, which gathers 2/3 of the global population and wealth. Under the background of coastal urbanization and ecological civilization construction in China, more attention has been attached to develop the coastal zone economy efficiently with the strong interference of human activities. However, the deficiency of a suitable method to evaluate coastal ecological environment, affects the balance between utilization and protection in the coastal zone. This research compared habitat quality in the present with that in the future, and used this as the evaluation index of the impact of land use on coastal ecological security. The impact of land use transformation on natural wetlands and the quality of natural habitats has been calculated based on the coastal land use data since 1980 and the forecast land use in 2050, which under the scenario of RCP 4.5 carbon dioxide emission simulated by FLUS model artificial intelligence. The results show that in recent 20 years, there have been obvious reclamation activities in China's coastal areas, especially in Bohai Bay area, Yangtze river delta and Pearl River Delta. From 1990 to 2010, the reclamation expansion areas are 272.49 km2，270.09 km2 and 50.57 km2, respectively. With the development of economic transformation and ecological priority in the southeast coastal areas in recent years, the effect of habitat restoration will be remarkable by 2050, while habitat in Bohai Bay area and Pearl River Delta present an obvious degradation trend. These results, including the 30-metre-resolution habitat quality, can be used for reference for coastal ecological security maintenance and economic restructuring in different regions. This research will help to build the national ecological security evaluation system and formulate future policies for coastal ecological environment protection, and accelerate China's economic transformation.
Quantitatively distinguish the impact of climate change and human activities on the vegetation changes in Mainland China based on the improved residual method
Authors: Zhang Yahai , Ye Aizhong
Published: March 2020

        Knowledge of the current severe global environmental changes, vegetation has faced the dual challenges posed by climate change and human activities. Quantitatively distinguishing the influence of climate change and human activities on vegetation changes is a key to develop adaptive ecological protection policies. This study used the Normalized Difference Vegetation Index (NDVI) and meteorological data from 1982 to 2015 to analyze the characteristic of vegetation changes and the relationship with climate factors in Mainland China. The contribution rates of climate change and human activities to vegetation dynamics are further calculated by the improved trend method of residual analysis. The results show that 68.81% vegetation of Mainland China is in a state of sustainable increase and cultivated vegetation (CV) and grass are the main greening vegetation types. The impact of human activities (54.45%-75.27%) on vegetation changes in Mainland China is higher than climate change (24.73%-45.46%). Human activities mainly affect grass, mixed coniferous broad-leaved forest (MCBF) and cultivated vegetation (CV), while swamp is more sensitive to climate change. The improved residual trend method considering temporal and spatial dimensions can reduce the uncertainty of the methods. This study provides a theoretical basis for future government implementation of ecological management.
The role of microorganisms in the bentonite barrier of high-level radioactive waste repositories
Authors: Matschiavelli Nicole , Dressler Magdalena , Neubert Tom , Kluge Sindy , Schierz Ariette , Cherkouk Andrea
Published: March 2020

The global production of 12,000 metric tonnes of high-level radioactive waste (HLW) every year is a big challenge with respect to its safe long-term storage. In the favored multi-barrier system, bentonite is discussed as a geo-technical barrier in many disposal programs worldwide. The bentonite seals the space between the canister containing the HLW and the surrounding host rock, thereby fulfilling two major tasks: 1) slow down the process of corrosion when water enters the disposal site, and 2) hinder the discharge of radionuclides into the bio-geosphere in case of a leaking canister. Due to their metabolic activity, microorganisms could significantly influence the properties of the bentonite barrier. In order to investigate the metabolic potential of naturally occurring microorganisms, we conducted anaerobic bentonite-slurry experiments containing uncompacted bentonite and a synthetic Opalinus Clay pore water solution. Within one-year incubation at 30 and 60 °C, lactate- or H2-stimulated microcosms at 30 °C showed the dominance and activity of strictly anaerobic, sulfate-reducing and spore-forming microorganisms. Consequently, hydrogen sulfide gas was generated in the respective set ups, leading to the formation of fractures and iron-sulfur precipitations. Experiments that incubated at 60 °C, showed the dominance of thermophilic bacteria, independent of the presence of substrates. The respective set-ups showed/revealed no significant changes in the analyzed bio-geochemical parameters. The obtained results clearly show that indigenous microorganisms evolve in a temperature- and substrate-dependent manner. The formed metabolites can potentially affect the dissolution behavior of minerals and ions within the bentonite as well as corrosion processes and require further investigations.