bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the Geochemical Anomaly of Copper Element Based on Hyperspectral Indices
Authors: Shanshan Wang , Kefa Zhou
Published: March 2020

Geochemical anomalies are an important indicator in prospecting. In particular, geochemical anomalies of Cu play a very important role in geological prospecting of minerals. Geochemical anomalies of Cu are mainly related to mafic-ultramafic rocks and porphyry bodies, which are also associated with ore-forming elements of the Co-Zn-Cr-Ni-Cu combination. The conventional technique of geochemical prospecting involves superimposition of element symbols (Au, Fe, Cu, Al, Ca, etc.) on the geological map of an area by analysing geochemical anomalies using geochemical data. However, this technique is not suitable for regions where geochemical anomaly data are limited. The development of hyperspectral remote sensing has enabled the mapping of spectral features related to characteristic absorption bands of elements in minerals at high spatial resolution, providing a means for precise and detailed reconstructions of geochemical anomalies facies (surface). Compared to conventional techniques for identifying elements, reflectance spectroscopy offers a rapid, inexpensive, and non-destructive tool for determining the mineralogy of rock and soil samples. Hyperspectral remote sensing also provides data for prospecting in areas without sufficient geochemical data, and thus is of vital significance in prospecting for ores in such regions. However, approaches for remotely sensing elements are still lacking, particularly for element content. In this study, a level analysis of Cu content via spectral indices in the northwestern Junggar region, Xinjiang, was conducted. Based on four levels (0–100 ppm, 100–1000 ppm, 1000–10000 ppm, and >10000 ppm) of Cu content and corresponding spectral reflectance, simple and useful spectral indices for estimating Cu content at different levels were explored. The best wavelength domains for a given type of index were determined from four types of spectral indices by screening all combinations using correlation analysis. The coefficient of determination (R2) for Cu was calculated for all indices derived from the spectra of rock samples and was found to range from 0.02–0.75. With sensitive wavelengths and a significant correlation coefficient (R2 = 0.63, P < 0.005), the Normalized Difference (ND)-type index was the most sensitive to Cu content exceeding 10000 ppm. Although the ND-type index has a few limitations, it is a useful, simple, and robust indicator for determining Cu at high concentrations. With the advent of new platforms and satellites in the future, such relationships with other elements are required to enable the widespread use of this index in broad-scale surveys of mineral elements in the field.
Coordinated influences of the tropical and extratropical intraseasonal oscillations on the 10–30-day variability of the summer rainfall over southeastern China
Authors: Li Jianying , Mao Jiangyu
Published: March 2020

This study explores the spatial variations and physical mechanisms of 10–30-day rainfall anomalies over southeastern China based on daily station-observed rainfall data for the period 1979‒2015. Empirical orthogonal function analysis shows that the dominant spatial distribution of 10–30-day rainfall anomalies is a monopole pattern over the south of the middle and lower reaches of the Yangtze River Valley (SMLY). Lead-lag composites reveal that the evolution of such a monopole pattern depends on the coordinated influences of 10–30-day atmospheric intraseasonal oscillations (ISOs) from the tropics and mid-high latitudes. In the upper troposphere, the southeastward-propagating Rossby wave train from the mid-high latitudes, which presents as anomalous anticyclones and cyclones alternating over eastern Europe to the southeastern coastal area of China, induces strong ascents (descents) over the SMLY via vorticity advection. Circulation anomalies associated with tropical ISO over East Asia/Western North Pacific trigger a vertical cell with strong updraft (downdraft) over the SMLY and downdraft (updraft) to the south, further enhancing the ascents (descents) over the SMLY, forming the wet (dry) phases of 10–30-day rainfall anomalies. Moreover, due to the meridional non-uniformity of ISO-related diabatic heating along the Indian Ocean longitudes, an anticyclone (cyclone) is generated over the central Indian–northern Bay of Bengal, which tends to anchor the anomalous ascents (descents) over the SMLY through its interaction with the intraseasonal Rossby wave from mid-high latitudes, thus favoring the persistence of wet (dry) phases of the 10–30-day SMLY rainfall anomalies.  
Methylmercury production and degradation by soil microbial communities
Authors: Liu Yu-Rong , Huang Qiaoyun
Published: March 2020

Rice consumption is now recognized as an important pathway of human exposure to the neurotoxin methylmercury (MeHg), particularly in countries where rice is a staple food. Although the discovery of a two-gene cluster hgcAB has linked Hg methylation to several phylogenetically diverse groups of anaerobic microorganisms converting inorganic mercury (Hg) to MeHg, the prevalence and diversity of microbial communities associated with MeHg production and degradation in paddy soils remain unclear. Both Illumina and PacBio sequencing analyses revealed that Hg methylating communities were dominated by iron-reducing bacteria (i.e., Geobacter) and methanogens, with a relatively low abundance of hgcA+ sulfate-reducing bacteria in the soil. A positive correlation was observed between the MeHg content in soil and the relative abundance of Geobacter carrying the hgcA gene. Our structure equation modeling suggested a much stronger link between bacterial community composition and %MeHg, compared to the abundance of methylating gene (hgcA) and edaphic properties. More importantly, random forest models suggested a more important role of non-Hg methylators than Hg methylators in predicting variations of soil %MeHg.

Microbial demethylation was demonstrated by significantly more degradation of MeHg in the unsterilized soils than the sterilized controls, although more degradation was observed in water-saturated soils than the unsaturated soil. 16S rRNA Illumina sequencing and metatranscriptomic analyses consistently revealed that Catenulisporaceae, Frankiaceae, Mycobacteriaceae, and Thermomonosporaceae were among the most likely microbial taxa in influencing These findings provide new insights into microbial communities associated with MeHg accumulation in paddy soils, with important implications in mitigating the net production and bioaccumulation of MeHg in rice worldwide.
Seasonal variations in chemical characterization of submicron aerosol particles in Shanghai, China: Insights from a high-resolution aerosol mass spectrometry
Authors: Zhu Wenfei , Lou Shengrong , Guo Song
Published: March 2020

As a characteristic pollutant of urban compound pollution, submicron particulate matter (PM1) has significantly impacted on human health and climate change. In this study, four intensive campaigns using a high-resolution time-of-flight AMS (HR-ToF-AMS) and other online instruments from 2016 to 2017 were conducted to investigate the seasonal characteristics of submicron particles in Shanghai. The average mass concentrations of submicron particulate matter during spring, summer, autumn and winter observations in Shanghai are 23.9 ± 20.7 μg/m3, 28.5 ± 17.6 μg/m3, 22.0 ± 17.2 μg/m3 and 31.9 ± 22.7 μg/m3, respectively. The major chemical components in submicron particulate matter showed obvious seasonal and daily variations. The increase of submicron particulate matter is mainly due to the contribution of nitrate in spring, autumn and winter, while the photochemical reaction promotes the rapid growth of sulfate in summer. Detailed source apportionment of organic aerosol showed that the fraction of more oxidized oxygenated organic aerosol in organic aerosol in spring was much lower than primary organic aerosol. Oxygenated organic aerosol dominated organic aerosol in summer (69%). More oxidized oxygenated organic aerosol account for 28% in autumn, suggesting that organic aerosol was aging. The liquid phase oxidation and the strong photochemical reaction concentration have a significant contribution to the formation of more oxidized oxygenated organic aerosol and less oxidized oxygenated organic aerosol in the spring, summer and winter observations, respectively. However, the photochemical reaction process dominated the formation of more oxidized oxygenated organic aerosol in autumn.
Nutrient sources in four forest watersheds in Japan: the contribution of precipitation, weathering and litter fall
Authors: Inagaki Yoshiyuki , Fujii Kazumichi
Published: March 2020

Base cation such as calcium and potassium is important nutrient for tree growth in forest ecosystems.  Major sources of basic cation to forest soil are precipitation, weathering of parent material and litter fall.  Weathering rate of basic cation is estimated from the input from precipitation, runoff from stream and uptake by vegetation.  Nutrient cycling of many Japanese forest ecosystems has been studied but information about the contribution of these sources is limited.  This study compared three nutrient sources in four forest watersheds in Japan.  These are Oyasan (Gunma Pref.), Kamikamo (Kyoto Pref.), Kiryu (Shiga pref.) and Takatori (Kochi Pref.).  We calculated nutrient budget of potassium, calcium and magnesium.  The rate of rock weathering of base cation ranged from 0.22 to 4.37 kmolc ha-1 yr-1 and increased in the order of Kamigamo < Kiryu < Oyasan < Takatori.  In potassium cycling, the contribution of litter fall was greater than that of weathering or precipitation.  The runoff of calcium and magnesium from soil was greater in Takatori, where the rate of weathering was high.  Although the rate of weathering varied substantially among forest watersheds, the annual flux of litter fall was relatively constant.  Similar calculation was applied for nitrogen cycling and the　source from soil was treated as that from nitrogen accumulated during the past pedogenesis.  Nitrogen input from the accumulated soil source was 36 % in Oyasan whereas that in other three watersheds was 0%. Oyasan was considered as a nitrogen-saturated forest and the result of the study suggest the ecosystem relies on different nitrogen source.
A 1 eV - 1000 eV ion beam system designed for the calibration of low-energy ion mass spectrometers
Authors: Li Yiren , Miao Bin , Hao Xinjun , Zhang Tielong , Wang Yuming
Published: March 2020

For the calibration of space plasma analyzers, in particular low-energy ion mass spectrometers, a low energy ion beam system was developed. The positive ion beam is produced by a hot-cathode penning source and modified by a series of electrostatic lenses. And a 75 mm diameter 2-D imaging system and a Faraday cup mounted on movable arms are used for ion beam diagnostics. With protons as primary species, the system provides an ion beam in the energy range of 1 eV - 1000 eV with a large area ( ~ 50 cm2), highly parallel ( ± 0.5°), and spatially uniform ( ± 5%).
Building spatial-temporal NO2 land use regression models in complex urban environment
Authors: Wei Peng , Xing Yang , Sun Li , Ning Zhi
Published: March 2020

Air quality and traffic-related pollutants in urban areas are major concerns especially in meg-cities. Current Air Quality Monitoring Station (AQMS) cannot sufficiently reveal these pollution conditions with limited point measurements and limited information cannot supply adequate insight on personal exposure in a complex urban environment. Land Use Regression (LUR) model provided a feasible solution for estimating outdoor personal exposure by adding multiple data sources. However, fixed-site passive monitoring still lacks enough spatial coverage or spatial flexibility to estimate pollutant distribution at the fine-scale level.

A Mobile Air Sensor Network (MASEN) project was deployed in the Hong Kong area, with electrochemical gas sensors installed on the routine buses to capture on-road NOx pollutant measurement, the data was collected by the integrated sensor system and transfer to the database for real-time visualization. Compared with previous mobile measurements used for LUR model building which limited to 1-2 routes, this measurement covered major roads in the Hong Kong area and get an overview of pollutant distribution at various ambient. Two main variables were introduced to improve the model performance: 1) Sky View Factor (SVF) which represented pollutant dispersion status were obtained from Google street view image, a deep learning model was used for scene parsing to recognized targets in this procedure, 2) a Real-time Traffic Congestion Index (RTCI) which represented traffic pollutants emission was obtained from Google map and merged with road network. A common LUR model will be built based on a distance-decay regression selection strategy for variables selection. Meanwhile, a spatial-temporal LUR model will be built which contained both diurnal variability and day-to-day variability. Finally, a high-resolution pollution map of the urban areas will illustrate NO2 pollutant distribution.

In this work, we aimed at estimating traffic-related pollutants in a complex city environment and identifying hotspots at both spatial and temporal aspects. Meanwhile, the novel data source which closely associated with traffic-related pollutant emission also gives a better understanding of guidance on urban planning.
Deceleration and deflection of solar wind ions by periodic shocks
Authors: Du Aimin , Shan Lican
Published: March 2020

Interacting with a supersonic solar wind, the escaping ions result in a series of phenomena in the Martian space environment. Observations from MAVEN magnetometer and plasma detector revealed a serial of small-amplitude quasi-monochromatic waves upstream of the Martian bow shock. Those waves have a dominant frequency at the local proton gyrofrequency. The waves evolve into periodic shock structures as they are convected downstream by the high-speed solar wind flow. We found those structures deflected and decelerated solar wind ions through magnetic mirror topology. A consequence of the effect is a significant loss of solar wind ion energy, accompanying with pitch angle scattering.
Developing future sea level services for Small Island Developing States
Authors: Jevrejeva Svetlana , Wolf Judith , Matthews Andy , Williams Joanne , Byrne David , Bradshaw Elizabeth , Williams Simon , Hibbert Angela , Gordon Kathy , Rickards Lesley , De Dominicis Michela , Bricheno Lucy
Published: March 2020

The Caribbean islands encompass some of the most vulnerable coastlines in terms of sea level rise, exposure to tropical cyclones, changes in waves and storm surges. Climate in the Caribbean is already changing and sea level rise impacts are already being felt. Considerable local and regional variations in the rate, magnitude, and direction of sea-level change can be expected as a result of thermal expansion, tectonic movements, and changes in ocean circulation. Governments in the Caribbean recognise that climate change and sea level rise are serious threats to the sustainable development and economic growth of the Caribbean islands and urgent actions are required to increase the resilience and make decisions about how to adapt to future climate change (Caribbean Marine Climate Change Report Card 2017; IPCC 2014).

As part of the UK Commonwealth Marine Economies (CME) Programme and through collaboration with local stakeholders in St Vincent, we have identified particular areas at risk from changing water level and wave conditions. The Caribbean Sea, particularly the Lesser Antilles, suffers from limited observational data due to a lack of coastal monitoring, making numerical models even more important to fill this gap. The current projects brings together improved access to tide gauge observations, as well as global, regional and local water level and wave modelling to provide useful tools for coastal planners.

We present our initial design of a coastal data hub with sea level information for stakeholder access in St. Vincent and Grenadines, Grenada and St Lucia, with potential development of the hub for the Caribbean region. The work presented here is a contribution to the wide range of ongoing activities under the Commonwealth Marine Economies (CME) Programme in the Caribbean, falling within the work package “Development of a coastal data hub for stakeholder access in the Caribbean region”, under the NOC led projects “Climate Change Impact Assessment: Ocean Modelling and Monitoring for the Caribbean CME states”.
Combination of Web Programming and DAN3D to Generate Interactive Plots for Debris Flow Hazard Assessment
Authors: Cheon Enok , Lee Seung Rae , Lee Deuk Hwan , Lim Hwan Hui , Lee Seung Min
Published: March 2020

In order to mitigate the potential damage from debris-flow hazards, the debris-flow hazard assessment is conducted to quantify the risk of landslide occurrence and assign potential levels of damage to surrounding buildings. DAN3D (Three-Dimensional Dynamic Analysis), a 3D numerical model for debris-flow simulation, has been widely used to conduct the debris-flow hazard assessment by computing the magnitudes of debris-flow characteristics, such as the velocity, depth, and volume. DAN3D software presents the results on a map plot that shows the magnitude of debris-flow characteristics over the inundated areas at a particular simulation time. These plots neither provide the exact values of debris-flow characteristics at a specific location nor compute the area and the width of debris-flow. Furthermore, a static image can be inconvenient for visualizing the changes in the debris-flow characteristics through time. Therefore, the present study created a program to interprets the DAN3D simulation results and to generate interactive plots using web programming. The interactive plots represent the position of a debris-flow cluster with a centroid location and show debris-flow characteristics, including the area and width of debris-flow, with a color scale. Additionally, the generated plots provide a graphical-user-interface to extract more details or change the plot. The accessibility and customization provided by the generated plots can be very useful for the design of the protection measures and evaluation of the effectiveness of them. A case study of the debris-flow at Sindonga watersheds, Mt. Umyeon, Korea, in 2011, was used to generate several interactive plots and their usefulness in designing barriers as mitigation against debris-flow.
Micropredators skulking in Silurian oceans?
Authors: Leonhard Isabella , Shirley Bryan , Murdock Duncan , Jarochowska Emilia
Published: March 2020

Predation is potentially one of the most impactful evolutionary traits to have ever developed. Conodonts, an extinct group of early vertebrates, developed the first phosphatic dental tools, known as elements. Elements ranged from simple coniform types to more complex morphologies, predominantly in more derived species. Unlike the teeth of other vertebrates, these continuously grew throughout their lifetime by the periodic accretion of new lamellar tissues. This unique growth process continuously records chemical and physical characteristics throughout its lifespan which, when accessed, gives direct insight into the animal’s ecology and mode of life. Multiple lines of evidence, such as microwear studies and growth allometry, indicate that adult conodonts fed as predators and/or scavengers. There is little direct independent evidence for feeding ecologies in the earliest conodonts with coniform elements apparatuses, although previous modelling of element position and mechanical properties indicate these were capable of processing or manipulation of food. A direct test would be provided through evidence of tissue damage and its chemical composition. Our research focuses on samples of the coniform genus Panderodus (Family: Panderodontidae) from the Silurian of Poland and Ukraine. Panderodus has the best constrained apparatus reconstruction of any coniform conodont. Here we employ Backscatter electron (BSE) imaging and Energy-dispersive X-Ray spectroscopy (EDX) to identify growth dynamics, microwear, and chemical sclerochronology recorded within this unique mode of growth. Our results have direct implications not just for understanding the feeding mode of Panderodus, but also the origination of predation in the earliest vertebrates in the fossil record.
Compound impact of rainfall, tidal level and storm surge on flood risk from tropical cyclones in the coastal area of shanghai
Authors: Xu Hanqing
Published: March 2020

Catastrophic flooding resulting from extreme tropical cyclones has occurred more frequently and drawn great attention in recent years in China. Coastal cities are particularly vulnerable to flood under multivariable conditions, such as heavy precipitation, high sea levels, and storms surge. In coastal areas, floods caused by rainstorms and storm surges have been one of the most costly and devastating natural hazards in coastal regions. Extreme precipitation and storm tide are both inducing factors of flooding and therefore their joint probability would be critical to determine the flooding risk. Usually, extreme events such as tidal level, storm surges, precipitation occur jointly, leading to compound flood events with significantly higher hazards compared to the sum of the single extreme events. The purpose of this study is to improve our understanding of multiple drivers to compound flooding in shanghai. The Wind Enhance Scheme (WES) model characterized by Holland model is devised to generate wind "spiderweb" both for historical (1949-2018) and future (2031-2060, 2069-2098) tropical cyclones. The tidal level and storm surge model based on Delft3D-FLOW is employed with an unstructured grid to simulate the change of water level. For precipitation, maximum value between tropical cyclone events is selected. Following this, multivariate Copula model would be employed to compare the change of joint probability between tidal level, storm surge and heavy precipitation under climate change, taking into account sea-level rise and land subsidence. Finally, the impact of tropical cyclone on the joint risk of tidal, storm surge and heavy precipitation is investigated. 
Ground Motions prediction Equations from a stochastic simulation approach for in-slab intermediate-depth earthquakes along the Hellenic subduction zone
Authors: Kkallas Harris , Papazachos Costas , Vamvakaris Dominikos
Published: March 2020

We have used a stochastic approach to simulate a large number of scenarios for in-slab intermediate-depth earthquakes in the southern Aegean Sea Hellenic subduction region, by applying an extended-source model using the EXSIM code. A large database of synthetic ground motion recordings for events with magnitudes in the range M6.0-8.5 has been compiled, covering the whole southern Aegean Benioff zone. For the stochastic simulations, we followed the approach developed in our previous works (Kkallas et al., 2018a,b), where we used the anelastic attenuation from the GMPEs modeling developed by Skarlatoudis et al. (2013) to constrain the different attenuation patterns and properties for the back-arc and fore-arc area. Simulation model parameters, such as stress parameters and attenuation parameters were also adopted from previous works, while for fault parameters we adopted the typical average focal mechanisms proposed by Papazachos et al. (2000), in agreement with the regional subduction tectonics. Estimates of expected ground motion measurements (PGA and PGV values) at different distances from different earthquakes have been employed to generate hybrid Ground-Motion Prediction Equations (GMPE). More specifically, we attempt to modify the existing Ground-Motion Prediction Equations (GMPE) from Skarlatoudis et al. (2013) for intermediate-depth earthquakes along the Hellenic Arc for large magnitude events (M>6.5), so that they can be efficiently used for Seismic Hazard assessment, as the original strong-motion dataset used for their development was lacking data in this magnitude range. Peak ground accelerations and velocities predicted by the EXSIM code are generally in very good agreement with the available GMPE results for magnitudes less than M7. However, significantly lower ground motions than those predicted by the GMPEs are predicted for large-magnitude events (M>7). Using the previous results, we propose a magnitude-dependent correction for the GMPE results both back-arc and along-arc ground motions. Moreover, we demonstrate how the final earthquake ground motion scenarios, as well as the modified GMPEs affect both deterministic and probabilistic seismic hazard analysis. This work has been partly supported by the HELPOS (MIS 5002697) project.
Machine-learning based wind turbine operating state detection and diagnosis
Authors: Meyer Angela
Published: March 2020

The operation cost for wind parks make up a major fraction of the park’s overall lifetime cost. To facilitate an optimal wind park operation and maintenance, we present a decision support system that automatically scans the stream of telemetry sensor data generated from the turbines. By learning decision boundaries and normal reference operating states using machine learning algorithms, the decision support system can detect anomalous operating behaviour in individual wind turbines and diagnose the involved turbine sub-systems. Operating personal can be alerted if a normal operating state boundary is exceeded. We demonstrate the successful detection and diagnosis of anomalous power production for a case study of a German onshore wind park for turbines of 3 MW rated power.
Atmospheric physics and microphysics research project in the Central Peruvian Andes. A multilateral approach.
Authors: Silva Yamina , Martínez-Castro Daniel , Moya-Álvarez Aldo , Estevan René , Flores Rojas José , Kumar Shailendra
Published: March 2020

The Mantaro river basin is surrounded by the central Andes of Peru, with altitudes of up to 5300 m.a.s.l. The Mantaro valley, has great economic and social importance for its rich agriculture, as well as water resources, of considerable weight in the generation of power supply electricity and drinking water. This favors the presence of numerous urban centers in the region, highlighting the city of Huancayo with more 500,000 population. The incidence of convective precipitation systems, influenced by the local orographic circulation, in agriculture and social activities in the region is conspicuous, both from the point of view of water supply and as potential weather hazards, in the case of hailstorms and heavy rains, as well as frost event. The project “Strengthening the research line on Atmospheric Physics and Microphysics”  was conceived with the objective of developing a multilateral research on the conditions of formation of precipitation systems in the basin, the dynamical factors influencing their development and the microstructure and phase composition of clouds and precipitation over the valley. The project includes three main components: 1. Characterization of the structure and evolution clouds and precipitation; 2.  Study of the atmospheric aerosol s in the region and their relationship with solar radiation and 3: Development of customized numerical weather forecasting tools focused on different scales and forecast terms, based mainly on the WRF-ARW modeling system. The experimental base of the project was centered in the instrumental complex of the Atmospheric Microphysics and Radiation Laboratory (LAMAR), in the Huancayo Observatory (3300 m.a.s.l), located in the Mantaro Valley. As a result of the project, an atmospheric database with very complete characteristics has been developed, which serves as a test base for the verification of models in different meteorological conditions, including the occurrence of dangerous phenomena.  The project started in April, 2017 and  must finish in April 2020. To date, twelve papers have been published in peer-reviewed journals, on topics such as the study of convective cloud fields and precipitation over South America and Peru from remote satellite sensors, tuning of the configuration of numerical models for the conditions of the central Andes of Peru, numerical weather forecast, study of the structure of convective systems producing  rain in the valley, characteristics of atmospheric aerosols over the valley and the radiative balance. Because of these researches, new numerical modeling tools have been developed for the conditions of the central Peruvian Andes. In this paper we will present the main results from the project, that contributed to increase our understanding of the Andes climate.
Ion Scale Flux Rope Observed at the Trailing Edge of the Hot Flow Anomaly
Authors: Bai Shi-Chen , Shi Quanqi , Liu Terry , Zhang Hui , Yue Chao , Sun Wei-Jie , Tian Anmin , Degeling Alexander , Bortnik Jacob , Rae Jonathan , Wang Mengmeng
Published: March 2020

  Magnetic reconnection occurring during the development of a Hot flow anomaly (HFA) has been generated in hybrid simulation, but has never been observed by spacecraft. Using MMS we report an ion scale flux rope like structure, which is Earthward moving, embedded within the trailing edge of a hot flow anomaly (HFA) upstream from the quasi-parallel bow shock. The driver discontinuity of the HFA, a tangential discontinuity, is observed in the solar wind, but no flux rope signatures are observed around it. This suggests that the earthward moving flux rope was generated inside the HFA. This flux rope is close to a one-dimensional structure and expands due to a strong magnetic pressure gradient force. Solar wind ions are decelerated inside the flux rope by the static electric field likely caused by the charge separation of solar wind particles. Our observations imply that magnetic reconnection may have occurred inside the HFA. Reconnection and flux ropes may play a role in particle acceleration/heating inside foreshock transients.
Seasonal variation of Mercury's exosphere deduced from MESSENGER data and simulation study
Authors: Suzuki Yudai , Yoshioka Kazuo , Murakami Go , Yoshikawa Ichiro
Published: March 2020

Celestial bodies with surface-bound exosphere are valuable because we can directly see the interaction between the bodies and space environment to which they are exposed. This interaction is especially expected to be clearly observed around Mercury. This research aims to clarify the generation process of neutral sodium exosphere, through the comparison between the data from MASCS onboard MESSENGER spacecraft and 3-D model calculation considering generation, transportation and dissipation processes.

First, seasonal variability of the amount of sodium exosphere is analyzed for each local time (LT) using MASCS data. Previous research has shown that the amount of sodium above LT12 reaches a maximum at aphelion, and it is found that this maximum is seen only above LT12. In addition, two hypotheses proposed by the research: the increase in the surface sodium density of the dayside due to fast rotation of terminator, and the expansion of exosphere owing to weaker radiation pressure, were turned out to be inconsistent with seasonal variability above LT06 and the results of test particle calculations.

Following these results, in order to understand the key process of the seasonal variation of the amount of sodium especially around LT12, 3-D sodium exosphere model including release from the surface, transport due to gravity and solar radiation pressure, and dissipation due to ionization caused by solar radiation is constructed. The results from numerical calculation is consistent with the observations by MASCS in terms of the vertical profile and the seasonal variability above LT06 and LT18, but the maximum at aphelion above LT12 could not be reproduced. Then, when the existence of the impact of comet dust stream is assumed as a local and short-term sodium source, the model with impact of 108kg comets per Mercury year could reproduce observations.

Using the model constructed in this study, the sodium distribution which would be observed by MSASI onboard MIO spacecraft is predicted. The comparison between the calculation and observation by MSASI will provide us new insights into the interaction between the celestial bodies and space environment.

In this presentation, we will summarize the results of comparison between observations by MASCS and 3-D Monte Carlo simulation about the seasonal variability of Mercury’s sodium exosphere.
Seismotectonic setting of Santorini-Amorgos zone and the surrounding area revealed from crustal earthquakes relocation and Vp/Vs distribution
Authors: Andinisari Ratri , Konstantinou Konstantinos I. , Ranjan Pratul , Hermawan Qori F.
Published: March 2020

The Santorini-Amorgos zone represents right-lateral transtensional regime from NE of Santorini to the south of Amorgos which also hosts Kolumbo submarine volcano. A total number of 1869 crustal events from 2002 to 2019 were recorded by permanent and temporal seismic networks deployed in southern Aegean. Absolute locations of these events were obtained by utilizing the probabilistic nonlinear algorithm NonLinLoc. Precise relative relocation by using double-difference algorithm with catalog and cross-correlation differential times was later performed, resulting in 1455 locations with horizontal and vertical uncertainties of less than 0.3 km. Clusters of earthquakes relocated between Naxos and Paros as well as north of Astypalaia do not coincide with any fault in the area. Similarly, the relocated crustal events across Santorini-Amorgos zone show that most of the earthquake clusters do not coincide with any of the existing faults. The distribution of Vp/Vs ratios in the area were investigated based on the P and S-wave travel times of all the events. Vp/Vs ratios in the area vary between 1.67 and 2.03 with errors less than 0.04. The highest Vp/Vs values were found to be distributed in the area between Naxos and Paros. Other areas with notably high Vp/Vs ratio are north of Santorini, Anydros, west of Amorgos, offshore area south of the easternmost tip of Amorgos, and the island of Astypalaia. These mentioned areas were also rich in seismic activities during the period of study. The high Vp/Vs ratios in the region of high seismicity signifies that these events were likely related to the migration of magmatic fluids to the surface and may not be caused by the existing faults.
Revegetation modifies patterns of temporal soil respiration responses to extreme-drying-and-rewetting in a semiarid ecosystem
Authors: Sun Wenhao
Published: March 2020

Changes in climate and land-use are altering soil respiration patterns and thus affecting C sequestration rates globally. This study aims to understand the effect of revegetation induced land-use change on the response of soil respiration to precipitation pulses during an extreme-drying-and-rewetting period. Soil respiration (SR) in cropland, grassland, shrubland, and orchard were intensively monitored along with environmental variables during an extreme drought period with precipitation pulse on China’s Loess Plateau. SR was strongly correlated to soil water content for all land-uses. However, the relationship was highly dependent on land-use types: SR was only strongly suppressed in cropland and orchard when moisture content exceeded 10.8% and 13.7%, respectively, whereas no clear suppression was observed under other land-uses. As a result, the C loss in grassland and shrubland was 49.1-78.9% higher than in cropland following significant precipitation events. In addition, SR was negatively and weakly correlated with soil temperature, indicating the change in the dominant control on SR due to extreme drought. Land-use change alters the response of soil respiration to soil moisture during extreme-drying-and-rewetting periods in this revegetated ecosystem. Its effect on respiration pulses will amplify as extreme climate events increase in the future, which may potentially alter the existing C balance.
Retrieving high resolution rainfall data for Ecuador using GOES-16 and IMERG data
Authors: Turini Nazli , Thies Boris , Rollenbeck Rütger , Fries Andreas , Pucha-Cofrep Franz , Orellana Alvear Johanna , Horna Natalia , Célleri Rolando , Bendix Jörg
Published: March 2020

Accurate rainfall information in high spatio-temporal resolution is important for water resource management, particularly in water-scarce remote areas which are characterized by a coarse network of operational precipitation gauge stations. For such regions, satellite-based rainfall products potentially represent a source for reliable and area-wide data on rainfall. The poster presents a new satellite-based precipitation algorithm for semi-arid regions in Ecuador with the elevation range between 12 to 5700 a.s.l. The algorithm relies on the combination of  precipitation information from the Integrated Multi-SatEllite Retrieval for the Global Precipitation Measurement (GPM) (IMERG) and infrared (IR) data from the Geostationary Operational Environmental Satellite 16 (GOES-16). The algorithm is developed to (i) classify the rainfall area and then (ii) to assign the rainfall rate. For the period between 19.04.2017 to 19.04.2018 the brightness temperature derived from GOES-16 IR channels and ancillary geo-information are trained with microwave only rainfall information of the half-hourly IMERG-V06 product using the machine learning algorithm random forest. The validation is done against independent microwave-only IMERG-V06 rainfall data not used for model training and available gauge stations. The validation results show overall very good accuracy of the new rainfall retrieval technique in this case study, mostly in comparison with the GPM IMERG IR-only rainfall product. The product offers the potential for high spatio-temporal (2 km, 15 min) rainfall resolution in near real-time for Ecuador.
Comb-veins as a marker for crustal-scale fluid circulation: insight from geochronological (U-Th dating), geochemical, and field to microstructural analyses along the seismogenic Val Roveto Fault (central Apennines, Italy)
Authors: Smeraglia Luca , Bernasconi Stefano M. , Berra Fabrizio , Billi Andrea , Boschi Chiara , Caracausi Antonio , Carminati Eugenio , Castorina Francesca , Doglioni Carlo , Italiano Francesco , Rizzo Andrea Luca , Uysal Ibrahim Tonguç , Zhao Jian-xin
Published: March 2020

Comb-veins are mineral-filled fractures oriented perpendicular to fault surfaces, with their intersection with the fault surface generating lineations that are perpendicular to the downdip slip direction. Despite the large occurrence along normal faults within seismogenic extensional tectonic settings (i.e. Greece, Turkey, Italy), their origin, geochemical signature, and kinematics are still poorly constrained. Here we present the first multidisciplinary study, combining field to microscale observations (optical microscope and cathodoluminescence) with geochemical-geochronological analyses (U-Th dating, stable-clumped isotopes, Strontium isotopes, whole-rock geochemistry, and fluid inclusions), on calcite-filled comb-veins cutting through the principal surface of the seismogenic Val Roveto Fault in the central Apennines, Italy. We show that comb-veins precipitated in Late Pleistocene time (between 300 ky and 140 ky) below the present-day outcrop level at a maximum depth of ∼350 m and temperatures between 32 and 64°C from deep-seated fluids modified by reactions with crustal rocks and with a mantle contribution (up to ∼39%). The observed geochemical signature and temperatures are not compatible which those of cold meteoric water and/or shallow groundwater (maximum temperature of 12 °C) circulating within shallow aquifers (≤ 500 m depth) in the study region. Therefore, we propose that deep-seated crust/mantle-derived warm fluids were squeezed upward during earthquakes and were hence responsible for calcite precipitation at shallow depths in co-seismic comb fractures. As comb-veins are rather common, particularly along seismogenic normal faults, we suggest that further studies are necessary to test whether these veins are often of co-seismic origin. If so, they may become a unique and irreplaceable tool to unravel the seismic history and crustal-scale fluid circulation of active faults.
Developing an integrated urban inundation flood model for extreme rainfall events with complex sewer system
Authors: Dasallas Lea , An Hyunuk
Published: March 2020

One of the major consequences of the changing climate is more intense rainfall episodes in climate vulnerable countries, specifically the Philippines. For over the last 10 years, extreme rainfall events had occurred in the country’s capital city, Metro Manila, which resulted to severe urban flooding occurrences.  The intense rainfall combined with the domain’s low elevation, close proximity to large water sheds and river basins, lack of proper urban planning and the un-systematized drainage system had aggravated the flood inundation. Numerous studies were conducted that had used flood models, but none of these had incorporated the effect of water drainage network, which is an integral part of simulating realistic urban flood inundation. Therefore, this research aims to develop an integrated urban inundation model based on digital surface model that assimilates the sewer system applicable for urban domains with complex pipe network. The quadtree shallow water method, a model that provides flexible grid generation that utilizes adaptive quadtree grid and cut method.  The results were analyzed and compared with the validation data obtained from previous extreme rainfall events. The integrated model was also compared to the existing flood inundation methodologies being used for the present flood early warning system. Research results show that present methodology is closer to the validated results as compared to the previous models. The developed model is also perceived to be best applicable for short term flood events. This shows the efficiency of utilizing integrated urban flood modeling in the Philippines, which can be used for extreme and conventional urban flood events in the future.
Laboratory testing for monitoring of reservoir properties during water injection
Authors: Geremia Davide , David Christian , Barnes Christophe , Menéndez Beatriz , Dautriat Jeremie , Esteban Lionel , Sarout Joel , Vandycke Sara , Descamps Fanny
Published: March 2020

Since the performances of geological reservoirs are continuously changing during the production history, tools capable of characterizing these changes are becoming day by day of relevant importance. A time-lapse monitoring is an important and widely used way to explore the variations induced by the oil depletion. In an enhanced oil recovery scenario, the seismic survey method has been mostly used to monitor the remaining oil fraction with respect to the injected water, however no particular attention has been addressed to the effects generated by the water-rock interaction, which might induce deformation with no stress variation. Indeed, it is well known that water can induce important mechanical weakening in reservoir rocks.

For that purpose, we performed injection tests on carbonate rocks in a conventional triaxial cell. An essential characteristic of these tests is the very low injection pressure, in order to minimize changes in the effective stresses and focus specifically on the rock - fluid interaction. The test consists in injecting water from the bottom in a critically loaded sample, initially in a dry state, until deformation is induced by the water-air substitution and failure is reached. While testing, the rock sample is instrumented with either 6 (at UCP, GEC lab) or 16 (at CSIRO, Geomechanics and Geophysics lab) P-wave transducers allowing us to perform an active ultrasonic survey with a narrow time intervals.

The described methodology allowed us to monitor how P-wave attributes (amplitude, velocity and frequency), elastic moduli, as well as, permeability and injection rate change while water is flooding the sample increasing the water saturation, and damage is produced by the water – rock interaction. For instance, injecting water into a dry rock sample could produce several patterns of variations in the P-wave velocity, which we ascribed to 1) partial water saturation; 2) water-induced damage with no failure; 3) water-induced failure and, in some cases, 4) total water saturation. More experiments are planned to mimic real EOR operation, like injecting water in an oil-saturated rock sample, with acoustic monitoring as well.

The outcome of this study indicates that combining multiple data sets from different sources is an effective tool for monitoring the exploitation of underground resources. This can certainly enhance our understanding of reservoir properties changing over time and target the attention toward the areas of greatest interest.
Plastic contamination of soil: is compost the source?
Authors: Braun Melanie , Krupp Aylin , Heyse Rene , Mail Matthias , Amelung Wulf
Published: March 2020

Plastic contamination is a major environmental topic, however, only little knowledge exists about plastic contamination of agroecosystems. Especially the prevalence of plastic in soil and potential entry paths remain largely unknown. Consequently, this study aims at evaluating to what degree compost application is a source of plastic for soil. To do so, we analyzed plastic in 8 different municipal and commercial composts and in topsoil (0-30 cm) of a 12-year compost fertilizer trial with 0, 5, 10 and 20 t compost per hectare. After method testing and adjustment (yielding 76-100% recovery of spiked plastic particles), plastic was analyzed via density separation (ZnCl2) and light microscopy. We found 12±8 to 46±8 plastic items kg-1 compost; concentrations of plastic items > 5 mm were highly variable and ranged between 0.04±0.08 to 1.35±0.53 g kg-1 compost. In contrast to sewage sludge, which contains mostly fibers, in compost particles were dominant. In soil we found 0 to 66±8.5 plastic items kg-1 soil, with highest plastic concentrations in variants with highest compost application, i.e. soils with compost application had 2 to 2.5 higher plastic concentrations than control variants. However, we also could detect additional plastic sources as fields on the border of the trial (near a road) had 3 times higher plastic concentrations than inner fields, leading to a plastic contamination of up to 23 items kg-1. Consequently, we could confirm compost application as an entry path for plastic into soil, leading to a twofold increased plastic contamination of agricultural soil. The determined plastic input via compost might be a minimum estimate since small plastic items like nanoplastics were not included, which warrants further attention.  
Open-ended, high cadence, Kp-like geomagnetic index Hp
Authors: Matzka Jürgen , Kervalishvili Guram , Rauberg Jan , Stolle Claudia , Yamazaki Yosuke
Published: March 2020

An open-ended, high cadence, Kp-like geomagnetic index, called Hp index, is developed within the H2020 project SWAMI (Space Weather Atmosphere Models and Indices). The traditional Kp index is an excellent measure for energy input by the solar wind and is widely used in space weather science and applications. The new planetary index Hp resembles the Kp index by having a similar derivation scheme and a nearly identical frequency distribution of index values. Hp is available from 1995 onward with different time resolutions, e.g., 30 minutes and 60 minutes, and thus provides a higher temporal resolution than the 3-hourly Kp index. Additionally, events with Hp > 9- were further subdivided using an open-ended scale (9o, 9+, 10-, 10o, 10+, 11-, ...) to represent the highest levels of geomagnetic activity with higher resolution.