bluuebunny/crossref_metadata_2025 huggingface dataset:
Hg(II)-Dissolved Organic Matter (DOM) Interactions in Freshwater and their Removal in Conventional Water Treatment
Authors: Diaz Farith , Katz Lynn , Lawler Desmond
Published: March 2020

In aquatic environments, Hg(II) is strongly reactive with the dissolved organic matter (DOM) and form complexes with acidic functional groups like carboxylic acids, phenols, ammonia, alcohol, and reduced sulfur ligands (Sred). It has been suggested, however, that both the concentration of Hg(II) and the composition of the DOM influence the potential for the removal of Hg(II) in water treatment.

Jar test experiments were performed at optimum coagulation conditions of pH and alum dose, using unfractionated DOM, humic substances (humic acids and fulvic acids) and different Hg(II) concentrations. Samples used in this work were obtained from the International Humic Substances Society (IHSS) and were selected based on the differences in aromatic carbon, reduced sulfur content, acidic functional groups concentration, geographical location, and commercial availability.

Results showed that good removal of Hg(II) can be achieved by alum coagulation under two circumstances: (1) when the DOM is low in Sred ligands but rich in aromatic content and (2) when the DOM is rich in Sred ligands and low in aromaticity. At low Hg/DOM ratio (0.05 μg Hg/mg DOM), Hg(II) removal can be as high as 95%, while at high Hg/DOM ratio (1.0 μg Hg/mg DOM) Hg removal can be as high as 73%. The aromaticity of the DOM and the presence of Hg(II)-binding ligands in the fraction of carbon that adsorbs to aluminum hydroxide flocs were the key variables that control the removal of mercury. All the same, the character of DOM determines the extent of the removal of carbon and the minimum amount of Hg(II) that can be removed from solution.
Seismicity of the Mt. Kinabalu fault system in Sabah, Borneo, revealed using waveform backprojection
Authors: Bacon Conor , Gilligan Amy , Rawlinson Nicholas , Tongkul Felix , Cornwell David , Pilia Simone , Volk Omry , Greenfield Tim
Published: March 2020

The aim of the Northern Borneo Orogeny Seismic Survey (nBOSS) is to better understand the mechanisms driving the processes that occur in a post-subduction setting. A network of 46 seismometers was deployed across Sabah, Borneo, between March 2018 and January 2020 (22 months) in order to investigate these mechanisms using a suite of seismic imaging techniques.

 

Mt. Kinabalu (~4100 m) is a large granitic pluton that was emplaced between ~7.9 and 7.2 Ma. The region around the mountain experiences infrequent earthquakes, with the M6.0 Sabah earthquake in 2015 being the second largest earthquake to strike the region in the past century. This earthquake caused the loss of 18 lives and an estimated 100 million Ringgit (~€22 million) of damage to buildings, roads and infrastructure. The 2015 earthquake has highlighted the importance of improving our understanding of seismic hazards in northern Borneo. Although both a network of faults striking along the spine of the Crocker range, and a complex network of faults around the Kinabalu massif have been mapped, which of these are currently active remains poorly understood. Using data from the nBOSS seismic network, together with additional data from the Malaysian Meteorological Service, we aim to quantify and categorise the seismicity associated with this fault system.

 

We have used QuakeMigrate, a new, modular, open-source Python package for waveform backprojection to efficiently, automatically and robustly detect and locate microseismicity in the region around Mt. Kinabalu. We provided QuakeMigrate with continuous raw seismic data, a velocity model derived using nBOSS seismic data, and a list of station locations. A realistic estimate of the event location uncertainty, phase picks with uncertainties, and a suite of visual outputs allows for rigorous selection of real events at a sub-SNR detection threshold.

 

Using data from March 7 2018 to 28 August 2018, we have detected and located over 1500 events with hypocentres highly concentrated beneath the Kinabalu massif. Given existing catalogues for the area around Mt. Kinabalu only record on the order of tens of events between 1990 and the present day, our results demonstrate that these catalogues are highly incomplete at low magnitudes and thus existing tectonic and hazard models for the area need to be revised.
Infiltration rate in unsaturated glass beads porous media under various gravity made by parabolic flight.
Authors: Sato Naoto , Maruo Yuichi , Nogawa Kento , Naganuma Natsumi , Noborio Kosuke
Published: March 2020

The Global Exploration Roadmap targets the realization of Mars manned exploration by the 2030s. It is necessary to understand water movement in porous media under microgravity to establish a plant growth system for crop production for astronauts to produce food in outer space. In previous researches, a decrease in infiltration rate was reported for coarse (1.5 mm diameter) glass beads porous media. On the other hand,  in the case of fine (0.4 mm diameter) glass beads porous media, the amount of reduction in the infiltration rate was small. We wanted knowledge of water movement under partial gravity conditions. We conducted water infiltration experiments under microgravity, 1/6G, and 1/3G conditions made by parabolic flights. The 0.2, 0.4, and 0.6 mm glass beads were used as porous media. The effects of particle size and partial gravity on water infiltration in porous media will be discussed.
Ocean climate response to anomalous surface buoyancy and momentum fluxes
Authors: Navarro-Labastida Rene , Farneti Riccardo
Published: March 2020

The aim of the project is to evaluate the response of the global ocean climate to anomalous surface fluxes in terms of ocean heat uptake and circulation changes. All simulations have been performed with the NOAA-GFDL Modular Ocean Model (MOM) version 5. Ocean-only MOM has been integrated toward a near-equilibrium state using as multicentinal initial conditions derivated from a former CORE-I protocol implementation (Griffies et al., 2009). After equilibrium, a restored control simulation has been obtained by a further 70 years of integration while effective total air-sea heat fluxes and freshwater fluxes were stored at daily intervals. A second control simulation has been obtained by the prescription of these storage fluxes. Differences between the restored and prescribed fluxes controls are rather small. Explicit flux sensitivity experiments are proposed by the Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) in which prescribed surface flux perturbations are applied to the ocean in separated simulations (Gregory et al., 2016). Experiments are 70 years long and branch from piControl conditions. Both wind stress and freshwater anomalies implies nearly-to-zero temperature changes in volume mean temperature. Only the last implies a rather small cooling effect after year 50 of integration. In contrast, anomalous heat flux causes significant volume mean temperature changes. Observed total temperature changes are solely determined by the local addition of heat implying vanishing of the redistribution effect in the entire ocean by inter-basin exchanges and vertical mixing. So far, surface heat anomalies produce the most notable zonal-mean change in ocean temperature. Strong positive temperature change is observed along the top ocean while deepening of temperature anomalies occurs at high latitudes in both hemispheres. Both added and redistributed temperature tracers show maxima in the same area. In most cases, both processes are proportionally inverse. Except for the northern ocean, added temperature tracer is roughly limited to the first 1000 m deep. In contrast, redistributed temperature tracer shows the cooling of subtropical areas and the warming of both the tropical and southern ocean. Maximum at the North Atlantic is possibly due to atmosphere-sea feedbacks, while near-surface tropical and subtropical changes are due to redistribution processes. Heat is mainly taken as a passive tracer in the North Atlantic Ocean and along the entire Southern Ocean. Warming up of mid and low latitudes by redistribution processes is due to the weakening of the Atlantic Meridional Overturning Circulation (AMOC). In turn, changes in AMOC are dominated by surface heat flux changes. The reduction of northward heat transport cools down high latitudes near the surface causing low latitudes to warm up.

 
Monster polar shift, shifts back: paleoclimate and CA-ID-TIMS evidence from northern China
Authors: Olsen Paul , Sha Jingeng , Maclennan Scott , Kinney Sean , Fang Yanan , Chang Clara , Kuhn Theo , Fu Roger , Kent Dennis , Schone Blair
Published: March 2020

The two great lacustrine fossil Konservat-Lagerstätten of northeastern China producing feathered dinosaurs, the Jurassic Yanliao Biota and the Jehol Biota, were deposited during relatively humid times and are separated by a major redbed interval, typified by the Tuchengzi Formation deposited under a much more arid climate (1). We present new zircon CA-TIMS U-Pb ages for the peaks of the Yanliao [~160 Ma] and the Jehol biotas [Yixian Fm ~125 Ma] constraining a shift in that region from a higher-latitude temperate zone to a lower-latitude semiarid zone consistent with a ~30° arc distance shift true polar wander shift (1, 2, 3). The Yanliao Biota and the Jehol Biota are preserved in remarkably similar facies almost lacking signs of desiccation, while the Tuchengzi Formation has abundant evidence for desiccation and even eolian dune sands. This suggests, under a simple zonal climate model, a rapid shift to the south from Jurassic times and a shift back into Early Cretaceous times. A very similar and even more dramatic shift is seen in northwest China in the Junggar Basin where Triassic-Middle Jurassic coal bearing sequences with evidence of seasonal freezing (4) is replaced by a Late Jurassic [~150 Ma (5)] redbed sequence [including the famous dinosaur- and crocodiliomorph-bearing Shishugou Formation], and again replaced by coal-bearing strata in the Early Cretaceous, suggesting a similar magnitude shift south and back north of the region. The hypothesis that the monster polar shift is transient, swinging south and then north in ~35 million years necessitates rigorous testing by inclination-error-corrected paleomagnetic data to cleanly separate rapid latitudinal effect from rapid global climate change or regional orographic effects.

Olsen P E et al. (2015) Geological Society of America, Abstracts with Programs 47, 378.

Muttoni G, Kent D V (2019)Journal of Geophysical Research. Solid Earth 124, 3288-3306.

Yi Z, Liu J, Meert, G (2019) Geology 47, 1112-1116.

Olsen P E et al. (2018) Geological Society of America Abstracts with Programs 50, doi: 10.1130/abs/2018AM-325061 (2018).

Fang Y et al. (2019) Topographic evolution of the Tianshan Mountains and their relation to the Junggar and Turpan Basins, Central Asia, from the Permian to the Neogene. Gondwana Research 75, 47-67 (2019).
Novel, real-time measurements of VOCs using a Cavity Ring-Down Spectrometer (CRDS)
Authors: Lucic Gregor , Rella Chris , Hoffnagle John , Skog Kai , McHale Laurie
Published: March 2020

Measurements of volatile organic compounds (VOCs) are important in a wide variety of scientific disciplines, including air quality, biogeochemistry, hydrology, plant and animal physiology, human health, and petrochemistry. Generally, these measurements are performed with expensive laboratory-based mass spectrometers, slow gas chromatographs, non-speciated flame- or photo-ionization detectors, or insensitive Fourier transform infrared spectrometers. Laser-based spectrometers based upon cavity enhanced techniques like cavity ring-down spectroscopy (CRDS) would in principle provide significant advantages over these methods in sensitivity, speed of response, simplicity, stability, and portability, as has been demonstrated in the last decade for the quantification of simple molecules like carbon dioxide, methane, or ammonia.  However, the majority of these instruments are based upon narrowly tunable lasers.  These lasers cannot tune across the broad spectral features, characteristic of VOCs.  In this paper we present a novel CRDS instrument based upon a broadband laser source that can in principle span more than hundred nanometers.  We show early measurements of ethylene oxide and BTEX (benzene, toluene, ethylbenzene, and xylene) at parts per billion and even parts per trillion levels.  Though our initial work has focused on measurements of hazardous air pollutants, there is future potential for speciated detection of other VOCs as well as greenhouse gases. These systems can be deployed on a bench-top and/or vehicle, and with per-second measurement intervals, are ideal for correlation with weather data for accurate source attribution. The analyzers are being developed to meet indoor and outdoor air quality requirements and may be deployed near sources (stack or fenceline monitoring) or far from sources (community monitoring). 
Future change in renewable energy availability in West Africa: a time of emergence approach
Authors: Gaetani Marco , Sultan Benjamin , Serge Janicot Serge Janicot , Vrac Mathieu , Vautard Robert , Famien Adjoua Moise , Buizza Roberto , Martina Mario
Published: March 2020

Independence in energy production is a key aspect of development in West African countries, which are facing fast population growth and climate change. Sustainable development is based on the availability of renewable energy sources, which are tightly tied to climate variability and change. In the context of current and projected climate change, development plans need reliable assessment of future availability of renewable resources.

In this study, the change in the availability of photovoltaic (PV) and wind energy in West Africa in the next decades is assessed. Specifically, the time of emergence (TOE) of climate change in PV and wind potential is estimated in 29 CMIP5 climate projections.

The ensemble robustly simulates a shift into a warmer climate in West Africa, which already occurred, and projects a decrease in solar radiation at the surface to occur by the 70s. The reduction in solar radiation is associated with a projected increase in the monsoonal precipitation in the 21st century. It results a likely change into climate conditions less favourable for PV energy production by the 40s. On the other hand, the projected change in the monsoonal dynamics will drive the increase in low level winds over the coast, which in turn will result in a robustly simulated shift into climate conditions favourable to wind power production by mid-century. Results show that climate model projections are skilful at providing usable information for adaptation measures to be taken in the energy sector.
Evolution of Modelling Zeta Potential: Impact of Brine Compositions and Concentration
Authors: Hidayat Miftah , Vinogradov Jan , Iglauer Stefan , Sarmadivaleh Mohammad
Published: March 2020

Electrochemical interactions of calcite with brines in natural subsurface settings have received ample attention in the last decades due to the broad range of their applications. These interactions can be described by an electrical property termed the zeta potential. Many numerical simulation studies using surface complexation modelling (SCM) have been performed to investigate the relationship between the zeta potential and a wide range of salinities and complex brine compositions. Although most of the simulated results, especially in low salinity conditions, successfully match the experimentally measured zeta potential, the simulated zeta potential for high salinity conditions is still poorly understood.

In this study, we present a new approach of SCM to simulate the zeta potential by considering the actual molecular-scale phenomena at the calcite-brine interface. Unlike previous SCM studies, our model considers the hydrated diameter of ions as the distance of approach, which depends on salinity. We also consider the permittivity of the Stern layer as a function of salinity, which is consistent with previous unrelated studies. We calculate the capacitance for each salinity based on the relationship between the hydrated diameter of ions and the permittivity of the Stern layer. Moreover, all calcite-brine surface reactions are described by new equilibrium constants independent of salinity and composition of brines.

Our results show that the simulated zeta potential which is obtained from our SCM at a broad range of salinities is successfully matched with the published experimental data for two different carbonate rock samples as long as the salinity dependence of the hydration diameter and electrical permittivity is accounted for. We find that the potential determining ions (Ca2+, Mg2+, SO42-, HCO3-,CO32-) play a dominating role compared to the indifferent ions (Na+, Cl-) in the calcite-brine surface reactions. The Implications of our findings are significant for wettability evaluation, characterisation of shallow and deep aquifers and CO2 geological sequestration.
Investigation of the effect of wind speed fluctuation on the drag coefficient
Authors: Suzuki Naoya , Waseda Takuji , Takagaki Naohisa
Published: March 2020

The drag coefficient is generally expressed as functions only of the wind speed U10. However, there exists considerable disagreement among the observed values of the drag coefficient. In this study, we observed the wind stress at the coastal tower of Hiratsuka Offshore Experimental Tower of the University of Tokyo in Japan. The 3-axis sonic anemometer was installed on the top of the tower, which was 20 m above mean sea level. The observation periods were from September 15, 2015 to December 31, 2019. The eddy correlation method was used to calculate the friction velocity every 10 minutes. The variation of the drag coefficient plotted against the wind speed U10 has very large using the all period data. The variation of the drag coefficient was reduced by excluding large fluctuation of wind speed in time series within one hour. Furthermore, the sudden changes of the wind speed and direction was also found to affect the variation of the drag coefficient. These results show that the wind speed fluctuation influenced the variation of the drag coefficient. We also investigate the effect of waves on the drag coefficient.
CO2 Capture and Storage from Flue Gas Using Novel Gas Hydrate-Based Technologies and Their Associated Impacts
Authors: Hassanpouryouzband Aliakbar , Edlmann Katriona , Yang Jinhai , Tohidi Bahman , Chuvilin Evgeny
Published: March 2020

Power plants emit large amounts of carbon dioxide into the atmosphere primarily through the combustion of fossil fuels, leading to accumulation of increased greenhouse gases in the earth’s atmosphere. Global climate changing has led to increasing global mean temperatures, particularly over the poles, which threatens to melt gas hydrate reservoirs, releasing previously trapped methane and exacerbating the situation.  Here we used gas hydrate-based technologies to develop techniques for capturing and storing CO2 present in power plant flue gas as stable hydrates, where CO2 replaces methane within the hydrate structure. First, we experimentally measured the thermodynamic properties of various flue gases, followed by modelling and tuning the equations of state. Second, we undertook proof of concept investigations of the injection of CO2 flue gas into methane gas hydrate reservoirs as an option for economically sustainable production of natural gas as well as carbon capture and storage. The optimum injection conditions were found and reaction kinetics was investigated experimentally under realistic conditions. Third, the kinetics of flue gas hydrate formation for both the geological storage of CO2 and the secondary sealing of CH4/CO2 release in one simple process was investigated, followed by a comprehensive investigation of hydrate formation kinetics using a highly accurate in house developed experimental apparatus, which included an assessment of the gas leakage risks associated with above processes.  Finally, the impact of the proposed methods on permeability and mechanical strength of the geological formations was investigated.
Progress and problems of gender equality in Japanese academia, and empowerment activities in science and geoscience
Authors: Hori, S. Rie
Published: March 2020

According to the Global gender equality Rankings by World Economic Forum, the Gender Index rank of Japan has been below 100 during the last 8 years. Every 4 years, Japan ranking has been slipping by 10 points, and has finally reached 121st in 2019. In 2011, the Japanese government released the “Promotion of Positive action” program targeting 30% of women’s participation in the workplace including Academia by 2020. However, this goal has not been met as yet. Based on the 15th survey by the Japan Association National Universities which includes most Geoscience departments of Japan, only 4% of national universities have achieved >30% female to total academic staff ratio. The average ratio increased slightly from 13.0% (2011) to 16.7% (2018). The change is quite slow and is hard to accelerate. In the STEM field, female staff ratios are 12.3% (Agriculture), 8.7% (Science) and 6.2% (Engineering). The percentage of undergraduate female students in Science has gradually decreased during these 10 years from ca. 28% to 25% in total, while the number of women in Ph.D. studies increased as a result of several empowerment programs. A recently organized All Nippon Diversity Network (OPENed: O-Progressive initiatives of Empowering Network for Diversity) provides a country-wide platform for networking institutional activities on diversity issues and sharing information on efficient activities and practices for empowerment. In this presentation, we are sharing information on ongoing action in Japan concerning gender issues, and try to identify and discuss unconscious problems/causes for improvement.
Produced water management - A mathematical model to trade-off economic cost and environmental impact for infrastructure utilisation
Authors: AlEdan Afrah , Erfani Tohid
Published: March 2020

This research provides an overview on several areas related to produced water management including cost, treatment methods, recycling options and environmental impact. Produced water is a type of water that has been trapped in different quantities in underground formations. After extracting crude oil and during the production process, the associated water from underground formations is known as produced water. This type of water is by far the largest volume by product or waste stream associated with oil and gas production. It is likely containing high level of total dissolved solids because of its longer residence time under the ground in addition to the smaller ﬂow rate. Moreover, many efforts have been paid globally to decrease the high salinity level in produced water by applying desalination technologies as sustainable water management solution.

Oilfield water management is one of the most challenging system and it follows a non-linear relationship between its components. We formulate and develop a mixed-integer mathematical model to a small case study related to Kuwait Oil Company for an optimal design and operations of produced water management. We show how the results allow studying the economic cost as well as environmental impact related to produced water management system.

 

 
Energetic and Suprathermal Particle Composition Measurements from Solar Orbiter
Authors: Ho George , Mason Glenn , Wimmer-Schweingruber Robert , Rodríguez-Pacheco Javier
Published: March 2020

Particles that have energies of a few times the solar wind plasma energy up to 100s of keV/q are called suprathermal particles. Recent studies have revealed that these particles play a significant role as seed particles for further acceleration to higher energies.  This may occur either close to the Sun in solar energetic particle (SEP) events, but also locally at 1 AU in energetic storm particle events, or even outside 1 AU as ions accelerated in Corotating Interaction Regions. The constituents of this suprathermal ion reservoir are therefore expected to vary in time and space. The composition and spectra of these ions provide us the telltale of their origin and acceleration mechanism.  It is therefore important to make high time resolution measurements of the composition and spectra of this particle population in the inner heliosphere to better characterize its origins and role as a seed population in particle acceleration processes. Because of the vastly different mass-per-charge ratios of the various possible origins of suprathermal ions, we expect to see distinct difference and radial dependencies in their abundances in low-energy accelerated particles in the inner heliosphere.  Here we describe the measurements that we will be making on Solar Orbiter that will make significant contributions to the understanding of the particle population in this largely unexplored energy range.
Incorporation of GPR data into characterization of the bitumen filled cracks in pavements: Lab and numerical study
Authors: Rasol Mezgeen , Gracia Vega Pérez , Solla Mercedes , Pais Jorge C. , Fernandes Francisco M. , Santos Caio , Roberts Sam
Published: March 2020

Road pavements are subject to a range of problems due to traffic and temperature variations 

producing cracks that propagate to the pavement surface. Cracks need to be assessed to avoid 

deterioration and provide confidence in the functioning of the road system. Cracks are usually 

maintained after visual inspection by filling with bitumen as a first rehabilitation technique to 

avoid further deterioration and absorbing water leakages. Although this temporary solution does 

not extend the pavement life cycle it can help to avoid additional problems occurring within the

pavement. This work is proposed to aid the development of understanding and characterization

of cracks filled with bitumen in both rigid and asphalt pavements.

This study reports on the results of several laboratory experiments that were performed to 

explore the capability of Ground Penetrating Radar (GPR) in the assesment of bitumen-filled 

cracks in both rigid and asphalt pavements, respectively. These tests were focused on the 

analysis of cracking filled with bitumen using a GPR system equipped with a ground-coupled 

antenna with a 2.3 GHz central frequency, and varying the antenna orientation with respect to the 

crack axis.

Results showed the variation in characterization and changes in amplitude that could be expected 

when analysing bitumen-filled cracks in concrete and asphalt specimens, dependent upon the 

antenna orientation being used; GPR B-scans were compared to images from computational 

models using a Finite-Difference Time-Domain (FDTD) method-based software package 

(gprMax2D). Additionally, a field survey carried out provided images consistent with the

comparable conditions of the lab tests. The results of this work proved the capability of the GPR

method to detect and characterize cracks filled with bitumen in pavements across a range of 

crack dimensions and pavement types.

 

Keywords

GPR, NDT, Rigid pavements, Asphalt Pavements, Cracks, Computational models, Target orientation,

Pavement assessmen
Precipitation Imputation using Optimal Probability Space-Based Interpolation
Authors: Teegavarapu Ramesh
Published: March 2020

Deterministic and stochastic spatial interpolation methods are widely used for the imputation of precipitation data to obtain gap-free datasets. Conceptually simple deterministic approaches using weighting methods that use Euclidean distances in spatial interpolation. Uses of probability space-based measures which include a measure from forecast verification and distribution similarity hypothesis test statistic values are evaluated in this study as possible replacements for Euclidean distances in weighting methods. Nonlinear optimization formulations are solved to obtain the best parameter values of the spatial interpolation methods. Long-term daily precipitation datasets from two climatic regions are used to impute missing precipitation data and several error and performance measures are used to assess the proposed methods. The proposed surrogates for Euclidean distances provide conceptually simple yet superior deterministic interpolation methods for improved estimation of missing precipitation data. Local and global variants of interpolations are evaluated. Preliminary results confirm the superiority of probability space-based methods for imputation of missing precipitation data at multiple temporal scales.
Using computer vision and deep learning for acquisition and processing of low-distortion sediment core images
Authors: Obrochta Stephen , Fazekas Szilárd , Morén Jan
Published: March 2020

Imaging the split surface of sediment cores is standard procedure across a range of geoscience fields. However, obtaining high-resolution, continuous images with very little distortion has traditionally required expensive and fragile line-scanning systems that may be difficult or impossible to transport into the field. Thus many researchers take photographs of entire core sections, which may result in distortion, particularly at the upper and lower edges. Using computer vision techniques, we developed a set of open source tools for seamlessly stitching together a series of photographs, taken with any camera, of the split surface of a sediment core. The resulting composite image contains less distortion than a single photograph of the entire core section, particularly when combined with a simple camera sliding mechanism. The method allows for detection of and correction for variable camera tilt and rotation between adjacent pairs of images. We trained a deep neural network to post-processe the image to automate the tedious task of segmenting the sediment core from the background, while also detecting the location of the accompanying scale bar and cracks or other areas of coring-induced disturbance. A color reflectance record is then generated from the isolated core image, ignoring variations from e.g., cracks and voids.
Long-term change of warm-season precipitation climatology in South Korea
Authors: Do Hyeon-seok , Kim Joowan
Published: March 2020

This study examines long-term changes of precipitation characteristics in South Korea focusing on warm season (June-September). Daily precipitation data are obtained from 15 surface stations that have continuously observed precipitation for 58 years (1961 – 2018). Precipitation characteristics and their long-term changes are examined including trend, amount, and intensity. The warm- season precipitation in South Korea is largely affected by the East Asian Summer Monsoon, which causes rainy season in late July and mid August (these are called “Changma” and “Post-Changma” seasons in Korea). Thus, these characteristics are also analyzed focusing on Changma season.

The warm-season precipitation increased roughly by 1.0 mm per day for the last thirty years. The change is particularly pronounced during Changma season, and it shows 1.6 mm of daily precipitation increase. Trend analysis for the 58 years also showed a consistent and significant result. The precipitation change is mostly founded in the intensity of 30 – 110 mm per day implying that the precipitation intensity is increasing in warm season. Multiple regression analysis further suggests that this change is more related to precipitation intensity than precipitation frequency. Global precipitation data reveals the similar change in precipitation over central eastern China presenting a band-like precipitation increase extending to the Korean peninsula. These results are likely caused by near-surface temperature and moisture increase in a warming climate.
Monitoring of "All-weather" Evapotranspiration Using Multi-source Remote Sensing Imagery in Cloudy and Mountainous Regions in Southwest China
Authors: Ma Yanfei , Zhou Ji , Liu Shaomin
Published: March 2020

Accurate estimation of surface evapotranspiration (ET) with high quality and fine spatiotemporal resolution is one of the biggest obstacles for routine applications of remote sensing in eco-hydrological studies and water resource management at basin scale. Integrating multi-source remote sensing data is one of the main ideas for many scholars to obtain synthesized frequent high spatial resolution surface ET. This study was based on the theoretically robust surface energy balance system (SEBS) model, which the model mechanism needs further investigation, including the applicability and the influencing factors, such as local environment, heterogeneity of the landscape, and optimized parametric scheme, for improving estimation accuracy. In addition, due to technical and budget limitations, so far, no single sensor provides both high spatial resolution and high temporal resolution. Optical remote sensing data is missing due to frequent cloud contamination and other poor atmospheric conditions. The passive microwave (PW) remote sensing has a better ability in overcoming the influences of clouds and rainy. The accurate "all-weather" ET estimation method had been proposed through blending multi-source remote sensing data acquired by optical, thermal infrared (TIR) and PW remote sensors on board polar satellite platforms. The estimation had been carried out for daily ET of the River Source Region in Southwest China, and then the "All-weather" remotely sensed ET results showed that the daily ET estimates had a mean absolute percent error (MAPE) of 36% and a root mean square error (RMSE) of 0.88 mm/day relative to ground measurements from 12 eddy covariance (EC) sites in the study area. The validation results indicated good accuracy using multi-source remote sensing data in cloudy and mountainous regions.
On the Drag parameter of ICME propagation models
Authors: Napoletano Gianluca , Foldes Raffaello , Del Moro Dario , Berrilli Francesco , Giovannelli Luca , Pietropaolo Ermanno
Published: March 2020

ICME (Interplanetary Coronal Mass Ejection) are violent phenomena of solar activity that affect the whole heliosphere and the prediction of their impact on different solar system bodies is one of the primary goals of the planetary space weather forecasting. The travel time of an ICME from the Sun to the Earth can be computed through the Drag-Based Model (DBM), which is based on a simple equation of motion for the ICME defining its acceleration as a=-Γ(v-w)v-w, where a and v are the CME acceleration and speed, w is the ambient solar-wind speed and Γ is the so-called drag parameter (Vršnak et al., 2013).
In this framework, Γ depends on the ICME mass and cross-section, on the solar-wind density and, to a lesser degree, on other parameters. The typical working hypothesis for DBM implies that both Γ and w are constant far from the Sun. To run the codes, forecasters use empirical
input values for Γ and w, derived by pre-existent knowledge of solar-wind condition and by solving the “inverted problem” (where the ICME travel time is known and the unknowns are Γ and/or w). In
the 'Ensemble' approaches (Dumbovich et al., 2018; Napoletano et al. 2018), the uncertainty about the actual values of such inputs are rendered by Probability Distribution Functions (PDFs), accounting for the values variability and our lack of knowledge. Among those PDFs, that of Γ is poorly defined due to the relatively scarce statistics of recorded values. 

Employing a list of past ICME events, for which initial conditions when leaving the Sun and arrival conditions at the Earth are known, we employ a statistical approach to the Drag-Based Model to determine a measure of Γ and w for each case. This allows to obtain distributions for the model parameters on experimental basis and, more importantly, to test whether different conditions of relative velocity to the solar wind influence the value of the drag efficiency, as it must be expected for solid objects moving into an external fluid. In addition, we perform numerical simulations of a solid ICME-shaped structure moving into the solar-wind modelled as an external fluid. Outcomes from these simulations are compared with our experimental results, and thus employed to interpret them on physical basis.
Dynamic changes of blowout in the fixed dune on the southeastern fringe of Otindag sandy land in recent decade
Authors: Hu Rina , Hasi Eerdun , Yin Jie
Published: March 2020

 Desertification is one of the main environmental problems in arid and semi-arid areas. In Otindag sandy land, the activation of fixed sand dunes caused by climate change and human activities is the main reason of the development of desertification, and the activation of fixed sand dunes is first manifested by the formation and evolution of blowouts. In recent years, with the increase of high-resolution image data, it has become possible to make use of dynamic monitoring of terrain and landscape changes in small areas, so as to accurately analyze the interaction between terrains and influencing factors on smaller landscape scales, especially dune-interdune scale. We use the high-resolution satellite image data in 2010, 2013, 2016 and 2019 with the ground survey data as the data source, as well as the ArcGIS software to adopt the visual interpretation method. According to the different developmental positions, the shapes of the blowouts can be divided into saucer, bowl, groove, dustpan and irregular shaped. In the study area, the ways of changes in blowout are mainly based on expansion and amalgamation between 2010 and 2019. The area of blowout increased by 6.47hm2 from 2010 to 2013. During 2013-2016, the area increased by 4.89hm2, following by the next three years, it continued growing by 3.04hm2. With little disturbance of human activity, the growth of blowouts in this area is largely affected by the change of climate factors. As the dynamic factor of blowouts, the reduction in sand drift potential, only decreases the development rate and slows down the process. The shapes of the blowout themselves also work as the main influencing factor.
Characterisation of East Siberian paleodiversity based on ancient DNA analyses of the Batagay megaslump exposure
Authors: Courtin Jeremy , Perfumo Amedea , Stoof-Leichsenring Kathleen , Herzschuh Ulrike
Published: March 2020

With the ongoing Arctic warming, permafrost thaw accelerated during the last decade as much as it is now a global concern for biodiversity loss, food webs and biogeochemical cycling. This rapid permafrost degradation forms features such as massive retrogressive thaw slumps that give access to exceptional records for Quaternary biodiversity change investigations. The Batagay megaslump located in northern Yakutia, East Siberia, is the world’s largest thawslump known to date, and along its ~55m high headwall it gives access to Late and Mid Pleistocene permafrost deposits up to more than 500 kyrs in age. During an expedition to this unique site in 2017, sediment samples were collected with ages from more than 500 kyrs to modern time for the analysis of ancient DNA (aDNA). Our aim is to characterise the biodiversity and changes over geological timescales of this region in East Siberia. Using the aDNA extracted from these ancient environmental samples, we first performed a metabarcoding analysis (chloroplast trnL) to investigate past vegetation composition. We then performed a shotgun metagenomic analysis, which enabled a much higher depth of sequence data and allowed us to access the entire biodiversity, from Eukaryotes to Prokaryotes, Archaea and Viruses. This approach opened up new horizons, making it possible not only to investigate biodiversity composition and changes but also to infer on potential interactions across taxa and kingdoms. Both methods together allowed comparison and ensured robustness of the results obtained. We present here one of the very first studies done on the global, past and modern, biodiversity of permafrost regions which holds an enormous potential to reveal new insights into the evolution of this fragile ecosystem.
TIEMPEROS. Meteorological specialists from the pre-Hispanic indigenous cosmogony of Mexico, and the use of technology to promote atmospheric sciences.
Authors: Duran Cintia
Published: March 2020

The cult of the mountains, the wind and the request for “good rain” constitute today, the fusion of pre-Hispanic religious beliefs and meteorological knowledge in the agricultural development of central Mexico. Understanding this cult of the earth, from an indigenous perspective, led by certain specialists who have extensive knowledge of the landscape and meteorology, called Tiemperos, is a fundamental and necessary feature for the development of atmospheric sciences and the inclusion of rural villages in environmental research, carried out in certain areas of Mexico. 

Understanding the world in which these specialists are inserted is complex if one does not have a joint vision of the ethnographic data and the social relevance that the Tiemperos have on the communities. During 2018 I carried out an investigation on the request of rain and “good weather” rituals that are carried out year after year in certain areas of central Mexico. From that initiative I developed an educational model and a prototype weather station that could be designed, built and adapted to the needs of each community, considering the traditions and teachings of the local Tiempero. Making use of microcontrollers, basic electronics, and a traditional indigenous technique, each station was built and designed with the people of the community where it would be installed, with the idea of ​​involving and enriching scientific meteorological knowledge, which could be useful for each community. The project, still in development, included meteorological stations designed by me and built by the communities, a series of educational exercises for children involved in the project and the proposal of a “good weather” ritual using the data collected by the meteorological stations, with the intention of using technology and science-based information with traditional indigenous practices giving way to new forms of research and inclusion of science in remote communities in Mexico.
Responses of temperate steppe to simulated nitrogen deposition: from community structure to ecosystem functions
Authors: Huang Yongmei
Published: March 2020

Effect of nitrogen deposition on terrestrial ecosystems are one of the hot spots in the study of global change, and the significantly different responses were reported widely among different ecosystems. In this study, field simulated nitrogen deposition experiment was carried out in a temperate steppe, norther China from 2011 to 2018. Treatments were designed as: CK (0 g N/m2), N2 level (2 g N/m2), N5 level (5 g N/m2), N10 level (10 g N/m2), N25 level (25 g N/m2) and N50 level (50 g N/m2). The results showed that the N addition did not cause a noticeable change in the net primary productivity and soil acidification. N addition caused a significant decline in community biodiversity with a major shift in species composition. N utilization strategy, photosynthetic capacity, and water use efficiency of three dominant species behaved differently under N deposition. Soil was the major sink for N deposition testified by the 15N isotope tracer experiment. N addition decreased soil microorganism and plant 15N recovery and increased soil of 30-40 cm layer 15N recovery. N saturation of the temperature steppe would occur when N deposition rate reached 5.4-8.4gN m-2a-1.
The impact of channel deepening and sand mining on estuarine tidal dynamics
Authors: Chu Nanyang , Yao Peng , Ou Suying , Hu Shuai , Huang Jie , Yang Qingshu
Published: March 2020

Lingding Bay (LDB) is a part of the Pearl River Estuary in south China. It is surrounded by large growing cities and has been subjected to heavy waterways traffic over the past 5 decades. The tide propagation pattern has been greatly modified ever since. It has widespread morphological and ecological impacts on the LDB system. However, a systematic study on the response of tide propagation pattern to channel deepening and sand mining is currently lacking to provide future management guidelines for the Lingding Bay. Based on a state-of-the-art modeling tool (Delft3D Flexible Mesh), we explore the tidal propagation pattern (tidal amplitude, tidal phase, residual current, and tidal-energy flux) of the LDB over the last century (1901-2016). Three stages of bathymetry and tidal dynamics variation are divided by our investigation. Stage I (1901-1964) is a natural evolution process, the LDB is manifested as gradually filling by fluvial sediment, the tidal amplitude decline, and tidal dynamics decrease. Stage II (1964-1989) is characterized by a slow increase in water depth and tidal dynamics, which affected by channel dredging activities. While stage III (1989-2016) is influenced by channel deepening and sand mining, shown an abrupt increase of water depth in a short time and the rapid enhancement of tidal dynamics.

The investigation indicating that the channel deepening and sand mining activities amplified the tidal dynamics distribution difference between the channel and shoal. The increased tidal dynamics in the channels may increase saline intrusion and coastal flooding risks. Spatially, these two activities may also lead to contrasting morphodynamic patterns between the inner and outer LDB. The morphology state of erosion in the inner LDB and deposition in the outer LDB reported by other studies are consistent with the hydrodynamic variation in our study. Most likely, channel deepening and sand mining in inner LDB cause the sea bed to appear to lose，lead to larger SSC levels in the vicinity. This resulting in the inner LDB formed a new sediment source, under the stronger runoff in inner LDB, the depocenter is moved southward, and outer LDB developed to a sedimentary area. Our findings conclude that channel deepening and sand mining can greatly change the tidal dynamics distribution in an estuary, thereafter affect the sediment transport pattern. We suggest that coastal engineering planning should pay more attention to sand mining activities. The insights obtained from this study are of value to the future management of the LDB and other estuaries that are also under similar stress.
Ecological security assessment for environmental restoration and management in SW China
Authors: Bai xiaoyong , Chen huan
Published: March 2020

Regional ecological security diagnosis is the most basic prerequisite for environmental management and restoration. However, the traditional single method is greatly affected by human and difficult to quickly identify. Thus, This paper combined principal component analysis and unsupervised k-means clustering algorithm to provide a fast and efficient method for  safety evaluation of environmental management. Basing on this method, the clustering result was defined as five different levels of ecological safety zone combining with the principle of place name + landform + danger degree. The results showed that there were more than half of the study area were unsafe (56.3%), what was even more surprising was that there were many high-value of NDVI and NPP in these areas. The partition result was finally verified in order to ensure the accuracy of the partition, and it had been proved that the ecological environment is not necessarily safe where in the areas with good vegetation coverage. This article provided a new technical reference for the evaluation of ecological areas.
Detecting footprints with GPR
Authors: urban thomas
Published: March 2020

Recent field research at White Sands National Park, New Mexico, USA, has used ground-penetrating radar to detect the footprints of Pleistocene humans, mammoths, and ground sloths. The technique has been succesful with a range of antenna frequencies and for detecting footprints of many different sizes. Perhaps more importantly, the method has been shown to successfully detect fooprints that are not visible to the human eye, often with sufficent detail to differntiate species. This work raises an obvious question about whether GPR could be used to detect footprints in a range of other contexts, or whether the circumstances seen at White Sands are unique. 