bluuebunny/crossref_metadata_2025 huggingface dataset:
Robust Late 21st Century Shift in the Regional Monsoons in RegCM-CORDEX Simulations
Authors: Ashfaq Moetasim , Cavazos Tereza , Reboita Michelle , Torres-Alavez José Abraham , Im Eun-Soon , Olusegun Christiana , Alves Lincoln , Key Kesondra , Adeniyi Mojisola , Tall Moustapha , Sylla Mouhamadou Bamba , Mehmood Shahid , Zafar Qudsia , Das Sushant , Diallo Ismaila , Coppola Erika
Published: March 2020

We use an unprecedented ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide, for the first time, an RCM-based global view of monsoon changes at various levels of increased greenhouse gas (GHG) forcing. All regional simulations are conducted using RegCM4 at a 25km horizontal grid spacing using lateral and lower boundary forcing from three General Circulation Models (GCMs), which are part of the fifth phase of the Coupled Model Inter-comparison Project (CMIP5). Each simulation covers the period from 1970 through 2100 under two Representative Concentration Pathways (RCP2.6 and RCP8.5). Regional climate simulations exhibit high fidelity in capturing key characteristics of precipitation and atmospheric dynamics across monsoon regions in the historical period. In the future period, regional monsoons exhibit a spatially robust delay in the monsoon onset, an increase in seasonality, and a reduction in the rainy season length at higher levels of radiative forcing. All regions with substantial delays in the monsoon onset exhibit a decrease in pre-monsoon precipitation, indicating a strong connection between pre-monsoon drying and a shift in the monsoon onset. The weakening of latent heat driven atmospheric warming during the pre-monsoon period delays the overturning of atmospheric subsidence in the monsoon regions, which defers their transitioning into deep convective states. Monsoon changes under the RCP2.6 scenario are mostly within the baseline variability. 
Distribution Characteristics and Environmental Impacts of Nutrients in the Dry Season of the Pearl River Estuary in 2016
Authors: Zeng Danna , Niu Lixia , Yang Qingshu
Published: March 2020

Based on the field efforts in 2016 during a dry season (30 Nov-6 Dec) in the Pearl River Estuary (PRE)，south China, this study aimed to investigate the tidal changes of phytoplankton variability (in terms of chlorophyll a) and their responses to multiple environmental factors.Time series analysis，principal component analysis (PCA)，Pearson correlation analysis, and Delft3D model were carried out. A significant difference was found in the tidal variations of dissolved nutrients, covering both a spring tide and neap tide . Moderate differences in salinity and suspended sediment played different roles in the nitrogen and phosphate. The negative correlations of salinity and nitrogen ecologically implied a stronger diluting-mixing effect than that of phosphate, which has a large impact on the water quality. The adsorption of phosphorus by sediment particles was stronger than that of nitrogen. Nitrogen was mainly contributed by river discharge. DIN was constrained by tide-river dynamics and their mutual increase-decline trend, and a new source was supplemented along the transport from river to sea. The weak correlation between PO4 and salinity suggested a different source contribution of the terrestrial emission from coastal cities; the contribution of river discharge was less compared with nitrogen. Over site, P-limitation was detected and was more frequently resulted in eutrophication and even bloom events. Characterizing the relationships among chlorophyll a, nutrients, and hydrological factors enables us to develop effective ecosystem management strategies, and to design studies more focused on ecological health and function.
Deep neural network model to predict N2O emission change by biochar amendment in upland agricultural soils
Authors: Hyun Junge , Park Eungyu , Yoo Gayoung
Published: March 2020

The N2O emission change by biochar addition in soils showed inconsistent trends depending on biochar types, soil properties, environmental conditions, and soil management practices. Especially in non-flooded upland agricultural soils, due to the complexity of N2O emission processes, which include nitrification, nitrifier-denitrification, and denitrification, there are still many gaps in the mechanistic understanding of biochar effects. In order to maximize climate change mitigating effect of biochar, the biochar application guidelines that consider N2O emission change need to be offered to farmers. However, the current lack of knowledge makes it challenging to create mechanistic models, and new approaches are needed. Machine learning techniques can be a solution because we can find the relationship between input and output variables without explicit mechanistic understanding and mathematical description. We aimed at developing a deep neural network (DNN) model to predict the N2O emission change from upland agricultural soils by biochar application. Among all the papers published between Jan 2007 ~ Jul 2019 collected from Web of Science Core Collection, 65 papers were chosen which report changes in N2O emissions by biochar addition in upland agricultural soils. Eleven variables, which have been reported as important factors influencing N2O emission, were selected as input parameters. These include 5 soil properties (Total carbon and nitrogen content, sand and clay content and pH), 3 biochar properties (Feedstock type, pyrolysis temperature and biochar application rate), and 3 agricultural practices (Fertilizer type, number of fertilization and N application rate). The output parameter is the ratio of the cumulative N2O emission of biochar treatment and control. Using 85% of the compiled dataset (training set), the DNN model was trained to predict the changes in N2O emission by biochar addition. The rest of the dataset (validation set) was used to validate the DNN model. As a result, the DNN model predicted the decreasing and increasing patterns of biochar driven N2O emission change in 84% of the validation data. This preliminary result could be a basis for developing practical biochar use guidelines. Further studies will be conducted to improve the prediction accuracy of the DNN model by combining principal component analysis.
CABra: a novel large-scale dataset for Brazilian catchments
Authors: Oliveira Paulo Tarso , Almagro André , Pitaluga Frederico , Meira Neto Antônio , Durcik Matej , Troch Peter
Published: March 2020

We present the Catchments Attributes for Brazil (CABra) dataset. This is the first large-scale dataset for Brazilian catchments and includes data for 1,252 catchments in seven main classes of catchment attributes (CA: streamflow, groundwater, geology, soil, topography, climate, and land-use and land-cover). We have collected and synthetized data from multi-sources (ground stations data, remote sensed data, and gridded data. CABra contains catchments over the six Brazilian biomes: Amazon, Atlantic Forest, Caatinga, Cerrado, Pampa, and Pantanal. We delineated all catchments using the coordinates of each streamflow station provided by the Brazilian Water Agency (ANA, in Portuguese). We only considered stations with more than 10 years of data records and less than 20% of missing data. Catchment areas range from 9 to 4,670,000 km² and the mean daily streamflow varies from 0.006 to 170,271 m³ s-1. We also calculated several hydrological signatures – based on distribution, frequency and duration, and dynamics of daily streamflow – and climate indices. Additionally, this dataset includes  boundary shapefiles, centroids latitude and longitude, and drainage area for each catchment, aside from more than 50 attributes within each CA class. The CABra intends to fill a huge gap of multisource data collection in Brazil. This dataset plays an important role towards a better understanding of the climate-landscape-hydrology related drivers in a country of continental dimensions and heterogeneous landscape characteristics. Moreover, we described the collection and processing methods and discussed the limitations of each of our multiple data sources. Aside from being a potential tool for large-scale studies in hydrology, our extensive dataset is of main importance for the development of high-quality hydrologic studies in Brazil.
Mass movement tendencies and interaction with climate change in the Northern Chilean Patagonia
Authors: Somos-Valenzuela Marcelo , Fustos-Toribio Ivo , Lizama-Montecinos Elizabeth , Morales-Vargas Bastián , Manque-Roa Nataly
Published: March 2020

Mass movement processes correspond to one of the most dangerous geological events, mainly where human settlements are present, due to their destructive power and unpredictable nature. Chilean Patagonia has experienced important mass removal events in recent years. In this work, we are seeking to detect trends in the occurrence of these events and the relationship with long-term and short-term dispositions driven mainly by hydrometeorological events and the geology of the study area.

In the Chilean Patagonia, the Chilean Geological Survey (Sernageomin) has detected more than 713 landslides events in the Chilean Northern Patagonia (~42.7ºS, ~72.4ºW)” alone, a small area compared to the Chilean Patagonia. However, there is a lack of understanding of the triggers and mechanisms that control such events, and further studies need to be carried in order to understand the evolution of these events, linkages to climate change or anthropogenic changes, and to understand where they potentially can affect village directly destroying houses and taking human lives.

In this study, we use remote sensing to detect mass removals, fieldwork data collection to understand the geological predisposition to enable mass removal, and the analysis of hydrometeorological information to statistically establish relationships between the events and the potential triggers. For the remote sensing, we use Google Engine to create an exhaustive dataset of mass removal of 35 years in the study area. We apply the Normalized Difference Vegetation Index (NDVI) and the Grain Size Index (GSI) in Landsat Imagery. We will use the Sernageomin dataset and fieldwork to validate the methodology. For the geology, we analyze the conditioning factors associated with the geomorphological, structural, and lithological characteristics of the area. Finally, we used ERA5 data to determine the relationship between climate and mass removal events, analyzing, for example, the total annual precipitation patterns (TP) and extreme indicators as the maximum number of consecutive dry days (CDD) as well as annual temperatures and heatwaves.

The results of this research sought to provide the foundations for a complete risk assessment in the Chilean Patagonia and to increase awareness and preparedness in the region.
Intensity Change of Binary Tropical Cyclones in an Idealized Three-Dimensional Model
Authors: Liu Haoyan
Published: March 2020

This study investigates the intensity change of binary tropical cyclones (TCs) under the influence of their mutual interaction in an idealized three-dimensional full-physics numerical model with a finest horizontal resolution of 3 km. The two identical TCs merge within the initial separation distance of 600 km.

Due to the interaction between binary TCs, the intensity evolution presents two weakening stages and an unchanged stage between them. Such intensity change of each one in binary TCs is correlated to the upper-layer vertical wind shear (VWS) caused by the other TC. During the first stage, the upper-layer anticyclone (ULA) of one TC results in the upper-layer VWS and ventilates the warm core of the other TC above the outflow layer, which causes the intensity of the binary TCs decreasing. During the second stage, as the ULA stretches downward and outward, the upper-layer VWS changes to the opposite direction, along with the intensity decreasing first and then increasing. Meanwhile, the intensity of the binary TCs stays unchanged. In the last stage, the binary TCs weaken again as the upper-layer VWS increases to some extent except the merging cases. When the two TCs approach each other before merging, the upper-layer VWS in one TC is almost caused by the upper-layer cyclone and outflow of the other, which induces highly asymmetric structure and weakens the vortex. In addition, the horizontal size of the ULA quantified by the Rossby radius of deformation seems to be a critical separation distance of binary TCs, exceeding which the VWS is small enough to influence the intensity.
Aviation meteorology in a changing climate
Authors: Williams Paul
Published: March 2020

The climate is changing, not just where we live at ground level, but also where we fly in the upper troposphere and lower stratosphere. Climate change has important consequences for aviation, because the atmosphere’s meteorological characteristics strongly influence flight routes, journey times, and turbulence. This presentation will review the possible impacts of climate change on aviation, which have only recently begun to emerge (as opposed to the impacts of aviation on climate change, which have long been recognised).

Turbulence currently injures hundreds of air passengers each year worldwide, costing airlines hundreds of millions of dollars and occasionally causing structural damage to planes. To investigate the influence of climate change on turbulence, we diagnose an ensemble of 21 clear-air turbulence measures from climate model simulations. We find that turbulence strengthens significantly under climate change, all around the world, in all seasons, and at a wide range of aircraft cruising altitudes. For example, within the transatlantic flight corridor in winter at around 39,000 feet, the occurrence of light turbulence increases by an ensemble-mean value of 59% (with an intra-ensemble range of 43–68%), light-to-moderate by 75% (39–96%), moderate by 94% (37–118%), moderate-to-severe by 127% (30–170%), and severe by 149% (36–188%). These findings underline the urgent need to improve the skill of operational clear-air turbulence forecasts, to avoid increases in on-board discomfort and injuries in the coming decades.

To investigate the influence of climate change on flight routes and journey times, we feed atmospheric wind fields generated from climate model simulations into a routing algorithm of the type used operationally by flight planners. We focus on transatlantic flights between London and New York, and how they change when the atmospheric carbon dioxide (CO2) concentration is doubled. We find that a strengthening of the prevailing jet-stream winds causes eastbound flights to significantly shorten and westbound flights to significantly lengthen in all seasons. For example, eastbound and westbound crossings in winter become approximately twice as likely to take under 5 hours 20 minutes and over 7 hours, respectively. Even assuming no future growth in aviation, the extrapolation of our results to all transatlantic traffic suggests that aircraft will collectively be airborne for an extra 2,000 hours each year, burning an extra 7.2 million gallons of jet fuel at a cost of US$ 22 million, and emitting an extra 70 million kg CO2.

The above findings provide further evidence of the two-way interaction between aviation and climate change, which is an emerging research area that deserves further study.
Temporal change of permeability in macro-fractured granite by accumulation of fine-grained minerals
Authors: Nara Yoshitaka , Kato Masaji , Sato Tsutomu , Kohno Masanori , Sato Toshinori
Published: March 2020

It is essential to understand the long-term migration of radionuclides when considering rock engineering projects such as the geological disposal of radioactive waste. The network of fractures and pores in a rock mass plays a major role in fluid migration as it provides a pathway for fluid flow. The geometry of the network can change due to fracture sealing by some fine-grained materials over long-term periods. Groundwater usually contains fine-grained minerals such as clay minerals. Therefore, it is possible that the accumulation of such fine-grained minerals occurs within a rock fracture under groundwater flow. In this case, the aperture of a fracture may decrease, which brings about the decrease of the permeability. It is therefore essential to conduct permeability measurements using water including fine-grained minerals in order to understand the permeability characteristics of a rock. However, this has not been investigated well. In this study, we use a macro-fractured granite sample to investigate the temporal change of the permeability that occurs under the flow of water that includes two different amounts of clay.

It was shown that the clay accumulated in the macro-fracture and that the permeability of the macro-fractured granite sample decreased over time. It was also recognized that the decrease of the permeability was more significant under the water flow with the higher clay content. As a result of the observation using microscope, it was recognized that the clay minerals accumulated in the macro-fracture in the granite sample, which decreased the aperture of the fracture. We concluded that the accumulation of clay minerals in the fracture decreased the permeability of the rock. Furthermore, it is concluded that the filling and closure of fractures in rock is possible under the flow of groundwater including clay minerals.

 
Reconciling Cover Thickness Estimates in Cloncurry Region in Queensland, Australia using Bayesian Estimate Fusion
Authors: Markov Jelena , Visser Gerhard
Published: March 2020

The Cloncurry region lies in NW of Queensland and includes the Mount Isa Inlier, one of the most highly endowed metallogenic provinces in Australia, which has a long history of mining and exploration. The area is covered by the Jurassic-Cretaceous Carpentaria and Eromanga Basin sediments with the Mount Isa Inlier outcropping to the West and South. The fully concealed Millungera Basin underlies younger basins to the East. In order to de-risk further mineral exploration in this region it is important to know the thickness of cover. There are a variety of geophysical data available that can be used to estimate cover thickness. The point depth estimates of cover are derived from geophysical data using different inference methods. In order to create a map, these individual depth estimates must be reconciled/interpolated. The conventional interpolation methods do not produce the most optimal solution since these methods don’t easily account for discrepancies in the geophysical data distribution, resolution of the data and consequently variable accuracy of the cover thickness depth estimates. Also, most of these techniques do not produce an uncertainty estimate of the result. We have developed a Bayesian estimate fusion method that accounts for the variable data inaccuracies of the point cover thickness estimates which produces a map of cover thickness and its uncertainty. Additionally, the method uses non-intersecting drill holes, which were not usually utilised to create a map of the cover thickness. The method deals with outliers, by differentiating between the point depth estimates related to the cover-basement interface and the false positives that might be coming from the intrasedimentary units or the deeper basement. Lastly, the method incorporates existing fault information which allows to better capture sharp cover thickness changes.
Aeolian Changes at the Insight Landing Site on Mars: Multi-instrument Observations
Authors: Charalambous Constantinos , Baker Mariah , Golombek Matthew , McClean John , Pike Tom , Spiga Aymeric , Stott Alexander , Ansan Veronique , Weitz Catherine , Grant John , Warner Nicholas , Rodriguez Sebastien , Lorenz Ralph , Mittelholz Anna , Johnson Catherine , Maki Justin , Lemmon Mark , Banks Maria , Murdoch Naomi , Daubar Ingrid ,   Co-authors
Published: March 2020

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in western Elysium Planitia on November 26, 2018. Because of its stationary position and a multi-instrument package, InSight offers the unique opportunity of detecting changes induced by aeolian activity and constraining the atmospheric conditions responsible for particle motion.

In this work, we present the most significant changes from aeolian activity as detected by the InSight lander during its first 400 Martian days of operations. We will show that particle entrainment by wind activity around InSight is a subtle process and report simultaneous measurements observed across multiple instruments. The changes observed are episodic and are seen correlated with excursions in both seismic and magnetic signals, which will be discussed further. Our observations show that all aeolian movements are consistent with the passage of deep convective vortices between noon to 3 pm local time. These vortices may be the primary initiators for aeolian transportation at InSight, inducing episodic particulate motion of grains up to 3 mm in diameter.
Volatile organic compound fluxes across the soils of a rainforest ecosystem during a simulated drought experiment
Authors: Purser Gemma , Kreuzwieser Jürgen , Ingrisch Johannes , Meeran Kathiravan , Gil Loaiza Juliana , Daber Erik , Ladd S. Nemiah , Meredith Laura , Werner Christiane
Published: March 2020

Rainforests have important role in global carbon cycle. They act as an important sink for carbon dioxide and are a net source of volatile organic compounds (VOCs), which are emitted predominately from trees. However, the functioning of rainforest ecosystems are particularly vulnerable to changes in climate and extreme weather events such as drought, which are expected to become more frequent as global temperatures rise.

The forest floor acts as an interface between the biosphere and atmosphere within a forest ecosystem. Both emission (source) and deposition (sink) of atmospheric volatile organic compounds (VOCs) occur at this interface. Organic matter such as leaf litter in particular is a well characterised source of VOCs which are released through both biotic and abiotic degradation processes. Other emission sources of VOCs include those emitted from roots within the soil and also from soil microbial communities. Typically leaf litter or vegetation is the dominant emission source of VOCs from the forest floor, which has previously been reported to contribute up to 5% of the total ecosystem emission of forests. It is predicted that leaf litter will begin to accumulate on the forest floor as trees become drought stressed increasing the contribution of this source to the atmosphere. However the response of the soils within the rainforest ecosystem under drought conditions is less well understood.

We investigated changes in the direction of VOC fluxes across the forest floor before, during, and after a 7-week artificial drought as part of the Biosphere 2 Water, Atmosphere, and Life Dynamics campaign (B2 WALD). Initial results from the campaign showed that the forest floor soils act as an important sink for atmospheric concentrations of VOCs such as isoprene. The unique setting of an enclosed ecosystem in Biosphere 2 leads to elevated concentrations of VOCs including monoterpenes in the atmosphere which have allowed for the uptake rates of different VOCs by forest soil to be assessed.

A dynamic flow through system was used to collect VOC samples from both ambient air and chambers situated on the forest soil at a flow rate of 0.2 L/min for approximately 2 hours onto glass cartridges filled with Tenax®. The samples were analysed using a thermal desorption-Gas chromatrography-Ion Ratio-Mass spectrometry instrument. Fluxes were calculated using the difference between the concentration of monoterpenes in the ambient air and chamber samples. Here we will discuss further the variability in fluxes of monoterpenes across the rainforest floor interface under both ambient and severe drought conditions alongside the environmental drivers that have an impact on this ecosystem process. 
Application of a priori primary production model to estimate water vapor flux
Authors: Tan Shen , Wang Han
Published: March 2020

Accurate estimation of terrestrial evapotranspiration (ET) is a basic request in researches about water cycle and the energy exchange at land-atmosphere interface. Modelling ET with water and carbon coupling theory has been proven to be a robust and effective strategy. However, there still remaining an assumption needs demonstration: if site-calibrated parameters in empirical models are universally accurate and could be generalized in different regions or future scenario. In this research, we present a prototype coupling ET and carbon assimilation based on a first-principle primary production model with only two parameters calibrated with independent datasets. The water vapor diffuses through leaf stomata, which is regulated by the ratio of leaf-internal to external CO2 (χ) and could be estimated by environmental factors using our universal model. We validated the prototype with three steps. In the first step, we prove that diffusion process is the key linkage of water cycle and carbon assimilation at canopy scale. In the second step, comparation was carried over different vegetation types between predicted gross primary production (GPP) and tower-based observation, where results displays good agreement was found. Thirdly, we use the predicted χ and GPP to estimate canopy ET. Due to the strict description of physical and physiological process, our ET model is free of further consideration about the variation of parameters, thus could be ideally used in non-site region or future scenario. Sensitivity analysis results show that GPP would increase following the rising of CO2 concentration, but exhibit a parabolic trend when faced with rising air temperature. On the other hand, simulated ET exhibits nearly linear trend against warmer environment, but nearly no obvious relation with rising CO2 concentration.
Influence of Urban Canopy Layer on a heavy rainfall over Beijing
Authors: ma minjin
Published: March 2020

Urban canopy layer (UCL) is generally considered in numerical study of urban meteorology. The weather research and forecasting Model (WRF) coupled with urban canopy layer scheme is used to simulate a heavy rainfall case in Beijing. Comparative analysis is applied for the case between coupled simulation and non coupled simulation and therefore exhibits the effect of the UCL on the rainfall. Sensitive experiments are performed to investigate anthropogenic heat source and urban area extension to affect the precipitation. The results show that the coupled UCL model has captured the rainfall characteristics at the regional scale. The coupled simulation has improved accuracy of the rainfall area, the peak value and the rainfall duration compared to the non coupled simulation. The main effect achieves as longer duriation of the ascending motions and enhancement of the layers unstabilities. Although the intensity of the vertical motion has a little reduction, the time of the motion has increased 2 hours in a day. Sensitive experiments present an obvious influence on precipitation intensity, precipitation centralization and heat island effect. The precipitation center moves toward the urban center, the accumulated rainfall increases 78.5 mm and the center moves by distance 13 km when anthropogenic heat source is perturbed to double. Urban area extension induces increase of the precipitation area and intensity due to high humidity and ascending motion. The experment also reveals shift of the island heat effect.
Recent scientific findings based on high-resolution core plasma imaging of the ionosphere with Swarm and ePOP
Authors: Knudsen David
Published: March 2020

The Thermal Ion Imagers on Swarm A-C, and the Suprathermal Electron/Ion Imager on ePOP (now “Swarm-E”) provide a unique view of charged particle distribution functions in the ionosphere at high time resolution (up to 100 images/s). Through high resolution, CCD-based imaging (~3000 pixels/image), ion drift velocity is derived from these images at a resolution of 20 m/s or better, and in general agreement with velocities derived from ground based radars [1] and an empirical convection model [2]. This talk reviews recent scientific applications of this technique, which are wide-ranging and include mechanisms of ion heating and upflow [3,4], M-I coupling via Alfven waves [5,6], electron acceleration and heating by Alfven waves [7,8, 9], intense plasma flows associated with “Steve” [10,11], and electrodynamics of large-scale FAC systems[ 12], among others. In addition, future opportunities made possible by these data will be discussed.

[1] Koustov et al. (2019), JGR, https://doi.org/10.1029/2018JA026245

[2] Lomidze et al. (2019), ESS, https://doi.org/10.1029/2018EA000546

[3] Shen and Knudsen (2020a), On O+ ion heating by BBELF waves at low altitude, JGR, in revision.

[4] van Irsel et al. (2020), Highly correlated ion upflow and electron temperature variations in the high latitude topside ionosphere, submitted to JGR.

[5] Pakhotin et al. (2020), JGR, https://doi.org/10.1029/2019JA027277

[6] Wu et al. (2020a), Swarm survey of Alfvenic fluctuations and their relation to nightside field-aligned current and auroral arcs systems, JGR, in revision.

[7] Liang et al. (2019), JGR, https://doi.org/10.1029/2019JA026679

[8] Wu et al. (2020b), e-POP observations of suprathermal electron bursts in the ionospheric Alfven resonator, GRL, submitted.  

[9] Shen and Knudsen (2020b), Suprathermal electron acceleration perpendicular to the magnetic field in the topside ionosphere, JGR, in press.

[10] Archer et al. (2019), JGR, https://doi.org/10.1029/2019GL082687

[11] Nishimura et al. (2019), JGR, https://doi.org/10.1029/2019GL082460

[12] Olifer et al (2020), Swarm observations of dawn/dusk asymmetries between Pedersen conductance in upward and downward FAC regions, submitted to JGR.

 
A calibration method for monitoring bedload transport rate using Japanese pipe-type hydrophone considering installation condition and aging
Authors: Izumiyama Hiroaki , Uchida Taro , Iuchi Takuma , Yoshimura Nobuya , Yamakoshi Takao
Published: March 2020

Observation of bedload is quite important for understanding temporal and spatial variation of sediment transport in mountainous regions. In government-owned mountain watersheds in Japan, Japanese pipe-type hydrophones (Hydrotech Co., Ltd.) have been installed as a surrogate monitoring tool since about 2009 and continuous observations have been conducted. According to positive correlation between sound pressure and bedload transport rate, observed sound pressure is used to be integrated with respect to time and its value is converted into bedload transport rate using proportionality constant. However, it remains challenging to obtain precise bedload transport rate with high accuracy, because we should consider the difference of the way to fix the hydrophone on river bed among installed sites, deformation of steel pipe due to collision of sediment particles, and the difference of initial performance and aging of microphone. Hence, we have to calibrate frequently the proportionality constant. In this study, we investigate a calibration method which is easily conducted by engineers. Because it takes time and effort to obtain time integral of sound pressure, we try to calibrate the proportionality constant with the maximum sound pressure, which can be obtained easily.
When Science Communication Becomes Difficult: Advice From The Battlefields
Authors: Williams Paul
Published: March 2020

Based on my 15 years of experience as a professional atmospheric scientist and amateur science communicator, I can confidently state that science communication usually goes really well. However, I will focus this presentation on the minority of times when it goes badly wrong.

I will give an example of a time when I was misquoted by a national newspaper: my suitably nuanced statement in the interview that "Reducing uncertainties in weather forecasts is a key research priority for the next ten years" ended up being printed as "Within ten years, I think we'll see a model that predicts the weather and climate change exactly". I will also give an example of a time when, at an organized event in Barcelona, I participated in a debate with a former MIT professor who is arguably the world's most famous disputer of climate change science. I will discuss how I handled both these difficult events, and I will give some advice on how to cope when science communication doesn't go according to plan.

I will finish with a plea not to over-simplify the scientific content when communicating with the public. There is evidence that doing so inclines people to under-value experts, which I believe may be a factor in public cynicism regarding climate change. The fact that I was recently quoted in The Times discussing the geekiest of topics in atmospheric science — the Coriolis force — demonstrates that there is a genuine public appetite for appropriate technical content in the mainstream media. I believe we must make the most of that appetite, in order to enthuse and inspire the next generation of geoscientists.
Determination method of the geotechnical parameters for assessing the collapse risk of mountain slope
Authors: Kim Namgyun , Kwak Jaehwan , Kim Man-Il
Published: March 2020

In Korea, occurrence frequency of mountain disasters like landslide, debris flow, rock fall are increasing due to the extreme weather such as localized heavy rainfall and typhoon during the summer season. The Korea government is investigating and discovering vulnerable areas of mountain disaster to mitigate the damage of people’s lives and property. In this study, we selected the mountain slope with high probability of collapse among the vulnerable areas of mountain disaster and suggested reinforcement method through risk assessment. The slope safety factor was calculated using the limit equilibrium analysis for risk assessment of mountain collapse. The risk of collapse was determined by comparing the calculated slope safety factor with Korea government (Ministry of Land, Infrastructure, and Transport) restrict slope safety factor. The Slope safety factor suggested by the government (Ministry of Land, Infrastructure and Transport) is divided into three conditions: dry season, rainy season, and earthquake. Geotechnical parameters for limit equilibrium analysis were obtained by soil test. However, the results of the soil test could be different depending on soil sampling location or the weather condition. Therefore, geotechnical parameters were determined by comprehensive analysis such as comparing literature data, reviewing existing design data, and applying empirical formula of N value by standard penetration test. As a result of risk assessment, it was analyzed that there was a risk of mountain collapse in all conditions except dry season, and it was determined that slope stabilization is necessary.
Analysis on the Accuracy of Marine Gravity Inversion from the Wide-swath Altimeter Mission
Authors: Zhou Mao , Jin Taoyong , Li Jiancheng , Zhang Shengjun , Hu Minzhang
Published: March 2020

Marine gravity is mainly inversed by the nadir satellite altimetry observations. However, the accuracy of the east-west component of vertical deflection is significantly lower than the north-south component. The wide-swath altimeter is one of the main altimetry missions in the future. Its two-dimensional design is expected to obtain high-precision and high-resolution sea surface height simultaneously, and to improve the accuracy of the marine gravity inversion. Taking the SWOT (Surface Water and Ocean Topography) wide-swath altimeter mission as an example, based on the parameters including the ground track and the width of swath, the static sea surface height observations of SWOT, as well as the nadir altimeter missions Jason-1/GM, Cryosat-2/LRM, and SARAL/GM were simulated. Then, the vertical deflections were calculated from above observations to analyze the ability of marine gravity inversion in the South China Sea and part of the Indian Ocean. Compared with EGM2008 model, the vertical deflections determined by one cycle of SWOT are better than the result determined by combining Jason-1/GM, Cryosat-2/LRM, and SARAL/GM. And the results determined by SWOT improve the accuracy of the east-west component of vertical deflection significantly. And then, several specific errors of SWOT satellite were simulated, and their influence on the determination of the vertical deflection was analyzed. It is noted that these errors have certain influence on the accuracy, but can be weakened by using a simple Gaussian filter. In addition, the influence of SWOT sea surface height resolution on the gravity field inversion was analyzed. As a result, under the premise of the designed accuracy and resolution of the SWOT mission, its observations can improve the quality of marine gravity inversion effectively.
Assessment of Observational Environments of the Automated Synoptic Observing Systems in Korea Using a CFD Model
Authors: Kang Jung-Eun , Kim Jae-Jin
Published: March 2020

  In this study, we analyzed the observation environments of the automated synoptic observing systems (ASOSs) using a computational fluid dynamics (CFD) model, focusing on the observational environments of air temperatures, wind speeds, and wind directions. The computational domain sizes are 2000 m × 2000 m × 750 m, and the grid sizes are 10 m × 10 m × 5 m in the x-, y-, and z- directions, respectively. We conducted the simulations for eight inflow directions (northerly, northeasterly, easterly, southeasterly, southerly, southwesterly, westerly, northwesterly) using the ASOS-observation wind speeds and air temperatures averaged in August from 2010 to 2019. We analyzed the effects of the surrounding buildings and terrains on the meteorological observations of the ASOSs, by comparing the wind speeds, wind directions, and air temperatures simulated at the ASOSs with those of inflows. The results showed that the meteorological observation environments were quite dependent on whether there existed the obstacles and surface heating on their surfaces at the observation altitude of the ASOSs.
Concentrations of Te, As, Bi, Sb (TABS) and Se in the Marginal Zone of the Bushveld Complex: evidence for crustal contamination and the nature of the magma that formed the Merensky Reef
Authors: Mansur Eduardo , Barnes Sarah-Jane
Published: March 2020

The association of platinum-group elements (PGE) and the chalcophile elements Te, As, Bi, Sb and Sn (TABS) has been documented in several magmatic sulfide deposits. These groups of elements are either hosted within sulfide minerals, or combine to form discrete platinum-group minerals (PGM) associated with sulfide minerals. However, the concentration of TABS in parental magmas from which magmatic sulfide deposits formed was still missing. This study presents the distribution of TABS and Se in B-1, B-2 and B-3 rocks of the Marginal Zone of the Bushveld Complex. These rocks have been proposed as representative of the parental liquids from which the Bushveld Complex crystallized, thus allowing us to assess the concentration of Se and TABS in the liquids from which some of the largest PGE deposits in the world have formed. Concentrations of As and Sb in the initial Bushveld liquid (B-1) are significantly higher than in primary magmas, whereas the Se and TABS of later magmas (B-2 and B-3) are similar to primary magmas. We attribute the difference due upper crustal contamination of the B-1 magma, whereas the B-2 and B-3 magmas were most likely contaminated with a plagioclase-rich residuum formed upon the partial melting of the upper crust. Moreover, we modeled the concentrations of the TABS in the Merensky Reef using a mixture of two of the magma types present in the Marginal Zone (the B-1 and B-2) as the initial silicate liquid. The modeled concentrations closely resemble the measured values obtained for a section across the Merensky Reef at the Impala mine. This supports the B-1 and B-2 mixture as an appropriate initial liquid for the crystallization of the Merensky Reef. The modeling also shows that the distributions of Se, Te and Bi across the Merensky Reef are controlled by the sulfide liquid component. In contrast, As and Sb distributions are influenced both by the amount of silicate melt component in the cumulates and the sulfide liquid component. This is because Se, Te and Bi are moderately to strongly chalcophile elements, but As and Sb are only slightly chalcophile elements. Consequently, the effect of crustal contamination for elements with high partition coefficients between sulfide and silicate liquid (Te, Bi and Se) is obscured by the interaction of sulfides with a large volume of silicate magma. Therefore, the concentrations of these elements are higher in samples with greater proportions of sulfide minerals. In contrast, for elements with lower partition coefficients (As and Sb), the whole-rock concentrations are not upgraded by the presence of sulfide minerals, and thus the effect of crustal contamination can be more readily assessed.
Modern Scientific Metadata Management: Atmospheric Radiation Measurement (ARM) Facility Data Center
Authors: Davis Maggie , Cederwall Richard , Prakash Giri , Devarakonda Ranjeet
Published: March 2020

 

Atmospheric Radiation Measurement (ARM), a U.S. Department of Energy (DOE) scientific user facility, is a key geophysical data source for national and international climate research. Utilizing a standardized schema that has evolved since ARM inception in 1989, the ARM Data Center (ADC) processes over 1.8 petabytes of stored data across over 10,000 data products. Data sources include ARM-owned instruments, as well as field campaign datasets, Value Added Products, evaluation data to test new instrumentation or models, Principal Investigator data products, and external data products (e.g., NASA satellite data). In line with FAIR principles, a team of metadata experts classifies instruments and defines spatial and temporal metadata to ensure accessibility through the ARM Data Discovery. To enhance geophysical metadata collaboration across American and European organizations, this work will summarize processes and tools which enable the management of ARM data and metadata. For example, this presentation will highlight recent enhancements in-field campaign metadata workflows to handle the ongoing Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC) data. Other key elements of ARM data center include: the architecture of ARM data transfer and storage processes, evaluation of data quality, ARM consolidated databases. We will also discuss tools developed for identifying and recommending datastreams and enhanced DOI assignments for all data types to assist an interdisciplinary user base in selecting, obtaining, and using data as well as citing the appropriate data source for reproducible atmospheric and climate research.
Application of tracer materials in the study of hydrological cycle mechanism
Authors: Ma Tao , Liu Hongwei , Zheng Hao , Min Xing , Liao Aimin , Wang Wenzhong
Published: March 2020

In this study, the characteristics of hydrogen and oxygen isotopes as well as four kind of ions(K+、Na+、Ca2+、Mg2+ )in rainfall-runoff processes are analyzed through designing an extensible soil water sampler. It is a kind of multipoint sampling installation with the characteristics of synchronous, in-situ and long-term in sampling. The sampling schemes were summarized, including site layout ways, capacities and materials selection, sample pretreatment and storage methods, and valid date. A series of experiments were carried out such as hydrogen and oxygen isotopes memory effects tests, repeatability test and dilution errors analysis. After recognizing the possible error sources in hydrogen and oxygen isotopes as well as the four kind of ions test, the solution on how to improve accuracy and precision were proposed. Moreover, the spatial-temporal evolution laws of the isotopes and cations was discussed by drawing the contour maps of hydrogen and oxygen isotopes as well as the four kind of ions in soil water and underground water. At last, the possibility and applicability of these substances as tracers in hydrological cycles were explored. These work were quite important for researches on coupling mechanism of hydrological and solute transport processes in critical zone.
Comparison of 1D vs 3D viscosity models for glacial isostatic adjustment
Authors: Prevost Paoline , Freymueller Jeffrey
Published: March 2020

Accurate calculation of displacements due to glacial isostatic adjustment (GIA) are essential for studies of tectonics, sea level projection, and the estimation of recent ice melting or other mass transport. However, most GIA studies to date have used a 1D viscosity model, with earth parameters varying only in the radial direction, while surface geology and seismic tomography show that the thickness of the lithosphere and the structure of the mantle also varies laterally. Therefore, models with 3D earth structure are needed. Using a 3D earth model requires finite element models, which are computationally expensive and hence make it difficult to compute a wide range of potential parameter values. Consequently, the question is for which application is a 3D model necessary, and for which parameters (and where) do 1D models give sufficiently accurate predictions?

 

In this study, we investigate the sensitivity of the GIA modeling to the earth structure, using the Abaqus finite element analysis software, an ice model assumed to be known, and various viscosity models. We start with Patagonia as a test region, because the 3D structure of the mantle is complex due to the proximity of the subduction of the Antarctic plate below South American and the Chile triple junction. In this region, the GIA contributes significantly to the regional recent rapid uplift.
Differences in calcite varve formation discerned by a dual lake monitoring approach in the southern Baltic lowlands
Authors: Roeser Patricia , Dräger Nadine , Brykała Dariusz , Ott Florian , Pinkerneil Sylvia , Gierszewski Piotr , Lindemann Christin , Plessen Birgit , Brademann Brian , Kaszubski Michał , Fojutowski Michał , Schwab Markus J. , Słowiński Michał , Błaszkiewicz Mirosław , Brauer Achim
Published: March 2020

Varved lake sediments are valuable archives for reconstructing climate and environmental change in the human habitat at seasonal resolution. However, it is still not fully understood which factors control varve thickness and, consequently, varve proxy records are differently interpreted with respect to their climatic significance. Here we present, for the first time, a dual lake monitoring in two lakes forming calcite varves to provide new insights into the seasonal depositional processes forming these varves. The study lakes, Tiefer See (TSK) in NE Germany and Czechowskie (JC) in N Poland, are located a few hundred km away from each other in the southern Baltic lowlands. This is an ideal test region for this investigation because it holds the major known geographical cluster of calcite varve producing lakes. The lake basins are different in morphology and bathymetry and, therefore, are ideal to investigate common processes and local differences of seasonal deposition. The monitoring setup in both lakes is largely identical and included instrumental observation of (1) meteorological parameters, (2) chemical profiling of the lake water column including water sampling and analyses, and, (3) sediment trapping at both bi-weekly and monthly intervals. Finally, we compared our six-year monitoring time series with varve micro-facies of sediments deposited during this time at the lake bottom. Based on this robust data-set, we present and discuss new findings with respect to the seasonal deposition of endogenic calcite varves, as well as their limnologic control factors.