bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of the Vertical Profile of Dust Aerosols with Land/sea Breezes over the Eastern Coast of the Red Sea from LIDAR and High-resolution WRF-Chem Simulations
Authors: Parajuli Sagar , Stenchikov Georgiy , Ukhov Alexander , Shevchenko Illia
Published: March 2020

With the advances in modeling approaches, and the application of satellite and ground-based data in dust-related research, our understanding of the dust cycle is significantly improved in recent decades. However, two aspects of the dust cycle, the vertical profiles and diurnal cycles of dust aerosols have not been understood adequately, mainly due to the sparsity of observations. A micro-pulse LIDAR has been operating at the King Abdullah University of Science and Technology (KAUST) campus located on the east coast of the Red Sea (22.3N, 39.1E), measuring the backscattering from atmospheric aerosols at a high temporal resolution for several years since 2015. It is the only operating LIDAR system over the Arabian Peninsula. We use this LIDAR data together with other collocated observations and high-resolution WRF-Chem model simulations to study the 3-d structure of aerosols, with a focus on dust over the Red Sea Arabian coastal plains. 

Firstly, we investigate the vertical profiles of aerosol extinction and concentration in terms of their seasonal and diurnal variability. Secondly, using the hourly model output and observations, we study the diurnal cycle of aerosols over the site. Thirdly, we explore the interactions between dust aerosols and land/sea breezes, which are the critical components of the local diurnal circulation in the region. 

We found a substantial variation in the vertical profile of aerosols in different seasons. There is also a marked difference in the daytime and nighttime vertical distribution of aerosols in the study site, as shown by LIDAR data. A prominent dust layer is observed at ~5-7km at night in the LIDAR data, corresponding to the long-range transported dust of non-local origin. The vertical profiles of aerosol extinction are consistently reproduced in LIDAR, MERRA-2 reanalysis, and CALIOP data, as well as in WRF-Chem simulations in all seasons. Our results show that the sea breezes are much deeper (~1km) than the land breezes (~200m), and both of them prominently affect the distribution of dust aerosols over the study site. Sea breezes mainly trap the dust aerosols near the coast, brought by the northeasterly trade winds from inland deserts, causing elevated dust maxima at the height of ~1.5km. Also, sea and land breezes intensify dust emissions from the coastal region in daytime and nighttime, respectively. Such dust emissions caused by sea breezes and land breezes are most active in spring and winter. Finally, WRF-Chem successfully captures the onset, demise, and the height of some large-scale dust events as compared to LIDAR data qualitatively. 
Methodology for sustainable development along an eco-fragile zone for land use management and mitigating climate change: Evidence of East Kolkata Wetlands
Authors: Kumar Sudeshna , Banerji Haimanti , Kanti Sengupta Biplab
Published: March 2020

Kolkata’s city core is getting depopulated but has experienced an explosive population growth leading to rapid urbanization which is encroaching the ecologically fragile wetlands of the eastern fringe of the main city. This contrasting urban growth along the East Kolkata wetland is accounted mainly for the increase in city size, expansion of tertiary and service sector activities especially the IT boom, and the improved transit facilities along the eastern fringe. This has helped the real estate sector to thrive along the vulnerable eastern fringe of the city, leading to a drastic change in the wetland ecosystem. Secondary studies have also indicated that consumption of wetlands, indicated by fragmented land use has altered the microclimate of Kolkata. The significant land cover change due to human-induced perturbations has led to an insurgence of temperature in the region (Li, Mitra, Dong, & Yang, 2018). The entire transit corridor is subjected to verticalization juxtaposing the cultural essence of Kolkata bringing with it a myriad of Economic, Social, Cultural and subsequent planning challenges. The critical review of the selective literature shows how the best planning practices have integrated transit policies with land use. This has further helped the researcher in formulating strategies and policies specific to the regional context in order to render sustainable development in the study area. The study explores how the transit policies in Kolkata have actually transformed the city physically, socially, culturally and changed its microclimate. The study identifies future trends and assesses the future development potential, intensification with the help of qualitative and quantitative analysis. The study also conducts land suitability analysis for framing proposals and recommendations for ensuring sustainable development along the East Kolkata Wetland.  The outcome of this study is a methodology for sustainability strategic planning for developing the growth node along the eastern fringe of Kolkata which will curb the encroachment of the East Kolkata Wetlands. The study also provides a platform for policy recommendations for land use management and mitigate future climate changes in this eco-fragile zone.

Keywords: landuse; climate change; transit policies; sustainable planning; wetlands

Reference

Li, X., Mitra, C., Dong, L., & Yang, Q. (2018). Understanding land use change impacts on microclimate using Weather Research and Forecasting (WRF) model. Physics and Chemistry of the Earth, 103, 115–126. https://doi.org/10.1016/j.pce.2017.01.017
Mirror instability driven by pickup ions in the outer heliosheath
Authors: Mousavianzehaie Amenehsadat , Liu Kaijun , Min Kyungguk
Published: March 2020

Kinetic linear instability analysis and hybrid simulations are carried out to examine the role of mirror instability in scattering the pickup ions in the outer heliosheath. The dynamics of these pickup ions is essential to
the understanding of the energetic neutral atom (ENA) ribbon observed by the Interstellar Boundary EXplorer
(IBEX). While most previous studies have focused on the ion cyclotron instability driven by the pickup ions,
recent work based on a simple ring velocity distribution of the pickup ions suggested that the mirror mode can
also be unstable and contribute to the scattering of the pickup ions. The present study performs linear analysis
as well as hybrid simulations for a more realistic, multi-component pickup ion velocity distribution given by the
global modeling of neutral atoms in the heliosphere. The linear theory results indicate unstable mirror modes
with considerable growth rates. The corresponding hybrid simulations further confirm that the mirror modes can
grow and aid the pitch-angle broadening of the pickup ions. So the role of mirror mode should not be ignored in
the stability study of the outer heliosheath pickup ions.
Research on dam inflow analysis based on radar rainfall data
Authors: Choi Gian , Shin Hongjoon , Yoon Seongsim
Published: March 2020

Estimation of dam inflow using rainfall needs for efficient and timely operation of dam. Accuracy rainfall data is important to estimate dam inflow. Currently, rainfall pattern has volatile temporal and spatial distribution. Dam inflow based on rainfall gauged data is inadequate for operating hydroelectric dam. Radar rainfall has been used as an alternative because radar data provides spatially distributed rainfall. In this study, we estimated inflow discharge for hydroelectric dam using both radar and rain gauged data to find a case to improve the accuracy. Hydrological modeling have been adopted to estimate inflow and based on rainfall data collected from 2018 to 2019.

This work was supported by KOREA HYDRO & NUCLEAR POWER CO., LTD(No. 2018-Tech-20)
The role of grazing exclusion by fence in regulating vegetation characteristics and plant diversity in Mongolian rangelands
Authors: Guo Tong
Published: March 2020

Grazing largely affects vegetation dynamic of grassland communities. An intensified grazing will likely lead to grassland degradation. Therefore, to restore degraded grasslands, grazing exclusion by fence might be very helpful. However, the direction and the strength of grazing management effects on vegetation characteristics and plant diversity are currently disputable. In addition, vegetation cover and species richness are often independently examined under different grazing regimes in typical studies. Diversity-cover relationship is not adequately detected in degraded grasslands.

In this study, I aim at understanding effects of grazing exclusion on vegetation characteristics, plant diversity and their relationship. For this, I performed a fencing experiment in three grassland types, namely meadow (since 2009), mountain steppe (since 2013) and dry steppe (since 2013) in Mongolia. Each of three grasslands was set by two treatments: grazing exclusion and freely grazing. Vegetation characteristics were mirrored by vegetation cover and height. Plant diversity was evaluated by indices of species richness, Shannon-Wiener diversity and Pielou evenness.

The empirical results show that grazing exclusion by fence generally increases vegetation height regardless of grassland types. On the other hand, the changing direction of vegetation cover caused by grazing exclusion is not consistent in three grasslands. Fencing decreases species richness and Shannon diversity. While Pielou evenness responds slightly to changes in grazing regimes. Greater species richness benefits an increment of vegetation cover independent of grazing treatments and grassland types.

This study fills the knowledge gap of grazing management effects on vegetation characteristics and plant diversity in Mongolian rangelands. The results clearly demonstrate that grazing exclusion by fence is not an efficient way to restore degraded grasslands. This will also allow to project the impact of changes in land use on ecosystem functioning.
The influence of plate strength on dynamic topography estimates
Authors: Kirby Jon
Published: March 2020

A common method used to evaluate dynamic topography amplitudes begins with an estimate of Moho depth, usually from seismic data but sometimes - or also - from the inversion of gravity data. Then the principles of Airy isostasy are applied: surface topography is assumed to be in isostatic equilibrium, buoyantly supported by the displacement of high-density mantle material by the low-density crustal ‘root’ that compensates the surface topographic mass. Hence, the actual relief of the Moho yields an ‘isostatic topography’ which will depart from the actual, observed topography by a component that, in theory, must arise from convective support or subsidence. Notwithstanding the fact that the errors on the seismic Moho may be larger than the topography itself, there is another source of uncertainty, that of the flexural rigidity of the lithosphere. Airy isostasy is essentially an end-member of plate flexure models, one in which the flexural rigidity is zero. However there are very few places on Earth where the flexural rigidity, usually represented by its geometric analogue the effective elastic thickness (Te), is indeed zero. In most environments, the rigidity of the plate will act to resist flexure, with the implication that the ‘Airy isostatic topography’ and therefore the dynamic topography will be in error. Here several scenarios will be presented illustrating these issues, and paths for remediation recommended.
A global analysis of climate-relevant aerosol properties retrieved from the network of GAW near-surface observatories
Authors: Laj Paolo , Rose Clémence , Bigi Alessandro , Collaud Coen Martine , Andrews Elisabeth , Lund Myhre Cathrine , Fiebig Markus , Aas Wenche , Wiedensohler Alfred , Schulz Michael , Mortier Augustin , Gliss Jonas , Putaud Jean-Philippe , Kim Sang-Woo , Mayol Olga , Keywood Melita , Petäjä Tuukka , Pandolfi Marco , Labrador Lorenzo , Ogren John ,   SARGAN team
Published: March 2020

Aerosol particles are essential constituents of the Earth’s atmosphere, impacting the earth radiation balance directly by scattering and absorbing solar radiation, and indirectly by acting as cloud condensation nuclei. In contrast to most greenhouse gases, aerosol particles have short atmospheric residence time resulting in a highly heterogeneous distribution in space and time. There is a clear need to document this variability at regional scale through observations involving, in particular, the in-situ near-surface segment of the atmospheric observations system. This paper will provide the widest effort so far to document variability of climate-relevant in-situ aerosol properties (namely wavelength dependent particle light scattering and absorption coefficients, particle number concentration and particle number size distribution) from all sites connected to the Global Atmosphere Watch network. High quality data from more than 90 stations worldwide have been collected and controlled for quality and are reported for a reference year in 2017, providing a very extended and robust view of the variability of these variables worldwide. The range of variability observed worldwide for light scattering and absorption coefficients, single scattering albedo and particle number concentration are presented together with preliminary information on their long-term trends and comparison with model simulation for the different stations. The scope of the present paper is also to provide the necessary suite of information including data provision procedures, quality control and analysis, data policy and usage of the ground-based aerosol measurements network. It delivers to users of the World Data Centre on Aerosol, the required confidence in data products in the form of a fully-characterized value chain, including uncertainty estimation and requirements for contributing to the global climate monitoring system.
Numerical modeling of snow avalanche dynamics based on the Material Point Method
Authors: Li Xingyue , Sovilla Betty , Wang Stephanie , Jiang Chenfanfu , Gaume Johan
Published: March 2020

Snow avalanches are one of the most dangerous and catastrophic hazards in mountainous regions, which cause fatalities and property losses. Understanding the dynamics of snow avalanches is essential for designing safe and optimised mitigation measures. This study presents numerical modeling of snow avalanche dynamics, based on the Material Point Method (MPM) and an elastoplastic constitutive model for porous cohesive materials. MPM is a hybrid Eulerian-Lagrangian numerical method, which can simulate processes with large deformation, collisions and fractures. The elastoplastic model consists of an ellipsoid yield surface, a hardening law, and an associative flow rule. It enables us to capture the mixed-mode failure of snow including tensile, shear and compressive failure. Both ideal and real terrains are modeled in our study. By varying the properties of snow on the ideal slope, the model can reproduce four typical reported flow regimes, namely, cold shear, warm shear, warm plug and slab sliding regimes. In addition, surges and roll-waves are observed especially for flows in the transition from cold shear to warm shear regimes. The evolution of the avalanche front, the free surface shape and the velocity vertical profile show distinct characteristics for the different flow regimes. In addition to the snow properties, slope angle and path length are changed to investigate their effects on the maximum velocity, the run-out distance and the avalanche deposit height. The relation between the maximum velocity and the run-out distance obtained from our MPM simulations is analyzed along with data collected from literature. Furthermore, we benchmark the MPM model by simulating snow avalanches on real terrain. The evolution of the avalanche front position and velocity from the MPM simulations are quantitatively compared with the measurement data from past studies.
Biochar manages salt-degraded land and conserves water: Effects and mechanism
Authors: Lee Xinqing , Huang Yimin , Yang Fang , Xing Ying , Xu Liang , Liu Zhongtang , Wang Rongmei , Holtzman Ran , Kan Iddo , Li Yunlong , Zhang Like , Wu Wei , Ma Yuena , Zhou Hui
Published: March 2020

Soil salinization represents a wide-spread land degradation in the world, especially in arid regions. Current management involves excessive water consumption. As a pyrolyzed residue of biomass waste, biochar has the potential to combat salinization at limited water supply, the effect and mechanism, however, remain to be clarified. We monitored the movement of salts and water in the profile of irrigation-silt soil during watering and evaporation in both laboratory and the field in Kashgar oasis in Xinjiang, China, and found that biochar exacerbates salinization within a short period of time after its application due to its high content of salts, nevertheless, it strengthens salt leaching in irrigation while intensifies salt accumulation in the top soil at the expense below during evaporation, all as results of invigorated movement of salts. Removing the top 2 cm before sowing, therefore, rejuvenates the soil well. Adsorption of biochar retards migration of salts in cation forms, but the effect is trivial. Due to increase to soil water content, biochar promotes evaporation before soil cracking. This is reversed, however, once the cracking occurs, which is inevitable in irrigated farmland and increases evaporation by 77%. Biochar counteracts soil cracking by alleviating soil compaction, lowering water evaporation by 43% at 10% of biochar application rate. Our results indicated that agriculture application of biochar creates salt distribution conducive to desalting in a mechanical way. In conjunction with the effect of anti-fracturing and enhanced salt leaching, it lowers water demand substantially, providing a new solution to the agricultural sustainability at reduced water supply.
Gap-filling continuously-measured soil respiration data with time-series-based methods
Authors: Zhao Junbin , Lange Holger , Meissner Helge
Published: March 2020

Soil respiration is an important ecosystem process that releases carbon dioxide into the atmosphere. While soil respiration can be measured continuously at high temporal resolutions, gaps in the dataset are inevitable, leading to uncertainties in carbon budget estimations. Therefore, robust methods used to fill the gaps are needed. The process-based non-linear least squares (NLS) regression is the most widely used gap-filling method, which utilizes the established relationship between the soil respiration and temperature. In addition to NLS, we also implemented three other methods based on: 1) artificial neural networks (ANN), driven by temperature and moisture measurements, 2) singular spectrum analysis (SSA), relying only on the time series itself, and 3) the expectation-maximization (EM) approach, referencing to parallel flux measurements in the spatial vicinity. Six soil respiration datasets (2017-2019) from two boreal forests were used for benchmarking. Artificial gaps were randomly introduced into the datasets and then filled using the four methods. The time-series-based methods, SSA and EM, showed higher accuracies than NLS and ANN in small gaps (<1 day). In larger gaps (15 days), the performance was similar among NLS, SSA and EM; however, ANN showed large errors in gaps that coincided with precipitation events. Compared to the observations, gap-filled data by SSA showed similar degree of variances and those filled by EM were associated with similar first-order autocorrelation coefficients. In contrast, data filled by both NLS and ANN exhibited lower variance and higher autocorrelation than the observations. For estimations of the annual soil respiration budget, NLS, SSA and EM produced satisfying results with budget errors < 6% while ANN exhibited larger errors up to 16.0%. Our study highlights the two time-series-based methods which showed great potential in gap-filling carbon flux data, especially when other environmental variables are unavailable. The R code to perform the gap-filling with the four methods in this study is incorporated into the R package “FluxGapsR” freely available at https://github.com/junbinzhao/FluxGapsR/.
Planetary saltation: Should we care about cohesion?
Authors: Comola Francesco , Pähtz Thomas , Duran Orencio
Published: March 2020

Sediment transport in saltation is an important driver of the morphodynamics of planetary sedimentary surfaces and particularly responsible for the formation and evolution of aeolian ripples and dunes. When estimating the incidence and persistence of saltation on extraterrestrial planetary bodies, geomorphologists usually ask by how much the atmospheric winds on such bodies exceed the threshold value required to initiate saltation, a question that is inherently linked to the cohesiveness of a body's surface sediments. For example, there is currently an ongoing controversy about the saltation initiation threshold on Saturn's moon Titan because of strongly varying estimations of the cohesiveness of Titan's soils. If the value of this threshold is outside a certain relatively small range, the currently leading explanation for an observed mismatch between Titan's dune orientation and the predominant atmospheric wind direction is thought to break down. Here we put up for discussion an alternative viewpoint on the importance of cohesion and saltation initiation. First, we briefly review experimental and theoretical evidence from the literature suggesting that, in the field (in contrast to wind tunnel experiments), saltation is almost always easily initiated, which means that one mainly needs to understands whether saltation can be sustained once initiated. Second, we present results from DEM-based numerical simulations suggesting that saturated saltation, in particular the smallest wind speed at which it can be sustained (i.e., the cessation threshold), is almost unaffected by cohesion. Third, we show a simple theoretical conceptualization that explains these numerical results and, when implemented in an analytical model, captures existing cessation threshold and saltation transport rate measurements. Finally, we show that the predictions of this model are consistent with several direct and indirect observations associated with extraterrestrial saltation, including the orientation of Titan's dunes.
Evaluation of the magnetite as a magnetic tracer of eroded sediment from ephemeral gullies: conditioning factors of magnetic susceptibility
Authors: Zubieta Elena , Larrasoaña Juan , Giménez Rafael , Aldaz Alaitz , Casalí Javier
Published: March 2020

In gully erosion, the soil detached by the action of the erosive flow can be transported over long distances along the drainage network of the watershed. In this long way, the eroded material can be redistributed and/or deposited on the soil surface, and then eventually buried by eroded material from subsequent erosion events. Likewise, the variability of the soil (i.e., in texture and moisture content) over which this material moves can be considerable. The presence of the eroded material could be detected through magnetic tracers attached/mixed with the eroded soil. In this experiment, the degree to which the magnetic signal of the magnetite is conditioned by (i) the burying tracer depth, (ii) the texture and moisture content of the soil covering the tracer and (iii) the tracer concentration was evaluated.

The study was carried out in the lab in different containers (0.5 x 0.5 x 0.3 m3). Each container was filled with a given soil. In the filling process, a 0.5-cm layer of a soil-magnetite mixture of a certain concentration was interspersed in the soil profile at a certain depth. Overall, 3 different soil:tracer concentrations (1000:1, 200:1, 100:1), 4 tracer burying depths (0 cm, 3 cm, 5 cm and 10 cm from soil surface), and  2 contrasting soils (silty clay and sandy clay loam) were used. In each case, the magnetic susceptibility was measured with a magnetometer (MS3 by Bartington Instruments). Experiments were repeated with different soil moisture contents (from field capacity to dry soil).

If the tracer is located under the soil surface a minimum soil:tracer concentration of 200:1 is required for its correct  detection from the surface using a magnetometer. The intensity of the magnetic signal decreases dramatically with the vertical distance  of the tracer from the soil  surface (burying depth). The maximum detection depth of the tracer magnetic signal is strongly dependent on the natural magnetic susceptibility of the soil which hides the own tracer signal. Variation in soil moisture content does not significantly affect the magnetic signal. For extensive field studies the soil-tracer volume to be handled would be very high. Therefore, it is necessary to explore new tracer application techniques.
Assessment of PCB trajectories along French river corridors between 1945 and 2018
Authors: Dendievel André-Marie , Mourier Brice , Coynel Alexandra , Evrard Olivier , Labadie Pierre , Ayrault Sophie , Debret Maxime , Faivre Quentin , Gardes Thomas , Vauclin Sophia , Budzinski Hélène , Grosbois Cécile , Desmet Marc , Winiarski Thierry
Published: March 2020

The reconstruction and modelling of contamination trajectories in rivers is a key concern to investigate spatio-temporal impacts of long-term anthropogenic activities. This issue is highly significant for persistent organic pollutants, such as polychlorinated biphenyls (PCBs), known for their toxicity, their low degradation rates and their hydrophobic properties leading to their accumulation in sediments and biota. Increasingly produced and released worldwide from the 1930s to the 1970-1980s, PCBs were analysed in numerous studies dealing with river sediment quality. However, data syntheses are uncommon at the scale of large hydrosystems, and source-to-estuary approaches along rivers are still needed. Accordingly, we propose an original work integrating PCBs analyses on different solid matrices (sediment cores, bed and flood deposits, suspended particulate matters, and dredged sediments) originating from both research programmes and monitoring. Based on more than 1400 validated analyses, temporal trends of the PCB contamination were reconstructed since 1945 along the four main fluvial corridors in France (Rhône, Seine, Loire and Garonne Rivers). The relationships with socio-environmental factors were also deciphered by integrating hydrological and human spatio-temporal data (cumulative river discharge, population hot spots, urban and industrial surfaces). This work highlighted that the main contaminant trends were driven by regulation, but also by sediment transport and accidental releases (especially since the 1990s). In general, urban and industrial areas were the main contributors to the PCB contamination of rivers: around and downstream of Paris and Rouen (Seine River), Lyon and its “Chemical Valley” (Rhône River), Saint-Etienne and Nantes conurbations (Loire River), and probably downstream of Toulouse and Bordeaux (Garonne River). Relatively high concentrations persisted after the end of the PCB production due to chronic diffuse inputs and accidental releases, particularly on the Rhône River. Moreover, the estimation of specific fluxes revealed that up to 12 µg/m²/yr (i.e. 0.9 t/yr on average) of PCBs were brought by French rivers, especially by the Rhône, Seine and Loire Rivers (ranked in order of importance) to Western European seas since the 1970s.
Global change has created a large subsoil carbon sink the U.S. Corn Belt
Authors: Castellano Michael , Archontoulis Sotirios , Mallarino Antonio , Russell Ann , Six Johan , Takle Eugene , Poffenbarger Hanna
Published: March 2020

Using long-term observations and experiments, we show that subsoils in the north central United States are a large modern organic carbon sink (~400 kg C ha-1 y-1). In this region, which is dominated by arable lands, the strongest signal of global change is a wetter environment. Precipitation amount and intensity have increased while atmospheric vapor pressure deficit has decreased. At the same time, this region has experienced a number of changes in agroecosystem properties and management; agroecosystems have become less diverse and total crop residue inputs to the soil have increased (>100%) due to large increases in crop yield. We used repeated measurements from two independent long-term (>40 years) cropping systems experiments to reject hypotheses that changes in cropping systems diversity and increases in crop residue input can explain the observed increase in subsoil carbon. In contrast, we used regional observations in climate to demonstrate that an increasingly wet environment is coincident with an increase in subsoil moisture content to a level that would inhibit soil carbon mineralization. As a result, we attribute the subsoil carbon sink to a wetter environment that has led to lower subsoil carbon outputs via microbial mineralization.

 
Force balance in current sheets
Authors: Mingalev Olеg , Mingalev Igor
Published: March 2020

A new form of the proton force balance equation for the plasma consisting of collisionless protons and magnetized electrons is obtained. In the equation, the electric field is expressed through the magnetic field and the divergence of electron pressure tensor. The latter is reqiured for the correct determination of boundary conditions in models of current sheets to control the force balance in the models of that type. From this, a general form of the force balance equation in a one-dimensional current sheet is obtained, and effects of electron pressure anisotropy are considered. We reproduce realistic stationary configurations of current sheets using novel methods of numerical simulations and the Vlasov equation solving. 
Is the Current Subtropical Position of the Tibetan Plateau Optimal for Intensifying the Asian Monsoon?
Authors: Wang Junbin , Yang Song
Published: March 2020

It is known that the existence of the Tibetan Plateau (TP) intensifies the Asian summer monsoon. However, is the current subtropical location of the TP optimal for energizing the monsoon? Would monsoon dynamics become simpler if the TP were located in the tropics? A series experiments with the NCAR CESM fully-coupled model show that a change in the current subtropical TP causes apparent responses in both divergent and rotational motions of the atmosphere in the tropics and higher latitudes, respectively. When the TP is moved southward, the atmospheric response is featured by more apparent thermally-driven and divergent part of atmospheric motion, and the tropical South Asian monsoon becomes stronger. However, the subtropical East Asian monsoon becomes weaker due to the intensify of Northwest Pacific subtropical high. In the experiments in which the TP is moved northward, the subtropical East Asian monsoon strengthens at some points but the tropical South Asian monsoon weakens. Besides, variations in the meridional position of the westerlies relative to the TP lead to anomalous distribution of precipitation in East Asia. In these latter experiments, the atmospheric response is apparently featured by rotational characteristics of the atmospheric motion.

Results also show that the meridional shift of the TP would also cause changes in the African summer monsoon, whose variability is closely linked to the variations of the Asian summer monsoon.
Lagrangian analysis of atmospheric water balance over the Bay of Bengal
Authors: Dey Dipanjan , Döös Kristofer
Published: March 2020

The origin of the atmospheric freshwater fluxes into the Bay of Bengal (BoB) are traced with Lagrangian water trajectories for both present and possible future climates. The water is traced backward from the precipitation at the sea surface to the evaporation regions. In the present-day simulation, the source is mostly from the Western Indian Ocean and near the Western Australian Coast. In the future climate scenario, simulated by EC-Earth, the origin of the moisture will not be the same as the present climate. In addition to it, the Bay of Bengal sourced water is also traced from the evaporation region to the precipitation locations. Most of the BoB originated moisture is precipitating within the neighbouring areas of the drainage basin and some part is transported into the Pacific Ocean. The Lagrangian model TRACMASS is currently running and a detailed analysis and results will be presented in the conference.
A new singular spectrum analysis approach for processing incomplete time series polluted by multiplicative noise
Authors: Shen Yunzhong , Wang Fengwei , Chen Qiujie
Published: March 2020

Since a time series is usually incomplete, the missing data are usually interpolated before employing singular spectrum analysis (SSA). We develop a new SSA for processing incomplete time series based on the property that an original time series can be reproduced from its principal components which are then estimated based on minimum norm criterion. When an incomplete time series is polluted by multiplicative noise, we first convert the multiplicative noise to additive noise by multiplying the signal estimate of the time series, then process the time series with weighted SSA, where the weight factor is determined according to the variance of additive noise, since the converted additive noise is heterogeneous. The proposed SSA approach is employed to process the real incomplete time series data of suspended-sediment concentration from San Francisco Bay compared to the traditional SSA and homomorphic log-transformation SSA approach. The first 10 principal components derived by our proposed SSA approach can capture more of the total variance and with less fitting error than traditional SSA approach and homomorphic log-transformation SSA approach. Furthermore, the results from the simulation cases conform that our proposed SSA outperform both traditional and homomorphic log-transformation SSA approaches.
Groundwater anomaly related to the 2018 Hokkaido Eastern Iburi earthquake in Northern Japan
Authors: Sano Yuji , Kagoshima Takanori , Takahata Naoto , Shirai Kotaro , Park Jin-Oh , Shibata Tomo , Yamamoto Junji , Nishio Yoshiro , Xu Sheng , Chen Ai-Ti , Daniele Pinti
Published: March 2020

In order to study groundwater anomaly related to the 2018 Hokkaido Eastern earthquake (Mw6.6) occurred on 6th September, we have measured δD and δ18O values of commercial bottled mineral water at two sites in Iburi region, Hokkaido, Northern Japan from June 2015 to May 2019. At the Uenae site, 21km west of the epicenter, both δD and δ18O values are constant from June 2015 to February 2018. Then these values have decreased substantially from April 2018 to December 2018 with significant fluctuations. These variations may be attributable to a mixing of groundwater with light δD and δ18O values. At the Eniwa site 34km northwest of the epicenter, δD values have decreased slightly and monotonically, while δ18O values are constant from June 2016 to October 2018. Observed isotopic variations of the Uenae site are different from those found at the 2016 Tottori earthquake where the δ18O value of groundwater increased a couple of months before the seismic event, while the δD value was constant. These data were attributable to water-rock interaction in the aquifer. Thus, the mechanism of groundwater isotopic anomaly may be different between Tottori and Hokkaido earthquakes. In addition to the M6.7 earthquake, CO2 injection by CCS project at Tomakomai, 13km southwest of the Uene site may be another factor to induce such variations. In order to evaluate the environmental impact of CO2 injection, we should measure total carbonate concentration and δ13C value of carbonate at both sites. Then we will discuss mechanism of groundwater anomaly.
How feasible is Regional Integration for reconciling land use conflicts across the urban-rural interface? Evidence from Beijing-Tianjin-Hebei metropolitan region in China
Authors: Ma Wenqiu
Published: March 2020

Competition among different uses for land is becoming acute under the process of urbanization, and conflicts related to this competition are becoming more frequent and more complex. This article presents a methodology for confronting this issue. By applying an integrated framework, we explore the implicit role of the Beijing-Tianjin-Hebei Regional Integration (BRI) policy in land use conflicts by focusing on the urban-rural interface, and try to address the research question: “How feasible is BRI for reconciling land use conflicts across the urban-rural interface?” An original structure of the analysis is developed based on the identification of three types of conflicts, namely, conflicts over land use structure, conflicts over land conversion and conflicts over landscape pattern. According to the interactions and relationships among these conflicts, we define broad categories of land use conflict areas. Indeed, these conflicts are all related to the unplanned use of agricultural land reserves, which competes with other more immediate uses, and the over-exploitation of land resources caused by unsustainable urban practices. This policy is clearly a critical objective for optimizing the land use structure. It, however, fails to reconcile the conflicts over land conversion and landscape pattern, especially for considerable agricultural land conversion to non-agricultural uses, and low-density development pattern with mixed residential and industrial land uses. Hence, alternative strategies involving public participation, spatial equity, rural revitalization, land-use system reform, and new type of urbanization, can be identified as viable solutions for land use conflict management, which may be complementary to regional integration. The findings of our paper may also contribute to the policy debate on BRI concerning land use planning and regional sustainability.
Integrated geophysical-petrological modelling of the Eifel region
Authors: Wansing Agnes , Ebbing Jörg , Bredow Eva
Published: March 2020

We present an integrated geophysical-petrological model of the Eifel region. The Eifel is a volcanic active region in West Germany that exhibits Tertiary as well as Quaternary volcanism. One suggestion for the source of this volcanism is a small-scale upper mantle plume.

The 3D model includes the crust and upper mantle and was generated by combined modelling of topography and the gravity field with constraints from seismology and geochemistry. In the best-fit model, the subcontinental lithospheric mantle is associated with a Phanerozoic-type composition, resulting in a depth of 80 km for the lithosphere-asthenosphere boundary (LAB) beneath the Eifel and in comparison 110 - 130 km beneath the Paris basin. A Proterozoic-type composition in contrast results in a LAB depth of 120 km in the Eifel. While the model fits the geophysical observables and features a thin lithosphere, it does not lead to a plume-like structure and does not feature a seismic low-velocity anomaly.

The measured low-velocity anomaly can be reproduced by introducing (1) an even thinner lithosphere or (2) a plume-like body above the thermal LAB with a composition based on data from Eifel xenoliths, which have a mainly basanitic composition. This additional structure results in a thermal anomaly and has an effect on the isostatic elevation of c. 360 m, but it does not result in a significant signal in the gravity anomalies. Further modelling showed how crustal intrusions could additionally mask the gravitational effect from such a small-scale upper mantle plume.

The model does not conclusively explain the source of the Eifel volcanism, but the models and the calculation of synthetic dispersion curves help to assess the possibility to resolve a small-scale upper mantle plume with joint inversion in future analysis.
On the modified Circumpolar Deep Water upwelling over the Four Ladies Bank in Prydz Bay, East Antarctica
Authors: Liu Chengyan , Wang Zhaomin , Cheng Chen , Liang Xi , Wu Yang , Li Xiang , Liu Yu , Yuan Xiaojun
Published: March 2020

We report on mooring observations of tidal currents in Prydz Bay, East Antarctica. Tides in Prydz Bay are mixed diurnal-semidiurnal and much weaker than that in the Ross Sea and the Weddell Sea, with the spatial and temporal averaged value of 2.58 cm s-1 for all the current meter observations over the continental shelf. The major axes of the tidal ellipses are generally aligned south-north, probably steered by the topography. The tidal phases are modulated by both the baroclinic and barotropic tidal components. The averaged tidal kinetic energy can account for a fraction of ~13% with respect to the total kinetic energy at the Amery Ice Shelf calving front during the observing period. The long-term average tidal heat flux across the Amery Ice Shelf calving front is negligible, but the ratio of the tidal heat flux standard deviation to the residual heat flux standard deviation can be up to 41%. We also report on borehole observations of tide-like pulsing of potential temperature and salinity, indicating the indispensable tidal influences in the ice-ocean boundary layer. These mooring and borehole data support that the tidal processes should be highlighted in the investigations of the interaction between the Amery Ice Shelf and ocean.
Release rate estimation of both long- and short-lived radionuclides for the Fukushima Daiichi nuclear accident based on local-scale observations
Authors: Fang Sheng , Li Xinpeng , Zhuang Shuhan
Published: March 2020

Many efforts have been devoted to estimate the release rate of the radionuclide emission in the Fukushima Daiichi nuclear accident using regional scale observations. Because of the radioactive decay, regional scale observations may not provide information of short-lived radionuclides, which contributes the majority of radiation exposure in the early stage. In this study, the local-scale gamma dose rates data were used to estimate the atmospheric release rates of both long- and short-lived radio nuclides.The proposed method uses reactor physics to obtain an a priori radionuclide composition and a reverse source term estimate as an a priori release rate. A weighted additive model is developed, which uses the local-scale gamma dose rates to handle the conflicts between the two priors and to simultaneously incorporate them into the source inversion. The proposed method is validated against both the local-scale gamma dose rates and the regional concentration measurements of Cs-137. The results prove that the retrieved a posteriori source term combines the advantages of both priors and substantially improves the predictions of the on-site gamma dose rates. Given a detailed priori release rate, this approach also improves the regional predictions of both airborne and deposited Cs-137 concentrations.
A gauss-function based approach for flood control capacity assessment of integrated green and grey infrastructure
Authors: Wang Jia , Liu Jiahong , Wang Hao , Mei Chao
Published: March 2020

Under the background of climate change and rapid urbanization，the risk of urban flood is increasing across the globe. To alleviate the urban flooding problems, the sponge city strategy has been proposed in China. The urban flood control system based on sponge city is gradually formed, which is an integrated system composed of green and grey infrastructure. However, mechanism of the corresponding flood control function and corresponding quantitative assessment of flood control capacity of the integrated green and grey infrastructure is relatively lacking. Based on polit sponge cities in China, this study summarized and put forward the construction mode of urban inundation control system of sponge city, including source control system, stormwater pipe network system, over-standard stormwater storage and drainage system, etc., identified the mechanism of urban flood control functions of urban flood control system, including detaining, releasing, peak rate cutting, peak rate delaying and discharging the stormwater runoff. Furthermore, a gauss-function based approach for quantitative flood control capacity assessment of integrated green and grey infrastructure was established. This study builds the relationship between the gauss function and mechanism of urban flood control capacity, according to the mathematical meaning of parameters of the gauss function. It provides a new method for urban flood control capacity assessment of the integrated green and grey infrastructure.
Future changes in high-impact events in pan-European convection-permitting projections
Authors: Kendon Elizabeth , Chan Steven , Berthou Segolene , Manning Colin , Kahraman Abdullah
Published: March 2020

At the UK Met Office we have recently completed climate change simulations at convection-permitting resolution (2.2km grid scale) across a pan-European domain, which are feeding into the CORDEX-FPS and European Climate Prediction System (EUCP) projects. At such high resolution, the model gives a much better representation of convection and is able to capture hourly precipitation characteristics, including extremes, as well as better representing the influence of mountains, coastlines and cities. In this talk, I will present results from these new convection-permitting climate simulations, looking at future changes in high impact events, including hourly precipitation extremes and severe winds. I will also discuss remaining outstanding issues, such as the deficiencies in land-surface-atmosphere coupling, and work underway to try and address these.
Multiproxy records on the fluvial successions of Assam-Arakan Basin: Implication for paleo-drainage evolution
Authors: Rai Priti , Borgohain Biraj , Mathew George
Published: March 2020

Assam-Arakan Basin comprises Cenozoic sedimentary successions, located in northeastern India is juxtaposed to both the Himalaya and Indo-Burman Ranges (IBR). The Upper Miocene-Pliocene (Tipam sandstone) and the overlying younger Upper Pliocene-Pleistocene units (Dupi-Tila/Namsang/Dihing) of this foreland basin are fluvial successions. Heavy mineral as detritus provenance indicator has been used as one of the multiproxy records on the fluvial sequences of Assam-Arakan Basin to unravel the drainage system that deposited the same in this basin. Previous workers have advocated that the paleo-Brahmaputra river had initially flowed east of Shillong Plateau before being deflected northwesterly taking the present-day course parallel to the Plateau. However, unequivocal evidence of paleo-Brahmaputra remains enigmatic. The study demonstrates the provenance for the fluvial sedimentary units of the above foreland basin using petrography and heavy mineral distributions. X-ray Diffraction (XRD) and Electron Probe Micro Analyzer (EPMA) analyses were employed to correctly identify the heavy mineral species and support the semi-quantitative analysis of heavy minerals in the basin. The outcome of the study provides new insights towards the paleo-drainage evolution of the river course accountable for the fluvial sedimentation in the Assam-Arakan Basin. Clast petrography and heavy mineral observations indicate the probable source from Lohit- Dibang valley. Initial analysis of detrital zircon U-Pb ages from studied samples reveals major age peaks at around 500 Ma and 1025 Ma with young ages between 16 Ma and ~140 Ma. These samples do not provide ages < 10 Ma, signifying the sediments not derived from Namche Barwa massif, eroded by the Tsangpo-Siang-Brahmaputra river system. It is in contrast to similar sediments in the Siwaliks of NE Himalaya. The data supports our observation that the paleo-Brahmaputra seems not the cause for these deposits, at least during the Pleistocene. If Paleo-Brahmaputra got diverted during this period, it requires scanning the detritus from Tipam units and additional samples from Dupi-Tila/Namsang/Dihing units across the entire Assam-Arakan range to infer source and drainage system for these deposits. We tentatively propose that the Tipam and the younger Dupi-Tila/Namsang/Dihing units in the Assam-Arakan Basin were deposited by drainage flowing from Dibang-Tezu valley, that was initially linked to the Irrawaddy river system. The uplift along Naga thrust caused drainage migration, eventually meeting the present-day Brahmaputra course.

Keywords: Heavy mineral; Detrital zircon U-Pb ages; Paleo-Brahmaputra; Assam-Arakan Basin