bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence of deformation control on the P-T record in compositionally heterogeneous shear zone during subduction-exhumation cycle
Authors: Maino Matteo , Casini Leonardo , Corvò Stefania , Langone Antonio , Schenker Filippo , Seno Silvio
Published: March 2020

Pressure-temperature paths are a major tool for tectonic reconstruction as proxies of the burial and exhumation history of the rocks during subduction-exhumation phases. The mineral assemblages are commonly considered to reflect lithostatic pressure and near-equilibrium regional geothermal gradients. These axioms ground on the assumptions that the rock cannot support high differential stress in one place, and that heat diffusion in rocks is fast enough to defocus localized thermal anomalies, respectively.

The rare but systematic occurrence, in actual mountain ranges, of ultrahigh-pressure and/or high-temperature rocks within lower grade metamorphic rocks rise a major challenge for developing a consistent geodynamic model for exhumation of such deep seated rocks. Subduction zones are, in fact, efficient player driving material from the surface down into the Earth's mantle. However, the mechanisms to exhume part of this material (and particularly the denser oceanic rocks) back to the shallow crust are still highly debated.

In this contribution, we present new structural, petrological and thermochronometric data from an exhumed subduction zone - the Cima di Gagnone in the Central Alps– where small ultramafic inclusions (peridotite) preserving high temperature and high pressure record are enveloped within amphibolite-facies gneisses, defining a classical inclusion-in-matrix system. We found evidence of heterogeneous metamorphic and temperature records in both peridotite and felsic rocks, being the gneisses generally characterized by much lower pressure. However, we detect also in the matrix gneiss close to peridotite inclusions high-pressure and high-temperature remnants, which are structurally and temporally associated with those of ultramafic bodies.

The coexistence, at the outcrop scale, of such different conditions implies either extreme mechanical decoupling or extremely variable metamorphic equilibrium during Alpine subduction and exhumation. A possible alternative explanation is to consider part of the metamorphic record as due to mechanical deviations from lithostatic pressure and equilibrium temperature. We compare the observed metamorphic pattern with the outcome of numerical simulations obtained from elasto-visco-plastic 2D Finite Difference models. The evolution of rocks strength and viscosity is furthermore monitored to control the effectiveness of physical conditions simulated with the analytical dataset. Finally, we discuss a possible positive feedback of tectonic stress on the development of apparently incompatible metamorphic patterns.
Role of support practices for minimizing the vulnerability of land degradation in sub-tropical India: positive and negative impacts on land resources
Authors: Chakrabortty Rabin , Chandra Pal Subodh
Published: March 2020

In the period of globalization, India a subtropical region, presently facing the acute problem of land degradation and it has severe impact on earth ecosystem as well as economy in defectively. Where India is a most populated agricultural based country, need a large volume of food grain production to control starvation condition with balancing between the need of the population and production yield. Though the conversion of fallow and forest cover area to agricultural land is increasing day by day but due to the people’s daily needs and rapid growth of settlement is capturing productive land and ultimately amount of agricultural land remains in static. Thus, such consequent processes are declining soil fertility and land degradation have been witnessed in different forms of erosion as like sheet, rills, gullies, ravines etc. with the passage of time non tillage farming practices are accreting by replacing the tillage farming for maximizing the rate of production which causes the large scale soil erosion and make a source of sedimentation. The government and local stakeholders are already taken some initiatives for reduction of land degradation by some support practices with considering both structural and non-structural measures. The structural measures especially the engineering construction (check dam, percolation tank etc.) are installed or constructed without considering eco-centric approach.

The current research work has focused the light to evaluate the positive and negative impact of support practices on land resources. This study is mainly conducted on the basis of empirical field observation in different parts of the India. For reducing the rate of soil erosion, the plantation programme has been initiated and still going on as an accepted scheme. This valuable programme has been committed through the plantation of traditional vegetation and external species (Acacia auriculiformis, Eucalyptus globulus). The introduction of external species which are not only changing the properties of soil but also demolishing the soil fertility and soil moisture to cause land degradation. The local administrations are providing this type of external species for plantation programme without making the consciousness about the heath of environment.

Key Words: subtropical region; conversion of fallow; land degradation; structural measures; plantation programme
Estimating submarine groundwater discharges of the Bohai Sea, China using radium, hydrogen and oxygen isotopes and salinity
Authors: Li Hailong , Zhang Xiaolang , Wang Xuejing , Xiao Kai , Zhang Yan , Jiao Jiu Jimmy
Published: March 2020

With an area of about 77,000 km2, the Bohai Sea includes three bays: Laizhou Bay, Bohai Bay and Liaodong Bay. In this study, 228Ra, δD, δ18O and salinity data were collected from surface seawater in the entire Bohai Sea, river water, and groundwater along its coastline in August 2017. Based on the spatial distributions of δD, δ18O, and salinity in surface water in the entire Bohai Sea and δD-salinity relations, the marine hydrological processes were investigated and the members of river water and groundwater for δD and δ18O were determined. The steady-state mass-balance models of δD, δ18O and salinity are given and used to estimate submarine fresh groundwater discharges and the flushing times of the entire Bohai Sea and its three bays. Based on the results of the flushing times, the steady-state mass-balance model of 228Ra is used to estimate submarine groundwater discharges of the entire Bohai Sea and its three bays.
The GEANT4 simulation of PKU Solar Electron and Ions Telescope
Authors: Yu Xiangqian , Huang Xin , Wang Linghua , Shi Weihong , Wang Yongfu , Fu Haobo , Liu Zixuan
Published: March 2020

The Solar Electron and Ion Telescope (SEIT), proposed by Peking University for a L1 non-spinning spacecraft mission, is designed to provide Omni-directional investigation of Solar energetic electrons and Ions with good time, energy and angular resolution. SEIT consists of multi group two dual double-ended magnet/foil particle telescopes which cleanly separate and measure electrons in the energy range from 50–400 keV and Ions from 60–7000 keV expected to be including protons, C and O. The multi group particle telescopes can cover the Omni-directional space. Each two dual double-ended magnet/foil particle telescopes set-up refers to the detector stack with view cones in two opposite directions: one side (electron side) is consisted of a 300um and a 500um Silicon detector whose distance is only 100um to chive a high performance, the 300um Silicon is on the front and covered by a 5um thin parylene foil to leave the electron spectrum essentially unchanged but stops low energy Ions, the other side (Ions side) is consisted of a 100um and a 500um Silicon detector whose distance is only 100um to chive a high performance and the front of the telescope is surrounded by a magnet to sweep away electrons but lets ions pass. The dead layer of the detector is only 100 Å and each detector is divided into five pixels to chive a high angular resolution. The time resolution is 1s. Simulation shows that the maximum counts of the 20 pixels can reach to 2452, while the minimum energy deposition of the 20 pixels is 300 keV. We now describe the design and GEANT4 simulation of SEIT.
Rift propagation vs inherited crustal fabrics in the Trans-Mexican Volcanic Belt (Mexico): insights into geothermal investigations from analogue models
Authors: Maestrelli Daniele , Bonini Marco , Corti Giacomo , Montanari Domenico , Moratti Giovanna
Published: March 2020

The Trans-Mexican Volcanic Belt (TMVB) is a large-scale, NW to SE trending volcano-tectonic feature extending through central Mexico for a length of more than 1000 km. In some models, its genesis is related to the interaction between the subducting Rivera and Cocos plates and the North America plate, with the eastward propagation of volcanism being associated with slab detachment and consequent asthenospheric upwelling (e.g., Ferrari, 2004). Progressive SE-directed slab tearing has been causing crustal extension and the emplacement of large-scale volcano and caldera edifices. In the frame of the GEMex Europe-Mexico cooperation project (Horizon 2020 Programme, grant agreement No. 727550), we aim to investigate the interplay between continental extension and inherited crustal fabrics. Particularly, in the easternmost part of the TMVB, where the GEMex Project is focusing geothermal investigation on two calderas (Los Humeros and Acoculco), the inherited fabric is represented by ca. NE-SW and NW-SE regional faults (Campos-Enriquez & Garduño-Monroy, 1987). This fabric may have localized volcanic centres, thereby bearing significant implications for geothermal investigation. We aim to evaluate if and how the inherited structures may have interacted with continental-scale rift propagation through analogue modelling. In the models, the upper continental crust was simulated by a Qz- and K-feldspar sand mixture (80%-20% proportion in weight), while a PDMS-corundum mixture reproduced the lower crust. Continental rift propagation was simulated using a deformation apparatus represented by two basal moving plates hinged at their topmost side, allowing rotational opening. Extensional deformation was distributed using a basal rubber sheet. Artificial dilation zones (simulating the inherited fabrics) have been introduced within the analogue brittle crust at various angles to the rift axis. Our modelling highlights that a propagating rift may reactivate the inherited fabrics as extensional structures or transfer zones (depending on their orientation) for angles ≤45° to the rift axis. Numerical analysis of slip and dilation tendency evaluated for the reactivated fabrics corroborate the modelling results, and suggest that they may represent favourable sites for magma emplacement, and ultimately for geothermal exploration.

Campos-Enriquez, J., & Garduño-Monroy, V. H. (1987). The shallow structure of Los Humeros and Las Derrumbadas geothermal fields, Mexico. Geothermics, 16(5-6), 539-554.

Ferrari, L. (2004). Slab detachment control on mafic volcanic pulse and mantle heterogeneity in central Mexico. Geology, 32(1), 77-80.
Gaussian process regression for spatiotemporal analysis of groundwater level variations.
Authors: Varouchakis Emmanouil A , Karatzas George P
Published: March 2020

In geostatistical analysis a Bayesian approach has more advantages over classical methods since it allows to deal with the parameters and the uncertainty in the model. Spatiotemporal geostatistical modelling can be performed by using the Gaussian process regression method under a Bayesian framework. In a Bayesian approach the overall uncertainty can be represented by a probability distribution. In this work the groundwater level spatiotemporal variability was assessed based on a ten years’ time series of biannual average data from an extensive network of wells in the island of Crete, Greece. The Gaussian process regression method was employed to produce reliable maps of groundwater level variability and to identify groundwater level patterns for the island of Crete. Thus, this work could help to detect areas where interventions of groundwater management are necessary considering the associated uncertainty.
Enhanced latent heat flux with moisture disequilibrium during rapid intensification of the strongest supertyphoon Mangkhut in 2018
Authors: Kang Sok Kuh , Landwehr Sebastian , Kim Eun Jin , Kim Kyeong Ok , Park Jae Hyoung
Published: March 2020

A summertime field survey in 2018 has been carried out to investigate the air-sea interaction over warm eddy in the Northwest Pacific. The strongest Supertyphoon Mangkhut in the Northwest Pacific got rapidly intensified from 80 kts to 120 kts during Sep.10, 2018, and it lasted as category 5 typhoon during Sep. 11 to 14. The maximum wind speed during intensification reached 100 kts on Sep.10. At distance 500 km off typhoon track the observations by sensors equipped on wave gliders were carried out in order to measure air-sea interaction parameters, as well as using instruments equipped on research vessel Isabu.

During the intensification of typhoon Mangkhut the enhanced bulk latent heat fluxes (LHF) were estimated over the several days. The latent heat flux was estimated from gust wind and 1 minute mean parameters. Peak LHF from gust wind reached over 1,100 W/m2, while 1 minute mean LHF reached about 900 W/m2. Data analysis reveals that the enhanced heat flux appears to exist due to an increase in moisture disequilibrium between the ocean and atmosphere. This supports the hypothesis that enhanced buoyant forcing from the ocean is likely to be an important mechanism in tropical cyclones over warm oceanic mesoscale eddy (Jaimes et al., 2016).

This work was supported by the project of “Study on air-sea interaction and process of rapidly intensifying typhoon in the Northwestern Pacific” funded by the Ministry of Ocean and Fisheries, Korea,
Characterizing large-scale circulation triggering heavy precipitation amounts over the northern French Alps
Authors: Blanc Antoine , Blanchet Juliette , Creutin Jean-Dominique
Published: March 2020

Large-scale circulations (LSCs) explain a significant part of Alpine precipitations. Characterizing circulations triggering heavy precipitation is usually done using weather-type classifications. A different characterization is implemented here, based on analogy using the atmospheric descriptors proposed in Blanchet et al 2018, 2019. These descriptors are both related to the dynamics of LSC and to their relative position in the atmospheric space. This work is applied to the Isère river catchment for the 1950-2011 period, considering a 3-day time step. The 500 hPa and 1000 hPa geopotential heights covering part of the western Europe are used separately to represent LSC. Two analogy criteria are investigated for constructing the atmospheric descriptors, namely TWS and RMSE.

Our results reveal that LSCs triggering heavy precipitation amounts correspond to strong geostrophic wind with quasi constant direction during the three days, corresponding to blocking situations in altitude. Moreover, those patterns of circulation are among the least singulars, and they show the highest degree of clustering in the atmospheric space. We interpret the latest results by the fact that heavy precipitation LSCs feature twin circulation patterns. In addition, the 500 hPa geopotential height appears to discriminate better heavy precipitation situations than the 1000 hPa one. Finally, our work points out the benefit of a combined use of TWS and RMSE. TWS gives information about the direction of geostrophic wind, while RMSE -combined with TWS- informs about its strength.

References:

Blanchet, J., Stalla, S., and Creutin, J.-D. (2018). Analogy of multi-day sequences of atmospheric circulation favoring large rainfall accumulation over the French Alps. Atmospheric Science Letters.

Blanchet, J., Creutin, J-D. (2019). Modelling rainfall accumulations over several days in the French Alps using low-dimensional atmospheric predictors based on analogy. Journal of Applied Meteorology and Climatology.
Biological lability of Dissolved Organic Matter released by phytoplankton
Authors: Bachi Giancarlo , Morelli Elisabetta , Gonnelli Margherita , Casotti Raffaella , Vestri Stefano , Evangelista Valter , Balestra Cecilia , Santinelli Chiara
Published: March 2020

Phytoplankton is the primary source of Dissolved Organic Matter (DOM) to the oceans. DOM is mainly released by extracellular exudation and used by heterotrophic prokaryotes to synthesise biomass and recycle inorganic nutrients. DOM released by phytoplankton is mainly composed by carbohydrates, proteins and lipids that are thought to be labile and by humic substances that are thought to be recalcitrant and thus resistant to bacterial degradation. There are a lot of uncertainties regarding the biological lability of exudates and the role of DOM released by phytoplankton in the marine carbon cycle. In this study, cultures of the diatom P. tricornutum were produced under axenic conditions and Dissolved Organic Carbon (DOC) concentration, Excitation-Emission matrices (EEMs) and cell density were measured with time in order to follow the release of DOM during the different growth phases. Exudates were then inoculated with a marine microbial community for 24 days, DOC removal and FDOM transformation were followed with time in the exudates and in the permeate (< 3k Da; Low Molecular Weight, LMW) and retentate (> 3k Da; High Molecular Weight, HMW) fractions. Heterotrophic prokaryotes abundance was also followed during the incubations. Our results show that ~75% of the total DOC pool was LMW. After 24 days, 28% of the initial DOC pool was removed. Fluorescence indicate high lability of protein-like molecules and degradation of bigger proteins into smaller peptides before their removal. The production of humic-like and flavin-like substances was also observed.

 
Geomorphological and ecological characterization of a hard-substrate complex in a temperate shallow shelf sea (SE North Sea) using hydroacoustic sensors and machine learning algorithms
Authors: Michaelis Rune , Sander Lasse , Mielck Finn , Papenmeier Svenja , Hass H. Christian
Published: March 2020

The North Sea is a shallow marine environment. The sediment distribution of the seabed is dominated by sand-sized material. Hard-substrate areas are a relatively rare, but important habitat for sessile and mobile species. This habitat type forms island-like geomorphic features owing to the presence of glacial deposits in the shallow subsurface. While their ecological importance is widely acknowledged, hard-substrate areas are characterized by a large degree of spatial heterogeneity and an unaccounted high local diversity in physical surface properties, sediment composition and temporal change.

The aim of this study is the detailed investigation into the spatial characteristics and temporal variability of an exemplary hard-substrate complex located 10 km offshore the island of Sylt (N-Germany). The area has a size of c. 3 km2and was investigated between 2008 and 2019 using a range of hydroacoustic and optical sensors (multibeam echosounder, sidescan sonar, sub-bottom profiler, acoustic ground discrimination system, underwater videos) and machine learning algorithms (haar-like features) to track the changes in the number and local distribution of exposed stones.

The maximum water depth in the area is 16 m and a linear arrangement of hard substrates emerges up to 4 m from the seabed. A layer of fine sand with a thickness of 0.5 m overlays the more planarly deposited coarse sediments in the proximity of the stony outcrop. This layer of fine sand is relatively mobile and leads to a frequent temporal change of the distribution of sediment on the seabed, whilst the stony outcrop is only marginally affected by the spatial dislocation of sediments. The spatial extent of hard substrates is variable due to the presence of a mobile sand cover on the seabed.

This study emphasizes the need for quick and automated object classification routines to be integrated in monitoring approaches in the highly dynamic coastal zone. It has shown that the geomorphological diversity and interannual variability of hard-substrate areas can be captured using the presented approach. Detailed studies and monitoring tools are important to better understand the interrelation of geomorphological and sedimentary processes at the seabed with the ecology of epibenthic organisms.

Keywords: North Sea; hard-substrate habitats; mobile sediments; hydroacoustic; haar-like features
Assimilating the SCATSAR-SWI with SURFEX for a high-resolution European soil moisture product
Authors: Vural Jasmin , Schneider Stefan , Bauer-Marschallinger Bernhard , Haslinger Klaus
Published: March 2020

Due to manifold land-atmosphere interactions, soil moisture is an essential part of the energy-water cycle. Especially when the incoming solar radiation is high, large effects of soil moisture onto the lower atmosphere can be expected. In addition, the knowledge of large-scale soil moisture fields is important for other applications, e.g., in hydrology and agriculture. Remotely sensed soil moisture products provide information on global scales, continuously yielding better quality as well as higher spatial and temporal resolution. The ingestion into data assimilation systems propagates the obtained information in time and – via subsequent modelling – onto other physical variables.

By the assimilation of a high-resolution soil moisture product, we aim to develop a high-level soil-moisture product for Europe and to provide an improved surface initialisation for the NWP model AROME. Our focus is on fully exploiting the high spatial resolution (1 km) of the multi-layer fused soil-moisture product SCATSAR-SWI. For assimilation, we use the surface model SURFEX, which employs a simplified Extended Kalman Filter and the multi-layer diffusion scheme ISBA-DIF. We ran the assimilation system on different resolutions and found an improvement of the forecast metrics of the 2 m temperature and 2m relative humidity using higher resolution systems. In addition, we use the water balance as a reference measure for a domain-covering verification of the soil moisture analysis.
The impact of rainstorms on nutrient loading for a large and deep reservoir
Authors: Li Huiyun , Luo Liancong , Zhang Yiming
Published: March 2020

A main cause of water eutrophication in lakes or reservoirs are nutrient enrichment, of which variations can be influenced by climatic changes and anthropogenic activities. It was reported that rainfall may lead to a short-term increase in nutrients that threaten the water quality of lakes or reservoirs. Daily meteorological data collected over the last few years in the Lake Qiandaohu basin highlight an increase in the frequency of extreme rainfall events. The relationships between nutrient (nitrogen and phosphorus) concentrations in the lake and external loading discharged into the lake during 2013-2016 were analyzed. Meanwhile, the fluid movement and the diffusion of the pollutants from the catchment were simulated by the ELCOM model. These were in order to evaluate the possible role of extreme precipitation events in affecting the nutrient availability in the lake. Our results show that, for the largest inflow (the Xinanjiang River), 32.5% of annual TN and 32.8% of annual TP were caused by rainstorm, respectively. The time of pollutant migration could be greatly shortened by heavy rains. For lakes and reservoirs, extreme precipitation will not only lead to a sharp increase in inflow but also result in a significant increase in nutrient loading in a short period of time. Therefore, rainstorms can be an important factor of climate-induced eutrophication in lakes or reservoirs.
Water Governance 2.0: A Review and Second Generation Research Agenda
Authors: Araral Eduardo
Published: March 2020

Water scholars and practitioners generally agree that improving water governance is the key to addressing water insecurity in developing countries. We review the literature on water governance in the last decade and argue for a second-generation research agenda, which pays more attention to the study of incentive structures, is multi and inter-disciplinary in orientation and with clear policy implications. We then illustrate how theories drawn from public economics, new institutional economics, political economy and public administration can help diagnose the challenges of integrated water resources management, improving efficiency of water utilities, privatization of utilities and public-private partnerships, water pricing reforms, virtual waters / water trading, among others. We conclude that these tools can help advance the second-generation research agenda on water governance.
Causes of the 1985-2014 Surface Warming over the Sanjiangyuan Region of the Tibetan Plateau from the Perspective of Energy Transport
Authors: Tian Yinglin , Zhong Deyu
Published: March 2020

The Tibetan Plateau (TP), known as the “World Roof”, has significant influences on hydrological and atmospheric circulation at both regional and global scale. As the Sanjiangyuan Region (SJY) supplies water resources to the adjacent river basin and the TP could exert strong thermal forcing on the atmosphere over Asian monsoon region, adequate understand of the climate change over this region and its underlying mechanisms is of great importance. Based on gridded data provided by China Meteorological Administration (CMA), a continuous warming trend higher than that over elsewhere in China has been observed over the TP during 1985-2014, especially in the cold season (0.69 K/decade) and over the SJY (1.0 K/decade). On the basis of ERA interim reanalysis datasets, this paper analyzed the factors facilitating this warming trend in the SJY from the perspective of energy transport. At first, the local processes involved were investigated by calculating partial temperature changes using the surface energy budget equation. Then the horizontal convection of heat was quantified by summing the heat flux across the boundaries of the SJY. Finally, a Lagrangian heat source diagnostic method was developed to identify the major heat source. As the results indicating, among all the local heat sources, the enhanced downward longwave radiation reflected to surface air and the increasing upward longwave radiation emitted by warmer land surface were responsible for the pronounced surface air warming. However, the changes in surface sensible and latent heat fluxes had a reduced warming effect on the surface air. As for the non-local horizontal heat sources, rising horizontal heat flux from the south, west and east boundaries into the SJY contributed to the higher surface temperature of the SJY. In winter season, the heat flows stemmed from the South Himalayan vein into the SJY played a dominant role. Moreover, the higher the temperature over the SJY was, the more inclined this heat source was to Nepal.
Stability of the gravel-sand transition of the Ganga Plains recorded in Siwalik stratigraphy; implications for extreme floods
Authors: Quick Laura , Sinclair Hugh , Attal Mikael , Sinha Rajiv , Kumar Rohtash
Published: March 2020

Many rivers of the Indo-Gangetic Plain are prone to abrupt switching of channel courses causing devastating floods over some of the world’s poorest and most densely populated regions. Recent work has identified the gravel-sand transition as an avulsion node for the channels; notably the avulsion of the Kosi River in 2008 occurred in close proximity to its gravel-sand transition. The gravel-sand transition is a geomorphic feature observed within all major mountain-fed, and smaller foothill-fed Himalayan rivers ranging from 10 to 20 km downstream from the mountain front. It is characterised by an abrupt downstream reduction in grain size from gravel to sand and is often associated with a break in channel gradient, which suggests it is a relatively stable feature over the last few thousands of years.

However, new subsurface data from the Kosi mega-fan in eastern Nepal reveals 10-20 Ka gravels located ~50 km downstream from the current gravel-sand transition. The implication is that this key geomorphic boundary can periodically prograde considerably further into the Ganga Plains. A greater long-term (>106 yrs) understanding of the controls on the gravel-sand transition is achieved by studying the stratigraphic record of the Miocene Siwalik Group, which is exhumed as a series of thrusted fault blocks at the Himalayan mountain front. The Siwalik succession is divided into three lithofacies units that coarsens upwards from siltstones and sandstones to coarse conglomerates. The units are termed the Lower, Middle and Upper Siwaliks respectively and reflect the current depositional environments found on the Ganga Plains.
The gravel-sand transition is recorded as the contact between the Middle and Upper Siwaliks. Significant gravel pulses have been identified directly below the Middle to Upper Siwalik contact and suggests that the gravel-sand transition is indeed mobile and can episodically prograde far into the plains. Sedimentological characteristics of the gravel pulses and sediment entrainment calculations suggest that extreme events (e.g. enhanced monsoon, earthquakes and GLOFS) can force gravel far into the Ganga Plains, impacting the position the gravel-sand transition. These episodes of distant gravel progradation must represent extreme floods from which the sedimentological system must take many years to recover. Such events are beyond the historic timescales of human narrative, and hence have not been recognised as a risk to the populations of the plains.
Impact of MODIS land cover data on surface predictions over Taiwan in the FV3GFS model
Authors: Hsiao Ling-Feng , Wang Feng-Ju
Published: March 2020

The global numerical weather prediction (NWP) system based on the FV3GFS model jointly developed by U.S. National Centers for Environmental Prediction (NCEP) and Geophysical Fluid Dynamics Laboratory (GFDL) has been implemented in the Taiwan’s Central Weather Bureau (CWB) forecast system for the next generation global NWP operations. Currently, NCEP FV3GFS model provides land use dataset retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations. The MODIS 20-category data is composed of roughly 12 km resolution data elements. However, the modified of the 20-class MODIS land cover dataset with a resolution of 500 m which defined by the International Geosphere-Biosphere Program (IGBP) is provided by WRF model. A significant difference between these two datasets is MODIS data from NCEP FV3GFS as being extremely urbanized in western Taiwan. In a case of weaker synoptic-scale forcing, the modified MODIS land cover dataset from WRF model result in a larger improvement in 2-m temperature and 2-m mixing ratio when compare to the surface observations over Taiwan. The reason results from the overestimation of urban area in NCEP FV3GFS model, which contains previous and low-resolution MODIS dataset. Moreover, there is a bias reduction in 10-m wind speed as well as thermal effects. The detailed results will be presented in the conference.
Russian Lunar Landers Luna-25 and Lna-27: goals of the missions and scientific investigations at Moon Polar Regions
Authors: Tretyakov Vladislav , Mitrofanov Igor , Zeleniy Lev
Published: March 2020

Scientific goals, current status and nearest plans for Russian Landers missions with Luna-25 (project Luna-Glob) and Luna-27 (project Luna-Resource) will be presented. Both projects aimed on search for volatiles and water ice in upper layer of regolith, study structure and content of regolith and investigate of Moon’s near-surface dust and plasma exosphere at lunar polar regions.

The scientific experiments which were selected in accordance to the main goals of these missions, will be described. Main and spare landing sites for Luna-25 will be presented selected on the base both of engineering suitability (flatness and roughness of surface, radio visibility, solar irradiation and so on) and of scientific motivation. Criteria for landing sites selection for Luna-27 will be discribed shortly too. The plan of surface operations during the first lunar days for Luna-25 and Luna-27 will be presented and discussed.

The content of international cooperation for Luna-25 and Luna-27 missions will be described.

It will be shown that Luna-25 and Luna-27 shell provide the necessary scientific and technological ground for future long life-time Landers at the Moon polar regions.
Quantitative Estimates of Holocene Glacier Mass Fluctuations on the Western Tibetan Plateau
Authors: Hou Juzhi
Published: March 2020

Knowledge of the alpine glacier mass fluctuations is a fundamental prerequisite for understanding glacier dynamics, projecting future glacier change, and assessing the availability of freshwater resources. The glaciers on the Tibetan Plateau (TP) are sources of water for most of the major Asian rivers and their fate remains unclear due to accurate estimates of glacier mass fluctuations are lacking over long time scales. Here, we used d18O record at a proglacial open lake as proxy to estimate the Holocene glacier mass fluctuations in the Western Kunlun Mountain (WKM) quantitatively and continuously. Relative to past decades, maximum WKM glacier mass loss (-28.62±25.76 Gt) occurred at 9.5-8.5 ka BP, and maximum glacier mass gain (24.53±25.02 Gt) occurred at 1.3~0.5 ka BP, the difference in WKM glacier mass between the two periods account for ~20% of the total glaciers. Long-term changes in glacier mass suggests the TP glaciers likely face severe threats at the current rates of global warming.
Analysis and Construction of Geodetic Data Classification Standard
Authors: Wang Yongshang
Published: March 2020

The new geodetic technology system characterized by high precision, real-time and popularization has gradually formed in the wave of new technological revolution. Taking advantage of modern information technology，the new geodetic technology system has new features for technology sharing and data sharing, in which geodetic data and positioning applications and geodetic applications can meet the requirements of real-time, public-sharedand interactivity. Geodetic Data Standards are the cornerstone in process of geodetic informationization, which describes scientifically the geodetic data processing, management and service, as well as the theory, methods and procedures used for implementation. Along with the development of geodetic informationization, the width and depth of data standardization application will far exceed the level of traditional standardization. With the advancement of measurement technology, there are less technical constraints in the relatively simple instruments operation process while more complicated data structure to be analyzed, and the more urgent socialization services requirements to be met. The focus of geodetic standardization will shift from operational standards to data standards. In this paper, the content, characteristics, classification principles and methods of geodetic data are studied for the new characteristics of modern geodetic informationization.
Comparative analysis of land surface parameters on three typical underlying surfaces over the Tibetan Plateau
Authors: Ding Zhangwei , Ma Yaoming , Chen Xuelong
Published: March 2020

To improve land surface parameterizations of radiation and energy balance, eddy covariance measurements were performed on three typical land covers types over the Tibetan Plateau , including bare soil, naturally sparse alpine meadow and dense alpine grassland from 2007 to 2012. We investigated how land surface parameters changed with surface properties and vegetation canopy growth and analyzed the characteristics of diurnal and seasonal variations of aerodynamic parameters. Results show that the annual mean surface albedo and surface roughness lengths for momentum were 0.27 and 2.29 cm, 0.241 and 1.39 cm and 0.19 and 6.52 cm over bare soil, naturally sparse alpine meadow and dense alpine grassland areas, respectively. The yearly average turbulence transfer coefficients for momentum and sensible heat under neutral condition were 4.12×10-3 and 2.29×10-3, 4.11×10-3 and 2.33×10-3 and 6.67×10-3 and 4.14×10-3, respectively. The median values of κB-1 averaged over multiple years are 6.65, 5.89 and 4.88, respectively.
The case of distributed rainfall and spatially adaptive modeling
Authors: Loritz Ralf , Ehret Uwe , Neuper Malte , Zehe Erwin
Published: March 2020

How important is information about distributed precipitation when we do rainfall-runoff modeling on the catchments scale?

The latter is surely one of the more frequently asked research questions in hydrological modeling. Most studies tackling the issue seem thereby to agree that distributed precipitation becomes more important if the ratio of catchment size against storm size decreases or if the spatial gradients of the rainfall field increase. Furthermore, is it often highlighted that catchments are surprisingly effective in smoothing out the spatial variability of the meteorological forcing, at least, if the focus is simulation integral fluxes and average states.

However, despite these agreements there is no straightforward guidance in the hydrological literature when these thresholds have been reached and when the spatial distribution of the precipitation starts dominating. This is because the answer to the above drawn question depends on the spatial variability of system characteristics, on the system state variables as well as on the strength of the rainfall forcing and its space-time variability. As all three controls vary greatly in space and time it is challenging to identify generally valid rules when information about the distribution of rainfall becomes important for predictive modelling.

The present study aims to overcome this limitation by developing a model framework to identify periods where the spatial gradients in rainfall intensity are larger than the ability of the landscape to internally dissipate those. This newly developed spatially adaptive modeling approach, uses the spatial information content of the precipitation to control the spatial distribution of our model. The main underlying idea of this approach is to use distributed models only when they are actually needed resulting in 1) a drastic decrease in computational times as well as 2) in a more appropriate representation of a hydrological system. Our results highlight that only during a few periods throughout a hydrological year do distributed precipitation data actually matter. However, they also show that these periods are often highly relevant with respect to certain extremes and that the successful simulation of these extremes require distributed information about the forcing and state of a given system.
Chronology of strong winds based on documentary evidence in the Czech Republic from AD 1510
Authors: Dolák Lukáš , Brázdil Rudolf , Dobrovolný Petr , Valášek Hubert , Řezníčková Ladislava , Chromá Kateřina , Kotyza Oldřich
Published: March 2020

To develop an understanding of recent variability in strong winds, it is necessary to analyse their past behaviour. While relatively short series of wind-speed measurement in the Czech Lands (recent Czech Republic) started mostly in the first half of the 20th century, documentary evidence represents a valuable source of information helping extend the knowledge of strong winds to the pre-instrumental period. In this study, we analyse strong winds on the basis of chronicles, weather diaries, early journalism, economic and financial sources, as well as old academic journals, newspapers, professional papers and recent scientific papers. The created dataset presents a chronology of strong winds in the Czech Lands from AD 1510 to present. The dataset contains more than 5000 events, which are classified on duration, location, extent, severity and type of damage on squalls (convective storms), tornadoes, blizzards, gales and windstorms. Gales, often accompanied by loss of human lives, damage to buildings and forests (windthrows), are the most frequently recorded type of strong winds (44%), followed by blizzards (26%), squalls (18%), and tornadoes (7%). Strong winds detected are concentrated 1820s to late-1840s, 1900s to late-1930s and in the 2000s. Seasonal distribution of strong winds is relatively equal throughout the chronology with the highest frequency in July (10.0%), January (8.6%), and December (8.1%). Uncertainties in results emerge from a different spatiotemporal density of documentary data and from the ambiguous nature of some records in determining the classification of strong winds or attribution of damage caused to particular events. Our results highlight the importance of documentary evidence in the analysis of strong winds and contribute to a better understanding of their spatiotemporal variability in the past.
Combined rock-magnetic and colorimetric stratigraphy for a 430 ka- covering loess-palaeosol sequence in the vicinity of Belgrade, Northern Serbia
Authors: Laag Christian , Hambach Ulrich , Zeeden Christian , Jovanović Mladjen , Marković Slobodan
Published: March 2020

Quaternary palaeoenvironmental recorders are particularly in the Northern Hemisphere provided by loess-palaeosol sequences (LPSs). In the Middle Danube basin, these terrestrial archives cover the last million years (Markovic et al., 2015) of the climate history as well as archaeological horizons from occupations by early humans. The Zemun loess site (ZLS, located in the Vojvodina, Northern Serbia) was declared as a protected site, based on artefacts of previous settlements found on the river bench. For providing a stratigraphy for this site and to set the archaeological findings into an environmental and temporal context, the ZLS was investigated by means of environmental magnetic and colorimetric properties. This requires not only to creation of a stratigraphy to be compared to already investigated sites of northern Serbia, but also provides independent age control, carried out by tephrochronology. Therefore, the ZLS contains two important chronological anchor-points, namely the L2-tephra (correlated to Vico Ignimbrite B and dated to 160.6 ± 4 ka, (Mannella et al., 2019)) and the Bag-Tephra (correlated to the Villa Senni eruption and dated to 351-357 ka (Fu et al., 2019)). This tephrochronological timeframe, in combination with the colorimetric and environmental magnetic parameters, witnesses an accumulation of mineral dust, providing insights from glacial to interglacial conditions ranging from marine oxygen isotope stage (MIS) 11 to MIS 4.

 

References

Fu et al. (2019): Chances and challenges in tephrochronology of loess: A case study from the Bag tephra in Serbia. Poster at the XX. INQUA International Quaternary Association Conference 25 – 31 July, Dublin, Ireland.

Mannella et al. (2019): Palaeoenvironmental and palaeohydrological variability of mointain areas in the central Mediterranean region: A 190 ka-long chronicle from the independently dated Fucino palaeolake record (central Italy). Qua. Sci Rev., 210, pp. 190-210.

Markovic et al. (2015): Danube loess stratigraphy – Towards a pan-European loess stratigraphic model. Earth-Sci. Rev., 148, pp. 228-258.
Engaging Schools with InSight Data
Authors: Berenguer Jean Luc , Bravo Tammy , Sauron-Sornette Anne , Stevenson John
Published: March 2020

After a 6-month flight to Mars and a successful landing, InSight has deployed SEIS … its seismometer designed to sit on the Martian surface. The goal of this mission is to investigate the dynamics of Martian seismic activity and understand the processes that shaped the Red Planet.

SEIS InSight has engaged a generation of school kids, teens and students which, like scientists, follow the mission live. The data from InSight offers a chance to leverage existing Seismometers in Schools networks to allow a large and growing number of students to interact with seismic data recorded on Mars as soon as it is available on Earth.  Students in these international networks have experience with seismic data and software and are primed to engage with this NASA Discovery mission.

Seismic data in the classroom has provided both a hook for inquiry with real data as well as a common language for international collaboration.

These resources input innovative educational strategies acculturating pupils in the acquisition, processing, display and exploration of seismic and weather data.

A very large school network (middle and high schools) share resources and activities using InSight data. Networks are preparing lessons, software, web tools, data viewers, and other resources to allow students to explore and interrogate shaking on Mars to better understand the heart of the planet.

In this presentation, we will show all the practical activities and all the different tools created for the kids, teens and students. This work has been developed by teachers, educators, and scientists in international cooperation, and can be found on dedicated websites.
Ground surface elevation changes estimated using multiple GNSS signal-to-noise ratio observations over permafrost area
Authors: Hu Yufeng
Published: March 2020

The ground surface over permafrost area subsides and uplifts annually due to the seasonal thawing and freezing of active layer. GPS Interferometric Reflectometry (GPS-IR) has been successfully applied to the signal-to-noise ratio (SNR) observations to retrieve elevation changes of frozen ground surface at Barrow, Alaska. In this study, the method is extended to include GLONASS and Galileo SNR observations. Based on the multiple SNR observations collected by SG27 in Barrow, the multiple GNSS-IR time series of ground surface elevation changes during snow-free days from late June to middle October in year 2018 are obtained at daily intervals. All the three time series show a similar pattern that the ground subsided in thaw season followed by uplifts in freezing season, which is well characterized by the previous composite physical model using thermal indexes. Fitted with the composite model, the amplitude of the GPS-derived elevation changes during the snow-free days is suggested to be 3.3 ± 0.2 cm. However, the time series of GLONASS-IR and Galileo-IR measurements are much noisier than that of GPS-IR due to their inconsistent daily satellite tracks. Applied with a specific strategy in the composite model fitting, the amplitudes of GLONASS- and Galileo-derived elevation changes are estimated to be 4.0 ± 0.3 cm and 3.9 ± 0.5 cm, respectively. Then, GLONASS-IR and Galileo-IR time series are reconstructed in turn with the fitting coefficients. Moreover, the occurrences of the short-term variations in time series of GNSS-IR measurements are found to coincidence with the precipitation events, indicating the hydrologic control on the movements of frozen ground surface. The results presented in this study show the feasibility to combine multiple GNSS to densely monitor frozen ground surface deformations, and provide an insight to understand the impacts of both thermal and hydrologic forces on the frozen ground dynamics.