bluuebunny/crossref_metadata_2025 huggingface dataset:
Crop Classification based Multi-Temporal Sentinel2 Data in the ShiYang River Basin
Authors: Yi Zhiwei
Published: March 2020

     Accurate and timely spatial distribution of crops is of great significance to agricultural security issues. They are not only important parameters for regional crop growth monitoring, yield prediction, model simulation, but also important basis for government decision-making to assess food security and predict comprehensive productivity of agricultural resources. The Shiyang River Basin is the inland river basin with the highest development intensity and the most prominent water resource conflicts in arid regions of Northwest China. The timely and accurate acquisition of crop distribution information in the watershed can provide data support for alleviating the water resource conflicts in the Shiyang River Basin. However, there is no publically available in-season crop distribution information with high spatial resolution in the watershed. To solve this problem and generate accurate ,in-season crop-type map with high spatial resolution, this study uses multi-temporal sentinel2 data to generate spectrum, texture, vegetation index, red edge multi-feature sets while exploiting random forest classification algorithm(RF).the study designed Experiments to evaluate what kind of feature is most effctitve and further dig which spectral information is most important for the training RF model to map crop types in Shiyang River Basin. The experimental results show that the spectral information outperforms other features in the highest classification accuracy, followed by vegetation index information and red edge index information, and texture information has no effect on crop classification in the watershed. Temporal information has a significant impact on crop classification. the classification accuracy increases with the progression of time, and the accuracy reaches a plateau (94%)around DOY 218. The highest accuracy for single-date classification is 87%, and for multi-temporal is 94.8%. The classification performance of SWIR1 band of Sentinel2 is better than the visible and near-infrared bands commonly used in crop classification at present, and crop classification based on the Sentinel2 Visible-NIR-SWIR1 three-band combination mode can achieve the effect of full-band classification. The Visible -NIR-SWIR1 data of sentinel2 before DOY218 was used to generate the 2019 crop distribution map of Shiyang River Basin, with an overall accuracy of 93.5%.
Numerical Modeling of Global Seismic Wave Propagation in the Whole Mars Models and Effect of Lateral Crustal Variation
Authors: Wang Yanbin , Xiao Wanbo , Deng Di
Published: March 2020

Investigating the interior structure of Mars is important to study not only its past and present state and future evolution, but also the formation and evolution of the Earth and solar system. Seismological methods played import roles in the study of the Earth and Moon’s interior. The first mission about Martian seismology began in 1976, but no seismic events were convincingly detected during the observation. The InSight Spacecraft landed on Mars on November 26, 2018 in Elysium Planitia and installed the first seismometer on Mars. It will provide the in situ observation of interior structure and seismic activity of Mars for the first time. In this study, we perform numerical modelling of seismic wave propagation in whole-mars models by solving the seismic wave equations using a hybrid pseudospectral and finite difference method on staggered grid. Firstly, based on the Martian internal models derived from geochemical analysis (Sohl and Spohn, 1997), we present numerical simulations of seismic wave propagation in the whole Mars models. The generation and propagation of various seismic phases in the whole Mars models are shown by synthetic seismograms and wavefield snapshots. We analyze the effects of crustal thickness and depth of core mantle boundary on seismic wave propagation. Then based on the present model of Martian crustal thickness (Wieczorek and Zuber, 2004), we simulate seismic wave propagation in laterally heterogeneous Martian crust and analyze the influence of lateral heterogeneity on global seismic wave propagation. Multiple reflections and conversions of seismic waves and their constructive interference occurred inside the low-velocity Martian crust form reverberating wave trains. Thickness of Martian crust has strong effect on the propagation of multiple surface reflections and surface waves. Seismic reflections from core-mantle boundary can be clearly identified from the calculated transverse component seismogram.
Estimation of surface reflectance using deep neural network with KOMPSAT-3A data
Authors: Jung Daeseong , Jin Donghyun , Choi Sungwon , Seong Noh-hun , Han Kyung-soo
Published: March 2020

The acquisition of image data from satellite is performed by the satellite’s sensor after the light from the sun is reflected in object at the surface. In this process, light passes through the earth's atmosphere twice and is affected by the scattering, absorption and reflection by the atmosphere. This effect of the atmosphere reduces the power of the sun's light entering the sensor and consequently influences image data. The process of removing this effect is called atmospheric correction. Generally, the radiative transfer model (RTM) such as the Second Simulation of a Satellite Signal in the Solar Spectrum (6S) is used in the atmospheric correction methods for surface reflectance retrieval. In general, RTM have high accuracy. But, RTM processing takes long time to perform atmospheric correction. So, several studies have applied the Look-up Table (LUT) method based on RTM. However, LUT is not an exact method due to the increment and range of input variables. In this study, we used the Deep Neural Network (DNN) method to predict surface reflectance for KOMPSAT-3A data. To Build an effective DNN model, 6S-based LUT is used as training data and the hyper-parameters have been adjusted. To evaluate the surface reflectance retrieval, we compared the surface reflectance derived of 6S RTM, 6S-based LUT and DNN methods.
Water Management and Transfers Optimization with Probabilistic Seasonal Forecasts
Authors: Zhu Tingju , Marques Guilherme , Medellin-Azuara Josué , Lund Jay
Published: March 2020

Advances in probabilistic seasonal flow forecasts sparked renewed interests to improve water management, through explicit incorporation of forecasts and forecast uncertainties into decision-making. Here, we develop a three-stage stochastic programming model to optimize integrated agricultural and urban water management decisions by directly considering probabilistic seasonal flow forecasts. The model represents urban water users which make short-term and long-term water conservation choices to maximize supply reliability and minimize conservation costs; it also represents irrigators which optimize land and water allocations to annual and perennial crops to maximize farm revenue, besides water transfers between agricultural and urban uses. Long-term urban conservation measures, areas of perennial crops, and capital investments in onfarm irrigation are considered in the first stage; annual crop areas, which depend on forecasted flows, are considered in the second stage; and reductions of irrigated annual and perennial crop areas due to water scarcity, conjunctive use operations, and water transfers informed by realized hydrologic year types are considered in the third stage. The temporal hierarchy of these decisions intends to approximate actual decision-making process by simultaneously considering long- and short-term decisions, forecasts, and forecasting skills. This paper provides a framework for quantifying the value of probabilistic forecasting information and forecasting skills, for managing complex regional water systems, including agricultural and urban water uses, water transfers, and conjunctive use of surface water and groundwater.
Effects of Gravel on Energy and Water Transport in the Soil of Qinghai-Tibet Plateau
Authors: lyu shihua
Published: March 2020

According to the shortcomings of the land surface model, the new scheme is developed and applied to the simulating soil process at Madoi and Nagqu. Simulations show that gravel tend to reduce soil water holding capacity and enhance soil hydraulic conductivity, surface infiltration and drainage. As a result, the upper layer of soil mixed with gravel tends to drier due to the soil water move to deeper layer. The mean biases of soil moisture between the simulation and observation reduced by 25- 48% at two sites. Soil thermal conductivity is increased with gravel content and the soil thermal inertia was decreased with gravel content increasing. Therefore the deeper layer temperature of soil containing gravel is rapid response to air temperature change. The mean biases of soil temperature between the simulation and observation reduced by 9.1-25% at two sites. From the simulation results at Madoi and Nagqu, we find that the new scheme performed better than the original scheme in simulating soil temperature and water content and the land model implemented the new scheme is suitable for simulating land process in the QTP.
Urban-PLUMBER: A new evaluation and benchmarking project for land surface models in urban areas
Authors: Lipson Mathew J. , Grimmond Sue , Best Martin J. , Abramowitz Gab , Pitman Andrew J. , Ward Helen C.
Published: March 2020

We welcome participants in the new project to evaluate land surface models (LSMs) in urban areas at multiple sites. Urban-PLUMBER will evaluate both specialised urban parameterisations and general LSMs typically used in weather/climate simulations. Assessment will be offline (uncoupled with an atmosphere model), with driving meteorology and general site characteristics provided at the neighbourhood scale.

The project builds upon the PLUMBER project (PALS Land sUrface Model Benchmarking Evaluation pRoject) by assessing models using simple benchmarks as well as error metrics. The PLUMBER experience indicates benchmarking can reveal where LSMs are not utilising available information effectively, helping focus future model development.

The project’s two phases are: 1) initial evaluation at one suburban site and 2) evaluation across multiple sites with varying degrees urbanised and vegetation/pervious fractions. The project will establish where on the urbanised/vegetated continuum models are more skilful, and assess the progress made in modelling urban areas over the last decade since the last major offline urban model comparison project (PILPS-Urban).

We expect the project to benefit both participating modelling groups and improve understanding of modelling urban areas as a whole. Contact us to get involved.
Species-specific relationship between sapflux density and diameter growth rates for six years
Authors: Lee Minsu , Park Juhan , Cho Sungsik , Kim Hyun-Seok
Published: March 2020

Transpiration and photosynthesis are connected each other through stomata, therefore, biomass increment of trees should have close relationships with their water use. However, the relationship is species specific and it is also dependent on various biotic and abiotic factors. The purpose of this study is to investigate the relationship of sapflux with diameter increment of individual trees among six different species using Granier type sapflow sensors and diameter growth band installed from 2012. The growth of two conifer (Pinus koraiensis, Abies holophylla), five broadleaf (Quercus aliena, Q. variabilis, Q. serrata, Carpinus laxiflora, C. cordata) were investigated at Mt. Taehwa and Gwangneung National Arboretum. Net Primary Production was calcualted based on speceis specific allometric equations. The relationship between sapflux density and diameter growth was different among species. For example, Q. aliena and A. holophylla had positive relationship between sapflux density and diameter growth (p = 0.037 and p =0.001, respectively), while P. koraiensis did not follow the trend (p = 0.5). However, when tree level transpiration was calculated by mulitiplying sapflux density with its sapwood area. In general, all species showed significant positive correlations between the transpiration and NPP (e.g., P. koraiensis(p = 0.003), Q. aliena and A. holophylla(p <0.001). In addition, comparison between conifer and broad leaves species, the conifers show the bigger changes in diameter growth and eventually NPP than that of the broad leaves tree in the same change of transpiration. Therefore, WUE for biomass increment was higher in conifer than broadleaf species.
Application of Bayesian Networks in Multi-Hazard Safety Assessment of Nuclear Power Plants
Authors: D. Mohan Varenya Kumar , Vardon Philip , Daniell James , Gehl Pierre , Schafer Andreas , van Gelder Pieter , Natarajan Venkat , Molenaar Cor , Foerster Evelyne , Ragon Florence
Published: March 2020

Low probability events occurring in sequence, within a limited operational time (damage and recovery window between events), are a key consideration in multi-hazard safety assessments of nuclear power plants (NPPs). Cascading effects from hazards and associated event sequences could potentially have a significant impact on risk estimates. The Bayesian network can act as a framework to consider aforementioned statistical dependencies between various hazards in multi-risk analyses of nuclear power plants.

Within the EU project NARSIS (New Approach to Reactor Safety Improvements), a Bayesian network-based risk assessment framework was developed to perform multi-hazard risk assessment of NPPs.

The Bayesian network method was applied for an external-event related station blackout (SBO) scenario at a NPP. Earthquake, flooding, and tornado were among the hazards considered at a decommissioned NPP site location in Europe. Both hazard dependency in time as well as a cascading scenario was also considered. The hazards, their interactions and the fragilities of selected systems, structures and components within the nuclear power plant were represented in the network and their probability distributions were obtained based on the multi-hazard and fragility approaches adopted within the NARSIS project.

Sensitivity analyses in the network were used to identify key hazards and interactions. Most influential hazard combinations and ranges of intensity measures were identified through diagnostic inference in the network. Discretisation of continuous variables (hazard curves in this case) is a key aspect of performing inference in Bayesian networks. The effect of various levels of discretisation of hazard probability distributions was assessed, to identify suitable discretisations of hazard data.

This application demonstrates the use and advantages of the Bayesian network methodology, developed in the NARSIS project, for probabilistic safety assessments of NPPs.
Estimation of Soil Moisture Content Using Deep Learning and High-Resolution Satellite Imagery (Sentinel-1 and 2)
Authors: Lee Soo-Jin , Lee Yang-Won
Published: March 2020

Soil moisture is an important factor affecting global circulation (climate, carbon, and water), disasters (drought, floods, and forest fires), and crop growth, so the production of soil moisture data is important. Currently, satellite-based soil moisture data is available from NASA’ SMAP (Soil Moisture Active Passive) and ESA’ SMOS (Soil Moisture and Ocean Salinity) data. Since these data are based on passive microwave sensor, they have low spatial resolution. Therefore, it is difficult to observe the distribution of soil moisture on a local scale. The purpose of this study is to produce high resolution soil moisture for monitoring on a local scale. For this purpose, we performed soil moisture modeling using high resolution satellite data (Sentinel-1 SAR (synthetic-aperture radar), Sentinel-2 MSI (multispectral instrument)) and deep learning. Deep learning is a method improving the problems of traditional neural networks such as overfitting, gradient vanishing, and local optimal solution through development of learning methods such as dropout, ReLU (Rectified Linear Unit), and so on. Recently, it has been used for estimation of surface hydrologic factors (soil moisture, evapotranspiration, etc.). The study area is an agricultural area located in Manitoba and Saskatoon, Canada. In-situ soil moisture data was constructed from RISMA (Real-Time In-Situ Soil Monitoring for Agriculture). In order to develop an optimal soil moisture model, various condition experiments on hyper-parameters affecting the performance of model were carried out and their performance was evaluated.
New Glacier Inventory of the Russian glaciers based on Sentinel images (2017/2018).
Authors: Khromova Tatiana , Nosenko Gennady , Glazovsky Andrey , Nikitin Stanislav , Muraviev Anton
Published: March 2020

We present new Glacier Inventory of the Russian glaciers based on Sentinel images (2017/2018).

The modern reduction in the size of glaciers is accompanied by the activation of natural processes leading to catastrophic consequences, changes in landscapes and prevailing nature management practices. To reduce risks and adapt to the consequences of ongoing changes, relevant data on the state of glacial systems are needed. In Russia, extensive glaciation is present in the Arctic zone, and in its continental part there are 18 mountain-glacial systems. According to the Glacier Inventory of the USSR in the mid-twentieth century in Russia there were 7167 glaciers with a total area of ​​60103, 99 km2. Of these, 685 glaciers with an area of ​​56,127.2 km2 accounted for the Arctic archipelagos. Despite the ever-increasing amount of information from space, and experimental studies in a number of glacial regions, a complete and reliable picture of the state of glaciation in Russia at the beginning of the 21st century has not been available to date.
The project aims to develop and create a unified information basis for the study of glacial regions of Russia using geoinformation technologies. The initial data were collected and systematized to assess the current state of Russia's glaciers: data from previous inventories, maps, historical and modern aerial and space images, digital elevation models. A classification of possible catastrophic phenomena of glacial genesis was developed: dynamically unstable glaciers, glacier lakes, icebergs, etc. The structure of the database for the study of Russian glaciers is developed, compatible with world and national data archives. Implementation of the project allowed to gain new knowledge about the state of Russian glaciers.

The presentation includes the results obtained in the framework of the following research projects: № 0148-2019-0004 of the Research Plan of the Institute of Geography of the Russian Academy of Sciences, № 05/2019/RGS-RFBR supported by the Russian Geographical Society, № 18-05-60067  supported by RFBR.
Exchange of CO2 between a Southeastern Salt Marsh and the Atmosphere
Authors: Nahrawi Hafsah , Leclerc Monique , Penning Steven , Zhang Gengsheng , Singh Navjot , Pahari Roshani
Published: March 2020

Coastal salt marshes are among the most productive ecosystems on Earth and play an important role in the global carbon cycle. The present study quantifies the net ecosystem exchange in a salt marsh dominated by large heterogeneous patches of Spartina alterniflora near Sapelo Island, GA, USA. Continuous high-frequency eddy-flux measurements were made between 2013 and 2016. The method provides both the temporally continuous and a spatial integration of the carbon exchange between the salt marsh and the atmosphere. Over the course of this multi-year study, the salt marsh ecosystem was found to be a net sink of carbon.  In 2015, annual net ecosystem exchange (-138.72 g C m2) was 55% smaller than in 2014 (-309.36 g C m-2). This can be attributed to the high temperatures and the occurrence of Proxigean Spring tides combined with persistent onshore winds arising from the indirect effect of Hurricane Joaquin. The ecosystem acted as carbon source with cumulative net ecosystem exchange value of 0.02 g m-2 day-1 during the event. In addition, both the photosynthetically active radiation and the air temperature are the main environmental drivers in the marsh. Higher air temperatures and incoming photosynthetic active radiation level limit photosynthetic activity. Further work suggests the collection of a longer record to capture the impact of climatic and other environmental variations on the strength of the carbon sink. Also, the inclusion of the lateral component of the carbon fluxes as part of the seasonal and annual budgets would also considerably augment our understanding of the functioning of the salt marsh along the southeastern coast on the US.
3D Crustal P-Wave Velocity Structure for the Ordos block and Its Adjacent Area based on travel time tomography
Authors: Liu Yaning , Wu Jianping
Published: March 2020

The Ordos block is located on the west side of the North China Carton, adjacent to the northeastern part of the Tibetan Plateau. Affected by two tectonic movements, Ordos block internal structure remains relatively stable structure, but surrounded by active tectonic belts. With the development of the second and third part of the “China Seismological Science Array”, the distribution of seismic observation stations in Ordos region has been greatly improved. This study will use the new seismic observation data of "Array III", and combined with the phase observation data of "Array II" to form a more complete seismic phase travel time data set. The regional seismic body-wave travel time tomography will figure out a more reliable three-dimensional velocity structure of P waves in Ordos.

Our study area spans from 32°N to 42°N and 108°E to 114°E , which includes the Ordos block and its adjacent structures . The seismic data we used for inversion were recorded by 1244 stations including: 198 permanent stations and 1043 temporary stations (ChinArray II and III), from November 2013 to August 2017. After manual labeled the seismic phase, we select events with more than ten phase records of individual seismic events. The epicentral distance is less than 200km. Finally, we obtained about 22,500 phase records of 1882 local seismic events.

The preliminary results are consistent with previous studies and surface structures of a wide range of velocity distributions. However, in the middle-upper crust under the Liupan Mountain west, the low-speed anomaly extending downward is shown, which may be caused by the shallow crustal damage caused with the continuous eastward compression of asthenosphere in the northeastern margin of the Qinghai-Tibet Plateau during the Cenozoic. It is worth noting that there is an EW-trending low-velocity zone under the Dingbian-Suide fault beneath the Ordos Basin, with a depth form lower crust to 50 km in upper mantel. This low-velocity anomaly divides the high-speed disturbance in the Ordos block into two parts，indicate the depth of the fault can reach the upper mantel. In the Taihang Mountains in the west of the study area, low-velocity anomalies extending to the upper layer of the mantle are shown. We initially believe that this anomaly is related to the volcanic thermal motion that once existed on the area.
Research on measurement and source distribution of atmospheric NO2 concentration by ground-based MAX-DOAS system in Nanjing, China
Authors: ren Bo , Xie Pinhua , Xu jin , Li Ang , Tian Xin , Hu Zhaokun , Li Xiaomei
Published: March 2020

Nanjing, as one of the important cities in the Yangtze River Delta of China, has a developed economy and a large population. Although the concentration of air pollutants in Nanjing has declined with the introduction of China’s strict air pollution prevention and control policies, the situation of air pollution is still severe. Therefore, understanding the source and distribution of atmospheric pollutants has an important role in implementing the prevention and controlling of atmospheric pollutants. In this study, we observed the vertical distribution characteristics of tropospheric NO2 by used the ground-based Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) technique in Nanjing. The contribution of transregional transport to NO2 in different seasons and different altitudes (200m, 500m, and 1000m) was analyzed by combining the potential source distribution model (PSCF). The analysis results showed that the distribution of NO2 sources were obvious seasonal changes. Due to the lower wind speed in spring, the distribution of NO2 sources at all altitudes was not obvious. In summer and autumn, the source of NO2 in the lower altitudes (200m) was concentrated in the urban area of ​​Nanjing and central Jiangsu Province. But for the winter, the NO2 concentrations of lower altitudes were seriously affected by Chuzhou and Ma'anshan area. The sources distribution in the middle and upper altitude were relatively scattered and the WPSCF value was smaller than lower altitudes, which may be caused by the NO2 concentrated in the near ground.
Cross-timescale interference and predictability of extremes: a chimera?
Authors: Muñoz Ángel G.
Published: March 2020

Cross-timescale interference involves linear and non-linear interactions between climate modes acting at multiple timescales (Muñoz et al., 2015, 2016, 2017; Robertson et al., 2015; Moron et al., 2015), and that are related to windows of opportunity for enhanced predictive skill (Mariotti et al., 2020), with relevant societal impacts (e.g., Doss-Gollin et al., 2018; Anderson et al., 2020). Using a simple mathematical model, reanalysis data and gridded observations, here we analyze plausible mechanisms for cross-timescale interference, describing conditions for coupling of oscillating modes and its impact on extreme rainfall occurrence and predictive skill. Concrete examples for Northeast North America and southern South America are discussed, as well as implications for climate model diagnostics.
Ultra-Low Frequency (ULF) waves originating in solar wind dynamic pressure oscillations and propagating through the magnetosheath to the inner magnetosphere
Authors: Georgiou Marina , Katsavrias Christos , Daglis Ioannis , Balasis Georgios
Published: March 2020

Several observational studies have shown that ULF oscillations of the solar wind dynamic pressure can drive periodic fluctuations in magnetic field measurements at corresponding frequencies. In this study, we use multi-spacecraft (Cluster, GOES, THEMIS and Van Allen Probes) mission measurements to investigate the propagation of pressure fluctuations-driven pulsations within the Pc5 and Pc4 frequency range (from ~0.5 to 25 mHz) into the magnetosphere. During intervals of slow solar wind — to exclude waves generated by velocity shear at the magnetopause — common periodicities in electromagnetic fields in the magnetosphere and the solar wind driver are first detected in Lomb-Scargle periodograms. Then, using the cross-wavelet transform, we examine the causal relationship and specifically, in cross-wavelet spectra and wavelet transform coherence. Lastly, spatial and temporal variations of wave properties are mapped from beyond the magnetopause to the inner magnetosphere through frequency, polarisation and power signatures of waves detected at the various probes. The observed dependence of wave properties on their localisation offers an excellent source for verification of the role that solar wind dynamic pressure oscillations as driver of ULF waves propagating through the magnetosheath into the dayside and nightside magnetosphere.
A Z-grid Based Dynamic Core for Global Numerical Prediction Model of Chinese Meteorological Agency
Authors: Xie Yuanfu
Published: March 2020

In order to provide multiple choices of dynamic cores for the next generation global numerical prediction system at Chinese Meteorological Administration (CMA), a Z-grid based dynamic core is under development. Among other important features of a Z-grid scheme, better dispersion relation, natural geostrophic adjustment and conservation attract numerical modeler’s interests. In this presentation, we will share the progress of such a development at CMA along with other dynamic cores, improving its accuracy on a sphere, efficient solvers and software design and implementation. We also developed some standard unit test cases for software reliability, which are also available and convenient for other dynamic cores. Some numerical experiment results will be presented as well.
Geochemistry of Cretaceous subduction initiation related cumulate gabbros in a forearc setting from Chaldoran ophiolite, NW Iran
Authors: Rezaei Mahleqa , Moazzen Mohssen , Yang Tian-Nan
Published: March 2020

The Neo-Tethys-related Chaldoran ophiolite in NW Iran and at the Turkish border is a part of the larger Khoy ophiolite. Cumulate and isotropic gabbro along with serpentinized peridotite, pillow basalt, pelagic limestone, rare radiolarites, and volcano-sedimentary units are the main rock types in the area. The gabbros occur as lenses with ultramafic rocks, or as relatively large exposures with fault contact with ultramafic rocks. In this study, we provide new whole-rock geochemistry, mineral chemistry and zircon U/Pb age for the cumulate gabbros from the Chaldoran area. Gabbros have tholeiitic composition and are highly depleted. Chondrite normalized rare earth elements (REE) pattern for gabbros are comparative with REE patterns for N-MORB, but overall with more depleted features. The N-MORB normalized multi-elements pattern shows high depletion in HREE and HFSE and enrichment in some LREE and LILEs. Negative anomaly for some HFSE relative to N-MORB, along with enrichment in LILE for the samples indicates the source region as subduction influenced mantle. The cumulated gabbro whole rock and Clinopyroxenes geochemistry indicate an intra-oceanic forearc setting for the studied samples. They also have many similarities to boninite in mineral and whole rock geochemistry. U-Pb zircon dating of the gabbro samples indicates 95.3-114.1 Ma ages for the generation of the gabbros parent magma. The original magma was related to the later stages of the forearc setting in the subduction initiation (SI) stage. This ‘SI’ related Albian-Cenomanian the Chaldoran depleted gabbro likely are the continuation of Taurus SI related late Cretaceous ophiolite complexes in Turkey.
Preliminary DORIS results on Precise Orbit Determination and on geocenter and scale solutions from CNES/CLS IDS Analysis Center contribution to the ITRF2020
Authors: Capdeville Hugues
Published: March 2020

The processing configuration for our IDS contribution to the International Terrestrial Reference Frame (ITRF2020) realization was defined. We adopted the last standards and models recommended by IERS. We took into account the IDS recommendations to mitigate the non-conservative force model error on satellites, to mitigate the effect of the South Atlantic Anomaly on the DORIS receivers and to improve the stability of the DORIS scale.

A Precise Orbit Determination (POD) status for DORIS satellites by taking into account all these improvements will be presented for the processed time span. We will give statistical results such as one per revolution empirical acceleration amplitudes and orbit residuals. We will also give some comparisons to some external precise orbits used for altimetry. Some external validations of our orbits will be done, such as with independent SLR measurements processing as well as through the use of altimeter crossovers when available. We will also look at the impact of our new ITRF2020 configuration on the DORIS geocenter and scale.

 
Energetic particles measurements on the lunar far-side by Lunar Lander Neutron and Dosimetry(LND) experiment
Authors: Xu Zigong , Wimmer-Schweingruber Robert F , Guo Jingnan , Yu Jia , Zhang Shenyi , Berger Thomas , Matthiae Daniel , Burmeister Soenke , Boettcher Stephan , Heber Bernd
Published: March 2020

After Chang’E 4 successfully landed on the far side of the moon on Jan 3rd, 2019, the Lunar Lander Neutron and Dosimetry experiment has been working for 13 lunar days from January, 2019 to January, 2020, sending back the measurements of dose, linear energy transfer (LET) spectrum, neutrons, and charged particles. Here, we show observations of charged particles especially protons and Helium ions during quiet time. We also present two solar energetic particle events registered by LND in May 2019, which are also the first such measurements on the far-side surface of the moon. The temporal variations of particle fluxes on the far side of the moon detected by LND provide a new observation site in space and can be helpful to improve our understanding of particle propagation and transport in the heliosphere.

 
Numerically Simulated Groundwater Age Distributions within Complex Flow Systems and Discrete Fracture Networks
Authors: Molson John , Frind Emil
Published: March 2020

Numerical simulations of mean groundwater age are presented for a variety of complex flow systems including heterogeneous aquifers and discretely-fractured porous rock. We apply the finite element models FLONET/TR2 (in the 2D vertical plane) and SALTFLOW (in 3D systems), using the standard advection-dispersion equation with an age source term. The age simulations are applied in a variety of contexts including defining capture zones for pumping wells, characterizing fractured rock aquifers, and for improved understanding of flow systems and geochemical evolution. Applications include real field sites and hypothetical conceptual models. Comparisons are also made with advective particle-tracking derived ages which are much faster to compute but do not include dispersive age mixing. Control of numerical (age) dispersion is critical, especially within discrete fracture networks where high age gradients can develop between the fractures and matrix. The presentation will highlight the broad applications of mean groundwater age simulations and will show how they can be useful for providing insight into hydrogeological systems.
Design of a low-cost Early Warning System (EWS) in informal settlements in Medellín, Colombia (Project Inform@Risk)
Authors: Gamperl Moritz , Singer John , Thuro Kurosch
Published: March 2020

Recent developments have led to an increased rural depopulation and migration into cities in Andean countries. This is especially the case in Colombia, where immigration from Venezuela has caused an increase in poverty in cities. In Medellín, the second largest Colombian city, this led to an accelerated growth of informal settlements in the steep slopes in the east and west of the city. Combined with the expected increase of heavy rainfall due to climate change, the landslide risk in this area is expected to increase further over the next decades. The risk is highest in the east of the city, where highly weathered dunites are exposed and the slope angle reaches 20-30° and more. In these regions, rotational slides have repeatedly occurred in the past, as detailed mapping has shown.

The project Inform@Risk tries to strengthen the resilience of these settlements against rainfall induced landslides, since relocation of the inhabitants at risk currently is not a feasible option. For this, an innovative low-cost EWS is being developed in the Barrio Bello Oriente in the east of the city. Since the exact location of a future landslide is unknown, the EWS requires a network of geosensors throughout the whole area at risk, whereby the network density is controlled by the landslide risk. This flexibility is achieved by combining horizontally installed CSM (Continuous Shear Monitor) cables with open-source wireless LoRa sensor nodes. The sensor nodes are developed on basis of an Arduino system and can be installed on infrastructure as well as in the ground. They all include a tilt sensor and additionally can be equipped with varying geotechnical and hydrogeological sensors, depending on the location and measuring target (e.g. piezometer, extensometer, inclinometer/tiltmeter).

The data produced by the geosensor network is processed by the Inform@Risk server and made available to the residents and municipal stake holders via an app and homepage. Based on meteorological, hydrological and geotechnical analyses the system can evaluate the current and make predictions of the future hazard situation. If necessary, a warning can be issued via app to the inhabitants.  Ultimately, the system should be replicable in other areas in the Andes and elsewhere in the world.

This work is funded by the German Ministry of Education and Research (BMBF).
An engine for social-ecological risk analysis and NBS recommendation to support risk mitigation management
Authors: Ommer Joy , Vranić Saša , Leo Laura S. , Kalas Milan , Debele Sisay E. , Bertini Flavio , Montesi Danilo , Pavlova Irina , Kumar Prashant , Di Sabatino Silvana
Published: March 2020

During the past decades, risk assessment experienced increasing interest in social science but also natural science and other disciplines. At the same time, risk reduction and mitigation gained in interest from local to global level due to the shift from reactive to proactive management. Hazard and risk assessment have been approached on different levels, nonetheless, they are lacking elements such as cross-border assessment or the integration of an ecological risk assessment. One of the objectives of the H2020 Operandum project is to provide an automated science-based assessment of risk for the social-ecological system and further of the applicability and performance of Nature-based Solutions (NBS) for risk mitigation of hydro-meteorological hazards.

Within this project, an interactive webGIS analytical engine and an NBS catalogue are being developed as part of the Geospatial Information Knowledge Platform (GeoIKP). The analytical engine will encompass open Europe-wide hazard maps and link them with local high-resolution information from public and innovative data sources (e.g. Facebook). These two geo-tools are combined into a recommendation engine - NBS toolkit - trained on existing NBS. Using a holistic approach, the NBS toolkit aims at providing risk assessment and advanced recommendations on NBS usage for mitigation. For this approach, the NBS toolkit incorporates hazard and risk assessment in space and time, cost-benefit analysis, and additionally main drivers and constraints for NBS implementations as well as their geographical transferability, replicability and performance/effectiveness. 

This contribution will offer an insight into the concept and development of the NBS toolkit. Primarily, it will focus on the added value of the NBS toolkit for future nature-based implementation, risk mitigation management and decision-making at all levels. Challenges and current limitations of real-time risk assessment will also be discussed, with a focus on their implications on NBS monitoring and effectiveness.
Modelling melt ponds in Global Circulation Models
Authors: Sterlin Jean , Fichefet Thierry , Massonnet François , Lecomte Olivier , Vancoppenolle Martin
Published: March 2020

Melt ponds appear during the Arctic summer on the sea ice cover when meltwater and liquid precipitation collect in the depressions of the ice surface. The albedo of the melt ponds is lower than that of surrounding ice and snow areas. Consequently, the melt ponds are an important factor for the ice-albedo feedback, a mechanism whereby a decrease in albedo results in greater absorption of solar radiation, further ice melt, and lower albedos 

To account for the effect of melt ponds on the climate, several numerical schemes have been introduced for Global Circulation Models. They can be classified into two groups. The first group makes use of an explicit relation to define the aspect ratio of the melt ponds. The scheme of Holland et al. (2012) uses a constant ratio of the melt pond depth to the fraction of sea ice covered by melt ponds. The second group relies on theoretical considerations to deduce the area and volume of the melt ponds. The scheme of Flocco et al. (2012) uses the ice thickness distribution to share the meltwater between the ice categories and determine the melt ponds characteristics.

Despite their complexity, current melt pond schemes fail to agree on the trends in melt pond fraction of sea ice area during the last decades. The disagreement casts doubts on the projected melt pond changes. It also raises questions on the definition of the physical processes governing the melt ponds in the schemes and their sensitivity to atmospheric surface conditions.

In this study, we aim at identifying 1) the conceptual difference of the aspect ratio definition in melt pond schemes; 2) the role of refreezing for melt ponds; 3) the impact of the uncertainties in the atmospheric reanalyses. To address these points, we have run the Louvain-la-Neuve Ice Model (LIM), part of the Nucleus for European Modelling of the Ocean (NEMO) version 3.6 along with two different atmospheric reanalyses as surface forcing sets. We used the reanalyses in association with Holland et al. (2012) and Flocco et al. (2012) melt pond schemes. We selected Holland et al. (2012) pond refreezing formulation for both schemes and tested two different threshold temperatures for refreezing. 

From the experiments, we describe the impact on Arctic sea ice and state the importance of including melt ponds in climate models. We attempt at disentangling the separate effects of the type of melt pond scheme, the refreezing mechanism, and the atmospheric surface forcing method, on the climate. We finally formulate a recommendation on the use of melt ponds in climate models. 
Air pollution studies in “street canyons” in Minsk and urban planning for minimization of its exposure
Authors: Krukowskaya Olga , Malchykhina Hanna
Published: March 2020

Reducing the risks associated with the effects of polluted air on public health is one of the main tasks of sustainable urban development. This problem can be solved in two different ways: by emission reduction and by minimization of human exposure to elevated concentrations of pollutants. In the context of the second approach, it is important to plan the urban area in order to minimize places with a large number of people and poor dispersion conditions.

For this purpose investigation and identification of street canyons in Minsk city was performed. With population ca 2 mln inhabitants Minsk is one of the most populated European cities. Due to many historical destructions of the city nowadays it has mainly planned structure of streets and buildings according to General plans of urban development designed in the second part of the XX century. According to the plans Minsk has relatively wide main transport lines surrounded by mid-level buildings and has good conditions for air circulation and air pollutions spatial dispersion. Nevertheless, there is some location in the city with conditions close to urban street canyons and is characterised with high pedestrian and traffic intensity. Besides in modern construction so density planning not so rare. That's in addition to limited air pollution concentration researches makes important measurements and assessments in such conditions in Minsk.

For sampling, urban canyons NOx concentration in the air were carried out in 2012-2019 in Minsk. Air was sampled on both sides of “street canyons” taking into account weather conditions. During sampling, traffic accounting was carried out. The concentration of NOx was determined by the fluorimetric method.

Obtained results have shown that the actual formation of “street canyons” occurs even with a low height of buildings along to the streets with heavy traffic. It has been shown that a statistically significant increase of NOx content by 20–50% on the windward side compared to the leeward with buildings height comparable to the width of streets. Besides statistical reliable correlation between emissions levels (assessed based on traffic data) and measured concentrations are observed.

Identified patterns of air concentration in combination with GIS allow identifying areas with potential increased risk of exposure. This knowledge will help to plan urban territory in a sustainable way.
Lake Mead and Hoover Dam monitoring in Nevada and Arizona states, USA using InSAR
Authors: Darvishi Mehdi , Destouni Georgia , Jaramillo Fernando
Published: March 2020

Man-made reservoirs and lakes are key elements in the terrestrial water system. The increased concern about the impact of anthropogenic interventions on and the dynamics of these water resources has given rise to various approaches for representing human-water interactions in land surface models. Synthetic aperture radar interferometry (InSAR) has become a powerful geodetic tool for this purpose, by evidencing changes of ground and water surfaces across time and space. In this research, the Lake Mead and associated Hoover Dam are studied using Small Baseline Subset (SBAS) technique. Lake Mead is the largest reservoir in the United States, in terms of water capacity, supplies water and hydropower for millions of people in Las Vegas, Los Angeles and southwestern part of the USA. In recent years, rising temperature, increasing evaporation and decreasing precipitation have decreased water levels substantially, and probably modified its surrounding groundwater and surface as well.

This study aims to identify a hydrology-induced ground deformation around the lake Mead and a probable Hoover dam movement displacement. For the reservoir, we used the SBAS technique using 138 SAR data, including ERS1/2, Envisat, ALOS PALSAR and Sentinel-1, covering a time-spam between 1995 and 2019. For the analysis on the dam, we used the SBAS technique from 2014 to 2019 with descending and ascending modes of Sentinel-1A/B imageries. We found two main deformation patterns around the lake associated with the water level changes. Firstly, ERS and Sentinel-1 data evidenced a ground deformation that manifested itself as as a subsidence pattern in 1995 that has gradually changed into an uplift up to 2019. Secondly, the correlation trend between the deformation and water level changes has changed from negative to positive, with a transition point around March 2008. A possible interpretation for this is that the ground has initially reacted to the water fluctuations in the reservoir before March 2008 but after no longer plays a dominant role in the deformation occurring around the lake. The findings will help us to have a better understanding over the changes happened around the lake due to the water level changes and provide the valuable information for more effective management and maintenance of hydraulic structures and facilities near by the lake and water control in the future.