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Assimilating ASAR Data for Estimating Soil Moisture Profile Using an Ensemble Kalman Filter

chinese Geographical Science 2013年第6期23卷 666-679页

作者： YU Fan LI Haitao GU Haiyan HAN Yanshun Key Laboratory of Geo-Informatics of State Bureau of surveying and mapping Chinese Academy of Surveying and Mapping

Active microwave remote sensing data were used to calculate the near-surface soil moisture in the vegetated *** this study,Advanced Synthetic Aperture Radar(ASAR)observations of surface soil moisture content were used in a data assimilation framework to improve the estimation of the soil moisture profile at the middle reaches of the Heihe River Basin,Northwest China.A one-dimensional soil moisture assimilation system based on the ensemble Kalman filter(EnKF),the forward radiative transfer model,crop model,and the Distributed Hydrology-Soil-Vegetation Model(DHSVM)was *** crop model,as a semi-empirical model,was used to estimate the surface backscattering of vegetated *** DHSVM is a distributed hydrology-vegetation model that explicitly represents the effects of topography and vegetation on water fluxes through the *** experiments were conducted to assimilate the ASAR data into the DHSVM and in situ soil moisture at the middle reaches of the Heihe River Basin from June20 to July 15,*** results indicated that EnKF is effective for assimilating ASAR observations into the hydrological *** with the simulation and in situ observations,the assimilated results were significantly improved in the surface layer and root layer,and the soil moisture varied slightly in the deep ***,EnKF is an efficient approach to handle the strongly nonlinear problem which is practical and effective for soil moisture estimation by assimilation of remote sensing ***,to improve the assimilation results,further studies on obtaining more reliable forcing data and model parameters and increasing the efficiency and accuracy of the remote sensing observations are needed,also improving estimation accuracy of model operator is important.

关键词： assimilation ensemble Kalman filter (EnKF) soil moisture hydrological model Advanced Synthetic Aperture Radar(ASAR)

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The trend of the APRGP velocity field and plates movement derived from GPS data

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Science China(Physics,Mechanics & Astronomy) 2010年第4期53卷 767-772页

作者： CHENG PengFei , WANG Hua, CHENG YingYan, WEN HanJiang & CAI YanHui chinese Academy of surveying and mapping, Beijing 100039, China chinese Academy of surveying and mapping Beijing China

High-precision data processing theories and methods for the wide area GPS network–––Asia Pacific Regional Geodesy Project (APRGP), are systematically discussed in this article. With the software bernese5.0 update, the annual results of APRGP coordinate, velocity field and the trend of plate movement are reestimated, and the corresponding accuracy of adjustment with different constraints, also the velocity field of APRGP, are presented and analyzed. Conclusions could be drawn that Eurasian plate (EURA) rotates clockwise, the Australian plate (AUST) and the Indian plate (INDI) move from southwest to northeast, while the Pacific plate (PCFC) is drifting to northwest, which shows agreement with those of IGS results.

关键词： APRGP Bernese5.0 GPS Data processing velocity field plate movement

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The concept, key technologies and applications of temporal-spatial information infrastructure

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Geo-Spatial Information Science 2016年第2期19卷中插6-中插6,148-156页

作者： Chengming Li Po Liu Jie Yin Xiaoli Liu chinese Academy of surveying and mapping BeijingChina

Smart city is the development of digital city; as its main supporting technology, the digital city geo-spatial framework has to be upgraded to the temporal-spatial information infrastructure (TSII). first, this paper proposes the concept and basic framework of smart city and defines the concept of TSII - processes, integration, mining analysis, and share time-stamps geographic data - and the related policy, regulations and standards, technology, facilities, mechanism, and human resources. The framework has four components: the benchmark of time and space, temporal-spatial big data, the cloud service platform and the related supporting environment. Second, the temporal-spatial big data and cloud service platform are elaborated. finally, an application of TSII constructed by the Xicheng District Planning Bureau in Beijing is introduced, which provides a useful reference for the construction of smart city.

关键词： Smart city temporal-spatial information infrastructure cloud platform big data data mining

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Technical progress of China’s national remote sensing mapping:from mapping western China to national dynamic mapping

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Geo-Spatial Information Science 2021年第1期24卷 121-133,I0013页

作者： Jixian Zhang Haiyan Gu Wei Hou Chunquan Cheng National Quality Inspection and Testing Center for surveying and mapping Products State BeijingChina chinese Academy of surveying and mapping BeijingChina

Remote sensing mapping is an important research direction in the development of geographic surveying and *** order to successfully implement the project of mapping Western China(MWC),a technical mapping system has been *** this project,many problems have been solved through technological innovation,such as block adjustment with scarce control points,large-scale aerial/satellite image mapping,and intelligent interpretation of multi-source *** softwares were developed,*** for aerial/satellite image mapping in a large area,FeatureStation for the integration of multi-source data in the complex terrain areas,and an airborne multi-band and multi-polarization interferometric data acquisition system for SAR *** the first time,full coverage of 1:50,000 topographic data of China’s land territory has been produced,which means the geospatial framework of digital China is basically *** the implementation of other key national plans and projects(*** geographic conditions monitoring and national remote sensing mapping),the focus has changed from MWC to national dynamic ***,a dynamic mapping system is *** data acquisition capability has developed from a single source to multiple sources and multiple *** mapping capability has developed into dynamic mapping,and the capability for database update shows the characteristics of *** national geographic condition monitoring creates a multi-scale index system for statistical analysis for various needs.A multi-level and multi-dimensional technical system for statistical computing and decision-making service is developed for the transformation from dynamic monitoring to information *** this paper,we give a brief introduction about the recent development of remote sensing mapping in China with respect to data acquisition,map production,and information *** purpose of this paper is to motivate the establishment

关键词： Remote sensing mapping mapping western China national dynamic monitoring data acquisition image interpretation information service

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Understanding geographical conditions monitoring: a perspective from China

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International Journal of Digital Earth 2015年第1期8卷 38-57页

作者： Jixian Zhang Weisen Li Liang Zhai chinese Academy of surveying and mapping BeijingChina National Administration of surveying Mapping and Geo-informationBeijingChina

The geographical condition is a very important component of a country’s national condition,and geographical conditions monitoring(GCM)has been of great concern to the chinese *** has a close relation with‘Digital China’and is a concrete embodiment of Digital *** paper discusses the content and classification of *** accordance with application areas,GCM can be divided into fundamental monitoring,thematic monitoring,and disaster *** application areas perspective includes the content of the three other perspectives,like the monitoring elements,the monitoring scope,and the monitoring cycle and fully reflects the essence of the *** monitoring mainly focuses on monitoring all of the geographical elements,which provides a basis for follow-up thematic monitoring;thematic monitoring is a special type of designated subject monitoring that concerns the public or the government;disaster monitoring focuses on the dynamic monitoring of the pre-disaster and disaster periods for natural *** monitoring results will provide timely information for governments so that they can meet management or decision-making requirements.A GCM case study in the area of the Qinghai−Tibet plateau was made,and some concrete conclusions were ***,this paper presents some thoughts on conducting GCM.

关键词： geographical conditions monitoring fundamental monitoring thematic monitoring disaster monitoring Qinghai−Tibet plateau

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Understanding the Moon's internal structure through moonquake observations and remote sensing technologies

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Science China Earth Sciences 2018年第8期61卷 995-1006页

作者： Weifeng HAO Fei LI Chi XIAO Jianguo YAN Mao YE chinese Antarctic Center of surveying and mapping Wuhan University State Key Laboratory of Information Engineering in surveying Mapping and Remote Sensing Wuhan University

Explorations for the interior structure of the Moon mainly involve three technologies: the early gravitational observations via circumlunar satellites, the moonquake observations during the Apollo period, and the recent high-resolution remote sensing observations. Based on these technologies, we divided the development of the moon's interior structure into three stages. The first stage is the discovery of high-density anomalous masses(mascons) on the lunar surface with the low-order gravitational field models, which were obtained by observing perturbations of the early lunar orbital satellites. The second stage is the preliminary understanding of the layer structure with the help of moonquake observations during the Apollo period. The third stage is the deep understanding of the structure of the lunar crust, mantle, and core, with the use of high-resolution remote sensing data and the reassessment of moonquake data from the Apollo's mission. This paper gave detailed introduction and comments on different observation technologies, gathered data, and data processing techniques used at the three stages. In addition, this paper analyzed the current issues in the researches on the Moon's internal structure and discussed the prospects for future explorations.

关键词： Moon Mascon Moonquake Remote sensing Lunar internal structure

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A Multi-component Decomposition Method for Polarimetric SAR Data

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chinese Journal of Electronics 2017年第1期26卷 205-210页

作者： WEI Jujie ZHAO Zheng YU Xiaoping LU Lijun chinese Academy of surveying and mapping Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences

There are more unknowns than equations to solve for previous four-component decomposition methods. So they have to determine each scattering power with some assumptions and avoid negative powers in decomposed results with physical power *** paper presents a multi-component decomposition for multi-look Polarimetric SAR(Pol SAR) data by combining the Generalized similarity parameter(GSP) and the eigenvalue decomposition. It extends the existing fourcomponent decomposition by adding the diffuse scattering as the fifth scattering component considering additional cross-polarized power that could represent terrain effects and rough surface scattering. And unlike the previous methods, the new method determines the volume scattering contribution by a modified nonnegative eigenvalue decomposition method and utilizes the GSP to determine the negative powers of the three scattering contributions(i.e., odd-bounce, double-bounce, and diffuse scattering)directly without extra assumptions and constraints. By experiment, the new method is proved to be more straightforward and reasonable.

关键词： Multi-component decomposition Polarimetric SAR(PolSAR) Generalized similarity parameter(GSP)

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Arctic sea ice thickness variations from CryoSat-2 satellite altimetry data

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Science China Earth Sciences 2021年第7期64卷 1080-1089页

作者： Feng XIAO Shengkai ZHANG Jiaxing LI Tong GENG Yue XUAN Fei LI chinese Antarctic Center of surveying and mapping Wuhan UniversityWuhan 430079China

Arctic sea ice plays an important role in Earth's climate and environmental *** ice thickness is one of the most important sea ice *** obtaining the sea ice thickness and its changes has great significance to Arctic and global change *** altimeters can be used to derive long-term and large-scale changes in sea ice *** leads detection is vital in sea ice thickness estimation by using satellite *** leads detection methods are compared with remote sensing images,and results show that the detection method that uses waveform parameters can obtain improved *** model for the conversion of freeboard to thickness is optimized by considering the incomplete penetration of snow for radar *** derive the estimates of the Arctic sea ice thickness for November 2010 to December 2019 by using the CryoSat-2 altimetry *** sea ice thickness from the IceBridge and draft data from the upward-looking sonar are used to validate our thickness *** show that the accuracy of our thickness estimates is within 0.2 *** in the Arctic sea ice thickness are analyzed using the PIOMAS model and air and sea surface temperatures.A sharp increase in sea ice thickness is found in 2014.

关键词： CryoSat-2 Arctic sea ice Thickness Global change

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Evaluation of the glacial isostatic adjustment(GIA) models for Antarctica based on GPS vertical velocities

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Science China Earth Sciences 2020年第4期63卷 575-590页

作者： Fei LI Chao MA Shengkai ZHANG Jintao LEI Weifeng HAO Qingchuan ZHANG Wenhao LI chinese Antarctic Center of surveying and mapping Wuhan UniversityWuhan 430079China

Due to the scarcity of data, modeling the glacial isostatic adjustment(GIA) for Antarctica is more difficult than it is for the ancient ice sheet area in North America and Northern Europe. Large uncertainties are observed in existing GIA models for Antarctica. Modern space-based geodetic measurements provide checks and constraints for GIA models. The present-day uplift velocities of global positioning system(GPS) stations at 73 stations in Antarctica and adjacent regions from 1996 to 2014 have been estimated using GAMIT/GLOBK version 10.5 with a colored noise model. To easily analyze the effect of difference sources on the vertical velocities, and for easy comparison with both GIA model predictions and GPS results from Argus et al.(2014) and Thomas et al.(2011), seven sub-regions are divided. They are the northern Antarctic Peninsula, the Filchner-Ronne Ice Shelf, the Amundsen Sea coast, the Ross Ice Shelf, Mount Erebus, inland Southwest Antarctica and the East Antarctic coast,respectively. The results show that the fast uplift in the north Antarctic Peninsula and Pine Island Bay regions may be caused by the elastic response to snow and ice mass loss. The fast subsidence near Mount Erebus may be related to the activity of a magma body. The uplift or subsidence near the East Antarctic coast is very slow while the uplift for the rest regions is mainly caused by GIA. By analyzing the correlation and the associated weighted root mean square(WRMS) between the GIA predictions and the GPS velocities, we found that the ICE-6G_C(VM5a) model and the Geruo 13 model show the most consistency with our GPS results, while the W12a and IJ05_R2 series models show poor consistency with our GPS results. Although improved greatly in recent years, the GIA modeling in Antarctica still lags behind the modeling of the North American. Some GPS stations, for example the Bennett Nunatak station(BENN), have observed large discrepancies between GIA predictions and GPS *** of the

关键词： Antarctica GPS Glacial isostatic adjustment Vertical velocity Uncertainty

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The absolute gravity measurements from A10 along the 1240 km route in East Antarctica

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Science China Earth Sciences 2022年第12期65卷 2417-2420页

作者： Yuande YANG Fei LI Key Laboratory of Polar surveying and mapping Ministry of Natural Resources/Chinese Antarctic Center of Surveying and MappingWuhan UniversityWuhan 430079China

*** Gravity data provide significant insights on ice mass balance and geological structure studies in Antarctica,which is the largest ice sheet on the earth(Xu,2001;Alley et al.,2005).Since the 1950s,the gravity ties have been introduced to Antarctica from Australia and South America(Sledzinski,2001;Amalvict,2004),which adopted the approach of relative gravity measurements with pendulum or spring *** gravity measurements were later conducted in Antarctica by several countries to provide gravity bases and to derive its dynamic change with the technique advance in gravimeter *** 2009,25 absolute gravity surveys had been carried out at 14 stations in Antarctica(Mäkinen et al.,2007;E et al.,2007,2011;Kazama et al.,2013).

关键词： Antarctica East absolute

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