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Validating global hydrological models by ground and space gravimetry

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chinese Science Bulletin 2009年第9期54卷 1534-1542页

作者： ZHOU JiangCun1,2.3, SUN HePing1,2.& XU JianQiao1,2.1 institute of geodesy and geophysics, chinese academy of sciences, {2. 430077, China 2.key laboratory of dynamic geodesy, chinese academy of sciences, {2. 430077, China 3 Graduate University of chinese academy of sciences, Beijing 100049, China institute of geodesy and {2. Chinese Academy of Sciences Wuhan 430077 China key laboratory of {2. geodesy Chinese Academy of Sciences Wuhan 430077 China Graduate University of chinese academy of sciences Beijing 100049 China

The long-term continuous gravity observations obtained by the superconducting gravimeters (SG) at seven globally-distributed stations are comprehensively analyzed. After removing the signals related to the Earth's tides and variations in the Earth's rotation, the gravity residuals are used to describe the seasonal fluctuations in gravity field. Meanwhile, the gravity changes due to the air pressure loading are theoretically modeled from the measurements of the local air pressure, and those due to land water and nontidal ocean loading are also calculated according to the corresponding numerical models. The numerical results show that the gravity changes due to both the air pressure and land water loading are as large as 100×10-9 m s-2.in magnitude, and about 10×10-9 m s-2.for those due to the nontidal ocean loading in the coastal area. On the other hand, the monthly-averaged gravity variations over the area surrounding the stations are derived from the spherical harmonic coefficients of the GRACE-recovered gravity fields, by using Gaussian smoothing technique in which the radius is set to be 600 km. Com-pared the land water induced gravity variations, the SG observations after removal of tides, polar mo-tion effects, air pressure and nontidal ocean loading effects and the GRACE-derived gravity variations with each other, it is inferred that both the ground- and space-based gravity observations can effec-tively detect the seasonal gravity variations with a magnitude of 100×10-9 m s-2.induced by the land water loading. This implies that high precision gravimetry is an effective technique to validate the re-liabilities of the hydrological models.

关键词：重力测量水文模型模型验证和空间地面重力变化季节性波动空气压力

Architecture and application of integrated spatial information service platform for digital mine

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中国有色金属学会会刊：英文版 2011年第S3期21卷 706-711页

作者： ZHANG Jin1, XIAO Jie2.1. College of Mining, Taiyuan University of Technology, Taiyuan 03002., China 2. institute of geodesy and geophysics, chinese academy of sciences, {2. 430077, China Taiyuan Univ Technol Coll Min Taiyuan 030024 Peoples R China chinese Acad Sci Inst Geodesy & Geophys Wuhan 430077 Peoples R China

Using enterprise GIS platform, spatial databases and modern information technology, building geo-spatial information service platform of digital mine which has the features of the data exchange service, enterprise GIS services, directory services, logging services, is key technology and application infrastructure for digital mine. Based on the support of geospatial information service platform of digital mine, the professional GIS application service adapter can be developed and the application supports related to mining application system can be realized. Using high-resolution satellite remote sensing data, the mine functional partition map and geographic grids can be divided, and the geographic grid parts, status and events of important features of the surface object were investigated and defined. The system architecture and technical characteristics of integrated spatial information service platform were analyzed firstly, which guarantee service ability of digital mine. The methods and applications of functional partition map for integrated management service platform were discussed which are the services scheme of digital mine. The application results indicated that digital mine upgrades and enhances the capability and range of mine surveying and mapping, and is of great significance for guarantee of efficient, green and intensive exploitation of mine.

关键词： platform architecture web services application services digital mine

Experimental earth tidal models in considering nearly diurnal free wobble of the Earth's liquid core

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Science Bulletin 2003年第9期48卷 935-940页

作者： SUN Heping, XU Jianqiao & B. Ducarme key laboratory of {2. geodesy, institute of geodesy and geophysics, chinese academy of sciences, wuhan 430077, China Observatoire Royal de Belgique, Av. Circulaire 3, B-1180, Brussels, Belgium Correspondence should be addressed to Sun Heping (e-mail: heping@ ***) 1. key laboratory of {2. geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China 2. Observatoire Royal de Belgique}{srAv. Circulaire 3 B-1180 Brussels Belgium

Based on the 2. series of the high precision and high minute sampling tidal gravity observations at 2. stations in Global Geodynamics Project (GGP) network, the resonant parameters of the Earth's nearly diurnal free wobble (including the eigenperiods, resonant strengths and quality factots) are precisely determined. The discrepancy of the eigenperiod between observed and theoretical values is studied, the important conclusion that the real dynamic ellipticity of the liquid core is about 5% larger than the one under the static equilibrium assumption is approved by using our gravity technique. The experimental Earth's tidal gravity models with considering the nearly diurnal free wobble of the Earth's liquid core are constructed in this study. The numerical results show that the difference among three experimental models is less than 0.1%, and the largest discrepancy compared to those widely used nowdays given by Dehant (1999) and Mathews (2.01) is only about 0.4%. It can provide with the most recent real

关键词： Earth’s nearly diurnal free wobble global observations of superconducting gravimeters dynamic ellipticity of liquid core experimental earth tidal models.

Study on Decision Support System of Agricultural Sustainable Development of Jianli County in Jianghan Plain

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wuhan University Journal of Natural sciences 2000年第3期5卷 334-338页

作者： Wang Xue\|lei, Liu Gong\|hu institute of geodesy and geophysics, chinese academy of sciences, {2. 430077 , China chinese academy of {2. Institute of Geodesy and Geophysics Wuhan China (GRID:grid.9227.e) (ISNI:***)

With the agricultural development and the modernization of decision-making, it is necessary to establish the agricultural sustainable development decision support system supported by GIS. We set Jianli county as an example; our aim is to realize decision spatialiazation with the support of information system, remote sensing and artificial intelligence. The system components are described in the aspects of database, knowledge base, model-base and method-base. This system will provide a workable system for local decision-makers and agricultural management sections.

关键词： key words agricultural sustainable development decision support system system function

Sea level variations in the South China Sea inferred from satellite gravity,altimetry,and oceanographic data

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Science China Earth sciences 2012年第10期55卷 1696-1701页

作者： FENG Wei 1,2.ZHONG Min 1,3 & XU HouZe 1,3 1 State key laboratory of {2. and Earth’s dynamics,institute of {2. and geophysics,chinese academy of sciences,wuhan 430077,China 2.Graduate University of chinese academy of sciences,Beijing 100049,China 3 institute of geophysics,Huazhong University of Science and Technology,wuhan 430074,China 1. State key laboratory of {2. and Earth’s dynamics Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. Institute of Geophysics Huazhong University of Science and Technology Wuhan 430074 China

Sea level variations(SLVs) can be divided into two major components:the steric SLV and the mass-induced *** two components of SLV in the South China Sea(SCS) are studied by using satellite altimetry,GRACE(Gravity Recovery and Climate Experiment) satellite gravity,and oceanographic data on annual and inter-annual *** the annual timescale,the geographic distribution of mass-induced SLV's amplitude jointly estimated from altimetry and the ECCO(Estimation of the Circulation and Climate of the Ocean) model agrees very well with that from *** observes obvious seasonal mass-induced SLV in the SCS with annual amplitude of 2.7±0.4 cm,which is consistent with the annual amplitude of 2.7±0.3 cm estimated from the steric-corrected *** the inter-annual timescales,the mean SLV in the SCS shows a large oscillation,which is mainly caused by the steric *** trend of mean SLV inferred from altimetry in the SCS is 5.5±0.7 mm/yr for the period of 1993-2.09,which is significantly higher than the global sea level rise rate of 3.3±0.4 mm/yr in the same *** is no obvious trend signal in the mass-induced SLV detected from GRACE that indicates the water exchange between the SCS and its adjacent seas and land is in balance within the study period.

关键词： altimetry GRACE ECCO the South China Sea sea level variation

The gravitational gradient tensor’s invariants and the related boundary conditions

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Science China Earth sciences 2010年第5期53卷 781-790页

作者： YU JinHai1,2.3 & ZHAO DongMing4.1 College of Earth Science, Graduate University of chinese academy of sciences, Beijing 100049, China 2.2., chinese academy of sciences, wuhan 430077, China 3 State key laboratory of Astronautic dynamics, Xi’an 710043, China 4 Zhengzhou institute of Surveying and Mapping, Zhengzhou 450052. China 1. College of Earth Science Graduate University of Chinese Academy of Sciences Beijing 100049 China2. Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China3. State Key Laboratory of Astronautic Dynamics Xi’an 710043 China4. Zhengzhou Institute of Surveying and Mapping Zhengzhou 450052 China

Here we report new approaches of recovering the Earth gravitational field from GOCE (Gravity field and steady-state Ocean Circulation Explorer) gradiometric data with the help of the gradient tensor’s invariants. Our results only depend on GOCE satellite’s position and gradiometry, in other words, they are completely independent of the satellite attitude. First, starting from the invariants, linearization models are established, which can be referred as the general boundary conditions on the satellite’s orbit. Then, the spherical approximation expressions for the models are derived, and the corresponding solving methods for them are discussed. Furthermore, considering effects of J2.term, the spherical approximation models are improved so that the accuracies of the boundary conditions can be theoretically raised to O ( J 2.2.T), which is approximately equivalent to O(T2.. Finally, some arithmetic examples are constructed from EGM96 model based on the derived theories, and the computational results illustrate that the spherical models have accuracies of 10-7 and the order recovering the gravitational field can reach up to 2.0, and the models with regard to effect of J2.term have accuracies of 10-8 and the order can reach up to 2.0.

关键词： the Earth’s gravitational field gravitational gravidiometry tensor’s invariant

Optimal carrier-smoothed-code algorithm for dual-frequency GPS data

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Progress in Natural Science:Materials International 2008年第5期18卷 591-594页

作者： Jianfeng Guo a,b, Jikun Ou a, Yunbin Yuan a, Haitao Wang a a key laboratory of Geo{2.s, institute of geodesy and geophysics, chinese academy of sciences, wuhan 430077, China b institute of Science, Information Engineering University, Zhengzhou 450001, China key laboratory of Geo{2.s Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China institute of Science Information Engineering University Zhengzhou 450001 China

Carrier-smoothed-code (CSC) algorithm is an e ective pseudorange multipath mitigation technique, which can alleviate the compu- tational burden and reduce the communication bandwidth needed for the transmission of GPS observations. This paper presents an improved Hatch lter and addresses the optimal CSC algorithm for dual-frequency GPS data based on the optimal parameter estimation theory. The smoothed observations have the same information content as that of the raw dual-frequency GPS data from which these are derived. Consequently, the optimal CSC algorithm is equivalent to the uncombined algorithm. Theoretical analyses show that the data precision of the optimal CSC algorithm is better than that of Hatch lter and its improved version.

关键词： GPS Carrier-smoothed-code algorithm Hatch lter Time-invariant combinations

GRACE detection of the medium-to far-field coseismic gravity changes caused by the 2.04 Mw9.3 Sumatra-Andaman earthquake

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Earthquake Science 2012年第3期25卷 235-240页

作者： Jin Li1,2.3 and Wenbin Shen1,3,4, 1 Department of geophysics, School of geodesy and Geomatics, {2. University, {2. 430079, China 2.key laboratory of Geodynamic geodesy of chinese academy, {2. 430077, China 3 key laboratory of Geospace Environment and geodesy (Ministry of Education), {2. University, {2. 430079, China 4 State key laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, {2. 430079, China 1. Department of geophysics School of Geodesy and Geomatics Wuhan University Wuhan 430079 China 2. key laboratory of Geo{2. geodesy of chinese academy Wuhan 430077 China 3. key laboratory of Geospace Environment and {2. (Ministry of Education) Wuhan University Wuhan 430079 China 4. State key laboratory of Information Engineering in Surveying Mapping and Remote Sensing Wuhan 430079 China

Large earthquakes cause observable changes in the Earth’s gravity field, which have been detected by the Gravity Recovery and Climate Experiment (GRACE). Since most previous studies focus on the detection of near-field gravity effects, this study provides the results from the medium- to far-field gravity changes caused by the 2.04 Sumatra-Andaman earthquake that are recorded within GRACE monthly solutions. Utilizing a spherical-earth dislocation model we documented that large-scale signals predominate in the global field of the coseismic gravity changes caused by the earthquake. After removing the near-field effects, the coseismic gravity changes show a negative anomaly feature with an average magnitude of -0.18×10-8 m·s-2.in the region ranging ～40° from the epicenter, which is considered as the 'medium ffield' in this study. From the GRACE data released by Center for Space Research from August 2.02.to December 2.08, we retrieved the large-scale gravity changes smoothed with 3 000 km Gaussian ffilter. The results show that the coseismic gravity changes detected by GRACE in the medium field have an average of (-0.2.±0.06)×10-8 m·s-2. which agrees with the model prediction. The detection confirms that GRACE is sensitive to large-scale medium-field coseismic gravitational effects of mega earthquakes, and also validates the spherical-earth dislocation model in the medium field from the perspective of satellite gravimetry.

关键词： GRACE medium-to far-field coseismic gravity change 2.04 Sumatra-Andaman earthquake spherical-Earth dislocation model

Ionospheric eclipse factor method (IEFM) for determining the ionospheric delay using GPS data

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Progress in Natural Science:Materials International 2004年第9期 56-60页

作者： YUAN Yunbin* and OU Jikun(key laboratory of {2. geodesy, institute of geodesy and geophysics, chinese academy of sciences, wuhan 430077, China) key laboratory of {2. geodesy Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China

By establishing the ionospheric eclipse factor (IEF) λ of the ionospheric pierce point (IPP) and its ionospheric influence factor (IFF) , and combining λ, with t of IPP, a new method of modeling high precision ionospheric delay using GPS data—ionospheric eclipse factor method (IEFM)—is presented in this paper. The IEFM can effectively select the proper ionospheric models to model the total electron content (TEC) with different changes corresponding to annual, seasonal and diurnal variations. Initial experimental results show that the correction precision of ionospheric delay modeled by the IEFM seems to be close to that of using L3 GPS observations to directly correct the corresponding ionospheric delay.

关键词： global positioning system (GPS) ionospheric delay total electron content ionospheric eclipse factor method.