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Cold Thermal Anomalous Structure within Lower Mantle and Its Geodynamic Implications

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Journal of China University of Geosciences 2001年第2期12卷 160-164页

作者： Xiong Xiong institute of geodesy and {2., Chinese Academy of Sciences, Wuhan 4.0077 institute of Geology and {2., Chinese Academy of Sciences, beijing 100101 hsu houtze institute of geodesy and geophysics, Chinese Academy of Sciences institute of geodesy and {2. Chinese Academy of Sciences institute of Geology and geophysics Chinese Academy of Sciences

The lateral temperature anomalous structure of the lower mantle is reconstructed from the seismic tomographical model and high temperature and high pressure laboratory results. A significant correlation between the distribution of the cold anomaly and the location of past subduction belts shows that the shallower anomaly corresponds to the younger subduction sites, while the deeper anomaly to the older ones. This correlation also suggests that the cold anomaly may have come from the subduction slabs and the scale of mantle convection may have been completed. The coldest and largest anomaly is concentrated near the core mantle boundary (CMB). Few cold anomalies float in the shallower and middle parts of the lower mantle, suggesting that the downward migration of the subduction slabs, discontinuous and step like, may be divided into the following three stages: subduction, stagnation at the 670 km discontinuity due to the phase transition, and disintegration when the size exceeds the critical point.

关键词： lower mantle cold thermal anomaly geodynamic implication.

Wetland vegetation biomass estimation and mapping from Landsat ETM data: a case study of Poyang Lake

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Journal of Geographical Sciences 2002年第1期12卷 35-41页

作者： LI Ren-dong1, 2. LIU Ji-yuan2.(1. institute of geodesy and {2., CAS, Wuhan 4.0077, China 2. institute of Geographic Sciences and Natural Resources Research, CAS, {4. 100101 China) institute of geodesy and {2. CAS Wuhan China institute of Geographic Sciences and Natural Resources Research CAS Beijing China

Poyang Lake is the largest freshwater lake in China. This paper conducted a digital and rapid investigation of the lake’s wetland vegetation biomass using Landsat ETM data acquired on April 16, 2.00. First, utilizing the false color composite derived from the ETM data as one of the main references, the authors designed a reasonable sampling route for field measurement of the biomass, and carried it out on April 18–2., 2.00. Then after both the sampling data and the ETM data were geometrically corrected to an equal-area projection of Albers, linear relationships among the sampling data and some transformed data derived from the ETM data and the ETM 4.were calculated. The results show that the sampling data is best relative to the band 4.data with a high correlation coefficient of 0.86, followed by the DVI and NDVI data with 0.83 and 0.80 respectively. Therefore, a linear regression model, which was based on the field data and band 4.data, was used to estimate the total biomass of entire Poyang Lake, and then the map of the biomass distribution was compiled.

关键词： Poyang Lake biomass wetland vegetation Landsat ETM data

Time Series Correlated Error's Simulation Scheme with the Application to Simulate the Ephemerides Error of CHAMP

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测绘学报 2002年第Z1期31卷 27-30页

作者： SHEN Yun zhong 1 , hsu Hou tse 2.(1. Department of Surveying and Geo informatics,Tongji University,Shanghai 2.0092.China 2. institute of {2. and {2., CAS, Wuhan 4.0077,China) Department of Surveying and Geo-informatics Tongji University 上海 200092 Wuhan 430077

Computer simulation experiment is very important in the phase of project design, the availability of simulated result highly depends on the scheme of error simulation. Time series observations are normally correlated. This paper first discusses the formula of correlated error propagation, then derives the formula of simulating time series correlated errors. This formula is then used to simulate correlated ephemerides errors of CHAMP, then the ephemerides are used to recover the gravity vector at satellite altitude with finite differential formula. The formulae derived in this paper are verified with the difference between the recovered gravity vectors and the `true values’ which are directly computed with the same gravity model as that generating the ephemerides.

关键词： time series observation simulation of correlated errors CHAMP ephemerides

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 geodesy and Earth’s Dynamics,institute of geodesy and geophysics,Chinese Academy of Sciences,Wuhan 4.0077,China 2.Graduate University of Chinese Academy of Sciences,{4. 10004.,China 3 institute of geophysics,Huazhong University of Science and Technology,Wuhan 4.0074.China 1. State Key Laboratory of geodesy 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

Spectral analysis of quasi-stationary sea surface topography from GRACE mission

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Science China Earth Sciences 2005年第11期48卷 2040-2048页

作者： ZHANG Zizhan1,2.& LU Yang1,3 1. institute of geodesy and {2., Chinese Academy of Sciences, Wuhan 4.0077, China 2. Graduate School of the Chinese Academy of Sciences, beijing 100039, China 3. Unite Center for Astro-geodymics Research, Chinese Academy of Sciences, Shanghai 2.0030, China 1. institute of geodesy and {2. Chinese Academy of Sciences 430077 Wuhan China 2. Graduate School of the Chinese Academy of Sciences 100039 Beijing China 3. Unite Center for Astro-geodymics Research Chinese Academy of Sciences 200030 Shanghai China

During the last two decades satellite altimetry has offered an abundance of meas-urements of the sea surface resulting in the improvement of global mean sea surface height (MSSH) and marine geoid determination. On the other hand, with the launching of new genera-tion gravity satellites, some high accuracy long-wavelength gravity models are available. These breakthroughs give us a great opportunity for new estimation of quasi-stationary sea surface topography (QSST). In this paper, the new gravity model GGM01C derived from GRACE mission is briefly presented, and a new global high precision and high-resolution QSST is determined based on the GGM01C model and the global MSSH. The spectral features of the QSST esti-mated by GGM01C and EGM96 gravity model to degree/order 2.0 are discussed by spectral analysis. As a result, the QSST is mainly composed of long waves, medium waves partially and short waves scarcely, its power spectral structures are different between the zonal direction and the meridional direction, there are great differences between the two models, which maybe ex-plain why the ocean currents derived from the two gravity models by Tapley show different pat-terns.

关键词： quasi-stationary sea surface topography, mean sea surface height, GGM01, fast Fourier transform, spectral analysis

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 10004., China 2.institute of {2. and geophysics, Chinese Academy of Sciences, Wuhan 4.0077, China 3 State Key Laboratory of Astronautic Dynamics, Xi’an 71004., China 4.Zhengzhou institute of Surveying and Mapping, Zhengzhou 4.0052. 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

Interactions between hotspots and the Southwest Indian Ridge during the last 90 Ma:Implications on the formation of oceanic plateaus and intra-plate seamounts

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Science China Earth Sciences 2011年第8期54卷 1177-1188页

作者： ZHANG Tao 1,2.3,4.LIN Jian 5 & GAO JinYao 3,4.1 {2. of geodesy and {2.,Chinese Academy of Sciences,Wuhan 4.0077,China 2.Graduate University of Chinese Academy of Sciences,beijing 10004.,China 3 The Second {2. of Oceanography,State Oceanic Administrator,Hangzhou 310012.China 4.Key Laboratory of Submarine Geosciences,State Oceanic Administrator,Hangzhou 310012.China 5 Department of Geology and {2.,Woods Hole Oceanographic Institution,Woods Hole,MA 02.4.,USA 1. institute of geodesy and {2. Chinese Academy of Sciences Wuhan 430077 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China3. The Second Institute of Oceanography State Oceanic Administrator Hangzhou 310012 China4. Key Laboratory of Submarine Geosciences State Oceanic Administrator Hangzhou 310012 China

This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian *** first calculated the relative distance between the Southwest Indian Ridge (SWIR) and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy *** results reveal that the activities of the Marion hotspot can be divided into three main phases:interaction with the paleo-Rodrigues triple junction (73.6-68.5 Ma),interaction with the SWIR (68.5-4..7 Ma),and intra-plate volcanism (4..7-0 Ma).These three phases correspond to the formation of the eastern,central,and western parts of the Del Cano Rise,*** magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge *** periodicity of the Marion hotspot is about 2. Ma,which is much longer than that of the Hawaii and Iceland hotspots (about 15 Ma).

关键词： Southwest Indian Ocean hotspot-ridge interaction magmatic volume flux oceanic plateaus seamounts

Variation properties of ionospheric eclipse factor and ionospheric influence factor

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Progress in Natural Science:Materials International 2005年第6期15卷 573-576页

作者： ZHAO Chunmei 1,2.*, YUAN Yunbin1, OU Jikun1 and CHEN Jinping3(1. institute of geodesy and {2., Chinese Academy of Sciences, Wuhan 4.0077, China 2. Graduate School of Chinese Academy of Sciences, beijing 100039, China 3. Department of Precision Instrument and Mechanology, Tsinghua University, beijing 100084. China) institute of geodesy and {2. Chinese Academy of Sciences Wuhan 430077 China Graduate School of Chinese Academy of Sciences Beijing 100039 China Department of Precision Instrument and Mechanology Tsinghua University Beijing 100084 China

The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

关键词： GPS ionospheric eclipse factor ionospheric influence factor

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 {2., Chinese Academy of Sciences, Wuhan 4.0077, China 2.Key Laboratory of dynamic geodesy, Chinese Academy of Sciences, Wuhan 4.0077, China 3 Graduate University of Chinese Academy of Sciences, {4. 10004., China institute of geodesy and {2. Chinese Academy of Sciences Wuhan 430077 China Key Laboratory of dynamic 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