Improving Gravity Anomalies Over China Marginal Sea from Retracked Geosat and ERS-1 Data  

作　　者：WANG Haihong YANG Yuande HWANG Chenway CHU Yonghai MA Xinying 

机构地区：[1]School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China [2]Key Laboratory of Surveying and Mapping Technology on Island and Reef, State Bureau of Surveying and Mapping, 579 Qiangangwan Road, Qingdao 266510, China [3]Department of Civil Engineering, Chiaotung University, Hsingchu 30050, China [4]Geodetic Data Processing Center, State Bureau of Suneying and Mapping, 334 East Youyi Road, Xi'an 710054, China

出　　处：《Geo-Spatial Information Science》2010年第2期144-149,共6页地球空间信息科学学报（英文）

基　　金：Supported by the National Natural Science Foundation of China(No.40704003);the National 973 Program of China(No.2007CB714405);the Key Laboratory of Surveying and Mapping Technology on Island and Reef,State Bureau of Surveying and Mapping,China(No.2009B04)

摘　　要：The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this contribution, three retracking methods (threshold, improved threshold and Beta-5) are investigated with the aim of improving the altimeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models: Sandwell&Smith(V16) and DNSC08.The quality of altimeter data and ocean tide model is critical to the recovery of coastal gravity anomalies. In this con- tribution, three retracking methods （threshold, improved threshold and Beta-5） are investigated with the aim of improving the al- timeter data over a shallow water area. Comparison indicates that the improved threshold is the best retracking method over China Sea. Two ocean tide models, NAO99b and CSR4.0, are analyzed. Results show that different tide models used in the processing of altimeter data may result in differences more than 10 mGal in recovered coastal gravity anomalies. Also, NAO99b is more suitable than CSR4.0 over the shallow water area of China Sea. Finally, gravity anomalies over China Sea are calculated from retracked Geosat/GM and ERS-1/GM data by least squares collocation. Comparison with shipborne gravimetry data demonstrates that gravity anomalies from retracked data are significantly superior to those from non-retracked data. Our results have the same order as the other two altimeter-derived gravity models： Sandwell＆Smith（V 16） and DNSC08.

关 键 词：satellite altimetry waveform retracking gravity anomaly tide model China marginal sea 

分 类 号：P229[天文地球—大地测量学与测量工程]