Chinese Coastal Gravity Anomalies from Waveform Retracked Geosat/GM Altimetry

Three retracking methods are compared in the area 117°E-129°E,21°N-41°N of China Sea,and the improved threshold shows the best result,using Geosat/GM waveform data.Least square collocation(LSC) gives a better result than IVM when comparing with the shipborne gravity and gravity anomaly from the improved threshold altimeter data.In order to improve the accuracy of altimeter gravity anomaly,the Guass filter is used and the wavelength is 16 km.The gravity anomalies from the improved threshold are compared with that of KMS02 and V15,the former is best in the East sea and a little worse than the other two in Taiwan area.