SARAL测高卫星近海域波形重定新方法

利用AVISO提供的SARAL卫星浙江近海海域周年的WAVEFORM数据,通过对卫星波形分析,提出一种新的波形重定方法,该方法在顾及波形物理机制的基础上,根据各波形的特征进行重定。通过对重定前后的波形数据进行粗差剔除、共线平均和对比分析,结果表明:当纬度为27°左右时,未进行波形重定数据求得的平均海面高为10.770 m、标准差为4.515 m,而进行波形重定后数据求得的平均海面高为12.601 m、标准差为1.263 9 m;当纬度为30°左右时,未进行波形重定数据求得的平均海面高为12.236 m、标准差为1.877 m,而进行波形重定后数据求得的平均海面高为12.503 m、标准差为0.419 m。通过对波形重定前后卫星测高数据与验潮站数据对比,得到未进行波形重定的卫星测高数据与验潮站数据差值平均值为0.275 m、标准差为0.273 m,进行波形重定后卫星测高数据与验潮站数据差值平均值为0.046 m、标准差为0.049 m。研究结果显示利用本文提出的方法能显著提高卫星测高数据的精度与质量。

A new method of offshore waveform retracking using SARAL altimetry satellite

Using the annual WAVEFORM data of the Zhejiang offshore area from the SARAL satellite provided by AVISO, we analyzed the satellite waveform and proposed a new method of waveform retracking for offshore areas. With this method, a waveform was retracked according to its characteristics based on the physical mechanism. Through gross error elimination, collinear averaging, and comparison analysis of the waveform before and after retracking, we found that at 27° latitude around, the mean sea level drawn from raw data was 10. 770 m, and the standard deviation was 4. 515 m; the mean sea level drawn from retracked data was 12. 601 m, and the standard deviation was 1. 263 9 m. Around 30° latitude, the mean sea level drawn from raw data was 12. 236 m, and the standard deviation was 1. 877 m; the mean sea level drawn from retracked data was 12. 503 m, and the standard deviation was 0. 419 m. We compared the altimetry data with tidal gauge data, and obtained the following results: the mean difference between the raw data and tidal gauge data was 0. 275 m, and the standard deviation was 0. 273 m; the mean difference between the retracked data and tidal gauge data was 0. 046 m, and the standard deviation was 0. 049 m. The results show that the method discussed in this paper can greatly improve the accuracy and quality of satellite altimetry data.