海面高数据与平均重力异常误差传播的球谐分析

SPHERICAL HARMONIC ANALYSIS OF ERROR PROPAGATION BETWEEN MEAN GRAVITY ANOMALY AND SEA SURFACE HEIGHT DATA

利用球谐分析法建立海面高数据与平均重力异常的误差传播公式,计算不同精度、不同分辨率的海面高数据对应相同分辨率平均重力异常所能达到的精度。实际算例表明,对于5′分辨率的观测数据,球谐分析法与传统的逆Stokes方法较为一致,随着海面高数据分辨率的降低,球谐分析法会造成较大的截断误差,使平均重力异常的精度低于实际精度。

The error propagation formulae between sea surface height and mean gravity anomaly are established by using spherical harmonic method. With these formulae, the accuracies of different resolution of mean gravity anomaly are computed. The computation results show that the spherical harmonic method has the same effects as the traditional inverse Stokes method and could be a reference mean for satellite altimetry accuracy design. The point that should be concerned is that the truncated error will increase quickly with the resolution falling, especially for the resolution smaller than 5＇, so the accuracies of mean gravity anomaly could be estimated worse than the actual results.