Abstract:According to the problem that signal leakage exists and noise reduction by de-striping is not sufficient in the approach of principal component analysis, we propose an improved method of extracting the signal using the principal component analysis directly from spherical harmonic coefficient. First, the principal component analysis is performed on the spherical harmonic coefficients to extract the main modes. Then, the appropriate filtering method and parameters are selected according to their own noise characteristics in different modes. Finally, the signal extraction is carried out. The GRACE temporal earth gravity field models of 2005-01~2013-12 (108 months) released by CSR are used to extract the equivalent water height signals, and the data of June and December 2006 are compared with unmodified principal component analysis. The results show that the modified method is effective and could both eliminate striping noise and reduce signal leakage.
LI Jie,FAN Dongming,YOU Wei et al. Extraction of GRACE Time-Varying Gravity Field Signal Based on Improved Principal Component Analysis[J]. jgg, 2018, 38(4): 414-421.