Global ocean mass variation in recent four years and its spatial and temporal characteristics

Global ocean mass variations in recent four years are computed by use of the data of satellite gravity, satellite altimetry and marine hydrology, and their spatial and temporal characteristics are also analyzed.Monthly GRACE gravity field models during the four years from January 2003 to December 2006 are selected from UTCSR (University of Texas Center for Space Research) , in which the spherical harmonic coefficients of the degree 1 and C_(20) are considered to be substituted.In the data processing, a new filter to remove correlative errors and Gaussian filter are applied, and the leakages of land hydrological signal are corrected to obtain the mass variation component of the sea level change expressed in equivalent water height.The global sea level changes are computed using Jason-1 data in the same duration, and the steric variations are obtained by inversion using monthly ocean temperature and salinity data, so that the mass variations of sea water are determined.The two type maps of the inversed mass variations agree well with each other in the characteristics of yearly variation.Compared to the long-term trends derived from altimetry, GRACE and ocean data observed during 1993 and 2003, we can see that the contribution of global ocean mass variations get larger, and becomes the main factor affecting the global mean sea level rise.