近四年全球海水质量变化及其时空特征分析

本文利用卫星重力、卫星测高和海洋温盐数据反演计算全球海水质量变化，并分析其时空变化特征.卫星重力数据利用2003年1月~2006年12月的GRACE月时变重力场球谐系数，同时考虑替换一阶项和C₂₀项，并进行了相关误差滤波、高斯滤波和陆地水文信号泄漏改正，计算得到海洋等效水高变化；利用相同时间跨度的卫星测高数据和海洋温度、盐度水文观测数据，计算全球海平面变化和比容海平面变化，反演得到海水质量变化.反演的两种海水质量变化的年际变化特征一致性较好.三种数据得到的长期趋势变化，与1993~2003年的结果相比，可以看出，海水质量变化加速，并已成为全球海平面上升的主要因素.

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.