基于EOF方法长江流域2002～2013年GRACE水储量时空变化研究

TEMPORAL AND SPATIAL VARIATIONS RESEARCH OF GRACE WATER STORAGE CHANGES OVER THE YANGTZE RIVER BASIN IN 2002-2013 BASED ON EOF METHOD

水资源变化一直是国家经济和社会发展的热点问题,GRACE重力卫星为陆地水储量时空变化研究提供了一种新的途径。利用GRACE数据、GLDAS同化数据、TRMM降雨数据,分析了2002年4月~2013年12月长江流域水储量的年际变化规律。同时,GRACE数据与GLDAS、TRMM数据的相关系数分别为0.752、0.634,利用线箱图分析了三个数据的月平均变化规律。最后基于经正交分解方法对GRACE水储量变化进行了分析,结果表明:前三个特征向量方差贡献之和达93.12%,第一特征向量从西南到东北方呈递减趋势,时间系数呈季节性变化,反映了水储量变化的季节性规律;第二特征向量空间上呈明显的东—西分布型,时间系数呈下降趋势;第三特征向量空间上呈现南—北分布型,时间系数在2010年达到最小值。

Water source change has always a hot issue of national economic and social development,GRACE satellite data provides a new way for studying temporal and spatial variation of land reserves.In this paper,GRACE,GLDAS and TRMM datas are used for analyzing the interannual variation of the Yangtze River Basin water reserves from April 2002 to December 2013;the correlation coefficient of GRACE and GLDAS,TRMM datas are 0.752,0.634.and the box plot method is used for the analysis of the variation of the average GRACE,GLDAS and TRMM month datas.Finally,based on EOF method we analyze the GRACE water storage changes,the result shows that the first three eigenvectors' variance is up to 94.12 percent,the EOF1 shows a decreasing trend from the southwest to the northeast,and the time factor is a seasonal variation,reflecting the changes of the water storage in the seasonal pattern;the EOF2 distributes in the east-west pattern,and the time factor decreases from 2003 to 2013;the EOF3 distributes in south-north patter,and the time factor reaches a minimum in 2010.