应用GPCP(全球气候降水计划)数据与地面观测降水资料分析比较了1980年--2006年我国长江中下游地区27年年平均、季平均降水量的空间分布,并给出了1月、4月、7月、10月份两种数据的散点分布图及线性回归方程。结果表明:27年年平均、季平均两种数据具有较好的一致性,能够真实反映长江中下游流域降水的气候变化特征,其中夏季GPCP数据与台站资料差异较大,降水偏少的冬春两季,两者的一致性较高。4个月的相关性分析说明相关系数都在0.9以上,两者具有较好的相似性,7月份的相关系数为0.91低于其他3个月。在验证GPCP数据具有很好的适用性的基础上,分析研究了1980年-2006年长江中下游地区降水演变规律,线性趋势和差积曲线结果表明,20世纪80年代初到中期属丰水期,90年代属枯水期。M-K检验结果说明全流域年降水呈现下降趋势,长江流域内的各二级区年降水无显著变化;四季27年降水量的结果除汉江流域冬季呈显著上升,夏季呈显著下降,太湖流域冬季显著减少,长江中下游流域秋季显著下降外,其它季节无显著性变化。
Applying GPCP (global precipitation climatology project) precipitation dataset and ground-based observations data, analyze and compare the year average and the seasonal mean precipitation of the middle-lower reaches of the Yangtze River in China from 1980 to 2006. Results exposed significantly consistent rainfall distribution between the both datasets in the multi- year mean and multi-year seasonal mean. And we found that the multi-year spring and winter mean of the two datasets also showed a high correlation. Departures of monthly rainfall of the two datasets also showed a high correlation with the correlation coefficient over 0. 9. Based on the above relationships of the two datasets, we used the GPCP to investigate evolution of precipi- tation of the middle-lower reaches of the Yangtze River from 1980 to 2006 year. Positive linear trend and difference curve indica- ted that the middle-lower reaches is in the wet period in mid-1980s, but in 1990s in the dry. Mann-Kendall results indicated that annual precipitation in the Yangtze River showed a downward trend, but no significant changes in other basins. Han River showed a significant upward trend in winter and downward in summer,Taihu Lake Basin a significant reduction in winter,and Yangtze River Basin decreased significantly in the fall. The fluctuation tendency of precipitation is not obvious.