我国降水变化趋势的空间特征

SPATIAL PATTERNS OF CHANGE TREND IN RAINFALL OF CHINA

利用 1 951年至 1 996年地面气象记录资料 ,计算了我国全年和季节降水量长期变化趋势特征指数 .结果表明 ,我国长江中下游地区年和夏季降水量呈现明显增加趋势 ;北方的黄河流域降水表现出微弱减少趋势 ,山东和辽宁省夏季雨量减少显著 ;但偏高纬度地区的新疆、东北北部、华北北部和内蒙古降水量或者增加 ,或者变化趋势不明显 .因此 ,1 997年黄河史无前例的断流和 1 998年长江特大洪水的发生 ,均有其相应的区域长期降水气候趋势作为背景条件 .研究还表明 ,我国一些地区降水的季节性也发生了变化 ,其中黄河中上游地区和长江中游地区春、秋季雨量占全年比例均有显著减少 ,而河北东部、辽宁西部和东北科尔沁沙地春季降水相对增加 .

WT5BZ]By using surface data from 1951 to 1996, the long term change trend index of annual and seasonal precipitation of China is calculated. The results show that total annual and summer precipitation over the middle and lower reaches of the Yangtze River increased during the 46 years, and a detectable decline trend in precipitation is found over the Yellow River basin, especially for Shandong and Liaoning provinces.In the high latitude areas such as Xinjiang, Inner Mongolia and North China,however, the change trend in rainfall is not obvious. It is also found that seasonal drift in precipitation occurred in some regions in the period. Rainfall during spring and autumn has significantly decreased over the upper and middle reaches of the Yellow River and the middle reach of the Yangtze River, and increased relatively in spring in eastern Hebei Province, western Liaoning Province and the Horqin Sand Land.[WT5BZ] [WT5HZ]