近44年青海东部农业区夏季降水变化特征及突变分析

Analysis of the Precipitation Variation Characteristics and its Abrupt Change in Eastern Qinghai

利用青海东部地区12个台站1961-2004年的气象资料,分析了近44年来的降水变化时空分布特征、变化趋势及突变。结果表明：青海东部农业区夏季降水量的总趋势呈水平,降水量无显著变化;对于10年及以上相对较大的时间尺度,17年左右的振荡周期较为明显;而对于10年以下相对较小的时间尺度,8-10年的周期突出;近44年东部夏季降水存在两次突变,分别发生在1970年,降水有弱回升趋势;1999年左右突变,降水有较弱的下降趋势。

Monthly precipitation data of 12 stations in eastern Qinghai from 1961 to 2004 were analyzed.The results indicated that the trend of summer precipitation was invariable change.There was relevant variation of summer precipitation in time in 10 years＇ period or less and the period of 8-10 years was very significant.From the large time scale of equal to or more than 10 years,the period of 17 years was very clear.The abrupt change was detected in eastern Qinghai in 1970 and 1999 separately.