中文摘要：

选用1958～2002年逐月600hPa2.5°×2.5°ECMWF再分析资料和1961～2000年鄂尔多斯高原夏季降水资料,计算了高原季风指数,分析了高原季风指数的年代际变化及其与鄂尔多斯高原夏季降水的关联。结果表明：近40年来,高原季风总体呈冬季风减弱、夏季风增强的趋势;高原季风的变化与鄂尔多斯高原夏季降水的多少密切相关,高原夏季风增强的年份,同期鄂尔多斯高原降水偏少,高原夏季风偏弱的年份,同期鄂尔多斯高原降水偏多。

英文摘要：

Based on monthly reanalysis data of 600 hPa and 2.5°×2.5°ECMWF for period 1958 - 2002 and the data of summer precipitation in Ordos Plateau during 1961-2000,Qinghai-Xizang plateau monsoon index series indicating monsoon characters in Qing-Xizang plateau was calculated,changes of monsoon in Qinghai-Xizang plateau and its correlation with summer precipitation in Ordos Plateau were analyzed.In recent 40 years,the change of Qinghai-Xizang plateau monsoon index appeared decrease in winter and increase in summer,and the change related closely to the summer precipitation of Ordos Plateau.In the years with strong winter monsoon in Qinghai-Xizang plateau there was more summer precipitation in Ordos Plateau,and vice versa.