内蒙古地区2001年夏季气候特征及前兆信号分析

2001年夏季，内蒙古地区发生了继1999、2000年连续两年的干旱之后的较为严重的全区性干旱。通过分析2001年内蒙古地区夏季气候特征及预测信息，研究内蒙古夏季（1739－2000年中西部地区、1774－2000年东部地区）旱涝气候变化规律，探讨影响内蒙古地区夏季干旱前期信息的变化特征。结果表明，严重干旱年多发生在La Nina事件峰值年次次，环流特征为北半球极涡强度前冬弱后冬强，自上年5月至当年4月呈现出鄂霍次克海高压偏强副高偏弱，并持续3－7个月，继而转成鄂霍次克海高压偏弱副高偏强，并持续2－6个月，可将这些特征作为内蒙古地区夏季严重干旱的前兆信号。

Climatic Characteristics of the Summer Drought in 2001 in Inner Mongolia and Its Signal

Based on analysis of the climatic characteristics of the summer drought in 2001 and the investigation of the climatic features of drought/flood from 1739 to 2000 in the central and western area, from 1774 to 2000 in the eastern area in the Inner Mongolia,the change features of previous signals of summer drought in Inner Mongolia area are discussed. The results show that the severe summer drought in Inner Mongolia occurred in next year after the La Nina event, when the Northern Hemisphere polar vortex is stronger in the early winter but weaker in the late winter, Ockotsk high is stronger and the western Pacific high is weaker, lasting three to seven months, from May in former year to April, then, the Ockotsk high is weaker but the western Pacific high is stronger lasting two to six months. These characteristics can be taken for the signals of severe summer drought in Inner Mongolia.