1971—2014年内蒙古初霜冻的气候特征及环流因子初步分析

Analysis on the Climate Characteristics and Circulation Factors of First Frost in Inner Mongolia from 1971 to 2014

文章对内蒙古110个气象站1971—2014年初霜冻日期长期变化趋势和突变特征详细分析,表明平均初霜冻日期总体呈现推迟趋势,其中呼伦贝尔市偏西部推迟幅度较大,并在1983和1999年分别两次从相对偏早期跃变为相对偏晚期。从年代际尺度上来看,近期内蒙古初霜日明显推迟。从多年平均初霜日空间分布来看,初霜冻从东到西出现。全区初霜日与9月欧亚500h Pa位势高度及850 h Pa水平风场相关分析的结果显示,内蒙古地区受到高压(低压)系统控制,对应于全区初霜冻日期整体偏晚(早)。与其相对应的当内蒙古地区受偏南风(偏北风)控制时,有利于(不利于)南部的暖湿气流输送到内蒙古,导致初霜冻推迟(提早)。初霜冻偏早年与偏晚年9月500 h Pa高度场的合成分析的结果表明,中纬度环流系统对内蒙古初霜冻发生早、晚起着重要的作用。

The long-term variation features and abrupt change of the first frost dates in 1971—2014 observed at 110 stations in Inner Mongolia are as follow： Most of stations have a late first frost dates,especially in the west side of Hulun Buir. There were abrupt changes in patterns in 1983 and 1999 from partial early to partial late. At the interdecadal time-scales,the first frost date of Inner Mongolia was delayed in the near future. The spatial distribution of years of average first frost dates showed that the first frost appeared from east to west. Correlation coefficients between the first frost dates in Inner Mongolia and the Eurasian 500 h P ageopotential height and the 850 h Pa wind in September indicate that when Inner Mongolia controlled by high（low）, the first frost dates are later（earlier）. The corresponding southerly wind（northerly wind） strengthens（weakens） the wet moisture in southern transportations to Inner Mongolia. It makes the first frost dates late. The late first frost dates and early first frost composite results of 500 h P ageopotential height in September also show that mid latitude circulation systems play important roles in the first frost dates appearing early or late.