【摘要】 利用NCEP再分析资料对北京地区 1 999～ 2 0 0 3年 7～ 8月出现的 2 4个雷暴大风日相当位温θe 的平均廓线进行了研究。结果表明 ,在对流层底层有一个θe 的极大值 ,在对流层中层 ( 50 0～ 6 6 0hPa)θe 达到其极小值。更多还原

【Abstract】 The reanalysis of NCEP data are used to analyze the average θ e profile characteristics of downburst days in July. and Aug. from 1999 to 2003 in Beijing area. The results show that there is a θ e max at the bottom of troposphere. In addition, there is a θ e min in the middle of troposphere (500—660hPa).更多还原