塔里木盆地夏季热低压的特征分析

Analysis on the Characteristics of Heat Low in Summer over the Tarim Basin

为更好地揭示塔里木盆地热低压的时空变化特征,利用1979-2016年欧洲中期预报中心的再分析资料,采用相关分析和合成分析的方法对塔里木盆地夏季热低压的时空特征和影响因子进行讨论和分析。结果表明,塔里木盆地夏季热低压主要在盆地南部生成,7月最多、强度最强,8月生成的热低压生命史最长。夏季热低压频数、生命史和强度均呈减少和减弱趋势。夜间型(日间型)和短生命史型(长生命史型)热低压频数均呈减少趋势,但对热低压总频数的贡献呈增加(减少)趋势。盆地南部和山区的热力对比及低空东风急流导致盆地南部海平面气压降低,为热低压的生成提供了有利条件。

In order to better reveal the spatio-temporal variation characteristics of heat low in summer over the Tarim Basin,based on the reanalysis dataset provided by the European Centre for Medium-Range Weather Forecasts(ECMWF)during 1979-2016,the spatio-temporal variation characteristics of heat low and its influencing factors are analyzed and discussed by using the methods of correlation and synthetic analysis.The results show that the heat low mainly generates in the southern part of the basin,with the most generated and the strongest intensity in July,and the heat low occurring in August has the longest duration.The frequency,intensity and duration of summer heat low all show a decreasing and weakening trend,but the contribution of the frequency of heat low occurring in night(daytime)or short duration(long duration)to total frequency shows an increasing(decreasing)trend.Furthermore analysis indicates that the thermal contrast between the mountains and the basin and low level easterly jet both are contributed to the decline of sea level pressure over the southern part of the basin,which are favorable to occurrence of heat low.