敦煌夏末大气垂直结构和边界层高度特征

Vertical Atmospheric Structure and Boundary Layer Height in the Summer Clear Days over Dunhuang

本文利用西北干旱区陆-气相互作用野外观测试验(NWC-ALIEX)2008年8月11～18日的探空试验资料,分析了中国西北干旱区敦煌地区的大气垂直结构和边界层高度特征。结果表明,对流层顶大约在距地15000m高度左右,为第二(副热带)对流层顶;水汽主要集中在距地6500m以下对流层,0℃层在距地3000～4000m高度波动,逆湿层高度在0℃层左右摆动;在距地5000m以上的对流层基本被西北风或偏西风统治,在距地9000～13000m左右的对流层高层,存在一个风速为25～50m/s的西北风或偏西风极大值;敦煌夏末存在特厚边界层,对流边界层高度可达4200m,稳定边界层高度可达1300m。

By using the sounding data from 11 to 18 August 2008 collected in the air-land interaction experiment in Northwest China （NWC-ALIEX）,the authors have analyzed the vertical atmospheric structure and boundary layer height in the summer clear days over Dunhuang,China.The results show that the height of the tropopause is at about 15000 m above the ground.It should be the second （subtropical） tropopause.The zero-temperature level varies between 3000 m and 4000 m above the ground.The vapor exists mainly in the lower troposphere below 6500 m above the ground.There is an inverse humidity layer around the zero-temperature level.The westerly and the northwest wind predominate the higher troposphere above 5000 m above the ground.The maximum wind speed of 25-50 m/s occurred between 9000 m and 13000 m above the ground.The thicker atmospheric boundary layers exist in late summer in Dunhuang.The height of the convection boundary layer can reach about 4200 m and the height of the stable boundary layer can be 1300 m.