边界层高度时间演变及尘卷风对总沙尘量的贡献

摘要

By using the method of dry adiabatic curve,the daily maximum convective boundary layer height (CBLmax) in Dunhuang was calculated and the influence factors were also analyzed.Then the dust devil contribution to dust aerosols were estimated.The results showed that the CBLmax had obviously the annual variations with the single-peak distribution from a minimum in December to a maximum in May.The annual average of CBLmax was 2.2km with an extreme height of nearly 6km.Thermal factors played a dominant role in the CBLmax variation,and cloud amount could affect the variation of CBLmax.More than 54.4％ amount of annual dust aerosols was contributed by dust devils.%采用干绝热曲线法,计算了敦煌地区每日最大对流边界层高度(简称:CBLmax)并分析了可能的影响因子,在此基础上计算出尘卷风对大气年沙尘气溶胶的贡献.结果表明:CBLmax具有非常显著的年变化特征,呈单峰分布,12月最低,5月最高.年平均高度为2.2km,极端时出现接近6km.热力因素对CBLmax的贡献具有决定性,云量的多寡可影响CBLmax的变化.尘卷风的起沙量对大气年均沙尘气溶胶总量的贡献至少在54.4％以上.