敦煌和酒泉夏季晴天和阴天边界层气象要素特征分析

利用国家重点基础研究发展规划项目《中国西北干旱区陆-气相互作用观测试验》2000年加强观测期(2000年5月29日～6月9日)敦煌探空观测资料和国家自然科学基金重点项目《绿洲系统能量与水分循环过程观测与数值研究》2004年加强观测期(2004年6月1日～7月16日)酒泉探空观测资料,分析了敦煌和酒泉地区夏季典型晴天和阴天天气下有关气象要素如风、温、湿的时空分布和变化特征,得到了以下结论:夏季,敦煌和酒泉地区大气边界层的东西分量风速(切变)晴天比阴天大;南北分量风速(切变)阴天比晴天大;东西分量风速(切变)比南北分量风速(切变)大。敦煌地区夏季晴天和阴天的风速比酒泉地区的大,但风速切变酒泉地区的要比敦煌地区的大。两地白天(晚上)的对流(稳定)边界层特征在晴天和阴天均很明显;阴天稳定边界层厚度和对流边界层的高度较晴天时的都低。比湿夜间比白天的大,阴天比晴天的大;在敦煌地区和酒泉地区都出现了逆湿现象;强逆湿主要出现在夜间,白天虽然也出现逆湿,但强度普遍较弱。

Weather elements'' characteristics of atmosphere boundary layer over Northwest Arid Area of China in typical day of summer

By using the radiosonde observation data of the National Basic Research Program"Field Experiment on Interaction between Land and Atmosphere over Arid Region in Northwest China" at Dunhuang in the Intensity Observation Period(IOP,May 29 to June 9,2000)and the National Natural Science Foundation of China program "the Study of Observation Experiment and Numerical Simulation on Energy and Moisture Circulation of Oasis System" in Jiuquan in IOP(June to July 16,2004),the temporal and spatial distributions and characteristics of wind velocity,potential temperature and specific humidity of the typical days(clear and cloudy day)in the two regions during summer were analyzed.It was found that the Zonal Wind Components(Meridional Wind Components)and the shears are bigger(smaller)in clear day than those in cloudy day,the Zonal Wind Components are bigger than Meridional Wind Components.The wind speeds at Dunhuang are greater than those at Jiuquan;the shears at Jiuquan are greater than those at Dunhuang.The characteristics of CBL(SBL)in daytime(nighttime)both in clear and cloudy day are obvious in the two regions;besides,the depths of SBL and the height of CBL are higher in clear day than those in cloudy day.The specific humidity of the night is bigger than that of the daytime,and also the specific humidity of the cloudy day is greater than that of the clear day.There are humidity inversion phenomena both at Dunhuang and Jiuquan region and the strong humidity inversion phenomena appear during night time.Although there are also humidity inversion phenomena during daytime,they are weak generally.