西北干旱区冬、夏季大气边界层结构对比研究  

Comparison of Atmospheric Boundary Layer in Winter and Summer over Arid Region of Northwest China

作　　者：乔娟[1,2] 张强[1] 张杰[1] 王胜[1] 

机构地区：[1]中国气象局兰州干旱气象研究所甘肃省干旱气候变化与减灾重点实验室中国气象局干旱气候变化与减灾重点开放实验室,甘肃兰州730020 [2]西安市气象局,陕西西安710016

出　　处：《中国沙漠》2010年第2期422-431,共10页Journal of Desert Research

基　　金：国家自然科学基金项目(40575006);干旱基金项目(IAM200615)共同资助

摘　　要：利用2006年6月28日至7月17日和2007年1月1日至1月10日敦煌加强观测期的探空资料,对比分析了位于西北干旱区的敦煌荒漠冬、夏季大气边界层的结构特征和变化规律。分析认为,该地区冬、夏季大气边界层结构一致,但夏季边界层的厚度明显大于冬季。夏季,白天对流边界层顶最高超过3500m,夜间稳定边界层的最大高度平均达到900m左右,而冬季,对流边界层和稳定边界层日最大高度分别较夏季低约2350m和500m,这说明西北干旱区夏季晴天的确存在极端深厚的大气边界层,但这种超厚大气边界层现象在冬季并不出现。冬、夏季大气比湿和风速在边界层的分布特征符合一般规律,夏季比湿普遍大于冬季,且夏季大气比湿随高度变化幅度明显大于冬季。冬季从地表开始就出现逆湿现象,夏季逆湿则出现在60～100m高度范围内。冬、夏季白天与夜间的风速均能呈现出Ekman螺线特征,且夏季地转风风速值与地转偏差均远高于冬季。The vertical structural characteristics of main physical factors over arid region of northwest China in winter and summer are analyzed based on the field intensive observation data of atmospheric boundary layer （ABL） in Dunhuang during the period of 28 June to 17 July 2006 and 1 Jan.to 10 Jan.2007.The results show that structure of ABL is similar in the two seasons,whereas the depth in summer is obviously thicker than that in winter.In summer,the maximal depth of convective boundary layer （CBL） exceeds 3 500 m and the stable boundary layer （SBL） can reach 900 m generally.However,in winter,the maximum depth of CBL and SBL is 2 350 m and 500 m lower than that in summer,respectively.Which indicates the particular deep structure of ABL generally exists in summer,but do not occur in winter.Moreover,the variation of humidity with height in summer is more significant than that in winter.The humidity inversion phenomenon in winter appears from ground surface,whereas in summer it takes place at heights of 60 to 100 m.What＇s more,both in summer and winter the wind velocity always shows Ekman spiral characteristic clearly from daytime to nighttime.The geo-strophic wind in summer and daytime is higher than that in winter and nighttime respectively.

关 键 词：西北干旱区 大气边界层结构 冬、夏季 

分 类 号：P421.3[天文地球—大气科学及气象学]