Comparison of Atmospheric Boundary Layer in Winter and Summer over Arid Region of Northwest China
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.
arid region of Northwest Chinastructure of the atmospheric boundary layerwintersummer
NETL
NSTL
万方数据
维普
