CHARACTERISTICS OF BULK TRANSFER COEFFICIENTS OVER THE TIBETAN PLATEAU

On the basis of data from four sets of AWS installed in Tibet in the observational period of July 1993 to December 1998,according to PRC-Japan Asian Monsoon Cooperative Research Program,the seasonal surface roughness lengthen in each station are determined by the least square method,and the bulk transfer coefficients each day are estimated by using the profile-flux method. The results show that the five years' mean of the bulk transfer coefficient for momentum and heat is 3.53×10-3 to 4.99×10-3 and 4.67×10-3 to 6.73×10-3,respectively.The diurnal and seasonal variations of the bulk transfer coefficients are obvious. In addition,the relationships between the bulk transfer coefficients,the atmospheric stability in the surface layer,surface roughness length and the surface wind velocity are analyzed. Moreover, a preliminary fitting formula for computing the bulk transfer coefficient of momentum using the routine data is also obtained.