In the global climatic system, the core of interaction of the surface processes and the atmosphere is energy and mass exchanges. For estimating these exchanges by routine meteorological data, the parameterization formulations involving the bulk transfer coefficients are usually used. Therefore, These bulk transfer coefficients are not only important for indicating the intensity of turbulent transfer but also necessary for dealing with some theoretical and practical problems, such as energy budget computation, diagnostic weather analysis and numerical simulation for the atmospheric circulation or climate. However, it is difficult to obtain appropriate bulk transfer coefficients. Even at present, more studies are laid emphasis on these transfer coefficients in the sea-air interaction, but less study on them in the land processes, especially in the atmospheric surface layer over the Tibetan Plateau. On the data from the Qinghai-Xizang Plateau Meteorological Sciences Experiment (QXPMEX, May-August 1979),Ye and Gao et al. (1979) gave the mean of the bulk transfer coefficient for momentum (i.e. drag coefficient) over the Tibetan Plateau as 8 x 10~(-3), however it also has the smaller value of 4 x 10~(-3) obtained by the energy budget on the Nimbus-7 satellite radiation data (Chen and Reiter et al., 1985), and the smallest value is 1.05 x 10~(-3) computed by the eddy correlation method on TIPEX (May-August 1998) data at Nagqu (Li ,Hong and Sun ,2000). Therefore, there is an obvious dispute about the intensity and distribution of plateau heating because of the different values of bulk transfer coefficients over the Tibetan Plateau (see Table 1).
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