Abstract
In this study, eddy covariance flux data collected from three research stations on the Tibetan Plateau—Qomolangma for Atmospheric and Environmental Observation and Research, Nam Co for Multisphere Observation and Research, and Southeast Tibet Station for Alpine Environment Observation and Research, Chinese Academy of Sciences—are used to analyze the variation of momentum transfer coefficient (CD), heat transfer coefficient (CH), aerodynamic roughness length (z0m), thermal roughness length (z0h), and excess resistance to heat transfer (kB−1, where k is von Kármán’s constant and B−1 is a non-dimensional bulk parameter). The following results are found. The monthly average surface roughness, bulk transfer coefficient, and excess resistance to heat transfer at all three stations are obtained. The values of average heat bulk transfer coefficients are larger than those of average momentum bulk transfer coefficients at all three stations. The parameter kB−1 exhibits clear diurnal variations with lower values in the night and higher values in the daytime, especially in the afternoon. Negative values of kB−1 are often observed in the night for relatively smooth surfaces on the Tibetan Plateau, indicating that heat transfer efficiency may exceed that of momentum transfer.
Bulk transfer coefficients of momentum and sensible heat over semiarid grassland surface and their parameterization scheme
