Characteristics of Energy Transfer and Micrometeorology in the Surface Layer of the Atmosphere in Summer over the Alpine Meadow of the Tibetan Plateau

Based on the observational data of the alpine meadow surface at Litang on eastern slope of the Tibetan Plateau from June to August in 2007, the characteristics of micrometeorology elements and energy fluxes are analyzed in the paper. The drag coefficient is calculated by eddy covariance method. Results show that: the diurnal cycles of micrometeorology elements and turbulence fluxes, such as wind, temperature, sensible heat flux, latent heat flux etc., are evident. The maximum and minimum values of diurnal averaged variations of horizontal wind speed, momentum flux, friction velocity etc., were observed in the afternoon and at sunrise respectively. The average CO2 concentration is high from night to morning and the peak value of specific humidity emerges before sunrise. The maximum and minimum values of diurnal averaged variations of radiation and the components of heat energy balance were observed at noon and sunrise. The surface albedo shows the variations of the U type in a day, with a daily mean value of 0.164. Intensity of surface heat is analyzed to be a heat source in the daytime, while it is not obvious at night. The latent heat transfer plays a dominant role in the heat transfer between the atmosphere and the land surface in summer, while the sensible heat transfer is secondary.