Measurements of turbulence transfer in the near-surface layer over the Southeastern Tibetan Plateau

Turbulent flux measurements at Qamdo site over the Tibetan Plateau during TIPEX from May 18 to June 30, 1998 are presented. Sensible heat dominated, accounting for about 66% of the available energy (the sum of net radiation and soil heat flux) prior to the monsoon (dry period), reducing to about 31%, with latent heat increased to about 56% of available energy, in the monsoon season (wet period). Surface energy budget closure on average was about 0.80 (0.85) prior to the monsoon and 0.89 (0.76) during the monsoon using eddy correlation (profile) methods. The sum of latent and sensible heat fluxes calculated from the flux-profile method was smaller by about 15% than that from eddy correlation. Martano's method is used to estimate the surface aerodynamic roughness length z0 and zero plane displacement d from single level sonic anemometer data, giving d = 0.12 m and z0 = 0.08 m. The overall neutral drag coefficient (CDN) and scalar coefficient (CHN) were found to be CDN = 0.0055 and CHN = 0.0059 in the southeastern area of Tibet. Their variations with the mean wind speed at 10 m are discussed.