NAME = Zhiqiu Gao ORGANIZATION = Naval Postgaduate School, USA; Chinese Academy of Meteorological Sciences, China ADDRESS = Department of Meteorology, Naval Postgraduate School, Monterey, CA93940, USA COUNTRY = USA, China PHONE = +001(831)656-2539 FAX = +001(831)656-3061 E-MAIL = zgao@nps.navy.mil, zgao2000@yahoo.com POSTER_ONLY = no THEME = T1 DATE = 05-Jun-04-08:27:14 ABSID = T1ZG05Jun04082714 TITLE = Validation of the Louis Scheme in a Central Prairie over the Tibetan Plateau Using Eddy Covariance Techniques AUTHOR_1 = Zhiqiu Gao INSTITUTION_1 = Naval Postgraduate School, USA; Chinese Academy of Meteorological Sciences, China. PRESENTER = AUTHOR_1 ABSTRACT = The Louis scheme [Louis 1979, Louis et al.1982] that was designed for use in atmospheric models was validated using eddy covariance techniques. This scheme was run alone in offline mode with identical atmospheric forcing values that were collected at Naqu flux site in a central prairie over the Tibetan plateau within the GAME/Tibet project frame. This procedure allowed us to better understand whether the Louis scheme could be used for the Tibetan Plateau surface. The validation showed that the Louis scheme estimated turbulent fluxes in good agreement with direct measurements. On average, the extended Louis scheme underestimated wind stress 4.4%, overestimated sensible heat flux 7.9% and estimated latent heat flux well. Statistically, the extended Louis scheme estimated wind stress best, sensible heat flux better and latent heat flux well. The aerodynamic roughness length, , found to be an essential parameter in determining the evolution of the turbulent fluxes, was determined previously by Martano¡¯s method [2000]. The scalar roughness lengths were assumed as . If the Louis scheme was going to be coupled to an atmospheric model, realistic specifications of the roughness lengths were crucial. Also, it was found that the partitioning of fluxes in to sensible and latent portions in monsoon season differs from that prior to monsoon in 1998.