Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Diurnal and Seasonal Variations of Surface Fluxes and Boundary Layer over the Tibetan Plateau

Osamu Tsukamoto (1), Hirohiko Ishikawa (2), Shin Miyazaki (3), Joon Kim (4), Yaoming Ma (5), Zeyong Hu (5)

During the GAME-Tibet IOP, surface eddy fluxes were directly measured at four stations@(Amdo, N-PAM, Naqu-BJ, S-PAM) as well as radiation fluxes. These flux data were summarized and compared in the diurnal and seasonal basis. It is very difficult to keep the eddy covariance data for long time, however, the observed flux data at the 4 stations is almost consistent. Other AWS station data are also included in the analysis including topographical information. Another important issue is the interaction between the surface fluxes and the atmospheric boundary layer. Boundary layer data is obtained from radio soundings at Amdo site. Based on the sounding data, monsoon onset is clearly observed as moist air intrusion in the lower layer and warm air intrusion in the upper layer. As the result, the boundary layer tended to be stabilized and vertical momentum transport was suppressed. This can lead to seasonal surface wind diurnal variation. It is also clearly observed in sensible heat flux and mixed layer development, and mixed layer during the daytime leads to large amplitude of diurnal variation in surface wind speed. Based on the preliminary analysis, the diurnal wind variation is most clearly observed at Naqu-BJ site, which is considered to be most flat and ideal site. While, the diurnal wind variation at the other sites are somehow influenced by local topography.

Submittal Information

Name : Date :
    Osamu Tsukamoto
    31-May-01-11:13:10
Organization : Theme :
    Okayama University
    Theme 2
Address : Presentation :
    Department of Earth Sciences, Okayama University, 3-1-1 Tsushima-naka Okayama
    Poster or oral
Country : Abstract ID :
    Japan
    T2OT31May01111310
Phone : Fax :
    +81-86-251-8505
    +81-86-251-8506
E-mail :
    tsuka@cc.okayama-u.ac.jp