Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Seasonal and Interannual Variations in the Troposphere over Indo-China Region

Fumitaka Kikuchi (1), Shin-Ya Ogino (1), Manabu D. Yamanaka (3), Akira Watanabe (4)

In recent years, observational studies on hydrology and meteorology have been proceeded under the GAME-T (GEWEX Asian Monsoon Experiment Tropics) project mainly in Thailand. However, description of climatology around Thailand is not established, so the interpretation of these estimation results from the climatological view point is extremely imperfect. In this study, we attempt to reveal seasonal and interannual variations of wind and temperature in the troposphere over the whole indo-china region by using the NCEP rawinsonde data. We have used the NCEP-collected daily rawinsonde data (1992-97) over the Indo-China region to reveal a broader structure of the troposphere. We have made pentad mean data for wind and temperature at each station. Seasonal variation (annual oscillation) is dominant of all meteorological elements analyzed here. We find strong westerly wind over the troposphere north of Chiang Mai from November to next April. On the other hand, the wind direction is easterly south of Bangkok during the same period. In meridional wind, we find strong southerly at 200-100 hPa levels south of Chiang Mai during the strong westerly wind period. Seasonal variation of temperature is clear over the troposphere north of Chiang Mai. However, south of Chiang Mai it is weak, and the period of the maximum peak of temperature near the surface is shifted from summer to spring. Difference in seasonal march, dry season and rainy season, causes seasonal variation of temperature in region. Westerly wind over the troposphere from March to next April is in particular predominant n 1992 and 1997 during the six years (1992-97). This westerly wind can be seen till the equator in these two periods, although zonal wind is easterly and weak south of Bangkok during these months in the other years. From the seasonal variations of winds and temperature, we find that the region north of Chiang Mai has characteristics of the Extratropics rather than those of the Tropics. We find westerly wind over the whole region from March to April in 1992 and 97. These winds may be related to a signal of the ENSO events occurred just in these years.

Submittal Information

Name : Date :
    Fumitaka Kikuchi
    01-Jun-01-16:59:00
Organization : Theme :
    Graduate School of Science and Technology, Kobe University
    Theme 5
Address : Presentation :
    1-1 Rokkodai-cho Kobe, Hyogo 657-8501, Japan
    Poster or oral
Country : Abstract ID :
    Japan
    T5FK01Jun01165900
Phone : Fax :
    +81 78 803 5787
    +81 78 803 5757
E-mail :
    fkikuchi@shizen.sci.kobe-u.ac.jp