Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Intra-seasonal change in rainfall in Mae Chaem Watershed, Thailand

KURAJI Koichiro (1), OTAKI Satoshi (2), KOWIT Punyatrong (3), SUZUKI Masakazu (1)

In the tropical monsoon Asia, rainy and dry season is distinct, but variation of rainfall pattern during the rainy season was not studied well. Even in the dry season, rainfall may occur especially in the high elevation area, but the characteristics of rainfall in the dry season was also not studied yet. The objective of this research is to examine intra-seasonal rainfall in a mountainous watershed under tropical monsoon climate in Thailand. The data obtained by GAME-T rain gauge network for three rainy and two dry seasons in the Mae Chaem watershed, 3,858 km2, were used in this study. Tipping time data from 15 points located from the top of the mountain to the valley bottom were used with the time resolution of one second. Rainfall amount, duration and intensity, rainfall start and end time, maximum rainfall intensity and diurnal pattern of rainfall was calculated from point measurement data with appropriate definition of a rain event. Considering spatial variability and altitudinal dependence, point information was converted to indicators of rainfall characteristics such as increment for elevation, relation with latitude and longtitude and coefficient of variation were calculated. These indicator itself have information of intra-seasonal variation in rainfall. For example, it was found that in April and October, rainfall was frequently observed but the spatial scale of these rainfall were mostly small, suggesting that pre- and after- monsoon period, different mechanism of rainfall prevail in this region. From the comparison of the diurnal variation in rainfall in each month, the pattern in one month was very different from the other months. In conclusion, there was a considerable intra-annual change in rainfall in the Mae Chaem watershed and this change is essential to determine inter-annual fluctuation in rainfall as well as the water resource in this region.

Submittal Information

Name : Date :
    KURAJI KOICHIRO
    25-May-01-21:34:26
Organization : Theme :
    The Tokyo University Forests
    Theme 2
Address : Presentation :
    1-1-1 Yayoi, Bunkyo, Tokyo
    Poster or oral
Country : Abstract ID :
    Japan
    T2KK25May01213426
Phone : Fax :
    03-5841-5493
    03-5841-5494
E-mail :
    kuraji@uf.a.u-tokyo.ac.jp