グローバルな海面水温とタイの降水量の長期変動

抄録

Thailand locates in sub-tropics, and it has distinct rainy and dry season. The interannual variability of monsoon rainfall is extremely large, which sometimes causes drought and flood in this country. The prediction of the rainfall during rainy season is particularly important in this region, because the dominant agriculture here is paddy. The water deficit or surplus also sways a single or double crops of rice for the year in some particular areas.
For the better understanding of the interannual variability and the prediction of rainfall in Thailand, station raingauge data were collected and analyzed with sea surface temperature by lag-regression. Daily rainfall data from Meteorological Department of Thailand, and SST data from Japan Meteorological Agency were used in monthly scale. The results shows that there are statistically good correlation between them, especially at the Gulf of Thailand and in the tropical Atlantic Ocean. An operational rule using the difference to the former year is proposed and it can predict the excess and shortage of seasonal rainfall by 80% qualitatively. It was also shown that there is a good correlation of interannual variation between Southern Oscillation Index and the rainfall in Thailand.