This study analyzed the monthly rainfall data of the Global Precipitation Climatology Centre (GPCC) over Thailand, covering the period of 1971 to 2010 using the Empirical Orthogonal Function (EOF) technique. The most dominant mode accounts for 21.6% of the total variance. The next part was a study of the relationship with ENSO using smoothed anomalies between the Nino 3.4 index and the principal component time series. It was found that the Nino 3.4 SST index leads the rainfall anomalies by 4 months. This study used ENSO event divided into weak and strong intensity classes. It was based on composites of fourteen weak La Nina event, six strong La Nina event, twelve weak El Nino event and six strong El Nino events. It was found that there was high rainfall in La Nina events, whereas there was low rainfall in El Nino events.
The monthly rainfall data of the Global Precipitation Climatology Centre (GPCC) was used to analyzed over Thailand