Rainfall anomalies in summer monsoon months (June to August, JJA) fluctuated from -242 to
465 mm for all stations. This summer monsoon rainfall anomaly positively correlated to DMI
index occurring in the previous summer monsoon (all-station r = 0.23), with stronger
correlation over the North (r = 0.31 to 0.38, see Figure 4 JJA). Chansaengkrachang et al.
(2011) report that strong negative (positive) IOD could cause higher (lower) Thailand rainfall
in corresponding months based on 1979 to 2008 monthly rainfall observations. This is simply
explained by warm SST anomalies, associated with negative IOD event, in the east of the
Indian Ocean lead to more evaporation and more rain and positive IOD event is with reverse
effect (Saji and Yamagata, 2000). In fact, our study also observed relationship between the