The result analysis of the eigenvectors and principal component time series (PC's) of SON in the first mode show that the relation or the variance of the eigenvectors is positive over the most region of Thailand but it is negative over the western part of southern region of Thailand, as shown in figure 3.11(a).Figure 3.9(b) shows the values of standardized (PC’s), which have positive and negative values. It was found that there was the most negative in 1964 found over the western part of southern region of Thailand there was high rainfall. On the contrary, there was the most positive in 2002 there was low rainfall.