The principal component between the first four modes of monthly mean rainfall anomalies, which are able to account for 79.77% of the total variance and DMI covering a 10-year period from the year 1979 to 1988, are shown in Fig. 9. The strong positive IOD occuring in the years 1982 and 1987 is in contrast correlation with the first four modes of rainfall. In addition, the strong negative IOD in the year 1980 is in contrast correlation with the first four modes of monthly mean rainfall