RELATIONSHIPS BETWEEN INDIAN-SUMMER MONSOON AND PACIFIC SST SOI TENDENCY FROM WINTER TO SPRING AND THEIR STABILITY/

Relationships of Indian monsoon rainfall with Sea Surface Temperature (SST) and Southern Oscillation Index (SOI) tendencies from DJF to MAM and those between concurrent SST and SOI tendencies are important in v iew of their large-scale character. Some of these have application in the field of forecasting. Bias on these or any other relationships can possibly arise from a few years of extreme data. Whether the bias res ults in suppression of an existing relationship, in creating a relatio nship when none exists, or strenghthening or weakening an existing rel ationship, over any period, needs to be examined, and if found so, the bias should be removed and bias-free relationships should be discusse d and considered for applications. This problem has been examined in r espect of the forementioned relationships by following an objective pr ocedure for removing the bias. Removal of the bias has made a notable difference in respect of the strength as well as significance of the r elationship over some periods, for some relationships. The main featur es of the relationships Free from such bias are: (a) Indian monsoon ra infall and SST tendency from DJF to MAM before as well as after monsoo n are significantly related except within 1904-1940 in respect of rela tionship with tendency before monsoon, (b) Indian monsoon rainfall and SOI tendency before and after monsoon are significantly related over some non-overlapping component periods only, (c) though the best SST-S OI tendency coupling is for DJF to MAM tendency, no coupling is observ ed between these tendencies within 1904-1940, (d) linkage of SST tende ncy from DJF to MAM with the preceding Indian monsoon rainfall appears to be stronger than that with the concurrent SOI tendency and continu es even during the period of no coupling between the tendencies, thus bringing out the dominating active role played by the Indian monsoon.