Linkage between north pole winter temperatures and summer monsoon rainfall over India

Abstract

An investigation of the possible linkage of the north pole temperatures at 30 mbar (lower stratosphere) for 26 pre-winters (November, 1955-1980), winters (December, 1955-1980; and January, 1956-1981), and springs (March, 1956-1981) with rainfall activity over India for the following 26 summer monsoons (June-September, 1956-1981) has been made. The study suggests an association of the mean warm/cold anomalies in the north pole temperatures at the lower stratosphere during pre-winter, winter and spring with the mean positive/negative percentage departures of rainfall over India during the following summer monsoon. The relationships between anomalies in the north pole temperatures during November and March and the rainfall activity during the following summer monsoons over India are, however, significant and may be responsible for 20 and 10% variabilities in monsoon rainfall. On most of the occasions the wet/dry summer monsoons (percentage departures of rainfall being more than ± 10) in India are preceded by warm/cold anomalies in the north pole winter temperatures at the lower stratosphere during winter. It seems that warm and cold anomalies in the north pole winter temperatures at the lower stratosphere are inter-locked with the oscillations of 500 mbar ridge during the following April over the Indian tropics in some manner which, in turn, influence the rainfall activity over India during the following summer monsoon.