The southwest monsoon over India and its teleconnections with the middle and upper tropospheric flow patterns over the Southern Hemisphere

Abstract

The paper contains an analysis of the daily synoptic charts of July 1972 between 50° N and the South Pole and between 50° E and 160° E with reference to the activity of the southwest monsoon (summer monsoon) over India. The month commenced with a spell of normally active monsoon for 8 days and ended with a spell of large-scale break in the monsoon for 9 days with two transitional phases in between. There was nearly simultaneous development in the middle-latitude westerlies in the middle and upper troposphere in both the hemispheres especially during the break period. Blocking ridges over and near the Tasman Sea extended far towards the southsoutheast during the break conditions. The pronounced troughs and ridges observed in the meridional profiles along 35° N and 35° S, especially along the latter during break conditions, have been discussed and certain tentative explanations have been put forward regarding the developments in the Southern Hemisphere.