Pressure, Wind and Cloudiness in the Tropical Pacific Related to the Southern Oscillation

Abstract

Maps of regression coefficients of sea level pressure, surface wind and cloudiness on a Southern Oscillation Index are presented for Northern Hemisphere fall and winter. To cheek the significance of the fields obtained, an attempt is made to relate the wind fields to the pressure fields by assuming a balance of the pressure gradient force, the frictional force and the Coriolis force. It turns out that the most conspicuous features of both the wind and cloudiness fields can be derived from the pressure field. It is found that the Southern Oscillation Index is positively correlated with surface easterlies and downward motion near the dateline. Significant fluctuations of the meridional wind are found over the Coral Sea and in the vicinity of the ITCZ.