TRADE WIND FIELD OVER THE PACIFIC OCEAN.

Abstract

The trade wind field over the Pacific Ocean between 30 degree N and 30 degree S has been studied on the basis of five million wind observations made from ships. Data were sorted by quadrangles of 2 degree latitude and 10 degree longitude to resolve north-south gradients in the wind field adequately. Maps of the surface wind stress vector for February and August are presented and the development of the field throughout the year is discussed. The computed divergence of the wind velocity revealed a little known area of convergence in the southeastern Pacific near the equator. Time series of the Pacific Ocean area covered by northeast and southeast trades, the mean zonal wind stress within the area, and the mean zonal wind stress in large, fixed areas are presented for the period from 1947 to 1972. There is no apparent relationship between fluctuations in the strength and areal extent of the northeast and southeast trades, except with the annual cycle.