Multi-Layered Structure of the Wind over the Equatorial Pacific During the Line Islands Experiment

Abstract

Analysis of serial rawinsonde observations over the Line Islands during March and April 1967 reveals a multi-layered wind structure, especially in the meridional component, which changes sign as many as eight times below 20 km. The layering is strongest above 14 and below 9 km, and is most marked near the equator. Very large vertical wind shears are observed, occurring most frequently near the tropopause. It is likely that the most extreme shears are accompanied by considerable turbulence and may, therefore, represent significant kinetic energy sinks. The layered winds above 14 and below 9 km may be associated with vertically propagating waves. The wind variations in the 9–14 km region appear to be linked to changes in position and intensity of circulation features in either hemisphere rather than with a regular progression of wave disturbances.