Formation and Structure of Equatorial Anticyclones Caused by Large-Scale Cross-Equatorial Flows Determined by ATS-I Photographs

Abstract Because of poor coverage by synoptic stations, the tropical circulation over the eastern Pacific has not been known too well. As a result of photographic experiments, using the geosynchronous ATS-I satellite, fields of cloud motion over the eastern equatorial Pacific were mapped in detail on a number of days in September 1967. It was found that a large-scale flow from the Southern Hemisphere recurves after crossing the equator to form an anticyclone centered around 10N. Dynamical characteristics of this type of anticyclone were investigated by estimating the vorticity dissipating force from computed values of divergence and vorticity of low-cloud velocities determined from successive ATS-I pictures. The vorticity dissipating force seems to be related closely to the sea-surface temperature which would reduce the frictional coupling between the low-level atmosphere and the underlying sea surface. It was found that the anticyclone in its development stage results in a discontinuity of the intertropi...