Atmospheric Water Vapor and Surface Flow Patterns over the Tropical Americas during May–August 1979

Some meteorological features have been examined as part of a more extensive study on general circulation in the eastern Pacific and Central American region. The analysis is based on twice-daily data from May to August 1979. Different FGGE data sets (Level III-b, TIROS-N) were used to obtain fields of precipitable water (PW), 1000 mb wind, and surface water vapor fluxes. The results concerning precipitable water and wind are presented as monthly mean fields. The time and spatial evolution of three layers of PW (surface to 700 mb, 700–500 mb and 500–300 mb) show the synoptic characteristics prevailing during this period. The fields of PW reveal fluctuations that are associated with the number and trajectories of tropical perturbations observed over the Atlantic and Pacific Oceans. The time series of the 1000 mb water vapor flux for latitudinal and longitudinal segments around Mexico and the eastern equatorial Pacific 0cean were determined. The strongest horizontal mean flux takes place over the Gulf of Mexico and the eastern Pacific Ocean. Minimum intensity occurs during August, coincident with the month of observed fewer-than-normal tropical perturbations.