Transporte atmosférico de vapor de agua sobre la región de América Tropical de mayo a septiembre de 1979

Abstract

It is analyzed the monthly evolution of the horizontal atmospheric water vapor transport (total, advective and eddy) over the región 40°N a 20°S y I400W a 500W, from May 1st to September 15, 1979. The data is derived from the First GARP Global Experiment, obtained by the European Center for Medium Range Weather Forecasts. The total zonal flux shows that the maximum eas.terly flux is over the tropics between 1 000 and 700 mb; there is a small westerly flux core located over the O- 10°N associated to the cross-equatorial flow from the southern hemisphere. The total meridional flux presents maximum values over the 1 000 to 850 mb layer and it is mainly controlled by the Hadley circulation, thus maintaining the meridional moisture gradient from the equator to the middle-latitudes. The zonal eddy (transient and permanent) flux is much weaker than the total flux; on the other hand the meridional eddy flux is of the same order of magnitude than the total meridional flux, specially outside the equatorial belt (10°N - 10°S), trying to homogenize the atmospheric moisture field. In particular, Mexico is strongly influenced by the easterly flux from the Atlantic Ocean, while over southwestern Mexico a weak summer monsoonal circulation is evidenced.