| Abstract: Data for the period from 1985 to 1993 from TAO moorings
along 110°W (5° S-5°N) and 140°W (2°S - 9°N) describe
the vertical, meridional, and temporal structure of the seasonal cycle
of several variables. The results have a number of interesting features.
The amplitude of the seasonal cycle is relatively constant in the surface
layers but varies considerably at the depth of the equatorial thermocline
where it was small before 1989, large thereafter. Also, vertical seasonal
movements of the thermocline have little effect on sea surface temperatures.
These seasonal variations are consistent with a westward propagating coupled
ocean-atmosphere mode in the surface layers. Conversely, the low-frequency
modulation of the seasonal cycle in the thermocline is associated with
changes in the seasonal cycle of the zonal wind in the central and western
tropical Pacific and might be attributable to equatorial Kelvin waves forced
resonantly by the surface winds. |