Chapter 4 Tropical Ocean Variability

Publisher Summary This chapter discusses altimetry and the tropical oceans along with tropical Pacific because it is important for short-term climate and thus the most studied. With some discussion on the Indo-Pacific throughflow, the chapter describes Indian Ocean followed by the tropical Atlantic. With a width nearly half the circumference of the earth, the tropical Pacific is by far the largest of the three tropical oceans. It is subject to a self-sustained air-sea coupled oscillation on interannual time-scales, which is the basis for the El Nino-Southern Oscillation (ENSO). From an oceanic point of view, the equatorial Pacific is separated into a cold tongue in the east and a warm pool in the west. The cold tongue is the signature of the wind-driven equatorial and coastal upwelling. The warm pool exists because of atmospheric heat fluxes at low latitudes and the lack of cold water entrainment from below. It is maintained in the western Pacific as a result of the trade winds and the associated westward surface currents.