Variability in equatorial Pacific sea surface topography during the verification phase of the TOPEX/POSEIDON mission

As part of the verification phase of the TOPEX/POSEIDON mission, 10-day gridded fields of altimeter data derived from TOPEX geophysical data records are compared with 10-day gridded fields of dynamic height derived from more than 60 moorings of the Tropical Ocean and Global Atmosphere-Tropical Atmosphere Ocean (TOGA-TAO) array in the equatorial Pacific Ocean. Access to TAO data in real time permits of the first 500 days of the TOPEX/POSEIDON mission to be placed in the context of complementary, in situ measurements of surface winds, sea surface temperatures, and upper ocean thermal structure, as well as the time history of these variables prior to launch. Cross correlations between the two data sets are generally >0.7, with RMS differences <4 cm. However, for reasons not fully understood, correlations drop to <0.5 in certain regions of the equator in the eastern Pacific, and RMS differences can be >5 cm north of the equator in the central and eastern Pacific. -from Authors