Detection of seasonal oceanic steric height change using TOPEX/Poseidon satellite altimetry

Over one year of altimeter data from the TOPEX/Poseidon satellite is analyzed to detect the seasonal steric variations in oceanic height. To accurately represent the long wavelength annual oceanographic signal using altimeter data, corrections for errors in the oceanic tidal model are applied to the data and short wavelength mesoscale features are removed. The data are then interpolated to a global grid at one degree resolution. Empirical orthogonal function (EOF) analysis is used to isolate the annual sea surface height variability. The amplitudes and spatial structure of this long wavelength annual signal agree well with climatological estimates of upper layer steric height fields in the mid-latitudes of the Northern Hemisphere