Two TOPEX/POSEIDON studies: Steric and tidal ocean modes

Part 1. Determining the contribution of thermal expansion is crucial to understanding long-term sea level changes. In recent years changes in global sea surface height have been measured accurately by the TOPEX/POSEIDON satellite altimetry mission. This accuracy may allow for the identification of the thermal expansion contribution.; Coupled pattern analysis (a method of analyzing physical processes in which two fields are simply and linearly related) is applied to five years of National Centers for Environmental Prediction sea surface temperature (SST) and TOPEX/POSEIDON sea surface height (SSH). It is shown that coupled pattern analysis (CPA) can identify the annually-varying steric signal of the ocean.; When CPA is contrasted to empirical orthogonal function analysis, the two methods are found to produce nearly identical results only when annual and semi-annual terms are removed. The primary mode in a non-seasonal CPA is related to the El Nino-Southern Oscillation. The secondary non-seasonal mode captures most of the secular trends present in both SST and SSH fields over five years. This mode has a significant SST/SSH spatial correlation, indicating that the source of its variability may be, in part, a thermal coupling.; Part 2. Frequently, tidal analysis assumes that the oceans response to tidal forces varies smoothly across each tidal band. However, resonances are known to exist in both the diurnal and semi-diurnal tidal bands. Establishing the effect of these resonances on the {dollar}Psisb1{dollar} tidal component has important implications for solid earth geophysics.; A barotropic ocean model is directly forced in order to isolate the normal modes that resonate in the diurnal tidal band. Forcing an ocean model is a more straightforward approach than directly solving the Laplace tidal equations for confirming that a small number of identifiable normal modes determines the structure of the major tidal components. Insight into the causes of the frequency dependence of the tidal response is gained from this methodology.