Topex data analysis to infer Earth's rotational fluctuations forced by the oceanic response to atmospheric pressure variations

The oceanic response to atmospheric pressure variations is a dynamic response that depends on the frequency and spatial scale of the forcing. In this dissertation, the actual oceanic response is derived from TOPEX satellite altimeter sea-surface height (SSH) observations (1993--2004) on a 4 degree latitude, 8 degree longitude grid corrected for tides, winds and annual variations. The SSH data obtained from Jet Propulsion Laboratory (JPL) website is already corrected for tides. The wind correction values are from the ECCO model, which had been obtained from JPL. The wind correction has been modified by a "Darwin" correction to insure mass conservation. To eliminate the large annual signal, which might otherwise overwhelm the analysis, a sinusoid of annual period and a trend for 12 years have been removed at each grid location. Pressure data were downloaded from AER in spherical harmonic form. For each harmonic of forcing, a Wiener filter---generalized for complex time series---is used to isolate that portion of the sea-surface height within each gridbox location due to pressure forcing. The input to the Wiener filter was the corrected SSH time series at that location and the desired output was the pressure harmonic time series.;Based on the reduction of the error between the desired and the actual output, this technique appears to be successful (mostly) in isolating that portion of SSH due to individual spherical harmonic pressure coefficients. This pressure-driven portion of the SSH has been used to calculate the associated oceanic currents. Then the combined effect of pressure forced SSH and associated currents on Earth's rotation---polar motion and change in Earth's spin rate---are calculated.;The ocean's response showed a spatial and temporal dependence. The currents due to at least some harmonics of forcing showed higher velocities along East-West direction and seemed to be associated with sectorial harmonics. In contrast, the currents along North-South direction showed peak velocities for zonal harmonics. The rotational effects calculated here are mainly due to the pressure-forced SSH and shows frequency dependence. The excitation due to dynamic barometer shows significant departures from the excitation due to inverted barometer.