Tidal analysis experiments with sun-synchronous satellite altimeter data

摘要

The ERS-1, ERS-2 and Envisat series of satellite altimeters provide the only extensive datasets that could conceivably be used to constrain ocean tide models in high latitudes. Their sun-synchronous sampling, however, severely limits the observations of solar tides, especially the principal semidiurnal S_2 constituent. The Munk-Cartwright response method is a natural choice when attempting to analyze sun-synchronous data. The present study examines various ways a response analysis might be implemented to extract tides from ERS data. Admittances expressed as simple linear or constant functions of frequency can sometimes improve estimates over standard parameterizations, especially if done in conjunction with a reasonably accurate prior solution. Some form of regularization, such as ridge regression, is also shown to improve the estimates. The approach proves beneficial in a test for the southern Indian Ocean tides. It offers some promise for regions otherwise void of useful observations.