Shallow water tides in the northwest European shelf region from TOPEX/POSEIDON altimetry

Abstract

During recent years the accurate measurements from the TOPEX/POSEIDON satellite have improved global ocean tide models considerably. However, these global ocean tide models are still not accurate enough on the continental shelves for detailed oceanographic studies. The need for increasing accuracy in shelf regions calls for inclusion of more than just semidiurnal and diurnal constituents in future global ocean tide models. This is because a considerable part of the tidal variability on the shelves is caused by shallow water constituents. One example is the M4 constituent, which exceeds 50 cm at several locations on the northwest European shelf. So far, TOPEX/POSEIDON has not been considered for resolving these constituents, mainly owing to its coarse ground track resolution. Reliable empirical estimates of several major shallow water constituents can be obtained from TOPEX/POSEIDON by combining along‐track and crossover observations. Estimates of the major shallow water constituents for the northwest European shelf, M4, M6, and MS4, are presented in this study and compared with tide gauges and existing hydrodynamic models.