GRACE observations of M2 and S2 ocean tides underneath the Filchner‐Ronne and Larsen ice shelves, Antarctica

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Abstract
By processing the GRACE satellite‐to‐satellite tracking data and estimating the temporal gravity fields regionally over the southern polar region with a 5‐day interval, we observed M2 and S2 ocean tides underneath the Filchner‐Ronne and Larsen ice shelves, Antarctica. Based on the predicted aliased periods, we extracted the M2 and S2 signals from the time‐series of 5‐daily mean GRACE regional gravity estimates. The GRACE observations agreed well with the predicted tides from the FES2004 and CATS02.01 models after smoothing the models to the commensurate spatial resolution as GRACE. Overall, the GRACE and the models agreed within 10∼20% difference in the tidal amplitude and 20° in phase for both M2 and S2. Our results suggest that GRACE provides valuable observations of ocean tides, with a spatial resolution as short as 300 km, over the remote area lacking of quality observations, such as the Antarctica ice shelves.