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

Abstract

[1] 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 M 2 and S 2 ocean tides underneath the Filchner-Ronne and Larsen ice shelves, Antarctica. Based on the predicted aliased periods, we extracted the M 2 and S 2 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 M 2 and S 2 . 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.

Regional ice-mass changes and glacial-isostatic adjustment in Antarctica from GRACE

“…Shelf may not have been completely removed from the GRACE gravity-field solutions King & Padman, 2005;Han et al, 2005). The bootstrap-estimated mean mass change is 9.0 m ESL (± ca.…”

Accuracy assessment of the monthly GRACE geoids based upon a simulation

“…The main conclusion is that GRACE was never optimized for being able to observe this type of signal as it was done for the T/P mission for tides. Nevertheless, there are advances in this area, such as in Han et al (2005), who have claimed to be able to see an unmodeled ice shelf ocean tide effect in the GRACE data.…”

GRACE, time-varying gravity, Earth system dynamics and climate change

“…These observations do not always cover the high latitudes, so that empirical tidal models are relatively poorly constrained in polar areas. Various studies have used the GRACE intersatellite range-rate observations to invert local tidal mass variations and revealed tidal variations not predicted by tidal models, in particular in the Arctic [296] and Antarctic [e.g., 36, 297] regions.…”

“…Non-isotropic filters have been developed [35,36], but these generally still require a large smoothing radius to remove all stripes in the GRACE maps. A closer inspection of the GRACE Stokes coefficients by Swenson and Wahr [37] revealed that striping patterns could be traced back to correlated errors in the Stokes coefficients of even and odd degree l, respectively.…”