Tides on the Ross Ice Shelf observed with ICESat

The Ice, Cloud and land Elevation Satellite (ICESat) provides the first opportunity for measurement of surface elevation h(i) over the portions of the Antarctic ice shelves that are south of the European Remote Sensing (ERS) satellite maximum latitude (81.5 degrees S). The dominant source of short-period variability in h(i) is ocean tides. We use crossover elevation difference (Delta h(i)) data from the Ross Ice Shelf (RIS) to demonstrate ICESat's ability to detect the tidal signal, and to compare the accuracy of several tide models. The root-mean-square (rms) value of all RIS measurements of Delta h(i) is approximate to 0.74 m; after removing the tide using the most accurate model, the rms of the residual signal in regions of optimal model performance is approximate to 0.16 +/- 0.03 m. This value corresponds to an uncertainty in h(i) of 0.11 +/- 0.02 m. We postulate that the primary sources of the residual signal are tide model errors and the inverse barometer effect.