Ice flow modulated by tides at up to annual periods at Rutford Ice Stream, West Antarctica
Article first published online: 21 SEP 2007
Copyright 2007 by the American Geophysical Union.
Geophysical Research Letters
Volume 34, Issue 18, September 2007
How to Cite
2007), Ice flow modulated by tides at up to annual periods at Rutford Ice Stream, West Antarctica, Geophys. Res. Lett., 34, L18503, doi:10.1029/2007GL031207., , , and (
- Issue published online: 21 SEP 2007
- Article first published online: 21 SEP 2007
- Manuscript Accepted: 24 AUG 2007
- Manuscript Revised: 8 AUG 2007
- Manuscript Received: 3 JUL 2007
- ice stream flow;
- tidal modulation;
- Antarctic ice stream
 For over 2-years we have collected GPS data ∼40 km upstream of the grounding line on Rutford Ice Stream, West Antarctica. Here we examine deviations from mean downstream flow. Although the record is incomplete during winter, there is clear modulation of flow at semi-diurnal, diurnal, two-weekly, semi-annual, and annual ocean tidal frequencies. This is the first observation of ice stream flow variations over such a long time-period, and such a wide range of frequencies. The ice stream flows fastest at equinoxes when there are two semi-diurnal tides of equal magnitude, and slowest at solstices when one of the semi-diurnal tides has lower amplitude. The sensitivity of the downstream flow is greatest to the long-period forcing, which suggests that ice stream velocity may be affected by future changes in sea level. If so, this effect would provide a feedback whereby rising sea levels could increase ice stream velocity and hence discharge.