Tidal dynamics of the Filchner-Ronne and Larsen C ice shelves from GPS observations and model assimilation
Lead Research Organisation:
Newcastle University
Department Name: Civil Engineering and Geosciences
Abstract
Some of the largest ocean tides in the world are found along the eastern coast of the Antarctic Peninsula and southern extent of the Filchner-Ronne ice shelf (FRIS) where the peak-to-peak tidal range can exceed 7 m. At present, however, our knowledge of the tides under these ice shelves is the most limited of any comparably-sized region on Earth. Mismodelled ocean tides and ocean tide loading propagate into satellite based measurements such as time-variable gravimetry (GRACE) and altimetry (e.g., ICESat), with present tide model uncertainties suggesting possible biases well above the measurement noise of these instruments. Recent exciting measurements have also demonstrated large tidally-driven modulations of ice shelf flow near the Rutford Ice Stream similar in appearance to those previously identified on the Brunt Ice Shelf over 1000 km away, suggesting such modulations may be widespread features and that ice shelves may play a larger role in ice stream flow modulation than previously thought. We propose to study the three dimensional tidal dynamics of the major Weddell Sea ice shelves, namely the FRIS and Larsen C ice shelves, through direct GPS measurements and assimilation into an Antarctic numerical tide model. Regional-scale validation of the improved numerical tide model will be undertaken using onshore GPS measurements of tidal loading. Our results will significantly reduce the systematic error component in geodetic data (e.g., GRACE, CryoSat, GPS) used for key studies in post-glacial rebound, ice shelf thinning and ice sheet mass balance, and improve understanding of the intriguing tidal modulations of ice flow and their driving mechanism(s).
Organisations
Publications
Rosier S
(2017)
Strong tidal variations in ice flow observed across the entire Ronne Ice Shelf and adjoining ice streams
in Earth System Science Data
King M
(2011)
Ocean tides in the Weddell Sea: New observations on the Filchner-Ronne and Larsen C ice shelves and model validation
in Journal of Geophysical Research
King M
(2011)
Nonlinear interaction between ocean tides and the Larsen C Ice Shelf system TIDES AND THE LARSEN C ICE SHELF SYSTEM
in Geophysical Research Letters
King M
(2017)
Non-linear responses of Rutford Ice Stream, Antarctica, to semi-diurnal and diurnal tidal forcing
in Journal of Glaciology
Makinson K
(2012)
Diurnal and semidiurnal tide-induced lateral movement of Ronne Ice Shelf, Antarctica
in Geophysical Research Letters
King M
(2011)
Correction to "Ocean tides in the Weddell Sea: New observations on the Filchner-Ronne and Larsen C ice shelves and model validation"
in Journal of Geophysical Research
Winberry J
(2009)
Basal mechanics of ice streams: Insights from the stick-slip motion of Whillans Ice Stream, West Antarctica
in Journal of Geophysical Research: Earth Surface
Description | We measured the ocean tides in the Weddell Sea region of Antarctica, as experienced by the Filchner-Ronne and Larsen C ice shelves. We used these data to show that present models of ocean tides do not explain the observations with an accuracy better than 5-15cm. We also highlight substantial non-linear tidal energy with unknown origin. The horizontal velocity field |
Exploitation Route | New tide models will be developed to better fit the observed tides; such models are required to correct satellite data of ice elevation or gravity change. The horizontal modulations of flow help constrain grounding line processes and may help constrain the rheology of ice. |
Sectors | Environment,Other |