Sensitivity of the divide position at Siple Dome, West Antarctica, to boundary forcing
Open Access
- 1 January 1998
- journal article
- Published by International Glaciological Society in Annals of Glaciology
- Vol. 27, 207-214
- https://doi.org/10.3189/1998aog27-1-207-214
Abstract
A linearized perturbation about a two-dimensional Vialov-Nyc ice-shect profile is used to investigate the sensitivity of the divide position at Siple Dome, West Antarctica, to small changes in the accumulation pattern and in the elevation of its lateral boundaries at the margins of Ice Streams C and D. Relaxation time-scales for the ice-sheet surface and divide position are derived from the perturbation theory. For Siple Dome, these time-scales are short: 450 800 years for surface adjustment, and 200-350 years for divide position adjustment. These short time-scales indicate that Siple Dome responds quickly to forcing at its boundaries. Therefore, the recent migration of the Siple Dome divide (determined from previous work) is probably a response to an ongoing, sustained forcing rather than a response to a long-past climate event such as the transition from the Last Glacial Maximum to the Holocene. Based on our analysis, the inferred rate of migration of the Siple Dome divide could be attained by: (1) a steady increase in the south north spatial accumulation gradient of 0.1-1.5 × 10−9 a −2, or (2) a steady increase (decrease) in elevation of the Siple Dome lateral boundary adjacent to a relict margin of Ice Stream D (Ice Stream C) of 0.005-0.040 m a−1 over the past several thousand years. The required forcing is quite small, and suggests that major changes in the configuration of Ice Streams C and D associated with major changes in the elevation at boundaries of Siple Dome have not occurred over the past several thousand years.Keywords
This publication has 5 references indexed in Scilit:
- Changes in the configuration of ice stream flow from the West Antarctic Ice SheetJournal of Geophysical Research, 1996
- Stochastic perturbation of divide positionAnnals of Glaciology, 1996
- Steady-state thermomechanical modelling of ice flow near the centre of large ice sheets with the finite-element techniqueAnnals of Glaciology, 1996
- Response of the East Antarctica ice sheet to sea‐level riseJournal of Geophysical Research: Oceans, 1984
- Position of Ice Divides and Ice Centers on Ice SheetsJournal of Glaciology, 1973