| Summary: | The Totten Glacier, East Antarctica, drains a sector that contains enough ice to raise global mean sea level byapproximately 4m and geophysical surveys indicate that the Totten Glacier is susceptible to the marine ice sheetinstability. However, the Totten Ice Shelf thickness has fluctuated over recent decades, with no clear evidence tosuggest persistent ice shelf thinning and glacier retreat. We present results from an ice sheet model forced byocean melt rates containing intrinsic variability characteristic of the present day. Basal melting produces an almostinstantaneous response in the ice shelf dynamics, through thickness and velocity changes, with lagged feedbacksto the grounded ice upstream persisting for decades. We find that intrinsic variability in ocean melt rates drivesice shelf thickness and velocity changes that can reproduce the magnitude of observed elevation changes over theTotten Glacier. Changes in mass flux over the grounding line resulting from the variability in ice sheet dynamicsare consistent with the magnitude of ice mass loss over the satellite period. Our results highlight the importanceof accounting for variability in ice sheet dynamics when modelling the evolution of Antarctic glaciers and theircontribution to sea level rise.
|
|---|