|Title||Reactivation of Kamb Ice Stream tributaries triggers century-scale reorganization of Siple Coast ice flow in West Antarctica|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||Bougamont M., Christoffersen P., Price S.F, Fricker H.A, Tulaczyk S., Carter S.P|
|Journal||Geophysical Research Letters|
|Type of Article||Article|
|Keywords||basal processes; beneath; grounding-line; ice flow modeling; Ice sheet; margins; mass balance; mass-balance; model; radar; ross; sheet dynamics; stagnation; subglacial hydrology; subglacial lake whillans; thermodynamics; West Antarctic|
Ongoing, centennial-scale flow variability within the Ross ice streams of West Antarctica suggests that the present-day positive mass balance in this region may reverse in the future. Here we use a three-dimensional ice sheet model to simulate ice flow in this region over 250years. The flow responds to changing basal properties, as a subglacial till layer interacts with water transported in an active subglacial hydrological system. We show that a persistent weak bed beneath the tributaries of the dormant Kamb Ice Stream is a source of internal ice flow instability, which reorganizes all ice streams in this region, leading to a reduced (positive) mass balance within decades and a net loss of ice within two centuries. This hitherto unaccounted for flow variability could raise sea level by 5mm this century. Better constraints on future sea level change from this region will require improved estimates of geothermal heat flux and subglacial water transport.