The annual glaciohydrology cycle in the ablation zone of the Greenland ice sheet: Part 2. Observed and modeled ice flow

William Colgan, Harihar Rajaram, Robert S. Anderson, Konrad Steffen, H. Jay Zwally, Thomas Phillips, Waleed Abdalati

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

25 Citationer (Scopus)

Abstrakt

Ice velocities observed in 2005/06 at three GPS stations along the Sermeq Avannarleq flowline, West Greenland, are used to characterize an observed annual velocity cycle. We attempt to reproduce this annual ice velocity cycle using a 1-D ice-flow model with longitudinal stresses coupled to a 1-D hydrology model that governs an empirical basal sliding rule. Seasonal basal sliding velocity is parameterized as a perturbation of prescribed winter sliding velocity that is proportional to the rate of change of glacier water storage. The coupled model reproduces the broad features of the annual basal sliding cycle observed along this flowline, namely a summer speed-up event followed by a fall slowdown event. We also evaluate the hypothesis that the observed annual velocity cycle is due to the annual calving cycle at the terminus. We demonstrate that the ice acceleration due to a catastrophic calving event takes an order of magnitude longer to reach CU/ETH ('Swiss') Camp (46km upstream of the terminus) than is observed. The seasonal acceleration observed at Swiss Camp is therefore unlikely to be the result of velocity perturbations propagated upstream via longitudinal coupling. Instead we interpret this velocity cycle to reflect the local history of glacier water balance.

OriginalsprogEngelsk
Sider (fra-til)51-64
Antal sider14
TidsskriftJournal of Glaciology
Vol/bind58
Udgave nummer207
DOI
StatusUdgivet - feb. 2012
Udgivet eksterntJa

Programområde

  • Programområde 5: Natur og klima

Fingeraftryk

Dyk ned i forskningsemnerne om 'The annual glaciohydrology cycle in the ablation zone of the Greenland ice sheet: Part 2. Observed and modeled ice flow'. Sammen danner de et unikt fingeraftryk.

Citationsformater