News & Events

Grad student talk - Seeing sliding from space: Observing and modeling seasonal velocity fluctuations

Thursday, October 08, 2015, 4:00PM - 5:00PM

Speaker

Billy Armstrong

Location:

RL-1 room 269

Full title

Seeing sliding from space: Observing and modeling seasonal velocity fluctuations on Kennicott Glacier, Alaska

Abstract

Glaciers often speed up in summer due to surface-generated meltwater reaching the bed, where it lubricates the ice-bed interface and induces rapid basal motion. We document the seasonal evolution of ice surface velocity on Kennicott Glacier by using cross-correlation of optical satellite imagery. We then use a two-dimensional cross-sectional glacier flow model to estimate the distribution of basal motion required to produce the summer ice surface speedup. We model two end-member sliding patterns to simulate the effects of different types of subglacial drainage and find the model is insensitive to the pattern of basal slip. This may be beneficial for glacier modeling because it suggestes models do not require a detailed representation of subglacial hydraulics to accurately characterize the spatial pattern of the glacier surface speedup.