TY - JOUR
T1 - Temperature-dependent shear flow and the absence of thermal runaway in valley glaciers
AU - Fowler, A. C.
AU - Toja, Raquel
AU - Vázquez, Carlos
PY - 2010/2/8
Y1 - 2010/2/8
N2 - We propose a two-dimensional model of a valley glacier in order to reconsider the question of whether thermal runaway could be a viable mechanism for the onset of creep instability in surging glaciers. We do this by providing an approximate solution for the temperature field based on the idea that shear is concentrated at the glacier bed. With this assumption, we show that a closed-form evolution equation for the glacier profile exists. While this is well known for isoviscous flows, it has not been previously derived for variable viscosity flows. During the process of deriving this equation, we show that thermal runaway does not occur.We provide numerical solutions of the model, and are led to infer that enhanced basal heating owing to refreezing of surface meltwater is an essential constituent in raising the bed temperature to the melting point.
AB - We propose a two-dimensional model of a valley glacier in order to reconsider the question of whether thermal runaway could be a viable mechanism for the onset of creep instability in surging glaciers. We do this by providing an approximate solution for the temperature field based on the idea that shear is concentrated at the glacier bed. With this assumption, we show that a closed-form evolution equation for the glacier profile exists. While this is well known for isoviscous flows, it has not been previously derived for variable viscosity flows. During the process of deriving this equation, we show that thermal runaway does not occur.We provide numerical solutions of the model, and are led to infer that enhanced basal heating owing to refreezing of surface meltwater is an essential constituent in raising the bed temperature to the melting point.
KW - Enhanced heat flux
KW - Glacier model
KW - Temperature-dependent flow
KW - Thermal runaway
UR - http://www.scopus.com/inward/record.url?scp=76049110483&partnerID=8YFLogxK
U2 - 10.1098/rspa.2009.0335
DO - 10.1098/rspa.2009.0335
M3 - Article
AN - SCOPUS:76049110483
SN - 1364-5021
VL - 466
SP - 363
EP - 382
JO - Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
JF - Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
IS - 2114
ER -