TY - JOUR
T1 - Sensitivity of the frozen/melted basal boundary to perturbations of basal traction and geothermal heat flux
T2 - Isunnguata Sermia, western Greenland
AU - Brinkerhoff, Douglas J.
AU - Meierbachtol, Toby W.
AU - Johnson, Jesse V.
AU - Harper, Joel T.
PY - 2011/12
Y1 - 2011/12
N2 - A full-stress, thermomechanically coupled, numerical model is used to explore the interaction between basal thermal conditions and motion of a terrestrially terminating section of the west Greenland ice sheet. The model domain is a two-dimensional flowline profile extending from the ice divide to the margin. We use data-assimilation techniques based on the adjoint model in order to optimize the basal traction field, minimizing the difference between modeled and observed surface velocities. We monitor the sensitivity of the frozen/melted boundary (FMB) to changes in prescribed geothermal heat flux and sliding speed by applying perturbations to each of these parameters. The FMB shows sensitivity to the prescribed geothermal heat flux below an upper threshold where a maximum portion of the bed is already melted. The position of the FMB is insensitive to perturbations applied to the basal traction field. This insensitivity is due to the short distances over which longitudinal stresses act in an ice sheet.
AB - A full-stress, thermomechanically coupled, numerical model is used to explore the interaction between basal thermal conditions and motion of a terrestrially terminating section of the west Greenland ice sheet. The model domain is a two-dimensional flowline profile extending from the ice divide to the margin. We use data-assimilation techniques based on the adjoint model in order to optimize the basal traction field, minimizing the difference between modeled and observed surface velocities. We monitor the sensitivity of the frozen/melted boundary (FMB) to changes in prescribed geothermal heat flux and sliding speed by applying perturbations to each of these parameters. The FMB shows sensitivity to the prescribed geothermal heat flux below an upper threshold where a maximum portion of the bed is already melted. The position of the FMB is insensitive to perturbations applied to the basal traction field. This insensitivity is due to the short distances over which longitudinal stresses act in an ice sheet.
UR - http://www.scopus.com/inward/record.url?scp=84863012450&partnerID=8YFLogxK
U2 - 10.3189/172756411799096330
DO - 10.3189/172756411799096330
M3 - Article
AN - SCOPUS:84863012450
SN - 0260-3055
VL - 52
SP - 43
EP - 50
JO - Annals of Glaciology
JF - Annals of Glaciology
IS - 59
ER -