Basal melt beneath Whillans Ice Stream and Ice Streams A and C, West Antarctica

• Main Authors: Ian R. Joughin, Slawek Tulaczyk, Hermann Engelhardt
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: West Antarctica; Whillans; Whillans Ice Stream; Antarc*; Antarctica; Ice Stream A; Ice Stream C
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.523.3516; http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37117/1/02-0847.pdf

We have used a recently derived map of the velocity of Whillans Ice Stream and Ice Streams A and C to help estimate basal melt. Temperature was modeled with a simple vertical advection-dif-fusion equation, “tuned ” to match temperature profiles. We find that most of the melt occurs beneath the tributaries where larger basal shear stresses and thicker ice favors greater melt (e.g., 10-20 mdyr). The occurrence of basal freezing is predicted beneath much of the ice plains of Ice Stream C and Whillans Ice Stream. Modelled melt rates for when Ice Stream C was active suggest there was just enough melt water generated in its tributaries to balance basal freezing on its ice plain. Net basal melt for Whillans Ice Stream is positive due to smaller basal temperature gradi-ents. Modelled temperatures on Whillans Ice Stream, however, were constrained by a single tem-perature profile at UpB. Basal temperature gradients for Whillans B 1 and Ice Stream A may have conditions more similar to those beneath Ice Streams C and D, in which case, there may not be sufficient melt to sustain motion. This would be consistent with the steady deceleration of Whil-lans stream over the last few decades. Topics Ice Streams (3) and Basal boundary conditions (4). March 21,2002 4:17 pm 2 of 18