Basal buoyancy and fast moving glaciers: in defense of analytic force balance

Abstract

Abstract. The geometric approach to force balance advocated by T. Hughes in a series of publications has challenged the analytic approach by implying that the latter does not adequately account for basal buoyancy on ice streams, thereby neglecting the contribution to the gravitational driving force associated with this basal buoyancy. Application of the geometric approach to Byrd Glacier, Antarctica, yields physically unrealistic results and it is argued that this is because of a key limiting assumption in the geometric approach. A more traditional analytical treatment of force balance shows that basal buoyancy does not affect the balance of forces on ice streams, except locally perhaps, through bridging effects.

Tidal Pressurization of the Ocean Cavity Near an Antarctic Ice Shelf Grounding Line

“…Flexure likely does play a role in maintaining the force balance at the grounding zone ice‐ocean interface. Longitudinal bending stresses or bridging stresses, by which the unsupported weight is transferred laterally via shear stress gradients (van der Veen, ), may provide a downward force at high tide and upward force at low tide that opposes the ocean pressure anomaly from glaciostatic pressure at the ice base (Rosier & Gudmundsson, ).…”