On the Formulation of Basal Debris Drag for the Case of Sparse Debris

Abstract

Abstract Two models are presented for the formulation of abrasion and basal drag due to rock–rock friction (debris drag) for the case of sparse debris entrained in the basal layers of a temperate glacier resting on a bedrock bed. The first model is formulated in terms of average basal melting rate, v a, and the concentration, C, of basal debris fragments which make intermittent bed contact. The second model is formulated in terms of v n the component of ice velocity normal to the bed flowing around rock fragments contacting the bed, and C c, the concentration of debris actually in contact with the bed. The relationship between the two models is given for the case of a sinusoidal bed. Generalizations are discussed as well as potentially important physical processes which remain to be investigated.