Earth and Climate Science, Indian Institute of Science Education and Research, Pune, India
Received: 16 May 2016 – Discussion started: 15 Jun 2016
Abstract. Recent geodetic mass-balance measurements reveal similar thinning rates on glaciers with or without debris cover in the Himalaya–Karakoram region. This comes as a surprise as a thick debris cover reduces the surface melting significantly due to its insulating effects. Here we present arguments, supported by results from numerical flowline model simulations of idealised glaciers, that a competition between the changes in the surface mass-balance forcing and that of the emergence/submergence velocities can lead to similar thinning rates on these two types of glaciers. As the climate starts warming, the thinning rate on a debris-covered glacier is initially smaller than that on a similar debris-free glacier. Subsequently, the rate on the debris-covered glacier becomes comparable to and then larger than that on the debris-free one. The time evolution of glacier-averaged thinning rates after an initial warming is strongly controlled by the time variation of the corresponding emergence velocity profile.
Revised: 20 Dec 2016 – Accepted: 25 Dec 2016 – Published: 18 Jan 2017
Banerjee, A.: Brief communication: Thinning of debris-covered and debris-free glaciers in a warming climate, The Cryosphere, 11, 133-138, doi:10.5194/tc-11-133-2017, 2017.