Thursday 13 February 2014

Week 5 - Calving events

I remember watching the largest glacier calving ever filmed in Chasing Ice. There is a clip from The Guardian that identifies it as the Ilulissat glacier although it appears to be the Jakobshavn Isbræ. It is an excellent film as is Thin Ice.

The recent paper by M. O’Leary and P. Christoffersen, Calving on tidewater glaciers amplified by submarine frontal melting, they use a finite-element model of stresses near the front of a tidewater glacier to investigate the effects of frontal melting on calving. They refer to earlier modelling studies which focused largely on the effects of basal and surface melting.

Solar and atmospheric warming are likely to increase surface melting.  Melt water that reaches the base of the glacier will increase melting there and by increasing lubrication increase the speed of the glacier.  This will cause calving to increase.

Increasing sea water temperature could increase undercutting of the ice front due to frontal melting considerably increasing the calving rate.

As the glacier calving front retreats the fjord topography may change which could also affect calving rate if the length of the calving front changes.

My thoughts are that the key controlling processes are basal, frontal and surface melting and that the length of the calving front will also have an impact.

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