Abstract: The thinning and subsequent acceleration of one of Greenland's major outlet glaciers, Jakobshavn Isbrae which doubled its speed starting in 1997 and sustained that speed today, has caught considerable attention. This is because of its potential impact of putting more of Greenland's ice into the ocean, and thereby raising global sea level.  In this talk, background material on the relevant oceanography and glaciology of this particular physical system is given.  A 3-D numerical model of the ocean-ice system is described and analyzed to reveal a non-linear increase in ice melt as a function of ocean temperature.  The equations of the 3-D model are reduced to a simplified set, and via dimensional analysis, the nature of the non-linearity is revealed.   In brief, the melt rate is a function of the product of ocean temperature and ocean velocity, with many other factors being of secondary importance.

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