Simple analytical models of glacier-climate interactions - by Prof. J ...

Introduction
In these lectures I present simple analytical models of glaciers and the interaction of
glaciers with climate. Do such models make sense in a time that computer power is almost
unlimited?
May be it is a matter of taste.
Glaciers shape their own surface climate. The height-mass balance feedback (HBMfeedback
in the following) is the dominating mechanism. It is a direct consequence of the
fact that the specific balance increases with altitude (and this is because air temperature
decreases with altitude and precipitation increases with altitude). It is the HMB-feedback
that may turn small glaciers into huge ice sheets. Without the HMB-feedback the glacial
cycles of the Pleistocene would not have occurred.
Therefore, if we want to study how glaciers and ice sheets grow and shrink, we need to
know about their geometry. In many cases the details are not important. For instance, if
we prescribe climatic conditions in such a way that the specific balance above the ablation
line is constant, the precise form of the ice sheet-profile above this line does not matter!
For valley glaciers we will see that it is the relation between mean surface elevation and
glacier size that matters.
These lectures do not form a systematic treatment, but have a kaleidoscopic nature. There
is a general idea, however. The philosophy is that glacier-climate interactions should first
of all be considered as a continuity problem, in which the glacier mechanics can be
strongly parameterised and most of the attention goes to the total mass budget.
The material presented in these lectures can also be found in:
• C.J. van der Veen (1999): Fundamentals of Glacier Dynamics. Balkema, 406 pp.
• J. Oerlemans (2001): Glaciers and Climate Change. Balkema, 148 pp.
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