ABSTRACT
The word model has a wide range of meanings, but in the context of this chapter, the meaning is restricted to computer code written and developed to simulate flow of glaciers and ice sheets. The primary motivation for developing numerical models of glaciers is to better understand the behavior of glaciers and how they may react to changes in external forcing. These models are commonly based on some fundamental laws or assumptions thought to describe glacier flow. However, these simplifications do not necessarily apply to real ice sheets, and it is therefore of fundamental importance that models are thoroughly evaluated.
