Abstract :
Slope aspect is an important geomorphic parameter. The
aspect of a slope controls its solar irradiation, thus affecting
a wide diversity of processes (for a partial review see Moore
et al. 1991). Slope aspect can be calculated from a digital
elevation model using one of several GIS-based algorithms
(e.g. Moore et al. 1991, Burrough & McDonnell 1998).
These algorithms are designed for mid-latitude regions,
calculating slope aspect as an angle relative to grid north. In
polar regions, however, this approach suffers from two
problems:
1. In the commonly-used polar stereographic projections,
grid north is parallel to either the prime meridian (for
the south pole) or the meridian at 180° (for the north
pole) while geographic north varies with longitude.
2. In the polar regions, the direction of geographic north
can vary significantly over a relatively small area.
