Air drainage

Using a moving window procedure, I'm attempting to determine where cold air is likely to collect. Cold air is most likely to pool at points where the elevation is a local minimum.

A program written by Darin Cowan allowed me to calculate the following images.

Legend:

yellow: local minimum (ie: centre cell of the moving window is the lowest value in the cell)
blue: flat area (ie: all cells in the moving window are equal)

Areas which are black are offsite, either because they are water bodies or because the center cell was not the lowest value and the area was not "flat".

Air drainage

3x3 window

5x5 window

7x7 window

9x9 window