Gradient

In v0.3.0, a combined coastal and elevation gradient approach is implemented. The method first computes an elevation gradient based on land points only, and then computes a land-sea gradient after correcting points in a neighbourhood with the elevation gradient.

The two gradients are then added.

Elevation gradient

Meteorological variables change predictably with elevation. When a high resolution topography is available, coarse resolution models can be downscaled by fitting the variable to the new topography.

For temperature, a standard 6.5°C/km lapse rate is often applied. In gridpp, this is done using

gridpp <input> <output> -v T -d gradient constantGradient=-0.0065

Land-sea gradient