R.sun

Help page

• r.sun manual page

Tips

The speed of r.sun is much higher if r.horizon is used first and the resulting maps are given as input to r.sun. Background: the horizon needs to be computed only one time before, not in every step within r.sun. See the example at the end of the r.sun help page.

Testing

Create an artificial surface containing a Gaussian mound:

r.surf.volcano out=gauss method=gaussian kurtosis=1

Time step

The following three images demonstrate the effects of using different time step parameters.

r.sun -s elevin="gauss" glob_rad="rad.global.30minT" day=180 step=0.5

Default 30 minute time step over a Gaussian mound.

r.sun -s elevin="gauss" glob_rad="rad.global.15minT" day=180 step=0.25

15 minute time step over a Gaussian mound.

r.sun -s elevin="gauss" glob_rad="rad.global.03minT" day=180 step=0.05

3 minute time step over a Gaussian mound.

The 3 minute time step takes roughly ten times as long to run as the 30 minute timestep.

ToDo

• Add support for OpenMP parallelization