Salvatore wrote: > I generate 2 maps with r.sun (1 Jan), the first one setting > albedo=0, and the second one setting albedo=2.0 but I > received the same values (look at statistics calculated by > r.univar). Why?
beam_rad only gives you the available incident radiation, not the absorption. As I understand it, albedo is used in the reflection maps in hilly terrain. > My goal is to generate a map for the exergy (available > energy) of solar radiation, so I need a map without diffuse > and reflected radiation. Is it correct to use r.sun and as > output beam_rad or global_rad? and if I set the albedo to > 2.0, is this effect added to the irradiation or is it > subtracted? I hope I was clear… if you want to know all incoming radiation, use the global sum. if you have a very reflective steep hillside positioned to reflect light back on your study site, the reflected radiation map should go up. I'm not sure if that 20% is removed from the steep hillside's value, or if that just stays as available incident light. further experimentation &/or reading the code would be needed to say for sure... Hamish _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
