[GRASS-user] solar exergy (r.sun)

[Salvatore Mellino]

Hi,

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?

n: 2399778
minimum: 0
maximum: 5007.23
range: 5007.23
mean: 1847.94
mean of absolute values: 1847.94
standard deviation: 678.436
variance: 460275
variation coefficient: 36.7131 %
sum: 4434638181.5777397156
1st quartile: 1567.93
median (even number of cells): 1825.47
3rd quartile: 2170.94
90th percentile: 2649.47


n: 2399778
minimum: 0
maximum: 5007.23
range: 5007.23
mean: 1847.94
mean of absolute values: 1847.94
standard deviation: 678.436
variance: 460275
variation coefficient: 36.7131 %
sum: 4434638181.5777397156
1st quartile: 1567.93
median (even number of cells): 1825.47
3rd quartile: 2170.94
90th percentile: 2649.47

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…

Thanks

Salvatore