WEM | Water Engineering

Applied Ecohydrology

Sidebar

The extraterrestrial solar radiation can be estimated from simple geometric relationships. The distance between the sun and the earth $d_{se}$ is needed. The formula for the extraterrestrial incoming radiation $S_{ext}$ reads:

$$S_{ex} = 15.392*d_{se} * (\omega_s * sin(\phi)*sin(\delta)+cos(\phi)*cos(\delta)*sin(\omega_s))$$

The result is in $mm/day$ of water that can be evaporated with the corresponding amount of energy. $\phi$ is the latitude.

from pylab import *
from numpy import *
show()