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Model : SolarRadiationDNDC
Simile version : 4.0
Date added : 20041122
Keywords :
Solar radiation ;
Ecophysiology ;
This model estimates the daily solar radiation incident at the earth's surface a given latitude and after passing through an atmosphere of given opacity (the cloudiness parameter in the model). Particularly it estimates:
The equations here were taken from the DNDC model (Li et al., 1992)
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SolarRadiationDNDCP.sml 
Equations in climateP1 Variable AC AC = TA=abs(z2),if TA<0.7 then 1.571atan(TA/(1TA^2)^0.5)else atan((1TA^2)^0.5/TA) Variable DayPAR : PAR (moles/m^2/day) DayPAR = solrad*2.05 Variable Day_Hrs : Length of day (hr) Day_Hrs = 2*(H*24)/(2*3.1416) Variable H : Sun elevation angle at noon (radians) H = if z2>=1 then 0 elseif z2<= 1 then pi()else acos Variable Jday : Day of Year Jday = time() Variable PARc : Daily instantaneous PAR (umol m^2 s^1) PARc = DayPAR/(Day_Hrs*0.0036) Variable Solar Constant : Solar constant (W m^2) Solar Constant = 1367.0 Comments: solar max Lean 1991 Rev. Geophysics 29 Variable Z Z = 0.398*sin(4.869+0.0172*Jday+0.0334*sin(6.224+0.0172*Jday)) Variable acos acos = if z2<0 then 3.1416AC else AC Variable decl : Declination of the sun (radians) decl = if abs(Z)<0.7 then atan(Z/(1Z^2)^0.5)else pi()/2atan((1Z^2)^0.5/Z) Variable lat : Latitude (radians) lat = l=Latitude*pi()/1.8E+02,if abs(l*1.0)>=pi()/2 then sgn(l*1.0)*(pi()/20.01)else l Comments: abs(lat) < 90 degrees Variable psolrad : potential insolation on a horizontal plane, J/m^2/day psolrad = isc*(86400/(3.1416*r*r))*(H*sin(lat)*sin(decl)+cos(lat)*cos(decl)*sin(H)) Where: isc=Solar Constant Variable r : radius vector of the sun r = 1.00.0167*cos(0.0172*(Jday3)) Variable solrad : Insolation (MJ/m^2/day) solrad = psolrad*cloud/1.0E+06 Variable z2 z2 = (tan(decl)*tan(lat))
Li et al., 1992. A model of nitrous oxide evolution from soil driven by rainfall events: 1. Model structure and sensitivity. Journal of Geophysical Research 97:97599776.
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