nightmares (version 0.0.2)

solrad: Solar radiation from air temperature differences

Description

This function is used to estimate the Solar Radiation in MJ/sq.m/day from air temperature differences by using the Hargreaves radiation formula. Please, see the equation 50 from the FAO Irrigation and drainage paper 56.

Usage

solrad(kRs, tmax, tmin, lat, doy)

Arguments

kRs

Adjustment coefficient. Interior locations = 0.16, ..., Coastal locations = 0.19.

tmax

Maximum air temperature in Celsius degrees.

tmin

Minimum air temperature in Celsius degrees.

lat

Latitude in decimal degrees.

doy

Day of the year.

Value

Solar radiation in MJ/sq.m/day.

References

Allen et al., 1998. Crop Evapotranspiration. Guidelines for computing crop water requirements. FAO Irrigation and drainage paper 56. http://www.fao.org/3/X0490E/x0490e00.htm.

Examples

# NOT RUN {
solrad(kRs= 0.19, tmax= 25, tmin= 15, lat= 43.5, doy= 150)

# }