cal_Rs_from_Na {simET}

Calculating Solar radiation from actual duration of sunshine

Description

Calculating Solar radiation from actual duration of sunshine

Usage

cal_Rs_from_Na(as = 0.25, bs = 0.5, Na, Latitude, J)

Arguments

as

regression constant, expressing the fraction of extraterrestrial radiation reaching the earth on overcast days (n = 0).Default is 0.25.

bs

as+bs is fraction of extraterrestrial radiation reaching the earth on clear days (n = N). Default is 0.50.

Na

actual duration of sunshine [hour].

Latitude

latitude (angert).

J

is the number of the day in the year between 1 (1 January) and 365 or 366 (31 December).

Value

A vector for solar radiation(MJ m-2 d-1)

References

Allen, R. G., Pereira, L. S., Raes, D., & Smith, M. FAO Irrigation and drainage paper No. 56. Rome: Food and Agriculture Organization of the United Nations, 1998.