cal_Rsi: Daily inward shortwave solar radiation.

In rpkgs/hydroTools: Tools for hydrological model

Daily inward shortwave solar radiation.

Description

Daily inward shortwave solar radiation at crop surface ⁠[MJ m-2 day-1]⁠ by providing sunshine duration (SSD) in hours or cloud cover in fraction.

Usage

cal_Rsi(lat, J, ssd = NULL, cld = NULL, Z = 0, a = 0.25, b = 0.5)

Arguments

lat	Latitude ⁠[degree]⁠.
J	day of year
ssd	sunshine duration hours. If ssd = NULL, Rsi is the clear-sky solar radiation.
cld	Cloud cover ⁠[fraction]⁠. If provided it would be directly used to calculate solar radiation rather than SSD and parameter a and b.
Z	elevation (m)
a	Coefficient of the Angstrom formula. Determine the relationship between ssd and radiation. Default 0.25.
b	Coefficient of the Angstrom formula. Default 0.50.

Value

A data.table, solar radiation at crop surface ⁠[MJ m-2 day-1]⁠.

• Rsi_toa: Clear-sky surface downward shortwave radiation

• Rsi: Surface downward shortwave radiation

References

1. Martinezlozano J A, Tena F, Onrubia J E, et al. The historical evolution of the Angstrom formula and its modifications: review and bibliography.J. Agricultural & Forest Meteorology, 1985, 33(2):109-128.

2. https://github.com/sbegueria/SPEI/blob/master/R/penman.R

See Also

cal_Rsi_toa(), cal_Rn()

rpkgs/hydroTools documentation built on Oct. 8, 2024, 7:47 p.m.