dlh {MeTo}

Dayligth hours (N)

Description

Dayligth hours in dependence to latitude.

Usage

dlh(x, lat.rad = NULL, lat.deg = NULL)

Arguments

x

date-time object or day of the year

lat.rad

latitude [rad] (either lat.rad or lat.deg). Latitude is positive for the northern hemisphere and negative for the southern hemisphere

lat.deg

latitude [degree] (either lat.rad or lat.deg). Latitude is positive for the northern hemisphere and negative for the southern hemisphere

Details

x:

must be provided as number (1-366) or as a common date-time object (e.g, POSIXct, POSIXlt or Date objects). All formats for which is.timepoint from the lubridate package returns TRUE can be used

Note

eq. 34 of reference

References

Allen, R. G., Pereira, L. S., Raes, D., & Smith, M. (1998). Crop evapotranspiration-Guidelines for computing crop water requirements-FAO Irrigation and drainage paper 56. FAO, Rome, 300(9).

Examples

dlh(x = 105, lat.deg = 13.73)
dlh(x = 105, lat.rad = 0.283)
dlh(x = as.Date('2018-04-15'), lat.deg = 13.73)