dr {MeTo}

Inverse relative distance Earth-Sun

Description

Calculate inverse relative distance Earth-Sun for daily and shorther periods.

Usage

dr(x)

Arguments

x

date-time object or Day of the year

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. 23 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).