insol (version 1.2.2)

sunr: Earth radius vector

Description

Calculates the Earth radius vector.

Usage

sunr(jd)

Arguments

jd

Julian Day

Value

Earth Radius Vector in Astronomical Units (AU). This is used to modify the solar constant as a function of the earth-sun distance.

References

https://www.esrl.noaa.gov/gmd/grad/solcalc/calcdetails.html

Meeus, J. 1999. Astronomical Algorithms. Willmann-Bell, Richmond, Virginia, USA.

Reda, I. and Andreas, A. 2003. Solar Position Algorithm for Solar Radiation Applications. 55 pp.; NREL Report No. TP-560-34302, Revised January 2008. https://www.nrel.gov/docs/fy08osti/34302.pdf

Examples

# NOT RUN {
# plot the variation of the earth radius vector over the next year
days_nexty = seq(Sys.time(),Sys.time()+86400*365,by='day')
plot(days_nexty,sunr(JD(days_nexty)),xlab='Date',ylab='Earth Radius Vector [AU]')
abline(h=1,col=8)
# }