declination: Declination

Description Usage Arguments Value Author(s) References Examples

View source: R/declination.R

Description

Computes the declination of the Sun for a given Julian Day.

Usage

1

Arguments

jd

Julian Day.

Value

Declination in degrees and decimal fraction.

Author(s)

Javier G. Corripio

References

http://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. http://www.nrel.gov/docs/fy08osti/34302.pdf

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
declination(JDymd(2012,1,1))

jdays=JD(ISOdate(2012,1:12,21))
declination(jdays)

## Find the solstices to the nearest hour
jdays=JD(seq(ISOdate(2013,1,1),ISOdate(2013,12,31),by='hour'))
decl=declination(jdays)
wintersolstice=which(decl==min(decl))
summersolstice=which(decl==max(decl))
JD(jdays[c(summersolstice,wintersolstice)],inv=TRUE)


## Plot daily changes in declination from 2012 to 2014
jdays=JD(seq(ISOdate(2012,1,1),ISOdate(2014,12,31),by='day'))
plot(declination(jdays),xlab='days from 2012-01-01',ylab='declination')

insol documentation built on May 29, 2017, 3:22 p.m.