solar_times function

Estimation of the sunrise and sunset hour

This function estimates the sunrise and sunset hour for a location, characterized by latitude, and the day of the year (DOY). The function uses the equations by Spencer (1971) and Almorox et al. (2005).

solar_times(latitude, DOY)

Arguments

• latitude: the latitude of the site, in decimal degrees.
• DOY: numeric value or vector specifying the day of the year for which calculations should be done.

Returns

list with Sunrise and Sunset times and Daylength.

Note

Code adapted from the function daylength, of the chillR Package

Examples

# Create a vector with 365 days in sequence and calculate sunrise and
# sunset hours for that year in a site placed a 45.5 N
Days <- seq(1:365)
Sunrise_Sunset <- solar_times(41.5,Days)

References

Almorox J, Hontoria C and Benito M, 2005. Statistical validation of daylength definitions for estimation of global solar radiation in Toledo, Spain. Energy Conversion and Management 46(9-10), 1465-1471

Luedeling E, 2018. chillR: Statistical Methods for Phenology Analysis in Temperate Fruit Trees. R package version 0.70.12. https://CRAN.R-project.org/package=chillR

Spencer JW, 1971. Fourier series representation of the position of the Sun. Search 2(5), 172.