R and C software for calculating solar zenith angles; time at sunrise, local noon and sunset; and photosynthetically available radiation (PAR) based on date, time and location
AstroCalc4R can be used to compute variables related to solar illuminance at the surface of the earth or ocean. These variables are useful in studying diel effects on biota and in calculating solar energy inputs for ecosystem studies. The software was developed for use with data from NEFSC bottom trawl survey in the Northwest Atlantic but can also be used for aquatic and terrestrial systems.
NOTE: AstroCalcPureRv V2.2 is now available in the R fishmethods library on CRAN. The name of the function has been changed to astrocalc4r in fishmethods.
See: Jacobson, L.D., Hendcrickson, L.C., and Tang, J. 2015. Solar zenith angles for biological research and an expected catch model for diel vertical migration patterns that affect stock size estimates for longfin inshore squid, Doryteuthis pealeii. Canadian Jouranal of Fisheries and Aquatic Sciences. 72: 1329–1338.