Incidence {solrad}

Solar Incidence Angle

Description

This function returns solar incidence angle (in degrees) for a given day of year and location and site slope and aspect. The solar incidence angle is the angle between sun's ray and the normal on a surface.

Usage

Incidence(DOY, Lat, Lon, SLon, DS, Slope, Aspect)

Arguments

DOY

Day of year

Lat

Latitude (in degrees)

Lon

Longitude in degrees

SLon

Standard longitude (based on time zone) in degrees

DS

Daylight saving in minutes

Slope

Site slope in degrees

Aspect

Site aspect with respect to the south in degrees

Examples

#Calculating solar incidence angle for two consecutive days on 45 degree latitude and
# 10 degree longitude

DOY <- seq(0, 2, .05)

theta <- Incidence(DOY, Lat = 45, Lon=10, SLon=10, DS=0, Slope = 10, Aspect = 0)
#Note: only the difference between Lon and SLon matters not each value

plot(DOY, theta)