SolarHourAngle Function

private function SolarHourAngle(time) result(w)

Compute the hour angle. the solar hour angle is an expression of time, hour angle is 0.000 degree, with the time before solar noon expressed as negative degrees, and the local time after solar noon expressed as positive degrees. For example, at 10:30 AM local apparent time the hour angle is -22.5 degree (15 degree per hour times 1.5 hours before noon).

References:

Iqbal, M.: An introduction to solar radiation, Academis Press Canada, Ontario, 1983.

Arguments

Return Value real(kind=float)

FUNCTION SolarHourAngle &
!
(time) &
!
RESULT (w)
    
IMPLICIT NONE

!Arguments with intent(in):
TYPE (DateTime), INTENT(in) :: time

!local declarations:
REAL (KIND = float) :: w ! hour angle [radians]
INTEGER (KIND = short) :: t !hour
!------------------------------------end of declarations-----------------------

t = GetHour (time)
w = 15. * pi / 180. * (t - 12.)

RETURN
END FUNCTION SolarHourAngle