juldat Subroutine

public pure subroutine juldat(i, m, k, h, tjd)

This subroutine computes julian date, given calendar date and time. input calendar date must be gregorian. input time value can be in any ut-like time scale (utc, ut1, tt, etc.) - output julian date will have same basis. algorithm by fliegel and van flandern.

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: i

year
integer, intent(in) :: m

month number
integer, intent(in) :: k

day of month
real(kind=wp), intent(in) :: h

ut hours
real(kind=wp), intent(out) :: tjd

julian date

Source Code

    pure subroutine juldat (i,m,k,h,tjd)

    implicit none

    integer,intent(in) :: i !! year
    integer,intent(in) :: m !! month number
    integer,intent(in) :: k !! day of month
    real(wp),intent(in) :: h !! ut hours
    real(wp),intent(out) :: tjd !! julian date

    integer :: jd !! julian day no for day beginning at greenwich noon on given date

    jd = k-32075+1461*(i+4800+(m-14)/12)/4+367*(m-2-(m-14)/12*12)/12 &
        -3*((i+4900+(m-14)/12)/100)/4
    tjd = jd - 0.5_wp + h/24.0_wp

    end subroutine juldat