source: LMDZ.3.3/branches/LF/libf/dyn3d/juldate.F @ 73

        subroutine juldate(ian,imoi,ijou,oh,om,os,tjd,tjdsec)
c       Sous-routine de changement de date:
c       gregorien>>>date julienne
c       En entree:an,mois,jour,heure,min.,sec.
c       En sortie:tjd
        implicit real (a-h,o-z)
        frac=((os/60.+om)/60.+oh)/24.
        ojou=dfloat(ijou)+frac
            year=dfloat(ian)
            rmon=dfloat(imoi)
        if (imoi .le. 2) then
            year=year-1.
            rmon=rmon+12.
        endif
        cf=year+(rmon/100.)+(ojou/10000.)
        if (cf .ge. 1582.1015) then
            a=int(year/100)
            b=2-a+int(a/4)
        else
            b=0
        endif
        tjd=int(365.25*year)+int(30.6001*(rmon+1))+int(ojou)
     +   +1720994.5+b
        tjdsec=(ojou-int(ojou))+(tjd-int(tjd))
        tjd=int(tjd)+int(tjdsec)
        tjdsec=tjdsec-int(tjdsec)
        return
        end