program info_KANTHA.f
c   uses version 3.0 of the csr loadtide for loadtide correction
c   use lpeqmt to calculate long period tides
c
c
c   NOTE:  The routine otide modifies the time that is passed to
c          it, if you need the time for something else, save a 
c          copy of the real time.

      implicit double precision (a-h,o-z)
      logical in_sol,pesudo,rad
      real*4 lat,lon,rtide
      double precision t
      dimension time(2),time1(2),rlat(2),rlon(2),u(3,2),v(3,2)

c...Read sample input data file to get time and position. 
c    rlat - north latitude (in degrees, -90 to  90)
c    rlon - east longitude (in degrees,  0  to 360)
c    time - desired time,  Modified Julian Date in days. e.g.,
c     Jan 1, 1992 is 48622.

      rlat(1) = -65.44040
      rlon(1) = 277.80185
      time(1) = 49354.41959

      rlat(2) = -63.10150
      rlon(2) = 291.97490
      time(2) = 49354.50178

      do i = 1,2

c...Convert time to seconds after Jan 1, 1992 desired by the model
c      MJD in days is 48622 for Jan 1, 1992
      time1(i) = (time(i)-48622.0)*86400.d0 

c...Call KANTHA model to compute the tide height
c       in_sol - logical denoting whether tide data exists
c                at desired location
c       tpd    - geocentric ocean tide height in cm
c       tld    - long period tide in cm
c       tod    - loading tide in cm
c       tide   - predicted ocean tide in cm

c conversion to real*4, because that is what otide likes
c  except time, which is real*8.  The time is copied to
c  t, so the real time can be saved.
c

        lat=real(rlat(i))
        lon=real(rlon(i))
        t=time1(i)
        print *,t
        call otide(lon,lat,t,rtide)
        tpd=dble(rtide)
        if (tpd .eq. -999.0) then
          in_sol=.FALSE.
        else
          in_sol=.TRUE.
          tpd=tpd*100.0
        endif

c...Compute long period ocean tide height
        call lpeqmt(time(i)*86400.d0,rlat(i),tld)

c...Compute loading ocean tide height
        call csrtptide(rlat(i),rlon(i),time(i)*86400.d0,tod,in_sol,
     &   u,v,pseudo,rad)

      if (in_sol) then
        tide = tpd+tld+tod
        write(6,1000) rlat(i),rlon(i),time(i),tide,tpd,tld,tod
      else
        write(6,*) 'No tide solution avaliable.'
      endif

      enddo
 1000 format(7F11.4)
      stop
      end 

c...The output data is:
c   -65.4404   277.8019 49354.4196    21.9738    26.1828    -2.3045    -1.9046
c   -63.1015   291.9749 49354.5018    28.1965    32.7134    -2.1931    -2.3238


c  Kantha.1/.2
c  ------ -  -
c       The Kantha  models  [Kantha,  1995]  are  high-resolution,  data-
c  assimilated,   fully  nonlinear  barotropic  ocean  tide  model.   The
c  Kantha.1 solution assimilates tidal values computed using  an  earlier
c  version of the Desai and Wahr model (denoted DW94.0 and based on JGM-2
c  orbits for 69 cycles of T/P data) and coastal tide gauge data  into  a
c  finite  difference, explicit, vertically-integrated barotropic scheme.
c  An orthotide approach is employed to extend the model results  into  a
c  total  of  30 semidiurnal and 30 diurnal tidal frequencies.  The model
c  grid spacing is !0.2^times^0.2! degrees (approximately 22  km  at  the
c  Equator).   The relatively high resolution of the model is expected to
c  provide more accurate tides  in  coastal  oceans  and  marginal  seas,
c  limited  however  by  the  accuracy  of available bathymetric and tide
c  gauge data.  The Kantha.1 represents an improved model which  provides
c  better quality control for assimilation of tide gauge measurements and
c  has been extended to 80 S to cover  Antarctic  oceans.   The  Kantha.2
c  model is a revised model using additional data and assimilates a later
c  version of the Desai-Wahr model (DW95 model).