program read_sst
c
c   Sample program showing read statements used to read in MCSST data.
c
c   The MCSST data is on a 1024 X 512 element grid with the origin at
c   90N latitude and 0 degrees longitude.  There are 12 monthly data
c   files for 1989.  Note that the 12 months do not entirely correspond
c   to calender months.  The days over which the data was collected are
c   stored in the files.
c
c
      integer*2 sst(1024,512)   ! SST data in 1/10s degree C
				! -9999 indicates land
                                ! 9999 indicates no data

      integer*2 yr,mon          ! year and month of data

      integer*2 smon,sday       ! month and day of start of defined 'month'

      integer*2 emon,eday       ! month and day of end of defined 'month'

      real j_to_lat, i_to_lon      ! conversion functions
      integer lat_to_j, lon_to_i

      open(8,file='sst8901.dat',form='unformatted')
      read(8) yr,mon
      write(*,*) yr,mon          ! Should be 89, 1 for first data file

      read(8) smon, sday, emon, eday
      write(*,*) smon,sday,emon,eday  ! should have values of 1,5,1,31
                                      ! for first data file.
      read(8) sst
      close(8)

      stop
      end
c
c
c  The following four functions can be used convert    grid  <----> lat/lon.
c
c  



      integer function lat_to_j(lat)
c
c     Function takes a latitude and returns the index of the grid row that
c     latitude falls in.  NOTE: assumes 512 grid cells over 180 degrees and
c     that latitude varies from -90 to 90.
c
      real lat
      lat_to_j=int((90.-lat)*2.844444)+1
      return
      end




      integer function lon_to_i(lon)
c
c     Function takes a longitude and returns the index of the grid column
c     that the longitude falls in.  NOTE: assumes 1024 grid cells over 360
c     degrees and that longitude varies from 0 to 360.
c
      real lon
      lon_to_i=int(lon*2.844444)+1
      return
      end



      real function j_to_lat(j)
c
c     Function takes the index of a grid row and returns the latitude of the
c     center of the grid cells in that row.  NOTE: assumes 512 grid cells
c     over 180 degrees and that latitude varies from -90 to 90.
c
      integer j
      j_to_lat=90.-((float(j)-.5)/2.844444)
      return
      end



      real function i_to_lon(i)
c
c     Function takes the index of a grid column and returns the longitude of
c     the center of the grid cells in that column.  NOTE: assumes 1024 grid
c     cells over 360 degrees and that longitude varies from 0 to 360.
c
      integer i
      i_to_lon=(float(i)-.5)/2.844444
      return
      end