c  This program reads in initial bio fields and outputs level fields

      parameter (imax=162)
      parameter (jmax=110)

      parameter (maxlev=401)
      dimension rntkml(maxlev),phykml(maxlev),zookml(maxlev),
     .          detkml(maxlev)

      dimension div(4)
      dimension rntkm(4),phykm(4),zookm(4),detkm(4)

C  Open input file
      open(10,file='initbio_layer.asc',status='old',readonly,
     .      carriagecontrol='list')

C  Open output file
      open(11,file='initbio_level.dat',status='new',form='unformatted')

      pi=4.*abs(atan(1.))
      rearth=6370.e5
      dypdeg=pi/180.*rearth
      ymin=-29.*dypdeg
      ymax=+25.*dypdeg
      xmin=0.*dypdeg
      xmax=+80.*dypdeg
      dx=(xmax-xmin)/(imax-2)
      dy=(ymax-ymin)/(jmax-2)

5     continue

      read(10,*)h1b,h2b,h3b,h4b
      read(10,*)rntkm
      read(10,*)phykm
      read(10,*)zookm
      read(10,*)detkm

c  Interpolate to levels
      do m=1,maxlev
c      Find the desired layer
       dep=(m-1)
       if(dep.le.h1b) then
         lay=1
       elseif(dep.le.(h1b+h2b)) then
         lay=2
       elseif(dep.le.(h1b+h2b+h3b)) then
         lay=3
       elseif(dep.le.(h1b+h2b+h3b+h4b)) then
         lay=4
       else
         lay=4
       endif

       rntkml(m)=rntkm(lay)
       phykml(m)=phykm(lay)
       zookml(m)=zookm(lay)
       detkml(m)=detkm(lay)

      enddo

      write(11)rntkml
      write(11)phykml
      write(11)zookml
      write(11)detkml

900   continue

      close(10)
      close(11)

      end