radiation_gases.f

 
 
!  ==========================================================  !!!!!
!              'module_radiation_gases'  description           !!!!!
!  ==========================================================  !!!!!
!                                                                      !
!   set up constant gas profiles, such as co2, ch4, n2o, o2, and those !
!   of cfc gases. All data are entered as mixing ratio by volume       !
!                                                                      !
!   in the module, the externally callabe subroutines are :            !
!                                                                      !
!      'gas_init'   -- initialization                                  !
!         input:                                                       !
!           ( me )                                                     !
!         output:                                                      !
!           ( errflg, errmsg )                                         !
!                                                                      !
!      'gas_update' -- read in data and update with time               !
!         input:                                                       !
!           ( iyear, imon, iday, ihour, ldoco2, me )                   !
!         output:                                                      !
!           ( errflg, errmsg )                                         !
!                                                                      !
!                                                                      !
!      'getgases'   -- setup constant gas profiles for LW and SW       !
!         input:                                                       !
!           ( plvl, xlon, xlat,                                        !
!             IMAX, LMAX )                                             !
!         output:                                                      !
!           ( gasdat )                                                 !
!                                                                      !
!   external modules referenced:                                       !
!       'module machine'                    in 'machine.f'             !
!       'module funcphys'                   in 'funcphys.f'            !
!       'module module_iounitdef'           in 'iounitdef.f'           !
!                                                                      !
!   unit used for radiative active gases:                              !
!      co2   : volume mixing ratio                   (p/p)             !
!      n2o   : volume mixing ratio                   (p/p)             !
!      ch4   : volume mixing ratio                   (p/p)             !
!      o2    : volume mixing ratio                   (p/p)             !
!      co    : volume mixing ratio                   (p/p)             !
!      cfc11 : volume mixing ratio                   (p/p)             !
!      cfc12 : volume mixing ratio                   (p/p)             !
!      cfc22 : volume mixing ratio                   (p/p)             !
!      ccl4  : volume mixing ratio                   (p/p)             !
!      cfc113: volume mixing ratio                   (p/p)             !
!                                                                      !
!                                                                      !
!   program history:                                                   !
!     may 2003 - y-t hou     create rad_module.f that collectively     !
!                  combines several radiation computation supporting   !
!                  programs into fortran 90 module structure (gases    !
!                  and aerosols, etc.)                                 !
!     apr 2004 - y-t hou     modified to add astronomy and surface     !
!                  module components.                                  !
!     feb 2005 - y-t hou     rewrite the component modules into        !
!                  separate individule modules for thier corresponding !
!                  tasks. here as radiation_gases.f                    !
!     mar 2006 - y-t hou     add initialization subroutine to co2 and  !
!                  other gases. historical 2-d co2 data are added.     !
!     sep 2008 - y-t hou     add parameter ictm to control the input   !
!                  data time at the model initial condition.           !
!     oct 2008 - y-t hou     modify the initialization code to add the !
!                  option of superimposing climatology seasonal cycle  !
!                  to the initial condition data (currently co2 only)  !
!     nov 2008 - y-t hou     fix bugs in superimposing climatology     !
!                  seasonal cycle calculations                         !
!     aug 2011 - y-t hou     fix a bug in subr getgases doing vertical !
!                  co2 mapping. (for top_at_1 case, not affact opr).   !
!     nov 2012 - y-t hou     modified control parameters thru module   !
!                  'physparam'.                                        !
!     jan 2013 - z. janjic/y. hou   modified ilon (longitude index)    !
!                  computing formula in subroutine getgases to work    !
!                  properly for models with either of  0->360 or       !
!                  -180->180 zonal grid directions.                    !
!                                                                      !
!                                                                      !
!!!!!  ==========================================================  !!!!!
!!!!!                       end descriptions                       !!!!!
!!!!!  ==========================================================  !!!!!
 
 
 
      module module_radiation_gases      
      use machine,           only : kind_phys, kind_io4
      use funcphys,          only : fpkapx
      use module_iounitdef,  only : nio3clm, nico2cn
!
      implicit   none
!
      private
 
!  ---  version tag and last revision date
      character(40), parameter ::                                       &
     &   VTAGGAS='NCEP-Radiation_gases     v5.1  Nov 2012 '
!    &   VTAGGAS='NCEP-Radiation_gases     v5.0  Aug 2012 '
 
      integer, parameter, public :: nf_vgas = 10   ! number of gas species
      integer, parameter         :: imxco2  = 24   ! input CO2 data longitude points
      integer, parameter         :: jmxco2  = 12   ! input CO2 data latitude points
      integer, parameter         :: minyear = 1957 ! earlist year 2D CO2 data available
 
      real (kind=kind_phys), parameter :: resco2=15.0            ! horizontal resolution in degree
      real (kind=kind_phys), parameter :: prsco2=788.0           ! pressure limitation for 2D CO2 (mb)
      real (kind=kind_phys)  :: raddeg                           ! rad->deg conversion
      real (kind=kind_phys)  :: hfpi                             ! half of pi
 
      real (kind=kind_phys), parameter :: co2vmr_def = 350.0e-6  ! parameter constant for CO2 volume mixing ratio
      real (kind=kind_phys), parameter :: n2ovmr_def = 0.31e-6   ! parameter constant for N2O volume mixing ratio
      real (kind=kind_phys), parameter :: ch4vmr_def = 1.50e-6   ! parameter constant for CH4 volume mixing ratio
      real (kind=kind_phys), parameter :: o2vmr_def  = 0.209     ! parameter constant for O2  volume mixing ratio
      real (kind=kind_phys), parameter :: covmr_def  = 1.50e-8   ! parameter constant for CO  colume mixing ratio
! aer 2003 value
      real (kind=kind_phys), parameter :: f11vmr_def = 3.520e-10
! aer 2003 value
      real (kind=kind_phys), parameter :: f12vmr_def = 6.358e-10
! aer 2003 value
      real (kind=kind_phys), parameter :: f22vmr_def = 1.500e-10
! aer 2003 value
      real (kind=kind_phys), parameter :: cl4vmr_def = 1.397e-10
! gfdl 1999 value
      real (kind=kind_phys), parameter :: f113vmr_def= 8.2000e-11
 
!  ---  module variables to be set in subroutin gas_init and/or gas_update
 
!  arrays for co2 2-d monthly data and global mean values from observed data
 
      real (kind=kind_phys), allocatable :: co2vmr_sav(:,:,:)
      real (kind=kind_phys), allocatable :: co2cyc_sav(:,:,:)
 
      real (kind=kind_phys) :: co2_glb = co2vmr_def
      real (kind=kind_phys) :: gco2cyc(12)
      data gco2cyc(:) / 12*0.0 /
 
      integer :: kyrsav  = 0
      integer :: kmonsav = 1
 
!  ---  public interfaces
 
      public  gas_init, gas_update, getgases
 
 
! =================
      contains
! =================
 
!-----------------------------------
      subroutine gas_init( me, co2usr_file, co2cyc_file, ico2flg,       &
     &     ictmflg, con_pi, errflg, errmsg)
 
!  ===================================================================  !
!                                                                       !
!  gas_init sets up co2, etc. parameters.                               !
!                                                                       !
!  inputs:                                                              !
!     me          - print message control flag                          !
!     ico2flg     - co2 data source control flag                        !
!                   =0: use prescribed co2 global mean value            !
!                   =1: use input global mean co2 value (co2_glb)       !
!                   =2: use input 2-d monthly co2 value (co2vmr_sav)    !
!     ictmflg     - =yyyy#, data ic time/date control flag              !
!                   =-2: same as 0, but superimpose seasonal cycle      !
!                        from climatology data set.                     !
!                   =-1: use user provided external data for the fcst   !
!                        time, no extrapolation.                        !
!                   =0: use data at initial cond time, if not existed   !
!                       then use latest, without extrapolation.         !
!                   =1: use data at the forecast time, if not existed   !
!                       then use latest and extrapolate to fcst time.   !
!                   =yyyy0: use yyyy data for the forecast time, no     !
!                           further data extrapolation.                 !
!                   =yyyy1: use yyyy data for the fcst. if needed, do   !
!                           extrapolation to match the fcst time.       !
!     co2usr_file - external co2 user defined data table                !
!     co2cyc_file - external co2 climotology monthly cycle data table   ! 
!     con_pi      - physical constant Pi                                !
!                                                                       !
!  outputs: (CCPP error handling)                                       !
!     errflg      - error flag                                          !
!     errmsg      - error message                                       !
!                                                                       !
!  usage:    call gas_init                                              !
!                                                                       !
!  subprograms called:  none                                            !
!                                                                       !
!  ===================================================================  !
!
      implicit none
 
!  ---  inputs:
      integer, intent(in) :: me, ictmflg, ico2flg
      character(len=26),intent(in) :: co2usr_file,co2cyc_file
      real(kind=kind_phys), intent(in) :: con_pi
 
!  ---  output:
      character(len=*), intent(out) :: errmsg
      integer,          intent(out) :: errflg
 
!  ---  locals:
      real (kind=kind_phys), dimension(IMXCO2,JMXCO2) :: co2dat
      real (kind=kind_phys) :: co2g1, co2g2
 
      integer    :: i, j, k, iyr, imo
      logical    :: file_exist, lextpl
      character  :: cline*100, cform*8
      data  cform  / '(24f7.2)' /       !! data format in IMXCO2*f7.2
!
!===>  ...  begin here
!
 
! Initialize the CCPP error handling variables
      errmsg = ''
      errflg = 0
 
! Initiailize module parameters
      raddeg = 180.0/con_pi
      hfpi   = 0.5*con_pi
 
      if ( me == 0 ) print *, vtaggas    ! print out version tag
 
      kyrsav  = 0
      kmonsav = 1
 
!  --- ...  co2 data section
 
      co2_glb = co2vmr_def
 
      lab_ico2 : if ( ico2flg == 0 ) then
 
        if ( me == 0 ) then
          print *,' - Using prescribed co2 global mean value=',         &
     &              co2vmr_def
        endif
 
      else  lab_ico2
 
        lab_ictm : if ( ictmflg == -1 ) then      ! input user provided data
 
          inquire (file=co2usr_file, exist=file_exist)
          if ( .not. file_exist ) then
            print *,'   Can not find user CO2 data file: ',co2usr_file
            errflg = 1
            errmsg = 'ERROR(gas_init): Can not find user CO2 data file'
            return
          else
            close (nico2cn)
            open(nico2cn,file=co2usr_file,form='formatted',status='old')
            rewind nico2cn
            read (nico2cn, 25) iyr, cline, co2g1, co2g2
  25        format(i4,a94,f7.2,16x,f5.2)
            co2_glb = co2g1 * 1.0e-6
 
            if ( ico2flg == 1 ) then
              if ( me == 0 ) then
                print *,' - Using co2 global annual mean value from',   &
     &                  ' user provided data set:',co2usr_file
                print *, iyr,cline(1:94),co2g1,'  GROWTH RATE =', co2g2
              endif
            elseif ( ico2flg == 2 ) then
              allocate ( co2vmr_sav(imxco2,jmxco2,12) )
 
              do imo = 1, 12
                read (nico2cn,cform) co2dat
!check          print cform, co2dat
 
                do j = 1, jmxco2
                  do i = 1, imxco2
                    co2vmr_sav(i,j,imo) = co2dat(i,j) * 1.0e-6
                  enddo
                enddo
              enddo
 
              if ( me == 0 ) then
                print *,' - Using co2 monthly 2-d data from user',      &
     &                ' provided data set:',co2usr_file
                print *, iyr,cline(1:94),co2g1,'  GROWTH RATE =', co2g2
 
                print *,' CHECK: Sample of selected months of CO2 data'
                do imo = 1, 12, 3
                  print *,'        Month =',imo
                  print *, (co2vmr_sav(1,j,imo),j=1,jmxco2)
                enddo
              endif
            else
              print *,' ICO2=',ico2flg,' is not a valid selection'
              errflg = 1
              errmsg = 'ERROR(gas_init): ICO2 is not valid'
              return
            endif    ! endif_ico2flg_block
 
            close (nico2cn)
          endif    ! endif_file_exist_block
 
        else   lab_ictm                           ! input from observed data
 
          if ( ico2flg == 1 ) then
            if ( me == 0 ) then
              print *,' - Using observed co2 global annual mean value'
            endiF
          elseif ( ico2flg == 2 ) then
            allocate ( co2vmr_sav(imxco2,jmxco2,12) )
 
            if ( me == 0 ) then
              print *,' - Using observed co2 monthly 2-d data'
            endif
          else
            print *,' ICO2=',ico2flg,' is not a valid selection'
            errflg = 1
            errmsg = 'ERROR(gas_init): ICO2 is not valid'
            return
          endif
 
          if ( ictmflg == -2 ) then
            inquire (file=co2cyc_file, exist=file_exist)
            if ( .not. file_exist ) then
              if ( me == 0 ) then
                print *,'   Can not find seasonal cycle CO2 data: ',    &
     &               co2cyc_file
              endif
              errflg = 1
              errmsg = 'ERROR(gas_init): Can not find seasonal cycle '//&
     &             'CO2 data'
              return
            else
              allocate( co2cyc_sav(imxco2,jmxco2,12) )
 
!  --- ...  read in co2 2-d seasonal cycle data
              close (nico2cn)
              open (nico2cn,file=co2cyc_file,form='formatted',          &
     &              status='old')
              rewind nico2cn
              read (nico2cn, 35) cline, co2g1, co2g2
  35          format(a98,f7.2,16x,f5.2)
              read (nico2cn,cform) co2dat        ! skip annual mean part
 
              if ( me == 0 ) then
                print *,' - Superimpose seasonal cycle to mean CO2 data'
                print *,'   Opened CO2 climatology seasonal cycle data',&
     &                  ' file: ',co2cyc_file
!check          print *, cline(1:98), co2g1, co2g2
              endif
 
              do imo = 1, 12
                read (nico2cn,45) cline, gco2cyc(imo)
  45            format(a58,f7.2)
!check          print *, cline(1:58),gco2cyc(imo)
                gco2cyc(imo) = gco2cyc(imo) * 1.0e-6
 
                read (nico2cn,cform) co2dat
!check          print cform, co2dat
                do j = 1, jmxco2
                  do i = 1, imxco2
                    co2cyc_sav(i,j,imo) = co2dat(i,j) * 1.0e-6
                  enddo
                enddo
              enddo
 
              close (nico2cn)
            endif   ! endif_file_exist_block
          endif
 
        endif   lab_ictm
      endif   lab_ico2
 
      return
!
!...................................
      end subroutine gas_init
!-----------------------------------
 
!-----------------------------------
      subroutine gas_update(iyear, imon, iday, ihour, ldoco2,           &
     &     me, co2dat_file, co2gbl_file, ictmflg, ico2flg,              &
     &     errflg, errmsg )
 
!  ===================================================================  !
!                                                                       !
!  gas_update reads in 2-d monthly co2 data set for a specified year.   !
!  data are in a 15 degree lat/lon horizontal resolution.               !
!                                                                       !
!  inputs:                                               dimemsion      !
!     iyear       - year of the requested data for fcst     1           !
!     imon        - month of the year                       1           !
!     iday        - day of the month                        1           !
!     ihour       - hour of the day                         1           !
!     ldoco2      - co2 update control flag                 1           !
!     me          - print message control flag              1           !
!     ico2flg     - co2 data source control flag                        !
!                   =0: use prescribed co2 global mean value            !
!                   =1: use input global mean co2 value (co2_glb)       !
!                   =2: use input 2-d monthly co2 value (co2vmr_sav)    !
!     ictmflg     - =yyyy#, data ic time/date control flag              !
!                   =-2: same as 0, but superimpose seasonal cycle      !
!                        from climatology data set.                     !
!                   =-1: use user provided external data for the fcst   !
!                        time, no extrapolation.                        !
!                   =0: use data at initial cond time, if not existed   !
!                       then use latest, without extrapolation.         !
!                   =1: use data at the forecast time, if not existed   !
!                       then use latest and extrapolate to fcst time.   !
!                   =yyyy0: use yyyy data for the forecast time, no     !
!                           further data extrapolation.                 !
!                   =yyyy1: use yyyy data for the fcst. if needed, do   !
!                           extrapolation to match the fcst time.       !
!     ivflip      - vertical profile indexing flag                      !
!     co2dat_file - external co2 2d monthly obsv data table             !
!     co2gbl_file - external co2 global annual mean data table          !
!                                                                       !
!  outputs: (CCPP error handling)                                       ! 
!     errflg      - error flag                                          !
!     errmsg      - error message                                       !
!                                                                       !
!  internal module variables:                                           !
!     co2vmr_sav - monthly co2 volume mixing ratio     IMXCO2*JMXCO2*12 !
!     co2cyc_sav - monthly cycle co2 vol mixing ratio  IMXCO2*JMXCO2*12 !
!     co2_glb    - global annual mean co2 mixing ratio                  !
!     gco2cyc    - global monthly mean co2 variation       12           !
!                                                                       !
!  usage:    call gas_update                                            !
!                                                                       !
!  subprograms called:  none                                            !
!                                                                       !
!  ===================================================================  !
!
      implicit none
 
!  ---  inputs:
      integer, intent(in) :: iyear,imon,iday,ihour,me,ictmflg,ico2flg
      character(len=26),intent(in) :: co2dat_file, co2gbl_file
      logical, intent(in) :: ldoco2
 
!  ---  output:
      character(len=*), intent(out) :: errmsg
      integer,          intent(out) :: errflg
 
!  ---  locals:
      real (kind=kind_phys), dimension(IMXCO2,JMXCO2) :: co2dat, co2ann
      real (kind=kind_phys) :: co2g1, co2g2, rate
 
      integer    :: i, id, j, l, iyr, imo, iyr1, iyr2, jyr, idyr
      integer, save :: mdays(13), midmon=15, midm=15, midp=45
!  ---  number of days in a month
      data mdays / 31,28,31,30,31,30,31,31,30,31,30,31,30 /
 
      logical    :: file_exist, lextpl, change
      character  :: cline*100, cform*8, cfile1*26
      data  cform  / '(24f7.2)' /       !! data format in IMXCO2*f7.2
!
!===>  ...  begin here
!
! Initialize the CCPP error handling variables
      errmsg = ''
      errflg = 0
 
 
      if ( ico2flg == 0 ) return    ! use prescribed global mean co2 data
      if ( ictmflg ==-1 ) return    ! use user provided co2 data
      if ( .not. ldoco2 ) return    ! no need to update co2 data
 
      if ( ictmflg < 0 ) then        ! use user provided external data
        lextpl = .false.                   ! no time extrapolation
        idyr   = iyear                     ! use the model year
      else                           ! use historically observed data
        lextpl = ( mod(ictmflg,10) == 1 )  ! flag for data extrapolation
        idyr   = ictmflg / 10              ! year of data source used
        if ( idyr == 0 ) idyr = iyear      ! not specified, use model year
      endif
 
!  --- ...  auto select co2 2-d data table for required year
 
      kmonsav = imon
      if ( kyrsav == iyear ) return
      kyrsav = iyear
      iyr    = iyear
 
!  --- ...  for data earlier than MINYEAR (1957), the data are in
!           the form of semi-yearly global mean values.  otherwise,
!           data are monthly mean in horizontal 2-d map.
 
      lab_if_idyr : if ( idyr < minyear .and. ictmflg > 0 ) then
 
        if ( me == 0 ) then
          print *,'   Requested CO2 data year',iyear,' earlier than',   &
     &            minyear
          print *,'   Which is the earliest monthly observation',       &
     &            ' data available.'
          print *,'   Thus, historical global mean data is used'
        endif
 
!  --- ... check to see if requested co2 data file existed
 
        inquire (file=co2gbl_file, exist=file_exist)
        if ( .not. file_exist ) then
          print *,'   Requested co2 data file "',co2gbl_file,           &
     &            '" not found'
          errflg = 1
          errmsg = 'ERROR(gas_update): Requested co2 data file not '//  &
     &         'found'
          return
        else
          close(nico2cn)
          open (nico2cn,file=co2gbl_file,form='formatted',status='old')
          rewind nico2cn
 
          read (nico2cn, 24) iyr1, iyr2, cline
  24      format(i4,4x,i4,a48)
 
          if ( me == 0 ) then
            print *,'   Opened co2 data file: ',co2gbl_file
!check      print *, iyr1, iyr2, cline(1:48)
          endif
 
          if ( idyr < iyr1 ) then
            iyr = iyr1
!check      if ( me == 0 ) then
!             print *,'   Using earlist available co2 data, year=',iyr1
!check      endif
          endif
 
          i = iyr2
          lab_dowhile1 : do while ( i >= iyr1 )
!           read (NICO2CN,26) jyr, co2g1, co2g2
! 26        format(i4,4x,2f7.2)
            read (nico2cn, *) jyr, co2g1, co2g2
 
            if ( i == iyr .and. iyr == jyr ) then
              co2_glb = (co2g1+co2g2) * 0.5e-6
              if ( ico2flg == 2 ) then
                do j = 1, jmxco2
                  do i = 1, imxco2
                    co2vmr_sav(i,j,1:6)  = co2g1 * 1.0e-6
                    co2vmr_sav(i,j,7:12) = co2g2 * 1.0e-6
                  enddo
                enddo
              endif
 
              if ( me == 0 ) print *,'   Co2 data for year',iyear,      &
     &                               co2_glb
              exit lab_dowhile1
            else
!check        if ( me == 0 ) print *,'   Skip co2 data for year',i
              i = i - 1
            endif
          enddo  lab_dowhile1
 
          close ( nico2cn )
        endif   ! end if_file_exist_block
 
      else  lab_if_idyr
 
!  --- ...  set up input data file name
 
        cfile1 = co2dat_file
        write(cfile1(19:22),34) idyr
  34    format(i4.4)
 
!  --- ... check to see if requested co2 data file existed
 
        inquire (file=cfile1, exist=file_exist)
        if ( .not. file_exist ) then
 
          lab_if_ictm : if ( ictmflg  > 10 ) then    ! specified year of data not found
            if ( me == 0 ) then
              print *,'   Specified co2 data for year',idyr,            &
     &               ' not found !!  Need to change namelist ICTM !!'
            endif
            errflg = 1
            errmsg = 'ERROR(gas_update): Specified co2 data for year '//&
     &           'not found'
            return
          else lab_if_ictm                        ! looking for latest available data
            if ( me == 0 ) then
              print *,'   Requested co2 data for year',idyr,            &
     &              ' not found, check for other available data set'
            endif
 
            lab_dowhile2 : do while ( iyr >= minyear )
              iyr = iyr - 1
              write(cfile1(19:22),34) iyr
 
              inquire (file=cfile1, exist=file_exist)
              if ( me == 0 ) then
                print *,' Looking for CO2 file ',cfile1
              endif
 
              if ( file_exist ) then
                exit lab_dowhile2
              endif
            enddo   lab_dowhile2
 
            if ( .not. file_exist ) then
              if ( me == 0 ) then
                print *,'   Can not find co2 data source file'
              endif
              errflg = 1
              errmsg = 'ERROR(gas_update): Can not find co2 data '//    &
     &             'source file'
              return
            endif
          endif  lab_if_ictm
        endif   ! end if_file_exist_block
 
!  --- ...  read in co2 2-d data for the requested month
 
        close(nico2cn)
        open (nico2cn,file=cfile1,form='formatted',status='old')
        rewind nico2cn
        read (nico2cn, 36) iyr, cline, co2g1, co2g2
  36    format(i4,a94,f7.2,16x,f5.2)
 
        if ( me == 0 ) then
          print *,'   Opened co2 data file: ',cfile1
          print *, iyr, cline(1:94), co2g1,'  GROWTH RATE =', co2g2
        endif
 
!  --- ...  add growth rate if needed
        if ( lextpl ) then
!         rate = co2g2 * (iyear - iyr)   ! rate from early year
!         rate = 1.60  * (iyear - iyr)   ! avg rate over long period
          rate = 2.00  * (iyear - iyr)   ! avg rate for recent period
        else
          rate = 0.0
        endif
 
        co2_glb = (co2g1 + rate) * 1.0e-6
        if ( me == 0 ) then
          print *,'   Global annual mean CO2 data for year',            &
     &              iyear, co2_glb
        endif
 
        if ( ictmflg == -2 ) then     ! need to calc ic time annual mean first
 
          if ( ico2flg == 1 ) then
            if ( me==0 ) then
              print *,' CHECK: Monthly deviations of climatology ',     &
     &                'to be superimposed on global annual mean'
              print *, gco2cyc
            endif
          elseif ( ico2flg == 2 ) then
            co2ann(:,:) = 0.0
 
            do imo = 1, 12
              read (nico2cn,cform) co2dat
!check        print cform, co2dat
 
              do j = 1, jmxco2
                do i = 1, imxco2
                  co2ann(i,j) = co2ann(i,j) + co2dat(i,j)
                enddo
              enddo
            enddo
 
            do j = 1, jmxco2
              do i = 1, imxco2
                co2ann(i,j) = co2ann(i,j) * 1.0e-6 / float(12)
              enddo
            enddo
 
            do imo = 1, 12
              do j = 1, jmxco2
                do i = 1, imxco2
                  co2vmr_sav(i,j,imo) = co2ann(i,j)+co2cyc_sav(i,j,imo)
                enddo
              enddo
            enddo
 
            if ( me==0 ) then
              print *,' CHECK: Sample of 2-d annual mean of CO2 ',      &
     &                'data used for year:',iyear
              print *, co2ann(1,:)
              print *,' CHECK: AFTER adding seasonal cycle, Sample ',   &
     &                'of selected months of CO2 data for year:',iyear
              do imo = 1, 12, 3
                print *,'        Month =',imo
                print *, co2vmr_sav(1,:,imo)
              enddo
            endif
          endif   ! endif_icl2flg_block
 
        else                  ! no need to calc ic time annual mean first
 
          if ( ico2flg == 2 ) then      ! directly save monthly data
            do imo = 1, 12
              read (nico2cn,cform) co2dat
!check        print cform, co2dat
 
              do j = 1, jmxco2
                do i = 1, imxco2
                  co2vmr_sav(i,j,imo) = (co2dat(i,j) + rate) * 1.0e-6
                enddo
              enddo
            enddo
 
            if ( me == 0 ) then
              print *,' CHECK: Sample of selected months of CO2 ',      &
     &                'data used for year:',iyear
              do imo = 1, 12, 3
                print *,'        Month =',imo
                print *, co2vmr_sav(1,:,imo)
              enddo
            endif
          endif   ! endif_ico2flg_block
 
          do imo = 1, 12
            gco2cyc(imo) = 0.0
          enddo
        endif   ! endif_ictmflg_block
        close ( nico2cn )
 
      endif  lab_if_idyr
 
      return
!
!...................................
      end subroutine gas_update
!-----------------------------------
 
!-----------------------------------
      subroutine getgases( plvl, xlon, xlat, IMAX, LMAX, ico2flg,       &
     &     top_at_1, con_pi, gasdat)
!  ===================================================================  !
!                                                                       !
!  getgases set up global distribution of radiation absorbing  gases    !
!  in volume mixing ratio.  currently only co2 has the options from     !
!  observed values, all other gases are asigned to the climatological   !
!  values.                                                              !
!                                                                       !
!  inputs:                                                              !
!     plvl(IMAX,LMAX+1)- pressure at model layer interfaces (mb)        !
!     xlon(IMAX)       - grid longitude in radians, ok both 0->2pi or   !
!                        -pi -> +pi arrangements                        !
!     xlat(IMAX)       - grid latitude in radians, default range to     !
!                        pi/2 -> -pi/2, otherwise see in-line comment   !
!     IMAX, LMAX       - horiz, vert dimensions for output data         !
!     ico2flg          - co2 data source control flag                   !
!                       =0: use prescribed co2 global mean value        !
!                       =1: use input global mean co2 value (co2_glb)   !
!                       =2: use input 2-d monthly co2 value (co2vmr_sav)!
!     top_at_1         - vertical profile indexing flag                 !
!     con_pi           - physical constant Pi                           !
!                                                                       !
!  outputs:                                                             !
!     gasdat(IMAX,LMAX,NF_VGAS) - gases volume mixing ratioes           !
!               (:,:,1)           - co2                                 !
!               (:,:,2)           - n2o                                 !
!               (:,:,3)           - ch4                                 !
!               (:,:,4)           - o2                                  !
!               (:,:,5)           - co                                  !
!               (:,:,6)           - cfc11                               !
!               (:,:,7)           - cfc12                               !
!               (:,:,8)           - cfc22                               !
!               (:,:,9)           - ccl4                                !
!               (:,:,10)          - cfc113                              !
!                                                                       !
!     note: for lower atmos co2vmr_sav may have clim monthly deviations !
!           superimposed on init-cond co2 value, while co2_glb only     !
!           contains the global mean value, thus needs to add the       !
!           monthly dglobal mean deviation gco2cyc at upper atmos. for  !
!           ictmflg/=-2, this value will be zero.                       !
!                                                                       !
!  usage:    call getgases                                              !
!                                                                       !
!  subprograms called:  none                                            !
!                                                                       !
!  ===================================================================  !
!
      implicit none
 
!  ---  input:
      integer,  intent(in)  :: imax, lmax, ico2flg
      real (kind=kind_phys), intent(in) :: plvl(:,:), xlon(:), xlat(:)
      logical, intent(in) :: top_at_1
      real(kind=kind_phys), intent(in) :: con_pi
 
!  ---  output:
      real (kind=kind_phys), intent(out) :: gasdat(:,:,:)
 
!  ---  local:
      integer :: i, k, ilat, ilon
 
      real (kind=kind_phys) :: xlon1, xlat1, tmp
 
!===>  ...  begin here
 
!  --- ...  assign default values
 
      do k = 1, lmax
      do i = 1, imax
        gasdat(i,k,1) = co2vmr_def
        gasdat(i,k,2) = n2ovmr_def
        gasdat(i,k,3) = ch4vmr_def
        gasdat(i,k,4) = o2vmr_def
        gasdat(i,k,5) = covmr_def
        gasdat(i,k,6) = f11vmr_def
        gasdat(i,k,7) = f12vmr_def
        gasdat(i,k,8) = f22vmr_def
        gasdat(i,k,9) = cl4vmr_def
        gasdat(i,k,10)= f113vmr_def
      enddo
      enddo
 
!  --- ...  co2 section
 
      if ( ico2flg == 1 ) then
!  ---  use obs co2 global annual mean value only
 
        do k = 1, lmax
          do i = 1, imax
            gasdat(i,k,1) = co2_glb + gco2cyc(kmonsav)
          enddo
        enddo
 
      elseif ( ico2flg == 2 ) then
!  ---  use obs co2 monthly data with 2-d variation at lower atmos
!       otherwise use global mean value
 
        tmp = raddeg / resco2
        do i = 1, imax
          xlon1 = xlon(i)
          if ( xlon1 < 0.0 ) xlon1 = xlon1 + con_pi  ! if xlon in -pi->pi, convert to 0->2pi
          xlat1 = hfpi - xlat(i)                     ! if xlat in pi/2 -> -pi/2 range
!note     xlat1 = xlat(i)                            ! if xlat in 0 -> pi range
 
          ilon = min( imxco2, int( xlon1*tmp + 1 ))
          ilat = min( jmxco2, int( xlat1*tmp + 1 ))
 
          if (top_at_1) then         ! index from toa to sfc
            do k = 1, lmax
              if ( plvl(i,k) >= prsco2 ) then
                gasdat(i,k,1) = co2vmr_sav(ilon,ilat,kmonsav)
              else
                gasdat(i,k,1) = co2_glb + gco2cyc(kmonsav)
              endif
            enddo
          else                            ! index from sfc to toa
            do k = 1, lmax
              if ( plvl(i,k+1) >= prsco2 ) then
                gasdat(i,k,1) = co2vmr_sav(ilon,ilat,kmonsav)
              else
                gasdat(i,k,1) = co2_glb + gco2cyc(kmonsav)
              endif
            enddo
          endif
        enddo
      endif
 
!
      return
!...................................
      end subroutine getgases
!-----------------------------------
 
!
!........................................!
      end module module_radiation_gases  !
!========================================!