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5. Output Format

Each modeling group must provide their output in the standard OCMIP-2 format. Model output that does not follow these formatting conventions cannot be included for analysis during OCMIP-2. Model groups must use the standard routines that we have developed specifically for writing output in standard form for OCMIP-2.

If this is the first OCMIP-2 simulation you have made, you will need to recuperate the routine write_nc_MaskAreaBathy.f to write out characteristics of your model grid, mask, and bathymetry using the standard OCMIP-2 format. Use of this routine is detailed in the CFC HOWTO (section 5.1).

Otherwise if you have submitted OCMIP-2 model output previously, you will only need to resubmit the output file produced by write_nc_MaskAreaBathy.f under two conditions:

  1. either your model's grid, mask, or bathymetry have changed; or
  2. you have been notified by the OCMIP-2 analysis center at IPSL that your output file from this subroutine did not pass the routine integrity tests.

5.1 Biotic-run output routines

For the Biotic simulation, each modeling group will need to store both their active and passive tracer output in OCMIP-2 standard format. Thus modelers need to call two additional routines. They should be called just once each. Those output routines and the fields which are passed as arguments are detailed in the following table.

-------------------------------------------------------------------------------
Routine                        Input                    Units          Comments
-------------------------------------------------------------------------------

write_nc_Biotic_equil.f    1) Conc. of PO4              mol/m^3        (*)
                           2) Conc. of DOP              mol/m^3
                           3) Conc. of O2               mol/m^3
                           4) Conc. of DIC              mol/m^3
                           5) Conc. of Alk               eq/m^3
                           6) Surf. ocean pCO2            uatm
                           7) Delta pCO2 (dpCO2)          uatm
                           8) Mean Gas Flux of CO2      mol/(m^2*s) 
                           9) Mean Gas Flux of O2       mol/(m^2*s)
                          10) Mean Virtual Flux of CO2  mol/(m^2*s)
                          11) Mean Virtual Flux of Alk  mol/(m^2*s)
                          12) Mean Downward flux        mol/(m^2*s)
                              of POP at compensation Z 
                          13) Mean Downward flux        mol/(m^2*s)
                              of DOP at compensation Z 
                          14) Mean Downward advective
                              flux of DOP at
                              compensation Z            mol/(m^2*s)
                          15) Mean Downward diffusive
                              flux of DOP at
                              compensation Z            mol/(m^2*s)
                          16) Mean Downward convective
                              flux of DOP at
                              compensation Z            mol/(m^2*s)

write_nc_Biotic_TS_year.f  1) Potential temperature     degrees C      (*)
                           2) Salinity                     psu

-------------------------------------------------------------------------------
(*) For online models, all 2- and 3-D fields should be averaged for
    each month over the last 10 years of the simulation.  

5.2 Downloading the output routines

The output routines can be transferred to your machine by clicking on the links below, while holding down the Shift key.

You will also need to transfer the subroutine handle_errors.f to properly deal with errors while you are writing your netCDF files.

5.3 Compiling the output routines

Here is a an example of how you would compile one of the Biotic run output routines:


f77 -c -O -L/usr/local/lib -lnetcdf -I/usr/local/include \
     write_nc_Biotic_equil.f

Because we have made the OCMIP-2 output routines F77 compatible, you may need a function len_trim.f (from F90), which we also provide and which returns the length of a character string (after neglecting trailing blanks).

5.4 Using the output routines

The Biotic-run output routines store your model results following the naming and output conventions (netCDF, GDT version 1.2) chosen for OCMIP-2. The output filename is constructed automatically within each routine from three of the arguments: the tracer name, the year, and the standard model code used during OCMIP-2 to identify your group.

For example, after compiling and linking the OCMIP-2 output routines, we add the following code to the IPSL routines to store output in standard OCMIP-2 form


        call write_nc_Biotic_equil ("IPSL", "NGL46_SI",
     &  imt, jmt, kmt,
     &  60*60*24*365, 1200,
     &  MPO4, MDOP, MO2, MDIC, MAlk,
     &  MpCO2surf, MdpCO2,
     &  MFgDIC, MFgO2,
     &  MFvDIC, FvAlk,
     &  MPnewPOP, MPnewDOP, 
     &  MPnewDOPa, MPnewDOPd, MPnewDOPc) 

By line, the arguments to write_nc_Biotic_equil include

  1. the OCMIP-2 model code AND your own model version indicator (in GDT 1.2 terminology, these 2 variables refer to the institution and production, respectively);
  2. dimensions;
  3. the number of seconds per year (in your model), and the number of timesteps per year;
  4. the 12 monthly means for the 3-D tracer arrays for passive tracers PO4, DOP, O2, DIC, and Alk;
  5. the 12 monthly means for the 2-D arrays for surface ocean pCO2 (pCO2surf) and the sea-air pCO2 difference (dpCO2).
  6. the 12 monthly means for the 2-D arrays for the air-sea fluxes for CO2 and O2;
  7. the 12 monthly means for the 2-D arrays for the surface "virtual" fluxes for DIC and Alk;
  8. the 12 monthly means for the 2-D arrays for the total downward fluxes of POP and DOP (at the compensation depth); and
  9. the 12 monthly means for the 2-D arrays for the advective, diffusive, and convective components of the downward flux of DOP (at the compensation depth).

All arguments are input. The only output is the final netCDF file ("IPSL_Biotic_equil.nc") which contains the information for analyzing the IPSL monthly results for the steady-state climatological solution.

Furthermore, we need monthly 3-D data for potential temperature T and salinity S from each model. Again as an example, we add the following code to the IPSL routines to store output in standard OCMIP-2 form.


        call write_nc_Biotic_TS_year("IPSL", "NGL46_SI",
     &  imt,jmt,kmt,
     &  year, 60*60*24*365, 1200,
     &  MT,MS)

where the arguments include

  1. the OCMIP-2 model code AND your own model version indicator (in GDT 1.2 terminology, these 2 variables refer to the institution and production, respectively);
  2. dimensions;
  3. the year, the number of seconds per year (in your model), and the number of timesteps per year;
  4. the 12 monthly means for the 3-D tracer arrays for potential temperature T and salinity S;

The only output is the final netCDF file ("IPSL_Biotic_TS_year.nc") which contains the information for analyzing the IPSL monthly results for the steady-state climatological solution.

Both "IPSL_Biotic_equil.nc" and "IPSL_Biotic_TS_year.nc" should be transferred to IPSL. Filenames should NOT be changed. Subsequently at IPSL, files will be (1) tested for consistency, (2) included in the OCMIP-2 data base, and (3) processed for base analysis.

5.5 Need more details?

See http://www.ipsl.jussieu.fr/OCMIP/tech for additional information about the format netCDF and other conventions (COARDS, GDT) chosen for storing OCMIP-2 model output.

If you have other questions, please contact Patrick.Brockmann@ipsl.jussieu.fr or orr@cea.fr


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