CCSM4 Compset-E (SOM) questions

[chris_fletcher@utoronto_ca]

I am running cases E_1850_CN and E_2000 using the slab ocean model. These simulations both run out of the box from initial stream file:

$CSM_INDATA/ocn/docn7/SOM/pop_frc.1x1d.090130.nc​

which has metadata description saying "Input data for DOCN7 mixed layer model from b40.999". I found the following information in the documentation for the CCSM4 data ocean model under "dataMode = "SOM" :

Scientifically appropriate bottom-of-the-slab Q-fluxes are normally ocean resolution dependent and are derived from the ocean model output of a fully coupled CCSM run. Note that while this mode runs out of the box, the default SOM forcing file is not scientifically appropriate and is provided for testing and development purposes only. Users must create scientifically appropriate data for their particular application. A tool is available to derive valid SOM forcing.​

My questions are:
1. Is the initial ocean file for the compset-E runs that ships with CCSM4 ($CSM_INDATA/ocn/docn7/SOM/pop_frc.1x1d.090130.nc) 'scientifically appropriate' to start new simulations from?
2. If not, then where is the tool to create new SOM forcing, since the defineqflux tool from CAM3 is no longer present?

Thanks in advance.

 

[hannay]

There are tools and documentation to create Q-flux in:
models/ocn/docn/tools/pop_som_frc

 

[chris_fletcher@utoronto_ca]

Thanks for the reply.

I found the pop_som_frc tool in the CESM1 distribution but not in the CCSM4 distribution. Is this significant? Should one be running the SOM with CESM1 (i.e. with CAM5) rather than with CCSM4?

 

[chris_fletcher@utoronto_ca]

On further inspection, the tools in models/ocn/docn/tools/pop_som_frc in the CESM1_0_1 distribution don't seem to match up with what's in the README file.

see: https://svn-ccsm-release.cgd.ucar.edu/model_versions/cesm1_0_1/models/ocn/docn/tools/pop_som_frc/​

For example, the script read_from_mss_month.csh is actually called "read_from_mss.csh" (reads all monthly files at once), and pop_frc_interp.ncl is actually called "pop_interp.ncl" and it is working with the displaced pole grid (gx1v3) rather than the regular 1x1 grid.

So, are there perhaps newer versions of these scripts that were used to create the file inputdata/ocn/docn7/SOM/pop_frc.1x1d.090130.nc that ships with CESM1?

 

[eaton]

Thanks for the reply.

I found the pop_som_frc tool in the CESM1 distribution but not in the CCSM4 distribution. Is this significant? Should one be running the SOM with CESM1 (i.e. with CAM5) rather than with CCSM4?

Note that the CAM5 model supports the cam4 physics package. In fact the E_* compsets in CESM1_0_1 all specify using the cam4 physics package.