Problem with recipe for using a B compset output to create SST/ICE forcing files for an F compset

[sean_m_davis@noaa_gov]

I'm trying to force an F compset with SSTs from a B compset, and following the recipe here:http://www.cesm.ucar.edu/models/cesm1.2/cesm/doc/usersguide/x2288.htmlIn step 8 it says to modify some code in models/atm/cam/tools/icesst, but that directory does not exist in in my distributions (I've checked CESM 1.0.5,1.1.0,and 1.2.0).Is this step no longer necessary? 

 

[hannay]

The tool is not part of the release itself. I am attaching the tool and all the relevant documentation to the post. 

 

[hannay]

.

 

[sean_m_davis@noaa_gov]

Thanks for sending this. I finally had a chance to look at this today. I have a few questions I hope you or someone else might be able to answer:

1. I don't understand the purpose of using bcgen (I read the comments in bcgen.f90, btw). I already have monthly-mean data that is defined at the midpoints of each month. I don't really see how the linear interpolation could cause a difference, but maybe there is something subtle I am missing.

2. Regarding re-gridding, is there a reason that this can't be done with the ESMF_* routines in ncl?  There's already a weights file at https://svn-ccsm-inputdata.cgd.ucar.edu/trunk/ncl/map_gx1v6_to_fv1.9x2.5_bilin_da_090206.nc that can be used as input to ESMF_regrid_with_weights()

3. Assuming I do need to proceed with regridding and bcgen, I'm going to need some help debugging -- everything compiled fine, but then I get a runtime error. To verify that my compiled version of regrid is running properly, it would be great if I could reproduce the out of box file for the F_2000 compset (i.e., sst_HadOIBl_bc_1.9x2.5_clim_c061031.nc). Looking at the metadata in that file, it looks like it was generated using the following regrid command:

regrid -i ../../data/MODEL.ICE.HAD187001-198110.OI198111-200602.nc -s ../../data/MODEL.SST.HAD187001-198110.OI198111-200602.nc -g ../../grids/fv_1.9x2.5.nc -o sstice_1.9x2.5.nc

I found the fv_*.nc file for the -g option at https://svn-ccsm-inputdata.cgd.ucar.edu/trunk/inputdata/atm/cam/coords/, but I can't find the MODEL.*.HAD* input files anywhere. Is there any way I could get  those files for testing purposes?

Thanks!

 

[hannay]

About the purpose of bcgen: bcgen modifies the monthly values of observed SSTs to ensure that the model reproduces the observed SSTs.
Why do we need to do this ? The observed SSTs are monthly means (mid month values). CAM needs the SSTs at higher frequency SSTs so it interpolates the observed SSTs (between mid month values). You want to make sure that when you compute the monthly mean from CAM, it matches the monthly mean from observations. (It is not automatically garanteed)
To insure the monthly mean from CAM matches the monthly mean from observations, you need modify the SSTs dataset used by CAM (i.e you slightly adjust the SST) and this is what bcgen does.Algorithms devised by Karl Taylor of PCMDI are used to accomplish these tasks. Taylor, K.E., D. Williamson, and F. Zwiers (2000): The sea surface temperature and sea-ice concentration boundary conditions for   AMIP II simulations. PCMDI Report No. 60 and UCRL-MI-125597,   Lawrence Livermore National Laboratory, Livermore, CA, 25 pp. About the regridding: you can use your own tool for regridding.  About the MODEL*HAD*: you can find them at ftp://ftp.cgd.ucar.edu/archive/SSTICE/ 

 

[chenyh1991@126_com]

is there come file suitable for using a B compset output to create SST  forcing files for an B compset

 

[hannay]

I am not sure  I understand your question.