How to generate a custom 1x1 SST forcing file for CAM using icesst?

[Wenshuo]

Hi everyone,

I would like to generate my own SST forcing files for CAM, similar to sst_HadOIBl_bc_1x1_clim_c101029.nc, but for a different time period.

From the file’s history attribute, I can see it was created using the following commands:

2010-10-28 13:32:31 regrid -i /project/amp/hannay/sst4cam3/data/MODEL.ICE.HAD187001-198110.OI198111-201006.nc \
 -s /project/amp/hannay/sst4cam3/data/MODEL.SST.HAD187001-198110.OI198111-201006.nc \
 -g /project/amp/hannay/sst4cam3/data/MODEL.SST.HAD187001-198110.OI198111-201006.nc \
 -o /project/amp/ccsm/hannay/sst/sstice_gauss_1x1.nc

2010-10-28 13:33:44 bcgen -i /project/amp/ccsm/hannay/sst/sstice_gauss_1x1.nc \
 -c /project/amp/hannay/sst4cam3/data/sst_HadOIBl_bc_1x1_clim.nc \
 -t /project/amp/hannay/sst4cam3/data/sst_HadOIBl_bc_1x1_1870_2009.nc

I have already compiled and installed the icesst tool successfully. However, I’m having trouble reproducing the workflow because I cannot find the sstice_gauss_1x1.nc grid file in the inputdata repository (for example, under inputdata/ocn/docn7/SSTDATA/coords or related directories).

I also found that, according to some CESM discussions, “The coordinate files were produced by running CAM for a single timestep”, and that for spectral grids one can do something like:

ncks -v lat,lon,gw in.nc out.nc

However, when I tried this command on an f19_g16 case, the output coordinates corresponded to the atmospheric grid, not the 1×1 Gaussian SST/ICE grid used by the DOCN forcing.

So my questions are:

1. Where can I obtain the sstice_gauss_1x1.nc file (or its modern equivalent) used to define the 1×1 Gaussian SST/ICE grid?
2. Does this 1×1 grid actually use Gaussian weights, or is it simply a regular lat–lon grid?

Any detailed instructions or example workflows for generating custom SST/ICE boundary datasets for CAM would be greatly appreciated.

Thank you very much!

 

[hplin]

Hi Wenshuo, thanks for writing. I think you could replicate sstice_gauss_1x1.nc from these input files in the regrid tool with icesst. The exact files do not appear to be available, but newer files are:

the paths are discussed in this thread

How to get extended prescribed SST data

Hi everyone, i am using FHIST compset, trying to do simulation in year 2021. However, the default prescribed SST data sst_HadOIBl_bc_0.9x1.25_1850_2017_c180507.nc only has time range from 1850 to 2017. Is there any way i can download SST of 2021 for initiation? I notice that...

bb.cgd.ucar.edu

/glade/campaign/cgd/cas/asphilli/cam_input_data/MODEL.ICE.HAD187001-198110.OI198111-202206.nc
and
/glade/campaign/cgd/cas/asphilli/cam_input_data/MODEL.SST.HAD187001-198110.OI198111-202206.nc