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CN/CNDV spinup with user specified atmosphere data

Hi all

I want to spinup the CN model using my own 3 hourly atmosphere data. I have followed chapter 4 of the CLM user guide ("Running with your own previous simulation as atmospheric forcing to spinup the model") but quickly run into problems.

I have successfully produced 3 hourly output from a previous coupled simulation as per the instructions in this chapter (by setting histaux_a2x3hr to true in the cpl namelist, example 4-8), however when I subsequently set up a I1850SPINUPCN case (example 4-9) pointing to this 3 hourly data as input it creates an input stream pointing to monthly files, when in fact the output when histaux_a2x3hr is set to true is 3 hourly data binned into daily files (so ~30 output files per month). To overcome this I simply ncrcatted these files to produce monthly files, though I'm not sure if the resultant files have the correct structure.

After this I start my CN spinup simulation however it bombs at initialisation stating "variable not found" in my 3 hourly atm forcing data. After looking at the modern default QIAN datasets and the output produced by setting histaux_a2x3hr to true, I can see some variables which might be missing, such as those relating to precipitation. I also notice in the cpl namelist a similar setting called "histaux_a2x3hrp", which outputs precipitation variables. I've run my coupled simulation with this set to true, though the resulting precip variables are output to separate files. So I end up with daily files for both histaux_a2x3hrp and histaux_a2x3hr output (~60 files per month instead of the implied 1).

Basically I would like some clarification on the process for using my own atm forcing in CN spinup cases. There seems to be some inconsistency between what chapter 4 says and how the model operates (or I'm doing something wrong). Has anyone spun up CLM CN with their own atmosphere data? I'm using CESM 1.0.4.

Thanks

Nick.
 
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