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Re: Completed HOWTO's - Abiotic and Biotic


> I am surprised to see that the units for the surface computations are
> different from previous HOWTO's, using constant density to interface with
> Chris & Bob's code. I wanted to make sure that this is the final OCMIP
> position on this matter and that other modelers, who may have started runs
> with the previous methodology, are aware of this change.

During OCMIP-2, we will definitely be using constant density to interface
with the standard carbon chemistry routines from Chris Sabine and Bob Key.
This is indeed the "final OCMIP position", as you put it, and is spelled
out in the Abiotic and Biotic HOWTO's.  The latest version of "co2calc.f",
available by the HOWTO Web pages, also has comments in this regard. Ray
Najjar, Chris Sabine, and I have discussed such concerns at some length. 

> The climatological data (P, Fice, xKw) consists of monthly means. We, at
> NCAR, are treating the values as mid-monthly values and are linearly
> interpolating to the model time step. This is slightly different than
> treating the values are monthly averages. Is this acceptable? This issue
> does not appear to be addressed by the HOWTO. What are other modelers
> doing?

The manner in which you linearly interpolate mid-monthly values is the
preferred approach.  I do not know of any groups which are using monthly
means and switching brutally between them at the end/beginning of each
month.  Sorry if the HOWTO's are not clear enough about this.  They
should probably be modified to make things clearer.

Regards, Jim

   James Orr                       Laboratoire des Sciences du Climat 
   LSCE, CEA Saclay                             et de l'Environnement    
   Bat. 709 - Orme                 Unite Mixte de Recherche CEA-CNRS    
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