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Re: Returned mail: Private list 'ocmip-all'

 	Thanks for the feedback on our routines. You have brought up an 
 point in that the functions we generated include the full carbon chemistry to 
be totally
 consistent with the measured carbon parameters. There are a number of shortcuts 
one can
 take to simplify these equations, but there are finite errors associated with 
each of
 the simplifications. For example, I gather that you ignore all of the secondary 
 that contribute to total alkalinity except for borate. Borate is by far the 
largest of 
 the secondary species and I think you agree that it needs to be included. As 
for sulfate
 and fluoride, their contribution is very small (<0.1 uatm in calculated fco2) 
 could probably be ignored without a problem. I guess it comes down to a trade 
 between being chemically correct versus the computer time for the 4 extra 
 (bt, ft, kb and and kf). Phosphate and Silicate are somewhere in the middle. I 
 disagree with your statement that the phosphate and silicate are "far below any
 precision of measurements"). Obviously in warm, low latitude surface waters 
where the
 concentrations are near 0 they are not significant, but they do certainly make 
 measurable difference in the Southern Ocean. If we take an example from the 
 layer in the South Pacific with: 
 alk=2275, TCO2=2150, Temp=1.5, Sal=34, phosphate=2, silicate=50
 With the full chemistry you would calculate an fCO2 of 384 uatm.
 If you ignore the phosphate and silicate, fco2=377, a difference of 7 uatm. 
 5 uatm of that error results from ignoring phosphate. The remaining 2 uatm 
 from the silicate. Since silicate can get as high as 200 umol/kg in the ocean 
 contribution can be larger. I can't say whether a 7 uatm error is significant 
 the model calculations. That is a decision you guys need to make. If you would 
 us to remove some or all of the secondary species just let me know.
 	As for using CO3-- and hydrogen to calculate the chemistry, I am not 
 I follow. Unfortunately, I was not able to completely follow the code you 
 without knowing the definitions for some of the variables you use. With our 
 I believe you can easily converge on an htotal with only 4 iterations if you 
 a little thought into your choice of ph ranges. I am not sure what the 
 are in our approach without a better understanding of your code. One thing to 
 remember is that the dissociation constants are strongly dependent on 
 and salinity, so the CO3-- can vary widely simply because of changes in 
 or salinity. The only carbon parameters that are not a function of temperature 
 salinity are total CO2 and total alkalinity (in mass units). Note that with the 
 accepted definition, carbonate alkalinity is not independent of Temp and Sal.
 	I hope this makes some sense. If you have further questions or would 
 us to modify the functions just let me know.
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