[MITgcm-support] tracer concentration

[Yuan Lian]

Are you running the ptracers package with passive tracers? Is any change 
in the atmospheric mass if
the tracer is passive? Do you have any sink or source of tracers? I 
don't see much problems
with most of the advection schemes for passive tracers, though some 
deviation exists but should be
smaller than 0.1% in most cases.

If the total atmospheric mass is changing, make sure the tracer mixing 
ratio is updated properly
(i.e, scaling the mixing ratio in columns).This should also work if the 
tracer is semi-passive, i.e., the
mass loading of tracer is considered in the model.

If you have sink and source of tracers, make sure they are 
self-consistent. Or if you are updating tracer
tendencies in physics grid, make sure the schemes are conservative.

Cheers,
Yuan



On 2/24/11 1:17 PM, Angela Marie Zalucha wrote:
> Hello, I am working with the ptracers package.  I am finding that 
> after running for about 5 days, the tracers are not conserving mass at 
> all--the increase in mass is about 50%, which is pretty significant.  
> I am using advection scheme 81 (I have tried 7, 30, 33, 77, 80, but 
> with similar results).  Is this typical?  Are there any ways around this?
>
> Thanks,
>   Angela
>
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> Massachusetts Institute of Technology
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