[MITgcm-support] tracer concentration

[Jean-Michel Campin]

Hi Angela,

If you consider the output of ptracer monitor (trcstat_ptracer01_mean),
it give the true global average tracer concentration (and account for
hFac, both the topography + r* streching factor).
If not fluid is added (dynstat_eta_mean = constant), and no source-sink,
trcstat_ptracer01_mean should stay constant.
Could you check this ?

And assuming that trcstat_ptracer01_mean is drifting, might want to have a look at:
a) all *OPTIONS.h files in your "code" dir
b) all parameter files data* (from your run dir).
If it's OK to put those in a tar file.

Thanks,
Jean-Michel

On Fri, Feb 25, 2011 at 12:45:49PM -0500, Angela Marie Zalucha wrote:
> Hi,
>
>   I don't really know what you mean by CD scheme.  I am using r*  
> coordinates and my simulation is based on the hs94.cs-32x32x5 experiment  
> (but with a different radiation scheme and 30 levels).  The ptracers  
> package I am using in the default setting except to specify the specific  
> initial tracer locations.  My data.ptracers file is
>
>  &PTRACERS_PARM01
>  PTRACERS_numInUse=1,
>  PTRACERS_advScheme=81,
>  PTRACERS_diffKh=0.,
>  PTRACERS_diffK4=0.E9,
>  PTRACERS_diffKr=0.,
>  PTRACERS_Iter0=201000,
>
> Is Yuan's suggestion correct (that I need to be multiplying the tracers 
> by hfac in the post-processing since I am using r*)?
>
>   Angela
>
> On Fri, 25 Feb 2011, Jean-Michel Campin wrote:
>
>> Hi Angela,
>>
>> MITgcm conserve passive tracer (even with CD-scheme on), i.e.,
>> the total content follows the integrated source-sink, and stay
>> constent if no source-sink.
>> Could you give more details about your problem/set-up (otherwise,
>> will not be able to provide a usefull advise).
>>
>> Thanks,
>> Jean-Michel
>>
>> On Thu, Feb 24, 2011 at 05:44:28PM -0500, Angela Marie Zalucha wrote:
>>> The tracers are passive.
>>>
>>> There is no change in atmospheric mass with time.
>>>
>>> There are no sources and sinks of tracers.
>>>
>>>
>>>   Angela
>>>
>>>
>>>
>>> On Thu, 24 Feb 2011, Yuan Lian wrote:
>>>
>>>> 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
>>>>>
>>>>> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
>>>>> Angela Zalucha, Ph.D.
>>>>> Postdoctoral Associate
>>>>> Department of Earth, Atmospheric,
>>>>>   and Planetary Sciences
>>>>> Massachusetts Institute of Technology
>>>>>
>>>>> Office located at Southwest Research Institute
>>>>> 1050 Walnut Street, Suite 300
>>>>> Boulder, CO 80302
>>>>> USA
>>>>> (720) 208-7211
>>>>>
>>>>>
>>>>> http://web.mit.edu/azalucha/www/index.html
>>>>> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
>>>>>
>>>>>
>>>>>
>>>>>
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>>>
>>> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
>>> Angela Zalucha, Ph.D.
>>> Postdoctoral Associate
>>> Department of Earth, Atmospheric,
>>>   and Planetary Sciences
>>> Massachusetts Institute of Technology
>>>
>>> Office located at Southwest Research Institute
>>> 1050 Walnut Street, Suite 300
>>> Boulder, CO 80302
>>> USA
>>> (720) 208-7211
>>>
>>>
>>> http://web.mit.edu/azalucha/www/index.html
>>> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
>>>
>>>
>>>
>>>
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>
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
> Angela Zalucha, Ph.D.
> Postdoctoral Associate
> Department of Earth, Atmospheric,
>   and Planetary Sciences
> Massachusetts Institute of Technology
>
> Office located at Southwest Research Institute
> 1050 Walnut Street, Suite 300
> Boulder, CO 80302
> USA
> (720) 208-7211
>
>
> http://web.mit.edu/azalucha/www/index.html
> _-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-
>
>
>
>
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