[MITgcm-support] tracer concentration

Angela Marie Zalucha azalucha at MIT.EDU
Fri Feb 25 12:45:49 EST 2011


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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>>>
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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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>
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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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