[RegCNET] Questions about CHE files with postproc

[R. Chris Owen]

Hi RegCM users

The problem was found - when using postproc on CHE files, one needs to 
set the number of tracers in postproc1.param (ntrac) exactly equal to 
the number of tracers used in regcm.in (chtrname). If set incorrectly, 
postproc will run without errors, but give you really weird results!

Chris

Moetasim Ashfaq wrote:
>
> Hello Chris,
>
>
> On Sep 27, 2009, at 10:15 PM, R. Chris Owen wrote:
>
>> Hello fellow RegCM users,
>>
>> I have a simulation with SO2, BC, and OC. I have used a version of 
>> postproc dated Apr 2009 (at the top of postproc.f) to compute monthly 
>> averages from the CHE files. It appears to run OK (i.e., no errors 
>> given). In the postproc output files, I have 3 things that seem odd 
>> and/or incorrect:
>
> I had an update after Apr 14 which can be downloaded from:
> http://web.ics.purdue.edu/~mashfaq/moet/PostProc.tar 
> <http://web.ics.purdue.edu/%7Emashfaq/moet/PostProc.tar> 
>
>>
>> 1) the units for each tracer are unstated and apparently ~1e9 time 
>> larger. The original CHE files have each tracer in mass mixing ratio 
>> (kg/kg), with values of an upper limit in the range of 1 ppb. The 
>> postproc files have values with an upper limit of 9 parts/part (an 
>> unachievable number). Could this be a conversion from part/part to 
>> ppb? Or some other conversion (to concentrations or volume mixing 
>> ratios)?
>
> There was 1.E9 multiplier in old postproc version. I do not have any 
> idea why it was there but I removed that in last update. Regarding 
> units, I have used the info from CHE grads control file or old 
> postproc. There can be some mismatch but I can only be able to fix 
> that after someone sends me accurate units. No other conversion has 
> been made in postproc, therefore, unrealistic values can be due to 
> some potential bug in CHE postproc. I will check this.
>>
>> 2) in the postproc files, the tracer at each output level, while 
>> different in the shape of the contours, is roughly equivalent in 
>> magnitude. Intuitively, species with a surface emission should be 
>> significantly higher at the surface than at an altitude of 10 km and 
>> the original CHE files indicate that the surface concentrations are 
>> 1e3-1e4 time larger than those in the top output level.
>
> I need to check this thing. Couple of months earlier, someone else 
> also had some issue. I will respond to this after making a thorough check.
>>
>> 3) the order of the levels from RegCM to posproc files seems to be 
>> reversed. The original CHE files have level 1 at the surface, while 
>> level 1 in the postproc files is apparently the upper most model 
>> level (though, it's hard to tell from looking at the data, since the 
>> data is of similar magnitude at each output level). this seems to be 
>> the case for the other file types as well (ICBC, SURF, ATM, etc.), so 
>> maybe this is also normal and I just don't know it.
>
> This is normal. 
>>
>> Any thoughts or experience with this? Or maybe know someone there who 
>> may have looked at the CHE output before and has some insight?
>
> I will upload the update after it is ready. In future, you may bug me 
> directly for any postproc related problems. 
>>
>> Many thanks for your help.
>>
>> Sincerely,
>>
>> Chris Owen
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