# Use observed BrO profile to constrain BrO concentrations

**URL:** <https://forum.cmascenter.org/t/use-observed-bro-profile-to-constrain-bro-concentrations/1889>\
**Category:** CMAQ\
**Created:** [November 5, 2020, 2:38pm UTC](https://forum.cmascenter.org/t/use-observed-bro-profile-to-constrain-bro-concentrations/1889 "2020-11-05T14:38:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![lwu127](https://avatars.discourse-cdn.com/v4/letter/l/ea666f/32.png) [@lwu127](https://forum.cmascenter.org/u/lwu127)\
**Post date:** [November 5, 2020, 2:38pm UTC](https://forum.cmascenter.org/t/use-observed-bro-profile-to-constrain-bro-concentrations/1889/1 "2020-11-05T14:38:03Z")

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Hi everyone,  
We want to use observed BrO profile to constrain BrO concentrations in CMAQ simulation. So we added a new module called FBR2 and the script is attached here.[FBR2.F.txt](https://forum.cmascenter.org/uploads/short-url/v4NiHaMVXvG3s3Ncrku6n1rlbnl.txt) (6.0 KB)

1. the new module is defined in bldit\_cctm.csh  
set ModFBR2 = FBR2/FBR2  
and i successfully compiled it.
2. I defined a new variable BR2F in run\_cctm.csh and designated it to be the BRO profile
3. in sciproc.F under interface section i added FBR2 module below COUPLE module and also under " IF ( .NOT. COLUMN\_MODEL ) THEN"

My problem is that, after running the model, my BRO concentration is the initial concentration which is 10e-30 and not the concentration from the BRO profile. Could you help with this?  
Thanks!  
Lin

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**Author:** ![gsarwar](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@gsarwar](https://forum.cmascenter.org/u/gsarwar)\
**Post date:** [November 6, 2020, 1:49pm UTC](https://forum.cmascenter.org/t/use-observed-bro-profile-to-constrain-bro-concentrations/1889/2 "2020-11-06T13:49:24Z")

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Dear Lin,

It is not clear what caused the problem. But I can try to take a look at the problem if you are willing to share the model and data for a day.

Thanks,  
Golam Sarwar

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**Author:** ![lwu127](https://avatars.discourse-cdn.com/v4/letter/l/ea666f/32.png) [@lwu127](https://forum.cmascenter.org/u/lwu127)\
**Post date:** [November 9, 2020, 1:06pm UTC](https://forum.cmascenter.org/t/use-observed-bro-profile-to-constrain-bro-concentrations/1889/3 "2020-11-09T13:06:31Z")

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Thanks gsarwar,  
I found out the reason, i used the wrong index for BRO, after i changed it, it works fine.  
Lin