# NaN values of NH3\_Emis variable in CCTM\_DRYDEP\_\* file

**URL:** <https://forum.cmascenter.org/t/nan-values-of-nh3-emis-variable-in-cctm-drydep-file/1964>\
**Category:** Post-processing\
**Created:** [December 4, 2020, 6:39pm UTC](https://forum.cmascenter.org/t/nan-values-of-nh3-emis-variable-in-cctm-drydep-file/1964 "2020-12-04T18:39:35Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![skunwar](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@skunwar](https://forum.cmascenter.org/u/skunwar)\
**Post date:** [December 4, 2020, 6:39pm UTC](https://forum.cmascenter.org/t/nan-values-of-nh3-emis-variable-in-cctm-drydep-file/1964/1 "2020-12-04T18:39:35Z")

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When I try to view the **NH3** variable of CMAQv5.3.2 output file **CCTM\_DRYDEP\_v532\_intel\_2016\_CONUS\_20140201.nc** on VERDI, I see white patches (as opposed to the widespread gray color) in some places although white color is not shown on the color bar on the right side:

 ![image](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/1X/867eae15264741ac4a081045f4a39f7a31a47721.png)

When the same variable+file is visualized on ncview, I am still seeing the same white patches that are not referenced on the colorbar all over the land surface:

 ![image](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/1X/dfd1cbd3bafcc59453e3ffd14503f9a23e607251.png)

When I perform M3STAT on the file, I get NaN as the mean value of NH3:  
 ![image](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/1X/9fd7c2fec7dfcb98bc03922e4b797c8eb13f9fcb.png)  
Actually, the two other ammonia variables in the same CCTM\_DRYDEP\_\* file also have NaN values:  
 ![image](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/1X/e62e6860e6d64c1f6f44ceae810a3f786b3c2ec2.png)

Since NH3\_Emis also has mean value of NaN, I checked (using M3STAT) the FEST model output file (Ammonia Bidi is activated in CMAQ runscript) but did not see any NaN mean value, only Infinity as the standard deviation:  
 ![image](https://canada1.discourse-cdn.com/flex027/uploads/cmas/original/1X/1a61d7fdde83b2a984e299de27cfe0edcd5eab2f.png)

Does this hint at a problem with NH3 in CMAQ simulation or input file?

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**Author:** ![dschwede](https://avatars.discourse-cdn.com/v4/letter/d/b3f665/32.png) [@dschwede](https://forum.cmascenter.org/u/dschwede)\
**Post date:** [December 7, 2020, 1:05pm UTC](https://forum.cmascenter.org/t/nan-values-of-nh3-emis-variable-in-cctm-drydep-file/1964/2 "2020-12-07T13:05:28Z")

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Thank you for your question. Could you please specify which deposition module (M3DRY or STAGE) was used in your model run? A value of infinity for the standard deviation in the FEST-C file suggests there is likely an error in the input.

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**Author:** ![skunwar](https://avatars.discourse-cdn.com/v4/letter/s/9f8e36/32.png) [@skunwar](https://forum.cmascenter.org/u/skunwar)\
**Post date:** [December 7, 2020, 1:58pm UTC](https://forum.cmascenter.org/t/nan-values-of-nh3-emis-variable-in-cctm-drydep-file/1964/3 "2020-12-07T13:58:31Z")

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Thanks for responding @dschwede ! I do not remember seeing deposition module option explicitly in the CMAQ runscript, but after running CMAQv5.3.2 cb6r3\_ae7, I have seen **m3dry** in the standard output, so I am pretty sure it is m3dry for my simulations.

Update: I just confirmed that I am using m3dry module looking at the m3dry.F and m3dry.o files in my CMAQ build directory.