# Using HARP for comparing WRF-Chem output to TROPOMI

**URL:** https://forum.atmospherictoolbox.org/t/using-harp-for-comparing-wrf-chem-output-to-tropomi/406
**Category:** HARP
**Created:** [October 11, 2021, 6:48am UTC](https://forum.atmospherictoolbox.org/t/using-harp-for-comparing-wrf-chem-output-to-tropomi/406 "2021-10-11T06:48:46Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![OpioCornelius](https://forum.atmospherictoolbox.org/letter_avatar_proxy/v4/letter/o/d9b06d/32.png) [@OpioCornelius](https://forum.atmospherictoolbox.org/u/OpioCornelius)
#### Post date: [October 11, 2021, 6:48am UTC](https://forum.atmospherictoolbox.org/t/using-harp-for-comparing-wrf-chem-output-to-tropomi/406/1 "2021-10-11T06:48:46Z")

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Hello colleagues.

I would like to compare the NO2 and CO from WRF-chem with the TROPOMI observations, either L2 gridded data or preferably L3 pixel data.

Does anyone have a script on how this can be done?

Thank you.

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### Author: ![sander.niemeijer](https://forum.atmospherictoolbox.org/user_avatar/forum.atmospherictoolbox.org/sander.niemeijer/32/5_2.png) [@sander.niemeijer](https://forum.atmospherictoolbox.org/u/sander.niemeijer)
#### Post date: [October 11, 2021, 7:11am UTC](https://forum.atmospherictoolbox.org/t/using-harp-for-comparing-wrf-chem-output-to-tropomi/406/2 "2021-10-11T07:11:43Z")

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You might want to look at this thread: [Using HARP and CAMS AQ forecast profile as an apriori to derive TROPOMI NO2 tropospheric column](https://forum.atmospherictoolbox.org/t/using-harp-and-cams-aq-forecast-profile-as-an-apriori-to-derive-tropomi-no2-tropospheric-column/240)

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### Author: ![OpioCornelius](https://forum.atmospherictoolbox.org/letter_avatar_proxy/v4/letter/o/d9b06d/32.png) [@OpioCornelius](https://forum.atmospherictoolbox.org/u/OpioCornelius)
#### Post date: [October 11, 2021, 10:30am UTC](https://forum.atmospherictoolbox.org/t/using-harp-for-comparing-wrf-chem-output-to-tropomi/406/3 "2021-10-11T10:30:05Z")

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Thank you Sander.  
Yes, I did take a look into that thread but their interest is to retrieve tropomi data using WRF-chem’s profiles… but this is not my interest.

As such, their code is hard for me to use. I am seeking for help with code that can simply compare the two, WRF-chem and Tropomi no2