# Adding new diagnostics to UKCA **URL:** \ **Category:** Unified Model\ **Created:** [4 January 2024 12:08 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293 "2024-01-04T12:08:38Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![hannahbryant](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@hannahbryant](https://cms-helpdesk.ncas.ac.uk/u/hannahbryant)\ **Post date:** [4 January 2024 12:08 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293/1 "2024-01-04T12:08:38Z")
Hi, I am currently adding some diagnostics to the asad\_flux\_dat.F90 code in vn11.1. When trying to add the reactions: COS + O(3P) - CO + SO2 and COS + photon - CO + SO2, I receive a ‘RXN NOT FOUND’ error in atmos main, however, these reactions are present within the ukca\_chem\_master.F90 file so I am confused as to why they are not being allowed to be output! Have you seen this error before? Thanks, Hannah ---
**Author:** ![Luke](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/luke/32/45_2.png) [@Luke](https://cms-helpdesk.ncas.ac.uk/u/Luke)\ **Post date:** [4 January 2024 12:28 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293/2 "2024-01-04T12:28:45Z")
Hi Hannah, Could you commit your changes and point me to your branch? This message will crop up if there are any string differences between how you list the reactions in `asad_flux_dat` and `ukca_chem_master`. Possible reasons for these differences could be coming from: 1. Extra or missing spaces in species definitions. These should be exactly 10 characters including spaces 2. Changes of case 3. Accidentally using a zero instead of a letter O 4. Accidentally using a tab instead of a space 5. Check that the number of reactants+products has been correctly specified for the definition in `asad_flux_dat` - if this is incorrect it will either miss a product or perhaps include a blank product 6. Are these reactions in the mechanism for this chemistry scheme at this version? You can check the `pe000` file in the `atmos_main/pe_output` directory within your suite’s `work` directory to see a full listing of the mechanism Best wishes, Luke ---
**Author:** ![hannahbryant](https://avatars.discourse-cdn.com/v4/letter/h/b5a626/32.png) [@hannahbryant](https://cms-helpdesk.ncas.ac.uk/u/hannahbryant)\ **Post date:** [5 January 2024 10:43 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293/3 "2024-01-05T10:43:05Z")
Hi Luke, Thanks! I think the issue is that the reactions are in strattrop but needed the aerosol scheme on so weren’t in the actual mechanism! I hadn’t realised they needed to be present to output them as I could see other diagnostics for reactions which aren’t occurring (CS2 + OH for example). Best wishes, Hannah ---
**Author:** ![system](https://europe1.discourse-cdn.com/flex013/uploads/cms_support/original/1X/1fd2411499ffcbc299fe756cd5cdf26e44956558.png) [@system](https://cms-helpdesk.ncas.ac.uk/u/system)\ **Post date:** [21 January 2024 18:06 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293/4 "2024-01-21T18:06:04Z")
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**Author:** ![system](https://europe1.discourse-cdn.com/flex013/uploads/cms_support/original/1X/1fd2411499ffcbc299fe756cd5cdf26e44956558.png) [@system](https://cms-helpdesk.ncas.ac.uk/u/system)\ **Post date:** [8 February 2024 22:38 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293/5 "2024-02-08T22:38:41Z")
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**Author:** ![RosalynHatcher](https://dub1.discourse-cdn.com/flex013/user_avatar/cms-helpdesk.ncas.ac.uk/rosalynhatcher/32/11_2.png) [@RosalynHatcher](https://cms-helpdesk.ncas.ac.uk/u/RosalynHatcher)\ **Post date:** [19 February 2024 14:37 UTC](https://cms-helpdesk.ncas.ac.uk/t/adding-new-diagnostics-to-ukca/1293/6 "2024-02-19T14:37:02Z")