UKCA Chemistry and Aerosol Tutorials: Background Motivation UMvn13.0

UKCA Chemistry and Aerosol Tutorials at UMvn13.0

These UKCA tutorials are designed with the following premise:

What are the most common things that a PhD student or Researcher will need to know how to do when they start using UKCA?

Often you will want to use UKCA to answer questions like these:

• What happens when I add in reaction A to form new species B?
• What is the effect of changing the emissions of C?
• How does the deposition of D affect process E?
• How do my changes affect the aerosol properties?
• What is the budget of F?
  • Output the fluxes of reactions G, H, and I to diagnose it.

When you have completed the UKCA Tutorials you should have a basic understanding how to make the required changes needed to answer these questions.

Throughout the tutorial you are asked to perform a series of tasks. In fact, these are mostly part of one big task which is:

Create two new species, ALICE and BOB, then include emissions of ALICE and the reaction

${\textrm {ALICE}}+{\textrm {OH}}\longrightarrow {\textrm {BOB}}+{\textrm {Secondary}}\ {\textrm {Organic}}\ {\textrm {Compound}}\ \left({\textrm {Sec}}\_{\textrm {Org}}\right)$

(with Sec_Org included if you are using GLOMAP-mode aerosols) before including the dry deposition of ALICE and the wet deposition of BOB. You should also output the fluxes through the reaction and deposition processes. You will then look at several aerosol diagnostics and perform a sensitivity experiment.

Despite seeming to be straight-forward, this is actually quite a big task as it involves

• UKCA code changes
  • New species
  • New/editing reactions & deposition
• UM-UKCA code changes
  • New emissions
• Working with various UM files
  • Regridding input data
  • Creating NetCDF files
  • Processing UM output
• Rose changes
  • Changing configuration settings
  • Editing of STASHmaster_A (UM diagnostic definition) file & associated metadata changes
  • Changes to STASH (diagnostic) output

When working with UKCA it is important to break the tasks down into manageable chunks (this is why the task is split across several tutorials).

The Tutorials are broken down into six sections

1. General use of the UKCA Box Model and Rose (Tutorials 1-2)
   • These tutorials cover the basics of the copying and running a UKCA Box Model suite, before changing various options and viewing output.
2. UKCA Box Model Chemistry (Tutorials 3-4)
   • Here we add new species and reactions in the UKCA Box Model and test with different configurations.
3. Basic UM-UKCA usage (Tutorials 5-6)
   • Here we cover the basics of the copying and running a UM-UKCA suite, before outputting a field through STASH
4. UM-UKCA Chemistry (Tutorials 7-11)
   • Adding tracers
   • Adding emissions
   • Adding dry and wet deposition
   • Adding chemical diagnostics
5. UM-UKCA Aerosols (Tutorial 12)
   • The aerosol tutorial covers looking at the aerosol optical depth and other quantities in more detail, as well as performing sensitivity experiments
6. Working with UKCA data (Tutorial 13)
   • Here we use the Iris and cf python libraries to look at UKCA and observational data

These tutorials have been designed so that you can go through them in your own pace and in your own time. This is partly because some people will work at different rates. While estimated times are given for each tutorial these are just a guide, so don't worry if you complete one quickly or spend longer on others. Throughout the Tutorials worked solutions are provided to allow you to compare to your own changes. Sample output is also provided from each Tutorial as well.

UKCA Chemistry and Aerosol Tutorials at UMvn13.0

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Written by Luke Abraham 2022.