vn7.3 vs. vn8.4
While UKCA had low NOy at vn7.3, this feature has not improved when moving to vn8.2/vn8.4 GA4.0 jobs, and may even have become worse.
A pair of simulations have been set-up to try to aid the diagnosis of the cause of this low NOy. While there have been many changes to the base atmospheric model, the differences between the UKCA chemistry scheme used have been minimised.
- All chemical emissions and the SST/Sea-Ice ancillaries are the same between both jobs
- All chemical reactions and rates are the same between both jobs
- The lower boundary conditions are the same for both jobs
- The initial conditions of the chemical species are the same for both jobs
NOTE: While the vn8.4 job does include GLOMAP-mode aerosols and some extra associated chemical reactions, the low NOy has also been observed in the vn8.2 CheST (only) configuration.
| VN7.3 | VN8.4 | |
| MONSooN jobid | xjcir | xjcin |
| Configuration | HadGEM3-A r2.0 | HadGEM3-A GA4.0 |
| Resolution | N48L60 | N96L85 |
| UKCA scheme | CheST | CheST+GLOMAP |
| Evaluation Suite Output |
|
|
| NOy species time evolution |  Xjcir_NOy.pdf  |
Xjcin_NOy_yr01-06.pdf
|
| Comparison with SLIMCAT | Compare_SLIMCAT_UKCA.pdf
|
