GA4.0 N216 Development

As part of the GA4.0 UKCA development, in Cambridge we are developing a N216L85 GA4.0 model using the CheT(+GLOMAP) configuration. However, there is no GA4.0 N216 base model existing at MetUM version 8.4.

Create a GA4.0 N216 Base model

There are a number of steps that need to be made before a base GA4.0 N216 model is ready for UKCA to be included:

1. Assess the models available at the GA development page
   • This shows that the only existing N216 job available is xhcea on MONSooN
     • This job ran for 30 years, and the output is available on MOOSE
     • The original UKMO version of this job is ajthw.
   • There are however GA4.0 N96 jobs available at vn8.0 (aliur) and vn8.4 (amche)
2. It is therefore necessary to regrid amche to N216 for use by UKCA
   • There is a guide on how change the horizontal resolution on the GA twiki.
     • The ancillary files can be taken from xhcea which already exist on MONSooN.
     • There may be other changes that have been made between aliur and xhcea which are not represented in the guide. I have therefore asked Jeremy Walton to port aliur as well as amche over to MONSooN to check the differences.
     • The new job xjgva has been created which is a GA4.0 N216L85 AMIP candidate, based on amche and using the differences from the guide and the differences between aliur and xhcea.
       • Differences between vn8.0 GA4.0 N216 (xhcea) and N96 (aliur): diff.xjgvx.xjgvz
       • Differences between vn8.4 GA4.0 N216 (xjgva) and N96 (amche): diff.xjgva.xjgvy