Minutes of the chemistry working group meeting 10/6/2014

UKCA Chemistry Working Group Telecon

Present: AA, GF, MD. Apologies: FOC, PTG, LA

Discussion: Stability issues – StratTrop is quite stable, but TropIsop still has some stability issues (see progress notes from FOC). How important is the upper boundary condition? Could prioritise doing this first (fixing the Noy issue in the UBC).

Will still be using TropIsop (into the next few years) so need to find a fix for this.

Release an 8.4 StratTrop – priority.

Main chemistry issues: Solver – no one took up the post. Now thinking about bringing in a consultant from Edinburgh to help with the solver. Potentially too much of an engineering position contributed to why the position wasn't filled. Two posts at MO for AQ and for Climate UKCA work. The latter position will focus on the aerosols for NWP. Scheme's

Direction for future chemistry updates:

Report to the Exec: Recommend investigation on the solver issues – bringing in expertise from previous/current ASAD users (MJP, OJW etc). GAF – its a big job for someone to be asked to be involved with fixing the solver with no clear benefit to them. GAF – define wish list for how we want the solver to work. What can we learn from the current problems and how other groups operate. Flexibility is an important desirable quality of the package. Fidelity. Next HCCP will include a report on future chemistry, time line of 6-12 months.

Noy bugs – So far implementing all the 'fixes' we discussed at the Noy 'PEG' meeting have failed to alleviate the problem. New runs: No P and L of Noy. Just initial conditions, will test if there is a numerical loss via advection. In the longer run trying an ENDGAME run would be useful. No time line at the moment for.

iBVOC working well in JULES. Plan to lodge code at UM9.1. iBVOC emissions for C5H8 (Arneth scheme), Terpenes, MeOH, and Acetone (c.f Guenther 95 method). C5H8 ~ 500 TgC/yr.

Need further work on FAST-Jx linking with MODE and with Aerosol (PJT is leading this). No time line at the moment for this.

Trop het chem. No one is sure about this. All agree that this needs to be implemented into StratTrop for UKESM1. No clear leader for this activity.

Future changes: HONO → sources FAST-JX → coupling with MODE very important. Updating the organic photolysis important. LNOx → massive scope to look into this. Porting of old tagged Nox job to ARCHER is a pain. Would be helpful.

GAF – interactive fire emissions running in JULES off-line. Hopeful that this will be implemented into the UM very soon. Likely to have a dev branch of interactive fire emissions fairly soon. Use LNOx scheme to provide flash rates. ESM team will be working on deposition. GAF notes some simple 'bugs' features to fix. Modifications to scheme from Edinburgh are understood - mainly a nomenclature issue. Not clear if they will be implemented into the trunk.

Next freeze is mid sept. Worth having a telecon mid august to see if there is anything that we can respond to.