[ERROR] co2mass in emission driven runs

[adagj]

Describe the error
co2mass = co2vmr*44/29*totalmass

where totalmass is 5.1127790e+21 g (CAM total dry air mass) and co2vmr is the model mean "CO2 volume mixing ratio", which we interpret as a molar ratio mol CO2/mol dry air (only entirely correct for ideal gasses).

HOWEVER: It seems we didn't do this correctly, since co2vmr doesn't hold the correct co2 mixing ratio in emission driven runs

https://bb.cgd.ucar.edu/cesm/threads/bprp-case-failed-to-calculate-co2-concentration.6235/

Way to correct
There is no easy way to correct this, so we suggest to retract the co2mass variable for all emission-driven runs, and not generate new co2mass variables when running the cmorization.

We need to remeber this bug for CMIP7 and make sure to get it correct :)

[YanchunHe]

Hi @adagj, Thanks!

So no co2mass in the future for CMIP6 esm-* type experiments? I will try to keep in mind this.

So the list of experiments will be, with NorESM2-LM:

* esm-1pct-brch-1000PgC
* esm-pi-cdr-pulse
* esm-ssp245
* esm-ssp585-ocn-alk
* esm-hist
* esm-piControl
* esm-ssp534-over
* esm-ssp585-ssp126Lu
* esm-pi-CO2pulse
* esm-ssp119
* esm-ssp585

For the bug itself, maybe it should be recorded in the NorESM/CAM github issue.

@monsieuralok could you please retract co2mass from above list of experiments?

[JorgSchwinger]

So no co2mass in the future for CMIP6 esm-* type experiments? I will try to keep in mind this.

There is ways to compute the correct CO2 mass in emission driven runs, but this wouldn't use co2vmr, which is not used by the model in emission driven runs. The easiest way would be to use the CAM variable TMCO2 (total CO2 column burden) and sum this up. Note that TMCO2 in turn is incorrect in concentration driven simulations...

[monsieuralok]

@YanchunHe I have retracted but I have not found experiment:- esm-ssp245, esm-ssp119.
Errata issue:- https://errata.ipsl.fr/static/view.html?uid=b93b2aff-ee8c-e0b6-b006-c226c26e2175