4xCO2 test

[MartinDix]

4xCO2 experiment based on ACCESS-NRI/access-esm1.6-configs@e05a52e, so including CMIP7 GHG and volcanic aerosol.

Configuration changes

atmosphere/namelists
- CO2_MMR= 4.3189e-04,
+ CO2_MMR= 1.72756e-03,

Started from /scratch/p66/jxs599/access-esm/archive/AprilSpinUp-AprilSpinUp-56aae814/restart500

Output in /scratch/p66/txz599/access-esm/archive/test_4xCO2-expt-862aa61d

[MartinDix]

Model	ECS
ESM1-5	3.88
ESM1-6	3.36

Feedback parameter	ESM1-5	ESM1-6
Net	-0.73	-0.88
LW clear	-1.80	-1.82
SW clear	0.81	0.66
LW CRE	-0.08	-0.13
SW CRE	0.33	0.41

Cloud radiative effect (CRE) is all sky - clear sky.

ESM1-6 is cooler so starts with more ice and hasn’t reached the more non-linear region of the SH ice. Therefore a smaller ice albedo feedback?

[ofa001]

Thes plots on the ice response at the maximum season were made to illustrate the different response in esm1.5 esm1.6

4xCO2_ice_sensivity_ESM1.6.pptx

[har917]

@MartinDix @ofa001 (In reviewing material for the upcoming presentation) Another factor that could be important here is the imposition of the ice-berg scheme in ESM1.6 (over ESM1.5). This was noted to impact heat transport (into deep ocean) so will (I expect) impact the emergent ECS.