ice albedo change does not show significant impact to sea ice cover

[littledddna@gmail_com]

Dear all,

I have a questions about the setting of ice albedo in iCESM1.2. Since I want to decease sea ice cover, i set the following line in use_nl_cice

ice_ic = 'default'
shortwave = 'dEdd'
tr_iso = .true.
R_ice = -0.9
R_snw = -0.9
R_pnd = -0.9

However, the model showed almost identical sea ice cover in the North Atlantic and the Antarctica compare to the control run (which i only set ice_ic = 'default' and shortwave = 'dEdd'). Both tests ran more than 200 model years.

Am I missing some setup here or should I try much larger parameter (R_ice etc.)?

Thanks very much,

Xiao

 

[dbailey]

This is curious. I suspect that you have a very cold period where the snow never disappears. You can try ice_ic = 'none' to start with no ice.

 

[littledddna@gmail_com]

This is curious. I suspect that you have a very cold period where the snow never disappears. You can try ice_ic = 'none' to start with no ice.

Thanks very much for the reply, David.
Your are right, it is indeed a cold period that I am simulating. I already tried to set ice_ice to none and the model is very unstable in terms of CFL condition. So.....are there any other way to decrease the sea ice in cold time instead of changing the albedo?

Best regards,

Xiao