temperature increase with co2 constant

[w_xuej@163_com]

Dear all, I want to keep co2 values is constant.so I set atm_in :ramp_co2_annual_rate = 0.0 ramp_co2_start_ymd = 0 scenario_ghg = 'RAMP_CO2_ONLY'This is CESM 1_2_0, -compset B_2000 -res f19_g16. It's a startup run, and the start date is 1950-01-01.CO2 is unchanged with time, the temperature of output is increased with time. So I want to know why?Please help me?Thank you.

 

[hannay]

There are many reasons the temperature can increase with a constant co2.
For instance, if you are inject heat into the system. 
Say the incoming radiation (FSNT) is larger that the outgoing radiation (FLNT), it might lead to an increase of the temperature because you are injecting heat in the system.Keeping co2 constant is not a garantuee that the temperature will be constant in cesm.