CCSM3 OUTPUT 1870/Pre industrial

[otieno_1@osu_edu]

Can someone tell me the difference between the 1870 control and the pre-industrial CCSM3 runs. I wanted to compare the 1990 control (b30.004) with an earlier run and found (b30.020-Preindustrial) and (b30.043- 1870). All three have different start times 0001-01,0400-01 and 0280-01. Why

 

[strandwg]

Can someone tell me the difference between the 1870 control and the pre-industrial CCSM3 runs. I wanted to compare the 1990 control (b30.004) with an earlier run and found (b30.020-Preindustrial) and (b30.043- 1870). All three have different start times 0001-01,0400-01 and 0280-01. Why

b30.004 is the T42_gx1v3 present-day control - constant 1990 conditions.
b30.043 is the T42_gx1v3 pre-industrial control - constant 1870 conditions.

b30.020 is the T85_gx1v3 pre-industrial control - constant 1870 conditions.

The two sets of runs are not directly intercomparable, because of the resolution difference. The analogous run to b30.004 for b30.020 is "b30.009".

The 1990 controls were run first - they have the earliest model time start values. The 1870 controls were branched from the 1990 controls at a date chosen after the model was in a reasonably stable state. That's why their start dates are larger values.