#### im2527@columbia_edu

##### New Member

I am running CESM-1-1-2-LENS model tag 21 on Cheyenne with compset B1850LENS, res f09_g16, and only thing I change is adding a CO2 forcing (2xPI). I get the following error in cesm.log after model runs for 14 years and 9 months:

QNEG4 WARNING from TPHYSAC Max possible LH flx exceeded at 1 points. , Worst excess = -1.1977E-02, lchnk = ***, i = 9, same as indices lat = 65, lon = 111

411: imp_sol: Time step 1.8000000000000E+03 failed to converge @ (lchnk,lev,col,nstep) = 3189 24 9241112

Interestingly, I ran the same model with CO2 values at 3xPI, and it ran for 150 years with no problem.

I tried the following things that didn't help:

-- setting stacksize to unlimited

-- setting fv_nsplit, fv_nspltrac, fv_nspltvrm to multiples of 2 (from 2 to 512) and inithist = 'DAILY' in user_nl_cam

Any suggestions?

Ivan Mitevski