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lnd_import ERROR: Longwave down sent from the atmosphere model is negative or zero


New Member
Dear all,
recently, I am working on CAM6 with variable-resolution simulation. I want to run the simulation with FHIST_BGC component set. I build the model and can successfully complete the the simulation for 5 days (STOP_N=5). However, the model always crash when I change the STOP_N to a longer time. The error occurs at time-step 1241 (dtime=450s), as "lnd_import ERROR: Longwave down sent from the atmosphere model is negative or zero". I already contacted to CLM community. They think that this error is from CAM. I have no idea how this error comes? Is there any one have idea how to fix it? Enclosed the log files. Thank you.



  • atm.log.txt
    545.8 KB · Views: 2
  • lnd.log.txt
    253.9 KB · Views: 1
  • cesm.log.txt
    317.5 KB · Views: 2


New Member
Hi Adam,

I confirm it. src/dynamics/se/dycore/global_norms_mod.F90 line 567-577

if (nu_q<0) nu_q = nu_p ! necessary for consistency
if (nu_s<0) nu_s = nu_p ! temperature damping is always equal to nu


New Member
Hi Bo,
Have you solved this problem?
I also encountered the same problem when I used THE CLM_BGC-CROP again when I did the step of "final" acceleration model.



New Member
Hi Adam.
I have solved the problem.The reason for the error is that there is a long-wave radiation error in my weather-driven data.