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Energy conservation error and advective heat flux to ocean

hshin74

Ho-Jeong Shin
New Member
Hello. I have been running CESM2.1.3 with B1850 compset but reset to year 2000 on a large computing system of Korea Meteorological Administration. I have encountered the same problem mentioned in a previous message (ERROR: ice: Vertical thermo error) twice. At the first time the model run stopped after simulating 50 years, I resolved the problem by changing a clubb_gamma coefficient a bit as suggested on the board. But the model stopped again after simulating 190 years. This time, I am looking into the source code and tracking down the energy terms.

Among the terms, I found out that the advective heat flux to ocean, fadvocn, is initialized to zero and then not updated with POP or CICE source codes, but that the subroutine conservation_check_vthermo in the ice_therm_vertical.F90 module printed an error message with a value of -570.xxx for fadvocn when the model stopped recently. I wonder where the actual value of fadvocn is calculated/updated after the initialization. I attached the cesm.log file to this message. Any help will be greatly appreciated. Thanks in advance!
 

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dbailey

CSEG and Liaisons
Staff member
The fadvocn should not be the problem. We do just get intermittent thermodynamic errors. The flux conservation error here is very small and fits into the category of point 5 here:

 

hshin74

Ho-Jeong Shin
New Member
The fadvocn should not be the problem. We do just get intermittent thermodynamic errors. The flux conservation error here is very small and fits into the category of point 5 here:

Thank you for your comment! Owing to your detailed explanation in the previous message, I could get the clue for my stopped simulation.

In my inquiry, I put the background of my current situation, and my true question was intended to be the advective heat flux where the non zero value came from. I apologize if I made my inquiry misleading, or if my English still do not make sense.

Based on my twenty years of experience in climate modeling, I have some doubt that it could be a problem if a variable prints out unintended output. And I wondered if 1e-3 is small enough so that it can be ignored when the variables were set in double precision. I am not pointing out these can be a problem affecting the scientific result. My concern is that I I just want to make sure if I understand the code correctly.

Thank you again. I appreciate your kind guidance.
 

dbailey

CSEG and Liaisons
Staff member
We typically use the threshold of 1.0e-3. So, even if it is slightly above this it is fine. There are roundoff issues in temperature and energy iteration in the thermodynamics that can lead to this.
 
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