[MITgcm-support] Heat budget Closure in MITgcm

[郑欢]

Dear all,

I am using MITgcm to investigate heat transport in the Southern Ocean. However, I encountered a problem where the heat budget does not close in my model. To verify this issue, I ran the Southern Ocean re-entrant channel example, keeping all default settings except increasing nTimesteps to simulate 30 years.

In this case, both the GM/Redi package and partial cells are enabled. I used the diagnostics package to output the following variables: 'TOTTEND', 'gTForc', 'ADVx_TH', 'ADVy_TH', 'ADVr_TH', 'DFxE_TH', 'DFyE_TH', 'DFrI_TH', 'DFrE_TH', 'TFLUX', and 'WTHMASS'.

I then read all the outputs into MATLAB and computed the heat budget terms. All terms were converted to units of °C/s for consistency.

However, I found a large mismatch: the magnitude of the advection term is around 10⁻⁶ °C/s, while 'TOTTEND' is around 10⁻¹¹ °C/s, resulting in a residual on the order of 10⁻⁵ °C/s. This indicates that the heat budget does not close.

I have attached my MATLAB script used for the calculation, as well as the relevant MITgcm output files.

I would greatly appreciate any suggestions or insights on how to resolve this heat budget issue. Thank you very much in advance for your time and help!

Best regards,

Huan Zheng
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250630/7696993e/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: heat_budget_cal.m
Type: application/octet-stream
Size: 4076 bytes
Desc: not available
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250630/7696993e/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: data
Type: application/octet-stream
Size: 3142 bytes
Desc: not available
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250630/7696993e/attachment-0003.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: heatbudget.jpg
Type: image/jpeg
Size: 381722 bytes
Desc: not available
URL: <http://mailman.mitgcm.org/pipermail/mitgcm-support/attachments/20250630/7696993e/attachment-0001.jpg>