[MITgcm-support] Re： Heat budget Closure in MITgcm

[钱钰坤]

Hi Huan,


I have done this before and details are recorded in this notebook:


https://github.com/miniufo/notebooks/blob/master/Budget%20in%20MITgcm%20Part%20I.ipynb

You may find some tips and pitfalls in this.  Hopefully it can help.



  Best regards 
 
-----------------------------------------
Yu-Kun Qian (钱钰坤)South China Sea Institute of Oceanology
Sun Yat-sen University
Xingang West Road, Haizhu District
Guangzhou, P.R. China
Email: qianyukun at scsio.ac.cn, qianyk at mail3.sysu.edu.cn
   
 

 
 
 
------------------ 原始邮件 ------------------
发件人: "郑欢"<huanzheng at stu.ouc.edu.cn>;
发送时间: 2025年6月30日(星期一) 上午8:31
收件人: "MITgcm-support"<mitgcm-support at mitgcm.org>; 

主题: [MITgcm-support] Heat budget Closure in MITgcm

 

 
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
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