[MITgcm-support] [Heat Budget] Non-closure in Southern Ocean Channel Example

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Dear MITgcm team,

I'm investigating heat budget closure in the default Southern Ocean Reentrant Channel Example (coarse resolution, 30-year run), with focus on heat budget diagnostics. Key findings:

1. Heat Budget Non-closure

All terms converted to °C/s (surface layer) :

TOTTEND: ~1e-11

Horizontal advection (ADVx_TH+ADVy_TH): ~1e-5

Vertical advection (ADVr_TH): ~1e-6

Diffusion (DFxE_TH+DFyE_TH+DFrE_TH): ~1e-23

Forcing (gTforc+oceQsw): ~1e-6

Residual (TOTTEND-RHS): ~1e-5 (≈horizontal advection magnitude)

Any layer is not closed (residual≈horizontal advection magnitude)

Questions:

Shouldheat budget close in this default case?

Why does residual match horizontal advection scale? Is this numerical or physical?

2. WTHMASS Vertical Distribution

Surface layer: Large values (expected due to surface fluxes)

Mid-layer: Small values

Bottom topography layer: Large values
Q3: Does this pattern imply proper mass flux conservation?

3. GM Parameterization Concerns

With GM enabled:
Q4: Could GM's subsurface bolus transport artificially alter surface layer heat balance?

I would appreciate any suggestions!

Best regards,

Huan Zheng














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