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CN balance error in v1.0.0-arctic-boreal-ctsm

lucia

luyaohuang
Member
Hello CLM community,

I am currently working on simulating carbon fluxes for high-altitude vegetation on the Tibetan Plateau. I encountered a problem when running CLM v1.0.0-arctic-boreal-ctsm that I would like your advice on.


What version of the code are you using?
I am using the CLM version v1.0.0-arctic-boreal-ctsm downloaded from Zenodo. The GitHub link is: GitHub - lmbirch89/CTSM at v1.0.0-arctic-boreal-ctsm

Have you made any changes to files in the source tree?
I modified the surface dataset for the Tibetan Plateau region. Specifically:
I created a regional surface dataset for the Tibetan Plateau.
Adjusted the PFT fractions for each grid cell according to the vegetation types.
Modified soil texture variables (PCT_SAND, PCT_CLAY, etc.) in the surface dataset.
No changes were made to the source code itself.


Describe your problem or question:
I first ran single-point simulations for 38 high-altitude sites on the Tibetan Plateau using this version. All runs were successful. Then, I attempted to run the full Tibetan Plateau region using the modified regional surface dataset. At the beginning of the simulation, I received warnings such as:
cbalance warning at c = 29095 8.030710067427616E-008
1058.94274076406


During the first year of spinup (July), the simulation failed with the following error:

cbalance warning at c = 29096 1.003214722128387E-007
1007.49734338346
column cbalance error = 1.003214722128387E-007 29096
Latdeg,Londeg= 37.8500000000000 101.550000000000
begcb = 1007.51353409379
endcb = 1007.49734338346
delta store = -1.619071033178443E-002
--- Inputs ---
gpp = 1.754905015525892E-002
--- Outputs ---
er = 3.373966016555526E-002
col_fire_closs = 0.0
col_hrv_xsmrpool_to_atm = 0.0
col_xsmrpool_to_atm = 0.0
wood_harvestc = 0.0
grainc_to_cropprodc = 0.0
-1*som_c_leached = -1.587317406070986E-014
ENDRUN:
ERROR: ERROR in CNBalanceCheckMod.F90 at line 317

I have confirmed that the same modified surface dataset runs successfully with the official release clm5.0.37.Since my focus is on simulating high-altitude Tibetan Plateau vegetation, I need to use v1.0.0-arctic-boreal-ctsm.I initially suspected the problem might be due to shallow bedrock, but I have set use_bedrock = .false.. The CN balance error still occurs.

I would like advice on how to resolve this CN balance error in v1.0.0-arctic-boreal-ctsm when running the Tibetan Plateau region. Which variables or initial values should I adjust (e.g., SOM, soil texture, PFT fractions) to make the model run without CN balance errors? Are there known differences between v1.0.0-arctic-boreal-ctsm and release-clm5.0.37 that might explain why the same surface dataset runs in the latter but fails in the former?

Thank you very much for your time and any guidance you can provide. I really appreciate your help!
 
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