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Question about clm-cn

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XinhaoSuo

Xinhao Suo
Member
Hi,
I tried to run I2000CLM50CN composet for ten model years without making any modifications.
However, when I checked the output TLAI or GPP, I found that its value was normal in the first year, but it began to decline rapidly in the second year and approached 0. I understood that this meant that the simulated vegetation died quickly. This is very different from CLM-BGC and I can't understand, is it because CLM-CN can't simulate vegetation growth?
 
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oleson

Keith Oleson
CSEG and Liaisons
Staff member
CLM-CN is capable of simulating vegetation growth. Your results will depend on parameter settings, initialization, atmospheric forcing, the model's fit for purpose, etc.
 
X

XinhaoSuo

Xinhao Suo
Member
Hi，
oleson
My two cases have not been modified at all, which means they are the default composites, namely I2000CLM50CN and HISTCLM50CN. However, the results of these two simulations both show that TLAI, except for the first year, tends to approach zero in the other years. I believe that the default composites are correct, but it doesn't seem to be the case.
In addition to this, I also tried I2000CLM50BGC, and in this case, TLAI does not go to zero after replacing it with BGC. This means that vegetation is growing normally. This rules out the influence of initial conditions, external forcing, and other factors on the model.
With everything left unmodified, I cannot understand why CN cannot simulate vegetation, and as you mentioned, CLMCN can simulate vegetation growth.
oleson said:
CLM-CN is capable of simulating vegetation growth. Your results will depend on parameter settings, initialization, atmospheric forcing, the model's fit for purpose, etc.
Click to expand...
 
O

oleson

Keith Oleson
CSEG and Liaisons
Staff member
I see now you are using CLM5 with CN. CLM5 is only scientifically supported in combination with BGC. The compsets you mention are ones we should probably remove as they are not actively used/tested. CN was previously used with CLM4, but CLM4 is also no longer supported.
 
Last edited:
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XinhaoSuo

Xinhao Suo
Member
oleson said:
I see now you are using CLM5 with CN. CLM5 is only scientifically supported in combination with BGC. The compsets you mention are ones we should probably remove as they are not actively used/tested. CN was previously used with CLM4, but CLM4 is also no longer supported.
Click to expand...
Thank you for your reply, which is very helpful to me!
 
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