question of FPSN and GPP

[zongrax]

Hi, I am working with I1850Clm50SpCru compset, but the model results do not provide GPP, how to use FPSN to calculate GPP? In addition, I tried to run a test case, and when I tried to build this case, I got the following errors: Invalid values ['10800.0'] ERROR: Variable 'coupling_period' has invalid value ['10800.0']. Thanks in advance. Best, Dong

 

[erik]

On the test failure. This is a known problem in older versions that had an issue with using python-3. It will work with an updated version, or with using python 2.7 rather than python-3. What version of the model are you using?

 

[oleson]

FPSN is the same thing as GPP in SP mode.

 

[zongrax]

On the test failure. This is a known problem in older versions that had an issue with using python-3. It will work with an updated version, or with using python 2.7 rather than python-3. What version of the model are you using?

Hi, Erik, thanks for your answer,the version of the model is CESM2.0, I have changed to version 2.1, and It now works. Thanks for your help again!

 

[zongrax]

FPSN is the same thing as GPP in SP mode.

Thanks for you answer, oleson!

 

[Ceil]

FPSN is the same thing as GPP in SP mode.

I am not sure whether they have the relationship like below:
GPP = FPSN*32*10^(-6), where GPP is gC/m^2/s, FPSN is umol/m^2/s

 

[oleson]

FPSN and GPP represent gross primary production in SP and BGC modes, respectively. Only FPSN is available in SP mode. In BGC mode, both FPSN and GPP are available. In BGC mode, FPSN represents photosynthesis/gpp before downregulation due to nitrogen limitation, while GPP represents photosynthesis after downregulation. The nitrogen cycle is not active in SP mode which is why only FPSN is available.
If you simply want to convert FPSN in SP mode (umol/m^2/s) to gC/m2/s, then multiply by:

10^(-6) * 12.0107

where 12.01017 is gC/mole.