Calibrating both crop and natural vegetation pfts in a single point CLM model

[Tanja]

I would like to calibrate a single point CLM model. The model consist of a mix of natural and crop pfts. I am able to change parameters for the crops through the params-file.

I have tried to change LAI of the natural vegetation by changing the MONTHLY_LAI in the surfdata-file, however this does not have any affect on the model output. I addition I tried to affect LAI of the natural vegetation through the laimx in the params-file, but as expected this did not give any affect on model output either.

According to CLM5 Documentation “…when the biogeochemistry model is inactive, leaf and stem area indices are updated daily by linearly interpolating between monthly values.” As in my model the biogeochemistry model is active (crop model), does that mean that I can´t calibrate LAI of the natural vegetation? Is there another way to calibrate/change e.g. LAI of the natural pft when the biogeochemistry model (crop model) is active?

Regards Tanja

 

[oleson]

You can also make changes to parameters that control the natural vegetation in BGC mode, much as you did for crops.
See section 2.3.11 of this paper for an introduction to parameters in CLM:

Lawrence, D.M. et al., 2019: The Community Land Model version 5: Description of new features, benchmarking, and impact of forcing uncertainty, JAMES, 11, doi:10.1029/2018MS001583.

See this paper for a more detailed discussion of model sensitivity to parameters:

Fisher, R. A., et al., 2019: Parametric controls on vegetation responses to biogeochemical forcing in the CLM5, JAMES, 11, doi:10.1029/2019MS001609.

For example, the parameter slatop has a large first-order impact on LAI.

 

[Tanja]

Thanks.
In my single point CLM model I would like to simulate 25% natural pft (grass) and 75% crop pft (spring wheat). I would like to calibrate model parameters of both grass and spring wheat.
I change til parameter values of e.g. mxlai and slatop in the params-file. However changing those values of natural pfts does not have any influence on the resulting LAI of natural pfts. However, when I change mxlai and slatop for the crop pfts there is a clear influence on LAI of crop pft. Changing MONTHLY_LAI in the surfdata-file does not change resulting LAI of natural ptfs either. Isn´t it possible to calibrate natural and crop pfts simultaneous?
Regards, Tanja

 

[Tanja]

Please ignore my last message. I figured you that I can actually influence LAI of natural pfts also. Sorry for the disruption.