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CLM5 crop yield

xgao304

Member
Dear Scientist,

I would like to compare the crop yield from CLM5 with some observations (i.e. from USDA). I am wondering what variable is the best to use.
Is "GRAINC_TO_FOOD" the right one if I generate the pft-based output? I am running compset "I2000Clm50BgcCrop" with GSWP3 data.

Thanks,

Xiang
 

oleson

Keith Oleson
CSEG and Liaisons
Staff member
I believe that is correct. See section 2.3 of this paper:

Lombardozzi, D.L., Y. Lu, P. Lawrence, D.M. Lawrence, S. Swenson, K.W. Oleson, W.R. Wieder, and E.A. Ainsworth, 2020: Simulating transient crop management in the Community Land Model version 5, J. Geophys. Res., doi: 10.1029/2019JG005529.
 

Lubin Han

Han Lubin
New Member
Dear scientists,

I am running the same compset "I2000Clm50BgcCrop" with GSWP3 data as xgao304. According to grain yield calculation in the CLM50_Tech_Note, I have got the result of GRAINC_TO_FOOD with 0.5° resolution. I am confused with the global spatial patterns of individual crop yields, such as maize or soybean. How can I get the spatial patterns of individual crop yields from GRAINC_TO_FOOD or CLM5.0? Do I need to extract it from the global crop distribution map by myself?

Thanks,
Han
 

dll@ucar_edu

Danica Lombardozzi
New Member
By default, CLM simulations only output grid-cell averaged data (also only monthly averages). To get yields for individual crop types, you need to specify that you would like PFT-level data in the user_nl_clm file prior to running your simulation. Here is an example of how I would add 'GRAINC_TO_FOOD' as a monthly-averaged PFT-level variable in the user_nl_clm:

hist_mfilt = 1,1
hist_nhtfrq = 0,0
hist_fincl2 = 'GRAINC_TO_FOOD'
hist_dov2xy = .true.,.false.

Note that the hist_mfilt and hist_nhtfrq variable specify the temporal frequency and averaging (in this example, for both the default output, or h0 files, and the PFT-level output). hist_fincl2 is the list of variables that you would like written out a different time or spatial resolution (these variables will be on a different file stream, e.g., 'h1') and hist_dov2xy specifies whether the variables are averaged by the gridcell (.true.) or provide sub-grid (e.g., PFT-level) information (.false.).
 
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