why the LAI of C4 grass is so high in clm5

[xiaoxiaokuishu]

Hi, all
I use release-clm5 to make a benchmark single-point simulation.
I set use_fun=.true, when I check the pft-level output, I see the LAI of PCT14 (C4 grass)
is as high as 20.... Not sure is it a problem or the model does handle it in this way....


Thanks for your help!

 

[oleson]

I would say that a TLAI of 20 for C4 grasses is unrealistic.

 

[oleson]

And I would say that such a large value is possible in CLM5, although not common and generally where the PFT fractions are small within the gridcell.
These are max TLAI values from monthly history data from the CLM5 historical simulation (year 2010) reported in Lawrence et al. 2019:

(0) Max TLAI for NL Evergreen Boreal Tree:10.6109
(0) Max TLAI for NL Deciduous Boreal Tree:10.7108
(0) Max TLAI for BL Evergreen Tropical Tree:7.67813
(0) Max TLAI for BL Evergreen Temperate Tree:7.60654
(0) Max TLAI for BL Deciduous Tropical Tree:12.5318
(0) Max TLAI for BL Deciduous Temperate Tree:12.7937
(0) Max TLAI for BL Deciduous Boreal Tree:8.24843
(0) Max TLAI for BL Evergreen Shrub:6.11496
(0) Max TLAI for BL Deciduous Temperate Shrub:5.71172
(0) Max TLAI for BL Deciduous Boreal Shrub:11.8843
(0) Max TLAI for C3 arctic grass:18.5222
(0) Max TLAI for C3 non-arctic grass:22.8415
(0) Max TLAI for C4 grass:17.0945
(0) Max TLAI for C3 crop:21.5434

So, a large value is possible for several of the PFTS.

 

[xiaoxiaokuishu]

And I would say that such a large value is possible in CLM5, although not common and generally where the PFT fractions are small within the gridcell.
These are max TLAI values from monthly history data from the CLM5 historical simulation (year 2010) reported in Lawrence et al. 2019:

(0) Max TLAI for NL Evergreen Boreal Tree:10.6109
(0) Max TLAI for NL Deciduous Boreal Tree:10.7108
(0) Max TLAI for BL Evergreen Tropical Tree:7.67813
(0) Max TLAI for BL Evergreen Temperate Tree:7.60654
(0) Max TLAI for BL Deciduous Tropical Tree:12.5318
(0) Max TLAI for BL Deciduous Temperate Tree:12.7937
(0) Max TLAI for BL Deciduous Boreal Tree:8.24843
(0) Max TLAI for BL Evergreen Shrub:6.11496
(0) Max TLAI for BL Deciduous Temperate Shrub:5.71172
(0) Max TLAI for BL Deciduous Boreal Shrub:11.8843
(0) Max TLAI for C3 arctic grass:18.5222
(0) Max TLAI for C3 non-arctic grass:22.8415
(0) Max TLAI for C4 grass:17.0945
(0) Max TLAI for C3 crop:21.5434

So, a large value is possible for several of the PFTS.

Hi, Oleson,

Thanks for the reply. I did not change any code for clm5, so maybe my pixel has problems,
I will change to other pixel to see what happened!

Thanks!