Most of the Earth system models predict higher GPP in the tropics than the MODIS satellite does, because of the saturation of remote sensing LAI in the tropics. You can reference on some paper like https://doi.org/10.1002/2015RG000483,Hi, all
I validated the GPP/npp from CLM5 with modis GPP and NPP across Amazon region,
not sure why it is poor... In other tropical regions, it is not good (with r2 round 0.4), but it is ok.
However, in Amazon, it seems super poor. Not sure if it is an issue that well known?
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Most of the Earth system models predict higher GPP in the tropics than the MODIS satellite does, because of the saturation of remote sensing LAI in the tropics. You can reference on some paper like https://doi.org/10.1002/2015RG000483,
View attachment 7339