PNNL

Abstract

The spatial dispersion of leaves within a vegetation canopy, quantified by the foliage clumping index (CI), directly regulates the within-canopy light environment and photosynthesis rate, but is not commonly implemented in terrestrial biosphere models to estimate ecosystem carbon cycle. A few global CI products have been developed recently with remote sensing measurements, making it possible to examine the global impacts of CI. This study deployed CI in the radiative transfer scheme of the Community Land Model version 5 (CLM5) and used the revised CLM5 to quantitatively evaluate the extent to which foliage clumping can affect canopy absorbed radiation and gross primary production (GPP), and for the first time, considering the uncertainty of CI from multiple remote sensing products.