Temporal Dynamics of Aerodynamic Canopy Height Derived From Eddy Covariance Momentum Flux Data Across North American Flux Networks

Abstract

Abstract Aerodynamic canopy height ( h a ) is the effective height of vegetation canopy for its influence on atmospheric fluxes and is a key parameter of surface‐atmosphere coupling. However, methods to estimate h a from data are limited. This synthesis evaluates the applicability and robustness of the calculation of h a from eddy covariance momentum‐flux data. At 69 forest sites, annual h a robustly predicted site‐to‐site and year‐to‐year differences in canopy heights ( R 2 = 0.88, 111 site‐years). At 23 cropland/grassland sites, weekly h a successfully captured the dynamics of vegetation canopies over growing seasons ( R 2 > 0.70 in 74 site‐years). Our results demonstrate the potential of flux‐derived h a determination for tracking the seasonal, interannual, and/or decadal dynamics of vegetation canopies including growth, harvest, land use change, and disturbance. The large‐scale and time‐varying h a derived from flux networks worldwide provides a new benchmark for regional and global Earth system models and satellite remote sensing of canopy structure.