Spatial variations in evapotranspiration over East Asian forest sites. II. Surface conductance and aerodynamic conductance

Abstract

Evapotranspiration over forest surfaces is mainly constrained by environmental and forest structural components through their influence on surface conductance (G_s) and aerodynamic conductance (G_a). Tower based eddy covariance data from 16 forest sites in East Asia (2°S to 64°N) were used to examine the sensitivity of Matsumoto and Nakai models for predicting G_s and G_a, respectively. Daytime dry-canopy data for the growing season were used in this study. Comparisons between model predictions and observed G_s and G_a showed good agreement, suggesting that the models were suitable for predicting G_s and G_a with reasonable accuracy. However, the model for G_s was unable to predict G_s accurately when soil water content was low (∼10%). In this circumstance, effective soil water content and a more comprehensive method for modelling the soil water content function must be used. G_s in East Asia was largely depended on vapour pressure deficit and secondarily on soil water content. G_a was largely affected by leaf area index compared with stand density.