Evaluating aerosol direct radiative effects on global terrestrial ecosystem carbon dynamics from 2003 to 2010

Abstract

An integrated terrestrial ecosystem model and an atmospheric radiative transfer module are developed and applied to evaluate aerosol direct radiative effects on carbon dynamics of global terrestrial ecosystems during 2003-2010. The Moderate-Resolution Imaging Spectroradiometer measurements of key atmosphere parameters have been used to quantify aerosol effects on downward solar radiation. Simulations with and without considering the aerosol loadings show that aerosol affects terrestrial ecosystem carbon dynamics through the effects on plant phenology, thermal and hydrological conditions as well as solar radiation. The simulations also show that aerosol enhances the terrestrial gross primary production by 4.9 Pg C yr-1, the net primary production by 3.8 Pg C yr-1, the net ecosystem production by 3.9 Pg C yr-1, and the plant respiration by 1.1 Pg C yr-1 during the period. The aerosol loading at a magnitude of 0.1 Pg C yr-1 reduces ecosystem heterotrophic respiration. These results support previous findings of the positive effects of aerosol light scattering on plant production, but suggest there is a strong spatial variation due to cloud cover. This study suggests that both direct and indirect aerosol radiative effects through aerosol-cloud interactions should be considered to quantify the global carbon cycle.