Multi-Decadal Trends of Solar Radiation Reaching the Surface Determined by Aerosol-Radiation Interaction and Aerosol-Cloud interaction

Incoming solar radiation drives the Earth’s climate system. Long-term surface observations of solar radiation reaching the surface have shown decreasing or increasing trends in different regions of the world in the past several decades, indicating the change of atmospheric components that reflect and/or absorb the solar radiation. This study investigates the roles of aerosol-radiation interaction (ARI, aerosol direct interaction and interaction through cloud adjustment) and aerosol-cloud interaction (ACI, through microphysics) in determining the multi-decadal surface radiation trends through a series of model simulations and analysis of ground-based observations and satellite-derived data products. We will 1) assess the effects of emissions on the trends of aerosol amount, 2) assess the effects of aerosols on the surface radiation trends through ARI, and 3) compare the effects of ARI with that of ACI and climate change in multi-decadal trends of solar radiation reaching the surface in different regions of the world.