Multi-Decadal Trends of Solar Radiation Reaching the Surface Determined by Aerosol-Cloud-Radiation Interactions, Climate Change, and Anthropogenic Emissions

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 aerosols and climate change in determining the surface radiation trends through the change of anthropogenic emission, aerosol-radiation interaction, and aerosol-cloud interactions. With a series of model simulations and analysis of ground-based observations and satellite-derived data products, we will 1) estimate the relative importance of aerosols, clouds, and other radiatively active atmospheric trace gases on the surface radiation budget, 2) compare the relative magnitudes of effects from atmospheric components (aerosols, clouds, and trace gases) and atmospheric processes (aerosol-radiation interactions and aerosol-cloud interactions) in determining the surface radiation trends, and 3) assess the consequences of climate change and anthropogenic emission trends in the change of surface radiation in different regions of the world.