Regional Effects of Aerosols on the Atmospheric Radiative Balance

Aerosols represent one of the greatest uncertainties in quantifying atmospheric sources of climate change. The role of aerosol particles in providing nucleation sites for cloud droplets is complex: this so-called “indirect effect” incorporates unsolved problems in atmospheric chemistry, thermodynamics, and fluid mechanics. Much of this uncertainty lies in our inability to describe the processes that control the evolution of particles in a chemically accurate and computationally efficient way. Even the simplest atmospheric scenarios of pristine marine conditions in remote areas involve significant challenges in understanding theoretically how different processes change aerosol particles, in describing numerically their impacts on climate, and in devising technical improvements to measure the variables needed to test our predictions.