Presented on March 12, 2025, by

Dr. David Richter
Department of Civil and Environmental Engineering and Earth Sciences
University of Notre Dame

ABSTRACT:

In the marine and terrestrial boundary layers, aerosol particles are continually being produced, transported, and deposited, and these particles play a central role in multiple atmospheric processes including chemistry and cloud microphysics. These particles range from the nanometer to millimeter scale in size, and are subject to different physics based on their origin, composition, and size. As such, it is important to understand their transport throughout the atmospheric boundary layer, since this ultimately dictates their lifetime and relative abundance. The problem, however, is in fully accounting for this particle dispersion, and gaps in our understanding have taken many forms over the decades. For example, relating measured airborne concentrations to local generation rates makes assumptions about particle deposition rates and locality in transport, neither of which has been fully verified. In this presentation, I will provide an overview of our group’s efforts at trying to understand the relevant mechanisms controlling transport, especially for large (i.e., potentially inertial) particles in the boundary layer. Our primary tool is turbulence-resolving large-eddy simulations, where particles are tracked in a Lagrangian frame. We have found that insufficient sampling strategies can lead to highly incorrect surface emission estimates, and that particle inertia can violate traditional deposition models. These and other key findings will be discussed.