CEE Seminar: Snowflake Settling in the Atmosphere: Insights From Field Imaging Experiments

Settling of snowflakes in the atmosphere, an exemplification of complex particle movement in turbulence, is not only of fundamental interest in fluid mechanics but also has direct implication on our forecast of ground snow accumulation and the corresponding mitigation strategies. Despite numerous studies on this topic using simulations and laboratory experiments, the direct field investigation of snowflakes settling are scarce. Using a combination super-large-scale particle imaging velocimetry, particle tracking velocimetry, and holographic imaging at the Eolos field station, Rosemount, MN, we performed a detailed characterization of turbulent flows, the movements of snowflakes and their properties. Such information enables us to elucidate the influence of atmospheric flows on snowflake concentration distribution and settling behaviors under different turbulence and snow conditions. The talk will also include our recent progress in advancing such field measurement techniques for imaging the flows and particle transport under broader settings in the atmosphere.