Observational Assessment of Aerosol Impacts on Updraft Speed in Deep Convection

Adele Igel, University of California, Davis (Principal Investigator)

The impact of aerosol particles on the dynamics of convective storms is a topic that continues to be highly debated yet critical to understanding aerosol impacts on all aspects of convective storms. Modeling studies and theoretical work often show that higher aerosol concentrations lead to an increase in the speed of an updraft – a consequence known as aerosol-induced invigoration. However, there have been few attempts to show such a direct connection using detailed observations.  This study seeks to fill that gap.

Developing deep convective storms will be automatically tracked with geostationary satellite data. Cloud top heights will be retrieved from the geostationary data and from these cloud top rise rates and cloud top kinetic energy will be derived. The cloud top rise rate will be an excellent proxy for storm updraft speed. These data will be paired with observations of aerosol concentration, surface fluxes, and environmental conditions at the ARM Southern Great Plains megasite. From these observations, the impact of aerosol concentration on updraft dynamics will be investigated. Should the observations support the existence of aerosol-induced invigoration, further analysis of these cloud top rise rates as a function of the cloud phase – warm, mixed, and ice – has unprecedented potential to discriminate which of the variety of processes-based explanations for aerosol-induced invigoration is most likely to drive the phenomenon.