Connecting Trace Gas and Aerosol Scavenging in DC3 Thunderstorms to Physical and Dynamical Properties of the Storm

Wet deposition is important because it removes soluble trace gases and aerosols from the atmosphere, thereby affecting ozone photochemistry, visibility, and potentially the radiation budget of the atmosphere. Wet deposition of chemical constituents not only depends on the solubility of the compound, but also on the storm properties, such as liquid and ice water contents, precipitation production and evaporation, and the ice-to-water partitioning. These storm properties, in turn, depend on the storm dynamics and the thermodynamic environment.

We analyze Deep Convective Clouds and Chemistry (DC3) storms from Colorado, Oklahoma, and Alabama, representing different storm environments, to connect the aircraft measurements of a range of soluble gases (e.g. nitric acid, hydrogen peroxide, formaldehyde, methyl hydrogen peroxide) and aerosols to the storm properties and environment observations. These observations include aircraft measurements of ice water content, radar reflectivity (including hydrometeor structure), radar vertical velocities, and pre-storm soundings of convective available potential energy (CAPE) and wind shear.

A 2-component mixture model is used to estimate scavenging and transport efficiencies. In general, more scavenging occurred in the Oklahoma and Colorado storms that had high precipitating ice mass, strong peak updrafts, and high CAPE and high 0-6 km shear storm environments than the Alabama storm. Interestingly, two Colorado storms that developed in the same storm environment exhibited more scavenging in the smaller storm (with smaller peak updrafts and precipitating ice mass, but likely more entrainment) than in the larger storm. Further analysis with hydrometeor content and cloud particle imaging data and of other DC3 storms will be presented.