Impacts of Tropopause-Penetrating Convection on the Chemical Composition of the Upper Troposphere and Lower Stratosphere

Tropopause-penetrating convection is capable of rapidly transporting air from the lower troposphere to the upper troposphere and lower stratosphere (UTLS). Since the vertical redistribution of gases in the atmosphere by convection can have important impacts on the chemistry of the UTLS, the radiative budget, and climate, it has become a recent focus of observational and modeling studies. Despite being otherwise limited in space and time, recent aircraft observations from field campaigns such as the Deep Convective Clouds and Chemistry (DC3) experiment have provided new high-resolution observations of convective transport. Modeling studies, on the other hand, offer the advantage of providing high-resolution spatially and temporally continuous output related to the physical, dynamical, and chemical characteristics of storms and their environments.

To examine the impact of tropopause-penetrating convection on the chemical composition of the UTLS, two 10-day periods of high frequency, tropopause-penetrating convection over the Central United States were simulated using the Weather Research and Forecasting model with Chemistry (WRF-Chem). During this period, convection routinely injects high concentrations of water vapor (greater than 50 ppmv) into the lowermost stratosphere (LMS). Environments in which water vapor transport most readily occurs will be discussed and related to the characteristics of responsible convection. Additionally, UTLS layer air is typically transported downward to lower altitudes, transporting high concentrations of ozone into the upper troposphere. While this process does not occur as often as water vapor transport, it occurs a significant amount over the simulation period. Responsible mechanisms for such transport will also be discussed.