Wednesday, 25 January 2012: 9:00 AM
Microphysical and Radiative Impacts of a Squall Line Dust Storm
Room 244 (New Orleans Convention Center )
Thunderstorm outflow in arid regions often leads to mesoscale dust storms that alter atmospheric processes such as cloud microphysics and radiation budgets, and impede ground-based activities such as military operations and aviation. These mesoscale dust storms vertically redistribute dust in the troposphere, which impacts the global radiation budget and alters the climate. In order to better understand the atmospheric effects from these hazardous events, we need to enhance our understanding of (1) how lofted dust impacts parent convection and associated cold pools, and (2) the amount of dust being vented by deep convection in the mid and upper troposphere. The goal of this research is to investigate the microphysical and radiative impacts of cold pool lofted dust on parent convection and the dynamical feedbacks on its cold pool. To accomplish this goal, we perform idealized simulations of a squall line and associated dust storm using the Regional Atmospheric Modeling System (RAMS) with a coupled on-line dust model. The dust model contains surface dust emission, precipitation scavenging, dry deposition and is both microphysically and radiatively active. Two sets of experiments are performed. In the first, dust radiation parameterization is turned on and off to understand both microphysical and radiative responses from vented dust on parent convection and the surrounding environment. In the second, low-level wind environment is varied to alter the amount of dust being ingested by the squall line in order to understand the microphysical implications of differing concentrations of ingested dust on storm and cold pool dynamics. Results of the sensitivity experiments will be presented.