9313716 Johnson Organized collections of thunderstorms, known as mesoscale convective systems (MCSs), have been identified as producers of most of the rainfall in the tropics and mid-latitudes during the Spring, Summer and Fall. Under prior NSF support, the Principal Investigator has exploited data sets from previously held field experiments to further understanding of MCSs and their interactions with the atmospheric boundary layer. He will continue these investigations using both numerical models and observational case studies. The Principal Investigator will focus on processes which initiate, maintain and modulate mesoscale convection as well as the coupling between convection and the atmospheric boundary layer. Specific meteorological phenomena to be studied include wake lows, mid-level mesoscale vortices and heat/moisture budgets in and near mountainous terrain. If successful, this research will lead to better understanding of MCSs which may lead to better predictions of timing, location and amount of rainfall as well as severe weather. ***
