Date: Monday, December 8, 2008
3:00 pm: Conversation and Cookies in Room 108 Atmospheric Sciences Building
3:30 pm: Seminar in Room 269 Everitt Lab
Deep convection and rainfall patterns strongly influence climate and atmospheric variability on scales ranging from the global to the microscale. Despite the many dynamical atmospheric phenomena in which deep convection plays an important role, myriad fundamental questions remain unresolved. I will explore three specific scientific questions regarding 1) the climatological location of rainfall over the tropical oceans, 2) the timing of maximum rainfall during the diurnal cycle over land and 3) intensity differences between deep convection over land and ocean.
I will begin by discussing my recent work regarding the mean distribution of rainfall (including vertical structure) over the tropical oceans, given the SST. Using a combination of theory and atmospheric reanalysis data, I explore the extent to which atmospheric boundary layer convergence due to SST gradients should be viewed as a cause or consequence of the distribution of deep convection. The results of this analysis are used to develop a simple, but highly skillful semi-empirical model of rainfall over the tropical oceans.
The latter portion of my talk will focus on the results of idealized cloud resolving model simulations of deep convection over land. The role of large-scale vertical motion and moisture-convection feedback in influencing the timing of the diurnal rainfall maximum in a simple setting will be discussed. Then, I will discuss insights from experiments designed to reproduce the observed differences in storm intensity between tropical and ocean
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