The Influences of Thermodynamics and Aerosols on Deep Convection and Lightning in the Tropics
Consistent with previous studies, 30 dBZ echo-top heights (within lightning-producing CF's) and total lightning density exhibit strong dependence on NCAPE. When CF's are simultaneously stratified by N40 and WCD, 30 dBZ echo-top height is insensitive to aerosol concentrations and WCD. This finding occurs over both land and ocean across the global Tropics. In contrast, total lightning density increases approximately by a factor of two between pristine and polluted environments (again for both land and ocean). Importantly, the results suggest that a synergy between thermodynamic and aerosol forcings exists as lightning activity is most enhanced in polluted environments where NCAPE is above the global median value and WCD is near an intermediate value (~3000-3500 m). Vertical Profiles of Radar Reflectivity (VPRR) constrained by the three chosen forcing parameters are shown to be significantly different from a statistical standpoint in line with the aforementioned results; however, it is difficult to discern if the observed differences in VPRR structure are due to one, two, or all three parameters. A statistical analysis aimed at deconvoluting these simultaneous influences in select regions in the Tropics is on-going. Finally, we offer potential explanations for these findings and place them in context of the relevant literature from the past two decades.