On Thunderstorm Microphysics under Urban Heat Island, Sea Breeze, and Cold Front Effects in the Metropolitan Area of São Paulo, Brazil

This work discusses issues related to the impact of urbanization on the microphysical processes of precipitating systems associated with synoptic, mesoscale, and local scale systems. Among the issues addressed is the impact of urban heat island (UHI) in São Paulo city center and urban densification (UD) in the Metropolitan Area of São Paulo (MASP) on the microphysical, dynamic, and thermodynamic properties and distribution of precipitation and heavier rainfall from sea-breeze (SB) e cold-front (CF) combined during their space-time evolutions. For this purpose, it used four components: classification of hydrometeors with fuzzy logic, calculation of the raindrop diameters, an estimate of liquid water mass and ice mass from polarimetric-variables measured with dual-pola- rization X-band meteorological radar. The results indicated that urban densification (UD) and heat island (UHI) of the São Paulo city center impact the formation of precipitation, liquid water mass, and ice mass, depth, and duration of a thunderstorm. It was also observed the asymmetric configuration of the thunderstorm is induced by the strong convergence in the São Paulo city center, and this strong convergence is induced by the intense heat island (UHI) in the São Paulo city center. Was also observed that this event that is formed in the Metropolitan Area of São Paulo (MASP) depends on microphysical processes of mixed-phase of the cloud (water and ice) above the 0°C isotherm for the production of intense rain and cold pool at the surface. These important microphysical processes within long-lasting secondary convective cells over the São Paulo city center should be taken into account on convective parameterization schemes as well as the associated cold pool dynamics.