Impact of Cloud Microphysics on Intensification of Tropical Cyclone GONU Using a Convection-Permitting Numerical Model: Isentropic Analyses

Tropical Cyclone GONU is simulated using WRF model at 3km horizontal resolution (i.e. convection permitting scale) using different Cloud Microphysical parameterizations, from a simple (no ice phase) to a more sophisticated scheme (double moment scheme). Intensity is becoming more realistic with the sophisticated scheme though the track simulation is independent of choice of microphysics. Tropical cyclones are associated with a wide range of scales, so a new technique is adopted based on isentropic analyses of convective motions to study the thermodynamic structure of the overturning circulation and also to identify the role of cloud microphysics in intensification of GONU simulations using different microphysical schemes. This approach separates the vertical mass transport in terms of the equivalent potential temperature for the rising air parcels at high entropy from the subsiding air at low entropy. This technique filters out oscillatory motions associated with gravity waves and separates convective overturning from the secondary circulations. The isentropic circulation for GONU exhibits a maximum mass transport near the surface associated with a shallow convection and entrainment in all the simulations. But the ascent in the eyewall can be readily identified as an upward mass flux of air with unusually high equivalent potential temperature in sophisticated schemes only. It is found that as GONU intensifies the vertical circulations become wider via the expansion of upward (downward) mass flux to higher (lower) equivalent potential temperature. The detail analyses for better performance of sophisticated microphysics scheme is underway.