Examination of the roles of intense convection and moisture field in tropical cyclone formation

The factors that control tropical cyclone (TC) formation are examined with airborne Doppler radar observations, in conjunction with TRMM satellite data and high-resolution numerical simulations. In this study, we first characterize the convective properties of the selected tropical waves (e.g., TCS-30 and Typhoon Nuri during TPARC/TCS08) using radar and satellite observations. The intensity, distribution and evolution of the convective systems are compared for developing and non-developing tropical waves. The relationship between intense convection and TC formation are evaluated. Then, the key findings from the data analyses are further studied by high-resolution numerical simulations and sensitivity studies. Specific attention is paid to the sensitivity of numerical simulations of TC formation to the moisture field.The general role of moist convection and the impact of intense convective bursts on TC formation are investigated. The related effect of the vertical velocity distribution and the dynamic constraints on TC formation are also discussed.