Convection in Tropical Cyclone Intensification

The elusive mechanisms of rapid intensification of tropical cyclones are hypothesized to be forced by the interaction of the tropical cyclone environment and convection embedded in it. The Tropical Cyclone Rapid Intensification (TCRI) project collected an unprecedented number of in-situ observations studying hurricane intensification with the emphasis on rapid intensification with the goal of shedding light on these mechanisms. During TCRI, over 1290 high-altitude dropsondes were collected with the G-IV aircraft from 2020 to 2022, in addition to various radar measurements and modules conducted during P3 flights.

We analyze 52 high-altitude flights with a 3d variational technique to obtain entropy, moisture, and vorticity budgets as well as thermodynamic parameters such as saturation fraction, instability index and deep convective inhibition, shown in previous work to be important for tropical cyclone intensification. In addition to presenting a systematic analysis of the 52 cases, we will present contrasting extreme cases: Sally (2020) which underwent rapid intensification and rapid realignment, versus Ian (2022) which intensified more steadily with alignment early on in its lifecycle.