Observed Kinematic and Thermodynamic Structure of Four Tropical Cyclones from the ONR TCI Field Experiment

A Zero-Wind-Center (ZWC) tool was developed that can produce accurate tropical cyclone center positions with respect to height using the High Density Digital Dropwindsonde (HDSS) system on board the WB-57 aircraft during the Office of Naval Research (ONR) Tropical Cyclone Intensity (TCI) field campaign. In this work, the ZWC tool is used to understand the kinematic and thermodynamic structure of all four tropical cyclones that were observed during the ONR TCI experiment in 2015: (i) Tropical Storm Erika, (ii) Hurricane Marty, and (iii), Hurricane Joaquin, and (iv) Hurricane Patricia.

The HDSS data is cast into a storm-relative cylindrical coordinate system. Tangential and radial velocity components are computed about the ZWC based upon improved speed and course calculations from double-pass radial legs into the storms. The temperature and geopotential fields are cast as anomalies from the local environment in the cylindrical coordinate system about the ZWC. Combining the kinematic and thermodynamic fields, a complete representation of the storm-relative mass and wind fields are obtained for each storm. The data are then used to understand the observed intensity and structure changes, with particular focus at the upper levels and interaction of outflow jets with the environment.