The Relationship Between Observed Thermodynamic and Precipitation Properties During Tropical Cyclone Intensity Change

This presentation examines the thermodynamic and precipitation evolutions of tropical cyclones (TCs) across a spectrum of intensity change rates. With an emphasis on midtropospheric relative humidity and stability, we investigate how thermodynamic conditions evolve during intensification, and how these conditions co-evolve with the observed precipitation distribution as seen by satellite-borne passive microwave overpasses. Of most interest are TCs experiencing at least moderate vertical wind shear, as these storms demonstrate a clear wavenumber-1 precipitation asymmetry, whereby precipitation prior to intensification is initially maximized downshear, while the upshear quadrants are relatively precipitation-free. In this study, we analyze dropsonde data accumulated from NASA-supported hurricane field programs (CAMEX-3, -4, NAMMA, GRIP, and HS3), which provide deep-tropospheric soundings from their DC-8, ER-2, and Global Hawk aircraft. These cases are supplemented with dropsonde data from NOAA aircraft (WP-3D and G-IV), which often flew in cooperation with the NASA aircraft. In the study, we examine multiple cases in which dropsonde data is analyzed in a shear-relative framework. We emphasize the thermodynamic profiles in the upshear quadrants, how they evolve during periods of intensity change, and their relationship to observed precipitation.