Expanding Database of Dual-Doppler Tropical Cyclone Observations

Studies of tropical cyclone (TC) structure, dynamics, and thermodynamics have long benefitted from databases of in-situ aircraft and dropwindsonde observations. With the first deployment of Doppler radar equipped aircraft into TCs in 1982, three-dimensional documentation of the wind field has become routine. A historical review of analyzed cases reveals how the development of radar scanning strategies designed to capture vortex evolution, combined with advancements in data synthesis techniques, have made airborne Doppler radar an indispensible tool in the study of TC dynamics. Unlike conventional sources of TC wind data, the accurate estimation of winds from Doppler radar requires a time-intensive quality control process and synthesis procedure, thus limiting the widespread use of the airborne Doppler data. In this thesis a database of airborne Doppler radar analyses is proposed, and its initial construction is presented. The initial database consists of eight distinct aircraft passes from four different storms. The raw Doppler data was provided by the Hurricane Research Division of NOAA's Atlantic Oceanographic and Meteorological Laboratory. A standard methodology for quality control and synthesis of the airborne Doppler data is suggested to ensure uniformity across the cases. The quality of each Doppler wind analysis is assessed through a statistical comparison with in-situ aircraft data, and then a direct comparison of wind structure resolved in both data sets. The usefulness of the database is demonstrated through an examination of five specific topics of current TC research: 1) variability of the symmetric vortex structure, 2) impact of baroclinicity on the dynamical response to heating, 3) vortex asymmetry in the hurricane inner core, 4) vertical shear forcing of hurricane asymmetry, and 5) eyewall budgets of angular momentum. In an effort to make the database more easily accessible to future investigators, a table of parameters grouped into synoptic, intensity, and structure categories was synthesized from the cases presently included. The utility of the synthesis table in selecting cases, and even revealing relationships amongst the variables, is discussed.