Airborne radar observations of tropical cyclone eyewalls
Department of Atmospheric Sciences
University of Hawaii at Manoa
Observing the structure of tropical cyclone eyewalls is an essential step in understanding the physical mechanisms that determine intensity and structure change. The eyewall convection of tropical cyclones is influenced by the environment, but the convection also influences the larger scale flow. Environmental factors such as vertical wind shear determine the azimuthal location of the strongest convection, while the location and timing of the eyewall convection impact the storm’s intensification efficiency. Airborne radars collect three-dimensional high-resolution precipitation and wind data, thus they are very well suited to give insight into the eyewall structure. This presentation will show analyses of radar, dropsonde, and aircraft data from two different tropical cyclones, Typhoon Sinlaku (2008) and Hurricane Rita (2005).
Typhoon Sinlaku is investigated at a late stage of its lifecycle, located poleward and undergoing extratropical transition. It will be shown that the storm structure is very similar to tropical cases where vertical wind shear is the primary factor impacting the location and character of the eyewall convection. However, some significant differences to the tropical cases will also be presented. Hurricane Rita is investigated to study the role of buoyancy in the eyewall during rapid intensification. There have been a few modeling studies that investigated the role of buoyancy, but so far only one observational study using flight level data has been conducted. A modified thermodynamic retrieval to estimate buoyancy from radar data will be presented, along with some preliminary results for Hurricane Rita.
Tuesday, 23 September 2014, 3:30PM
3450 Mitchell Lane
Bldg. 2 Large Auditorium (Rm 1022)