Name: Addison Alford
Title: Radar Observations of Landfalling Hurricanes: Synthesizing Three Years of SMART Radar Missions
Location: NWC 5600
Time: 3:00 PM
Series: Weather and Climate Systems
Abstract: The Shared Mobile Atmospheric Research and Teaching radars observed five landfalling tropical cyclones (TCs) from 2016-2018. The observations were largely targeted toward understanding asymmetric convective and dynamic processes. Such processes are thought to lead to the intensification of the TC primary tangential circulation, affect the distribution of extreme winds, and promote locally heavy rainfall. Relative to more traditional, aircraft-based analyses, the SMART radar datasets afford continuous high temporal and spatial resolution observations. These observations can be used to compliment and extend aircraft observed and numerically simulated TC processes.
A leading hypothesis in the literature is that vortex Rossby wave (VRW) propagation on the radial gradient of storm-relative vorticity is thought to promote the redistribution of momentum in the inner core and lead to the symmetrization of the primary circulation. In addition, the process is also thought to lead to the formation of inner core spiral rainbands as a component of the wave energy propagates radially away from its initial asymmetry in or near the eyewall. Traditional aircraft observations from 100-200 km transects of the inner core only provide instantaneous glimpses into these processes.
Using observations from Hurricanes Isabel (2003), Hermine (2016), Matthew (2016), Harvey (2017), and Florence (2018), a comprehensive overview of all components of the VRW process will be presented. Specifically, the simultaneous role of VRW dynamics in rainband distribution and intensity changes will be discussed in Hurricanes Matthew and Harvey. In addition, the role of VRWs during landfall will be explored in Hermine and Harvey. Manifesting as mesovortices during the landfall of Hurricane Harvey, VRWs will be shown to augment the background flow locally in dual-Doppler wind retrievals as well as dual-Doppler-projected estimates of contiguous maximum wind distributions at 10 m above the surface.