EOL Seminar Series - Lou Lussier (RAF/EOL)

Tuesday, September 30, 2014 - 03:30 to 04:30
FL2-1022 (Large Auditorium)
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Whitney Robinson
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Case studies of tropical cyclogenesis of within the critical layer of easterly waves: typhoon Nuri (2008) and hurricane Sandy (2012)

Lou Lussier
Research Aviation Facility
Earth Observing Laboratory

A recently proposed tropical cyclogenesis model showed that the Kelvin’s cat’s eye within the critical layer of a tropical easterly wave (EW) was the preferred location for storm formation, observed near the intersection of the wave's critical latitude and trough axis. In this talk, mesoscale organization of low-level vorticity substance and convection within the critical layer of an EW is examined. After discussing the theoretical framework of the new tropical cyclogenesis model, two observational case studies are presented that illustrate the usefulness of the model. The first case, Typhoon Nuri (2008), was observed during the T-PARC field project. A 3D-VAR analysis scheme that synthesizes aircraft Doppler radar and dropwindsonde data is used to document low-level spin-up and vorticity organization on the mesoscale. The second case examined is Hurricane Sandy (2012), which offers an interesting deviation from the standard tropical cyclogenesis model in that the critical layer of the parent EW exhibited an opening to the south. Fortuitously, the opening was juxtaposed with a favorable dynamic and thermodynamic environment that allowed accretion of cyclonic vorticity into the critical layer, leading to growth and intensification of the nascent storm.

Tuesday, 30 September 2014, 3:30PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg. 2 Large Auditorium (Rm 1022)

Seminar will be live webcast at the following link: http://www.fin.ucar.edu/it/mms/fl-live.htm