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Results from Vaisala’s long range lightning detection network (LLDN) tropical cyclone studies. Nicholas W. S. Demetriades Applications Manager, Meteorology Business Area Vaisala, Inc. Monterey, CA 24 March 2009. Hurricane Rita (2005). Demetriades and Holle (2008) Introduction - Goal.
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Results from Vaisala’s long range lightning detection network (LLDN) tropical cyclone studies Nicholas W. S. Demetriades Applications Manager, Meteorology Business Area Vaisala, Inc. Monterey, CA 24 March 2009
Demetriades and Holle (2008)Introduction - Goal • Study inner core lightning rates throughout the full lifecycle of Atlantic tropical cyclones for a large sample size
Methodology • Full lifecycle of tropical cyclones that occurred in Atlantic basin from 2004 through 2007 • Landfall not excluded • Subtropical storms not studied • Tropical cyclone position and maximum sustained wind speeds obtained from National Hurricane Center best track data • Interpolated positions and maximum sustained wind speeds between 6-hour intervals to obtain 3-hour values • Tropical cyclone inner core lightning defined as 3-hourly CG lightning flash rates within 100 km of center of storm position • Day/Night detection efficiency corrections were applied
Atlantic basin resultsDay/Night, DE-corrected cumulative lightning rate distribution table
Atlantic basin resultsInner core lightning with respect to landfall
Conclusions • New finding: Atlantic tropical cyclones produce the highest inner core lightning rates during the tropical storm stage and the lowest inner core lightning rates during the hurricane stage • High inner core (eyewall) lightning rates occur infrequently in category 3-5 hurricanes • Appear to be related to eyewall replacement cycles (Knabb et al., 2008) • Atlantic tropical cyclones produce more inner core lightning during the 24-hour period leading up to, and including landfall, than they do during the 24-hour period after landfall
Hurricane Katrina (2005)Eyewall replacement & Continuous eyewall lightning