Geophys. Res. Lett., 35 (2008) L24803; doi:10.1029/2008GL035866
Effects of microphysical drop size distribution on tornadogenesis in supercell thunderstorms
Nathan Snook and Ming Xue (School of Meteorology and Center for Analysis and Prediction of Storms, University of Oklahoma, Norman, OK, U.S.A.)
Abstract
Idealized simulations of tornadogenesis in supercell storms are performed using a grid of 100 m spacing. The cold pool intensity and low-level storm dynamics are found to be very sensitive to the intercept parameters of rain and hail drop size distributions (DSD). DSDs favoring smaller (larger) hydrometeors result in stronger (weaker) cold pools due to enhanced (reduced) evaporative cooling/melting over a larger (smaller) geographic region. Sustained tornadic circulations of EF2 intensity are produced in two of the simulations with relatively weak cold pools. When the cold pool is strong, the updraft is tilted rearward by the strong, surging gust front, causing a disconnect between low-level circulation centers near gust front and the mid-level mesocyclone. Weaker cold pool cases have strong, sustained, vertical updrafts positioned near and above the low-level circulation centers, providing strong dynamic lifting and vertical stretching to the low-level parcels and favoring tornadogenesis.
(Received 31 August 2008, accepted 18 November 2008, published 20 December 2008.)
Citation: (2008), Effects of microphysical drop size distribution on tornadogenesis in supercell thunderstorms, Geophys. Res. Lett., 35, L24803, doi:10.1029/2008GL035866.
Link to abstract: http://www.agu.org/pubs/crossref/2008/2008GL035866.shtml
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