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contributor authorLilly, Douglas K.
date accessioned2017-06-09T14:26:10Z
date available2017-06-09T14:26:10Z
date copyright1986/01/01
date issued1986
identifier issn0022-4928
identifier otherams-19213.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4155305
description abstractRotating ?supercell? thunderstorms are shown to be characterized by high helicity, the vector inner product of velocity and vorticity, which is obtained both from the mean flow in which they are embedded and from buoyancy enrichment. Some unique properties of supercell helical flow are described, including a tendency for trajectory rotation to be reversed from parcel vorticity. A simple helical (Beltrami) flow model resembles gross supercell structure and also provides a prediction of storm motion. Since theory, closure model calculations and numerical simulations indicate that helicity suppresses turbulent dissipation, it is suggested that supercells owe their noted stability and long life to this effect. Enhanced predictability of such storms is then expected and is apparently seen in some results of Wilhelmson and Klemp. It is concluded that rotating storm structure and propagation must involve a compromise between the energetic effects discussed by Lilly in Part I of this study and those considered here, but that the helicity effects seem to be dominant in long-lived storms.
publisherAmerican Meteorological Society
titleThe Structure, Energetics and Propagation of Rotating Convective Storms. Part II: Helicity and Storm Stabilization
typeJournal Paper
journal volume43
journal issue2
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/1520-0469(1986)043<0126:TSEAPO>2.0.CO;2
journal fristpage126
journal lastpage140
treeJournal of the Atmospheric Sciences:;1986:;Volume( 043 ):;issue: 002
contenttypeFulltext


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