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contributor authorGilmore, Matthew S.
contributor authorWicker, Louis J.
date accessioned2017-06-09T16:11:50Z
date available2017-06-09T16:11:50Z
date copyright1998/04/01
date issued1998
identifier issn0027-0644
identifier otherams-63087.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4204051
description abstractThis work studies the relationship between midtropospheric dryness and supercell thunderstorm morphology and evolution using a three-dimensional, nonhydrostatic cloud model. Environments that differ only in midtropospheric dryness are found to produce supercells having different low-level outflow and rotational characteristics. Thunderstorms forming in environments with moderate vertical wind shear, large instability, and very dry midtropospheric air produce strong low-level outflow. When this low-level outflow propagates faster than the midlevel mesocyclone, the storm updraft and low-level mesocyclone weaken. However, in environments with larger vertical wind shear or with higher-altitude dry midtropospheric air, the low-level outflow is not as detrimental to the supercell. This provides a possible explanation for why some environments that appear favorable for the development of strong low-level mesocyclones in supercells fail to do so. Downdraft convective available potential energy (DCAPE) is also investigated as one possible index for estimating potential downdraft strength. Trajectory analysis shows that the strongest downdrafts are subsaturated and diluted due to mixing between the downdraft and the surrounding environment. These significant violations of parcel theory make DCAPE a worse estimate for supercell downdraft intensity than convective available potential energy is for the updraft. A more sophisticated parameter is needed in order to determine downdraft intensity and low-level outflow strength within supercells.
publisherAmerican Meteorological Society
titleThe Influence of Midtropospheric Dryness on Supercell Morphology and Evolution
typeJournal Paper
journal volume126
journal issue4
journal titleMonthly Weather Review
identifier doi10.1175/1520-0493(1998)126<0943:TIOMDO>2.0.CO;2
journal fristpage943
journal lastpage958
treeMonthly Weather Review:;1998:;volume( 126 ):;issue: 004
contenttypeFulltext


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