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Interpretation of Satellite Imagery of A Rapidly Deepening Cyclone
Author(s) -
Young M. V.,
Monk G. A.,
Browning K. A.
Publication year - 1987
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49711347803
Subject(s) - cyclogenesis , tropopause , baroclinity , geology , potential vorticity , trough (economics) , extratropical cyclone , streak , climatology , troposphere , cloud height , meteorology , atmospheric sciences , cyclone (programming language) , environmental science , vorticity , cloud computing , vortex , cloud cover , geography , geophysics , field programmable gate array , computer science , economics , macroeconomics , operating system , computer hardware
Model output and observational data are used to interpret, in detail, satellite images of a distinctive cloud system several hundred kilometres long which was observed before and during rapid cyclonic development that occurred over England. Conceptual models are forwarded which account for the structure of the major cloud areas and upper‐level moisture fields (as observed by water vapour imagery) immediately prior to and following the onset of vigorous cyclogenesis. The cloud system corresponded to what R. B. Weldon refers to as a baroclinic leaf cloud and was characterized by ‘ana’ cold frontal ascent. the baroclinic leaf lay within an area of enhanced ascent ahead of a major upper‐level trough. A jet streak which originated upstream, propagated rapidly around the base of the upper trough. A tongue of dry air centred on the left flank of this jet streak lay immediately upstream of the leaf cloud and had a major influence on its subsequent development. This intrusion of dry air was well represented by the Meteorological Office fine mesh model, which showed it as a pronounced tongue of recently descended air with high potential vorticity, which originated in the upper troposphere and lower stratosphere. Rapid cyclogenesis occurred as the dry intrusion overran low‐level air of high θ w within a warm conveyor belt at the southern tip of the leaf cloud. Interaction of the dry intrusion and baroclinic leaf cloud is shown to be particularly important in accounting for the detailed distribution of weather. It also suggests a way of pinpointing the location and timing of vigorous cyclogenesis.