Jet Fibres

60 Minutes

Natasa Strelec Mahovic
Dunja Mazzocco Drvar

Jet Fibres

Published: 01 January 2005

Jet Fibres, also known as cirrus streaks, are elongated patches of cirrus clouds, which move rapidly near the jet axis. There is no single theory explaining the formation of the Jet Fibres, but there are several mechanisms probably acting in combination. Generally, there are two necessary conditions needed for clouds to develop: sufficient humidity content and upward motion. In general, bands of cirrus clouds tend to form or persist on the anticyclonic side of the jet. The reason for this is that jet streams are associated with the strong thermal contrast across frontal zones and the layered clouds form in the warm moist air of the Warm Conveyor Belt with cloud edge lying along the jet core. This synoptic scale upward motion would bring a lot of humid air to upper levels and form a broad band of clouds. In order to produce a cloud structure of relatively small dimensions, such as Jet Fibres, there must be an additional smaller scale mechanism. Since a jet is necessarily involved in the formation of Jet Fibres, ascent may also occur because of the circulation in the cells around the entrance and the exit regions of the jet streak. Taking into account the vertical wind shear, directly above the jet core there is also upward motion on a smaller (turbulence) scale

Great Britain Go to Conceptual Model...

Filed under Keywords:

Conceptual Models, Jet, Synoptic Scale Meteorology