A Case Study of GATE Convective Activity.

This paper presents the synoptic and mesoacale aspects of the intense convcective activity of 2 September 1974 in the Eastern Atlantic. Two main features were evident in the GATE B-scale array: a broad convective band associated with the 700-mb trough, and long and narrow lines of convection oriented SE-NW. One of these lines, which moved across the B-scale array and was penetrated by several aircraft, is described in detail. The structure of the cloud and precipitation fields, obtainedfrom the analysis of satellite and radar data, indicates that intense precipitation occurred mainly at the leading edge of the line where new cells were continuously generating. Cross-sectionsth rough the line (from boom, aircraft and tethered balloon data) show a gust front at the surface, a downdraft region associated with the rain area, and a wind shaft in the lowest 300m. The circulations around and within this line appear to be similar to a class of tropical squall-lines studied at length by Zipser, (1977) and Houze (1977) with the important difference that the horizontal gradients of the dynamic and thermodynamic variables across the line were typically weaker.

Related Topics

• Clouds,
• Convection,
• GATE,
• Tropics