Convectively Induced Transverse Band Signatures in Satellite Imagery

Abstract

Transverse cirrus bands have commonly been observed in the outflow of thunderstorms, though little literature exists on the subject. The primary objective of this paper is to characterize the transverse band signature in satellite imagery with references to storm location, movement, and life cycle. The transverse band signature was observed in nearly half of all convective systems analyzed between May and August 2006, commonly in the mature and decay stages of the system. Storm size and propagation did not appear to influence transverse bands, though the bands did appear to be associated with negative 300-hPa relative vorticity and positive divergence. Transverse bands lasted an average duration of 9 h and generally occurred during the nighttime hours. The satellite analysis was combined with eddy dissipation rate (EDR) atmospheric turbulence observations collected by commercial aircraft. At least one observation of light (moderate) turbulence was found within transverse bands for 93% (44%) of events, indicating that the presence of transverse bands in satellite imagery is a strong indicator for aviation turbulence.