Acoustical origin of rainbands in an ideal tropical hurricane

Abstract

An acoustical model of hurricane rainband formation is proposed. Self-excited acoustic resonance inside the spinning eye produces strong azimuthal and radial standing waves. These modes can cause large temperature fluctuations about the dew point which are believed to be responsible for observed dry/wet bands in the outer storm disk. Distortion of standing wavefronts into spirals occurs in the transition layer region between approximately geostrophic flow inside the eyewall and irrotational flow outside. Tonal emissions from hurricane eyes should be detectable at great distances and are likely to be in a range below 0.01Hz.