ON THE SPACING OF CONVECTIVE CLOUD BANDS

Abstract

A theoretical investigation is made on the spacing of convective cloud bands aligned parallel to the general wind. The primary concern to be discussed here deals with the ratio of the spacing of the bands to their depth as they are frequently observed in the atmosphere, which is taken here to be much larger than the one depending on Rayleigh's theory of thermal convection. A preferred mode of convective cloud bands is determined so as to maximize the upward heat transport, based on the cellular cumulus model proposed by Asai [1967] for a thermal convection in a conditionally unstable atmosphere which is unstable for moist ascending motion and stable for dry descending motion. The result obtained suggests that the spacing of bands being 10 times or more larger than the depth may be realized in the atmosphere as well as that comparable to the depth.