The Role of the Quasi-Biennial Oscillation in Stratospheric Dehydration

Abstract

Among Professor Richard Reed’s many contributions to the understanding of the meteorology of the middle atmosphere, his discovery of the equatorial quasi-biennial oscillation (QBO) has perhaps had the most enduring influence. In a paper presented at the 40th anniversary meeting of the American Meteorological Society, January 1960, he showed that rawinsonde data from Canton Island (2.8°S) revealed “alternate bands of easterly and westerly winds which originate above 30 km and which move downward through the stratosphere at a speed of about 1 km per month.” He pointed out that the alternating wind regimes “appear at intervals of roughly 13 months, 26 months being required for a complete cycle.” This work appeared in print in Reed et al. (1961). Although several other workers noted the occurrence of this strange wind oscillation at about the same time, unlike Reed they seem not to have appreciated its dynamical significance, and the challenges that the momentum budget and periodicity of this strange oscillation presented for theoreticians.

“Perhaps a simple explanation will soon be found, and what now seems an intriguing mystery will be relegated to the category of a meteorological freak. Or perhaps the phenomenon will prove to have a greater significance than we now might envisage, either because of some intrinsic property it possesses or because of its effect on other related areas of research.”—(Reed 1967)