Chlorine chemistry and the potential for ozone depletion in the Arctic stratosphere in the winter of 1991/92

Abstract

We present an analysis of chlorine chemistry in the Arctic stratosphere during the winter of 1991/92 and assess its potential implications for ozone depletion. In accordance with observations of total organic chlorine, ClONO 2 and HCl, box model results indicate the following: (1) An almost complete activation of chlorine during the cold winter period. (2) A possible contribution from the heterogeneous reaction HOCl + HCl and the gas‐phase reaction CH 3 O 2 + ClO to the complete conversion of HCl to active chlorine. (3) A strong buildup of ClONO 2 following PSC disappearance which remains the main chlorine reservoir for about a month, after which HCl becomes dominant. (4) Appreciable chemical ozone loss in the lower stratosphere inside the polar vortex is conceivable for the winter of 1991/92.