UNCERTAINTIES IN REACTIVE UPTAKE COEFFICIENTS FOR SOLID STRATOSPHERICPARTICLES .2. EFFECT ON OZONE DEPLETION

Uncertainties in reactive uptake coefficients for reactions involving KCI, ClONO2 and HOCl on nitric acid trihydrate (NAT) and sulfuric acid tetrahydrate (SAT) are shown to affect modeled Arctic stratospheric o zone depletion in a photochemical box model. The main contribution to the difference arises from the reaction ClONO2 + HCl --> Cl-2 + HNO3 i n early to mid-winter. During this period, differences in predicted HC l and ClONO2 are more than 1 ppbv for several weeks when an upper limi t for solid PSC existence is assumed. Ozone depletion is greater when liquid aerosols persist through the winter compared with cases where s olid particles are assumed to form.