Chemistry and Transport in a Three-Dimensional Stratospheric Model' Chlorine Species During a Simulated Stratospheric Warming

Calculations of coupled chemistry and transport for the stratosphere are carried out for a 6-day period during the February 1979 stratospheric major warming, using winds derived from a spectral forecast model. All major families of stratospheric chemistry (odd oxygen, odd nitrogen, odd hydrogen, and odd chlorine), as well as longitudinally varying reaction rate coefficients and photolysis rates, are included in the model. Eight constituents and/or families are transported in the model; additional ones are held fixed or inferred by photochemical equilibrium approximations. Results presented include zonal mean fields, latitude-longitude distributions (and their changes with time), vertical profiles, and time series of the mixing ratios of transported constituents and families as well as of their total stratospheric column amounts. The results obtained show the relative importance of chemistry and transport for the chlorinecontaining species C10, C1ONO 2, HC1, and HOC1. Dynamical effects dominate the variability of HC1, while diurnal ones dominate that of CIONO 2 and C10. Diurnal chemistry and dynamical variability are of similar magnitude for HOC1. The effects of strong planetary wave activity may be seen as large longitudinal variability of the total HC1 and C1ONO 2 columns in the stratosphere; in middle and high northern latitudes it is sufficiently large that it exceeds the diurnal variability of the column.