Modeling the spatial distribution of total ozone in northern hemisphere winter: 1979-1991

A form of the linearized steady state ozone continuity equation, expressed in terms of perturbations in lower stratospheric temperature and geopotential height, is used to model the spatial distribution (i.e., deviations from the zonal mean) of total ozone in northern hemisphere (NB) winter for the period 1979-1991. Lower stratospheric temperatures from channel 4 of the microwave sounding unit (MSU), geopotential height and temperature analyses provided by the Stratospheric Research Group at the Free University of Berlin (FUB), and climatological values of the zonal mean ozone mixing ratio are used to calculate the ozone mixing ratio perturbation for a given location at three levels in the lower stratosphere: 100, 50, and 30 mbar. These values are then summed together to provide an estimate of the total ozone perturbation at northern extratropical latitudes for the months of January and February. By applying this modeling approach to individual months on a year-to-year basis, much of the observed year-to-year variability in the spatial distribution of total ozone is approximately simulated. A significant decrease of the wave-induced variance in the wintertime total ozone distribution over the 1979-1991 period is indicated, consistent with the observed longitude dependences of total ozone trends in NH winter.