A reconstructed view of polar stratospheric chemistry

We describe a technique that uses relatively sparse observations from aircr aft of vertical column amounts together with a quasi-conserved parameter, p otential vorticity (PV), to reconstruct column abundances on a near-global scale. Stratospheric column amounts for a number of gases (including HF, NO , NO2, HNO3, ClONO2, O-3, and HCl) were measured during airborne field depl oyments to both polar regions in four separate years. Functions are determi ned that relate vertical column amounts to the isentropic potential vortici ty at two potential temperature levels (440 K and 520 K) at the observation points. Gridded PV values, derived from National Center for Environmental Prediction temperature and heights, are used to reconstruct column distribu tions for an entire polar region. Reconstructed fields are used to explore the usefulness of column observations to describe vertically averaged prope rties of the polar vortex and to compare one year and hemisphere with anoth er.