Near -tropopause structure and dynamics from comparisons of total column ozone and model analyses

This study makes comparisons between observed total column ozone (or simply total ozone) from the Earth Probe Total Ozone Mapping Spectrometer (EP/TOMS) and mesoscale model analyses fields for midlatitude, baroclinic cyclone cases. We emphasize the consistency and agreement of total ozone fields with meteorological quantities at smaller scales than previously demonstrated. The results may aid in assimilation of total ozone into models to improve dynamics and forecasting ability. Significant to stratosphere-troposphere exchange studies, the use of total ozone data to identify potential regions of cross-tropopause transport is also illustrated.;In case studies of large-scale, midlatitude cyclones over the United States, fine-scale consistency is shown for total ozone and the Mesoscale Analysis and Prediction System (MAPS) model analysis fields. The tropopause pressure field shows good agreement with total ozone outside of regions of stratosphere-troposphere exchange (STE). Geopotential height contours on isobaric surfaces near the tropopause are seen to compare well to total ozone. Complex vertical structure of potential vorticity (PV) in the lower stratosphere can be associated with small scale total ozone maxima and minima. In addition, EP/TOMS retrieval errors on the order of ∼10% are identified with high thunderstorm cloud anvils, particularly along frontal zones.;Two types of STE are discussed in relation to the evidence and their signature within the model and total ozone fields. "PV-holes" of varying strengths are frequently found near the center or eastern part of cyclones. These appear as isolated regions of tropospheric PV values and enhanced total ozone. Back trajectories illustrate that the destruction of PV by precipitation-induced latent heating causes a raising of the PV-defined tropopause, leaving stratospheric air below. In the second type of STE, cross-jet exchange along the southern edge of the cyclone, total ozone is not observed to be significantly enhanced. This suggests mixing of ozone-rich stratospheric air with ozone-poor tropospheric air as the PV is destroyed.