Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 6 2005 10.5194/acpd-5-11617-2005 http://www.atmos-chem-phys-discuss.net/5/11617/2005/ http://www.atmos-chem-phys-discuss.net/5/11617/2005/acpd-5-11617-2005.html http://www.atmos-chem-phys-discuss.net/5/11617/2005/acpd-5-11617-2005.pdf 11617 11642 2005-11-14 Comparison of high-latitude line-of-sight ozone column density with derived ozone fields and the effects of horizontal inhomogeneity W. H. Swartz bill.swartz@jhuapl.edu J.-H. Yee C. E. Randall R. E. Shetter E. V. Browell J. F. Burris T. J. McGee M. A. Avery The Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland, USA Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado, USA National Center for Atmospheric Research, Boulder, Colorado, USA NASA Langley Research Center, Hampton, Virginia, USA NASA Goddard Space Flight Center, Greenbelt, Maryland, USA Extensive ozone measurements were made during the second SAGE&nbsp;III Ozone Loss and Validation Experiment (SOLVE&nbsp;II). We compare high-latitude line-of-sight (LOS) slant column ozone measurements from the NASA DC-8 to ozone simulated by forward integration of measurement-derived ozone fields constructed both with and without the assumption of horizontal homogeneity. The average bias and rms error of the simulations assuming homogeneity are relatively small (&minus;6 and 10%, respectively) in comparison to the LOS measurements. The comparison improves significantly (&minus;2% bias; 8% rms error) using forward integrations of three-dimensional proxy ozone fields reconstructed from potential vorticity-O<sub>3</sub> correlations. The comparisons provide additional verification of the proxy fields and quantify the influence of large-scale ozone inhomogeneity. The spatial inhomogeneity of the atmosphere is a source of error in the retrieval of trace gas vertical profiles and column abundance from LOS measurements, as well as a complicating factor in intercomparisons that include LOS measurements at large solar zenith angles.