Articles | Volume 5, issue 3
01 Mar 2005
01 Mar 2005

Column ozone and aerosol optical properties retrieved from direct solar irradiance measurements during SOLVE II

W. H. Swartz, J.-H. Yee, R. E. Shetter, S. R. Hall, B. L. Lefer, J. M. Livingston, P. B. Russell, E. V. Browell, and M. A. Avery

Abstract. Direct observation of the Sun at large solar zenith angles during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II)/Validation of International Satellites and study of Ozone Loss (VINTERSOL) campaign by several instruments provided a rich dataset for the retrieval and analysis of line-of-sight column composition, intercomparison, and measurement validation. A flexible, multi-species spectral fitting technique is presented and applied to spectral solar irradiance measurements made by the NCAR Direct beam Irradiance Atmospheric Spectrometer (DIAS) on-board the NASA DC-8. The approach allows for the independent retrieval of O3, O2·O2, and aerosol optical properties, by constraining Rayleigh extinction. We examine the 19 January 2003 and 6 February 2003 flights and find very good agreement of O3 and O2·O2 retrievals with forward-modeling calculations, even at large solar zenith angles, where refraction is important. Intercomparisons of retrieved ozone and aerosol optical thickness with results from the Ames Airborne Tracking Sunphotometer (AATS-14) are summarized.

Final-revised paper