Showing papers by "Samuel R. Hall published in 2004"

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

Abstract: Direct observation of the Sun at large solar zenith angles during the second SAGE III Ozone Loss and Val- idation Experiment (SOLVE II)/Validation of International Satellites and study of Ozone Loss (VINTERSOL) cam- paign 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 ap- plied 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 exam- ine the 19 January 2003 and 6 February 2003 flights and find very good agreement of O 3 and O2·O2 retrievals with forward-modeling calculations, even at large solar zenith an- gles, where refraction is important. Intercomparisons of re- trieved ozone and aerosol optical thickness with results from the Ames Airborne Tracking Sunphotometer (AATS-14) are summarized.