Applications of ultraviolet absolute radiometry in satellite and surface-based remote sensing of atmospheric ozone

Abstract

Side-by-side comparisons of Langley-type Dobson AD double wavelength pair direct sun observations between SBUV/2, SSBUV flight models, and the NOAA world primary standard Dobson spectrophotometer 83 and 61 show that the SBUV/2-type instruments yield column ozone amounts that are 2% higher than the NOAA Dobson spectrometers. Similar results have been obtained with a radiometrically stable multifilter spectroradiometer (MFS) under less than ideal conditions. A new approach based on a modeled table look-up method for using zenith sky radiances to derive total column ozone from zenith clear sky conditions has been tested using SBUV/2, SSBUV flight models and the MFS equipped with narrowband interference filters at the Dobson AD wavelength pairs. These clear zenith sky observations yield total column ozone that is in good agreement with ozone from the NOAA Dobson spectrophotometer direct sun observations. New model calculations on the relationship between satellite nadir radiances and surface-based zenith clear sky radiances suggest that the combination of a very radiometrically stable surface-based spectroradiometer combined with a compact high performance double monochromator could be used to derive a common radiometric scale among satellite-borne ozone monitoring instruments.