A comparison of 40 years of SBUV measurements of column ozone with data from the Dobson/Brewer network

Abstract

AbstractTotal column ozone data from the Nimbus‐4 Backscatter UltraViolet (BUV) instrument, Nimbus‐7 Solar Backscatter Ultraviolet (SBUV) instrument, as well as from seven NOAA SBUV/2 instruments have been newly reprocessed with the Version 8.6 ozone retrieval algorithm. This yields a coherent data set that, unlike the Total Ozone Mapping Spectrometer ozone record, has no data gaps or significant time periods with large uncertainties due to calibration issues from 1979 to the present. The column ozone data from the first 3 years of the BUV record (1970–1972) is of high quality and can be used to extend the satellite ozone record back over 40 years. With the new algorithm, an improved total column ozone value is calculated by summing up the profile information as opposed to a single direct column measurement, and the algorithm is optimized for the detection of long‐term trends. The results from this processing of these data have been systematically compared to total ozone data from Brewer and Dobson spectrophotometers for many individual ground stations as a function of time, satellite solar zenith angle, and latitude. The time series comparisons show an agreement within ± 1% over the past 40 years with the bias approaching zero over the last decade. The aerosols associated with the eruption of Mt Pinatubo in 1991 produced an underestimation of ozone for our retrievals at high slant columns while the near‐nadir values were relatively unaffected. There is very little systematic offset between the satellite and ground‐based measurements as a function of latitude with the Nimbus‐4 BUV data (1970–1976) showing the largest offsets. The comparisons as a function of satellite solar zenith angle show consistent behavior for all instruments. Comparisons with ozonesonde data show good agreement in the integrated column up to 25 hPa with differences of no more than 5%.