Comparison of total ozone from the satellite instruments GOME and TOMS with measurements from the Dobson network 1996–2000 K. Bramstedt1, J. Gleason2, D. Loyola3, W. Thomas3, A. Bracher1, M. Weber1, and J. P. Burrows1 1Institute of Environmental Physics, University of Bremen, Bremen, Germany 2NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA 3DLR Remote Sensing Technology Institute (DLR/IMF), Wessling, Germany
Abstract. Over the last 3 decades, satellite data have been used to monitor long-term
global changes in stratospheric ozone. The TOMS series (1978-present) and GOME
(1995-present) are two very important instruments in this context. In this paper, TOMS total ozone and three approaches to derive total ozone
from GOME measurements are validated with ground-based Dobson network data.
Beyond the operational products of both instruments, e.g. TOMS version 7 and
GOME Data Processor version 2.7, total ozone is calculated by integrating FURM ozone profiles and by applying the TOMS algorithm to the
GOME spectra. All algorithms show in general good agreement with ground-based measurements. The operational GOME total ozone shows seasonal
variations, most likely introduced by difficulties in the derivation of airmass factors, which convert measured slant columns into vertical columns.
The TOMS algorithm estimates on average 2% higher total ozone in the southern hemisphere than in the northern for both
instruments as compared to the ground-based data, indicating that the source of the observed hemispheric differences is
in the TOMS algorithm. Both instruments show aging effects in 2000, leading to enhanced variability in
the ozone column differences with respect to Dobson data. In addition, the integrated GOME ozone
profiles and the TOMS algorithm applied to GOME data show larger mean deviations in 2000.
Citation: Bramstedt, K., Gleason, J., Loyola, D., Thomas, W., Bracher, A., Weber, M., and Burrows, J. P.: Comparison of total ozone from the satellite instruments GOME and TOMS with measurements from the Dobson network 1996–2000, Atmos. Chem. Phys., 3, 1409-1419, doi:10.5194/acp-3-1409-2003, 2003.