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50 Years of Balloon-borne Ozone Profile Measurements at Uccle, Belgium

R. Van Malderen1, H. De Backer1, D. De Muer1, D. Poyraz1, W. Verstraeten1, V. De Bock1, A. Delcloo1, A. Mangold1, Q. Laffineur1, M. Allaart2, F. Fierens3 and V. Thouret4

1Royal Meteorological Institute of Belgium, Brussels, Belgium; +32-2-373-05-95, E-mail: roeland.vanmalderen@meteo.be
2Royal Netherlands Meteorological Institute (KNMI), De Bilt, Netherlands
3Belgian Interregional Environment Agency, Brussels, Belgium
4Laboratoire dAĆ©rologie, The National Center for Scientific Research (CNRS), and Universite Paul Sabatier Toulouse III, Toulouse, France

Starting in 1969, and with three launches a week, the Uccle (Brussels, Belgium) ozonesonde dataset is one of longest and densest of the world. Moreover, as the only major change was the switch from Brewer-Mast (BM) to Electrochemical Concentration Cell (ECC) ozonesonde types in 1997 (when the emissions of ozone depleting substances peaked), the Uccle time series is very homogenous. We will briefly present the efforts taken during the first three decades of the 50 years of ozonesonde observations to guarantee the homogeneity between ascent and descent profiles, under changing environmental conditions (e.g. SO2), and between the different ozonesonde types.

We will show a few findings based on the time series, such as long term stratospheric ozone trends based on the Long-term Ozone Trends and Uncertainties in the Stratosphere (LOTUS) multiple linear regression model. The Uccle tropospheric ozone trends are compared with the In-service Aircraft for a Global Observing System (IAGOS) measurements gathered at nearby Frankfurt airport, while the surface ozone observations from the ozonesondes are evaluated with ground level observations at the same site. Finally, we present comparisons with other ozone measurement techniques, such as co-located total ozone column and satellite retrievals.

Reference: Van Malderen, R., De Muer, D., De Backer, H., Poyraz, D., Verstraeten, W. W., De Bock, V., Delcloo, A. W., Mangold, A., Laffineur, Q., Allaart, M., Fierens, F., and Thouret, V.: Fifty years of balloon-borne ozone profile measurements at Uccle, Belgium: a short history, the scientific relevance, and the achievements in understanding the vertical ozone distribution, Atmos. Chem. Phys., 21, 12385–12411, https://doi.org/10.5194/acp-21-12385-2021, 2021.

Figure 1

Figure 1. Vertical distribution of trends in stratospheric ozone concentrations at Uccle for different periods and at De Bilt (2000–2018). The trends and their uncertainties are calculated with the LOTUS multiple linear regression model, including an independent linear trend term. The 2 error bars represent the trend uncertainty estimated by the regression model (using the fit residuals). For the Uccle 1969–2018 time series only, one linear trend term is included in the model instead.