Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 5 2 2005 10.5194/acpd-5-2017-2005 http://www.atmos-chem-phys-discuss.net/5/2017/2005/ http://www.atmos-chem-phys-discuss.net/5/2017/2005/acpd-5-2017-2005.html http://www.atmos-chem-phys-discuss.net/5/2017/2005/acpd-5-2017-2005.pdf 2017 2045 2005-04-06 Airborne multi-axis DOAS measurements of tropospheric SO₂ plumes in the Po-valley, Italy P. Wang A. Richter M. Bruns J. P. Burrows W. Junkermann K.-P. Heue T. Wagner U. Platt I. Pundt Institute of Environmental Physics, University of Bremen, Germany Research Center Karlsruhe, IMK-IFU, Garmisch-Partenkirchen, Germany Institute of Environmental Physics, University of Heidelberg, Germany During the second FORMAT (FORMaldehyde as A Tracer of oxidation in the troposphere) campaign in 2003 the airborne multi-axis DOAS instrument (AMAXDOAS) performed spectroscopic measurements of SO₂ from the city of Mantova and the power plant Porto Tolle using scattered sun-light during two flights on 26 and 27 September 2003. Measurements were performed in 10 different viewing directions, providing information on the vertical SO₂ distribution and the SO₂ vertical column. The SO₂ emission flux from the power plant Porto Tolle was calculated to 1.6×10²⁵ molec cm^-2 (1.7 kg s^-1) and was found to be the same on both measurement days, and also comparable to official emission data, which quote 2.25×10²⁵ molec s^-1 (26 September) and 2.07×10²⁵ molec s^-1 (27 September). Over the city of Mantova, the observed SO₂ vertical columns were 1.1×10¹⁶ molec cm^-2 and 1.9×10¹⁶ molec cm^-2 on 26 and 27 September, respectively. This is in good agreement with ground-based measurements of 5.9 ppbv and 10.0 ppbv which correspond to 1.2×10¹⁶ molec cm^-2 and 2.2×10¹⁶ molec cm^-2.