Airborne multi-axis DOAS measurements of tropospheric SO2 plumes in the Po-valley, Italy
1Institute of Environmental Physics, University of Bremen, Germany
2Research Center Karlsruhe, IMK-IFU, Garmisch-Partenkirchen, Germany
3Institute of Environmental Physics, University of Heidelberg, Germany
Abstract. 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.