Leipzig 2002 – scientific programme
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UP: Umweltphysik
UP 9: Atmosphäre, Aerosole, Klima - Poster
UP 9.2: Poster
Monday, March 18, 2002, 16:30–18:00, Galerie 1
MAX-DOAS-measurements of BrO and NO2 in the marine boundary layer — •Hans Leser, Hönninger Gerd, and Ulrich Platt — Institut für Umweltphysik Im Neuenheimer Feld 229 69120 Heidelberg
During a cruise of the German research vessel Polarstern in October 2000 from Bremerhaven, Germany to Capetown, South Africa tropospheric bromine oxide abundance in mid latitudes were investigated by means of the MAX-DOAS method (scattered light Multi Axis Differential Optical Absorption Spectroscopy).
This method is used to investigate vertical distributions of absorbers. Using the scattered light DOAS technique slant column densities of those absorbers are obtained. By comparing the column densities of measurements taken at different viewing angles above the horizon (elevation angles) it is possible to draw conclusions regarding the vertical distribution of the trace gases.
During the period of 21 days measurements at six different elevation angles were performed one after another repeating every hour.
The quantitative analysis concludes with an average mixing ratio of BrO to air molecules of 0.7 ± 0.2 ppt in the planetary boundary layer during the period of two days north of the Canary Islands (around 13∘W 35∘N) and an upper limit of 3 ppt for the whole time frame of the measurements.
Tropospheric NO2 was found near Europe and the Canary Islands up to a mixing ratio of 3,7± 0,2 ppb and for the clean air south westerly of Africa an upper limit of 60 ppt could be concluded.