Bremen 2000 – scientific programme

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UP: Umweltphysik

UP 5: Datenauswertung (Atmosph
äre) I

UP 5.4: Talk

Wednesday, March 22, 2000, 12:00–12:15, H2

SURFACE NO, NO₂, AND NO_y MIXING RATIOS AT NEUMAYER BASE, ANTARCTICA (70deg S, 8deg W) — •Rolf Weller¹, Andrea Wille¹, Katja Riedel¹, Otto Schrems¹, Anna Jones², and Eric Wolff² — ¹Alfred Wegener Instutute for Polar and Marine Research — ²British Antartic Survey, NERC; High Cross, Madingley Road, Cambridge, CB3 0ET, UK

One major goal of the PEAN99 campaign (Photochemical Experiment at Neumayer, January/February 1999) was to assess the photochemistry of reactive nitrogen oxide compounds and their chemical and physical exchange processes with the firn layer. For this purpose we measured NO/NO₂/NO _y by two chemiluminescence detectors coupled with a photolytical NO ₂ and a Au/CO catalysed NO_y convertor, respectively. The focus of this contribution are gaseous NO/NO2 mixing ratios measured during the campaign and the first results of the continuous NO_y record started in February 1999. Typically, background NO and NO ₂ mixing ratios were below 10 pptv throughout the campaign and showed a distinct photochemically driven diurnal variation with maximum NO and NO ₂ values around noon and midnight, respectively. Up to now (Nov. 99) the NO _y mixing ratios were found to be in the range from 20 to 100 pptv. The diurnal and seasonal variability of the observed NO/NO ₂ and NO _y mixing ratios and the influence on local boundary layer photochemistry will be discussed.