Heidelberg 2015 – scientific programme

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UP: Fachverband Umweltphysik

UP 4: Postersession Atmosphäre

UP 4.14: Poster

Wednesday, March 25, 2015, 10:45–19:45, G/Foyer

Observations of RHS concentrations and processes at the Dead Sea Valley — •Stefan Schmitt¹, Robert Holla^1,2, Denis Pöhler¹, Udo Frieß¹, Ulrich Platt¹, Andreas Held³, Katharina Kamilli³, Ulrich Corsmeier⁵, and Jutta Zingler⁴ — ¹IUP, Heidelberg — ²Deutscher Wetterdienst — ³BayCEER, Bayreuth — ⁴FTU, Karlsruher Institut für Technologie — ⁵IMK, Karlsruher Institut für Technologie

The Dead Sea Valley (DSV), located at the border of Israel and Jordan, is a unique place with high activity of reactive halogen species (RHS). Former DOAS measurements revealed high abundances of bromine monoxide (BrO) as well as iodine monoxide (IO) but the processes and sources are still not understood. Therefore we performed intensive LP-DOAS measurements in May 2012. We observed mixing ratios of up to 90 ppt, 5ppt and 60 ppt for BrO, IO and I₂ respectively. NO₂ mixing ratios dropped from about 6 ppb to below the detection limit of 0,5 ppb during sunrise on every day while significant BrO and IO concentrations were only detected at low NO₂ mixing ratios. This supports the assumption that NO₂ is consumed by the formation of BrONO₂ and IONO₂ from released RHS. The data shows several interesting chemical features which are presented.

Further, condensation particle counter (CPC) measurements of particles with sizes of 9-800 nm indicate that significant mixing ratios of IO were observed only at low particle loads while BrO seems to prefer high particle concentrations. This indicates a possible influence of aerosols on the halogen chemistry at the DSV.