Darmstadt 2008 – scientific programme

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UP: Fachverband Umweltphysik

UP 1: Atmosphäre und Klima

UP 1.3: Talk

Tuesday, March 11, 2008, 09:00–09:15, 3B

MAX-DOAS measurements of bromine monoxide during Polarstern cruise ANTXXIII-7 — •Henning Kirk, Andreas Richter, Anja Schönhardt, Folkard Wittrock, and John P. Burrows — Institut für Umweltphysik, Universität Bremen

During springtime, a strong increase of BrO-concentrations in the polar boundary layer, so called bromine explosions, are observed, mainly by satellite instruments, e.g. SCIAMACHY. Those events are correlated with two further phenomena: The depletion of O₃ (ODE) and of Hg (AMDE) in the boundary layer. The AMDEs are on suspicion to be the main reason for the enhancement of Hg in the polar ecosystems.

Until now, neither the release mechanism of the BrO is understood in detail, nor is the exact source of the Br. Due to their high concentration in sea salt, the surfaces of frost flowers or aerosols originating from their erosion, are candidates to be the source of the Br.

We will present results of continuous ship borne MAX-DOAS measurements taken in the Weddell Sea during the Polarstern cruise ANTXXIII-7, from Aug. 24 - Oct. 29 2006. The main aim of our measurements was to identify specific bromine releasing areas. Simultaneously, the involved chemical components were measured as well as the surrounding conditions. Several bromine events have been observed, albeit at much lower levels than expected. A good correlation was found with the coincident O₃ and Hg measurements. Besides a case study of a moderate event, BrO time series, their relations to the relevant parameters, e.g. weather conditions, and their interpretation as effect of transport or local chemistry will be shown.