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Trace Gas Measurements in Eureka by UV-visible Spectrometer

A ground-based, UV-visible, triple-grating spectrometer was installed at the Polar Environment Atmospheric Research Laboratory (PEARL, 86.4°W, 80.1°N) in August 2006. Since then, the instrument has been making daily measurements, with the exception of polar night. A sun-tracker was installed directly above this instrument, the PEARL-GBS (PEARL Ground-Based Spectrometer), in 2008, enabling Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) and direct-Sun/Moon observations.

Around the same time as the discovery of the Antarctic ozone hole in the stratosphere, scientists became aware of severe ozone depletion events (ODEs) in the polar troposphere. These events have since been linked to extremely high concentrations of bromine, which are called bromine explosion events (BEEs). In this talk, we will start at introduce the BEE and describe the MAX-DOAS measurements which were used for the observation of these ODEs. A case study of a BEE in April 2011 will be shown in detail. Evidence suggests that this BEE was generated from unstable boundary layer m eteorological conditions, which is unusual for BEEs. Some facts about the BrO DOAS fitting window selections will also be presented, to give the audience some insight into the technical details of the trace gas retrievals, and reveal one of the challenges in the BrO study.

In addition to the MAX-DOAS measurements for the BEE study, we also implemented direct-moon measurements last winter. Our preliminary polar night ozone and NO 3 data are very promising, and will be briefly described at the end of the talk.