Airborne Imaging-DOAS measurements of the horizontal and vertical distribution of bromine monoxide during the BROMEX campaign in spring 2012 around Barrow, AK
Abstract
During the past few decades, the amount of multi-year sea ice in the Arctic has decreased dramatically, and this loss is predicted to continue due to the warming climate. This means a shift of the dominance from perennial to seasonal ice, which implies that vast regions of the Arctic are being occupied by seasonal, saltier ice. This younger and also thinner seasonal ice is also more susceptible to formation of leads, polynyas and frost flowers, which are saltier compared to perennial ice, and can facilitate chemical processes leading to bromine enhancement in the Arctic. Bromine monoxide (BrO) is a reactive halogen species (RHS) and has been known for quite a while to have a profound impact on the chemistry of the polar tropospheric boundary layer. Especially during springtime, BrO regularly causes the complete depletion of ozone in the lowermost ~1000m through autocatalytic photochemistry during so called Ozone Depletion Events (ODEs). Despite numerous advances during the last few years, details of the bromine release and reaction processes are still unclear, especially the role of frost flowers, first-year sea ice, atmospheric stability and snow. To investigate these important details of this process, a novel imaging DOAS instrument for the ultraviolet wavelength range (300 to 400 nanometer) was deployed aboard a light twin-engine aircraft (ALAR, Purdue Univ.) as part of the BRomine, Ozone, and Mercury EXperiment (BROMEX) in Barrow, Alaska, in spring 2012. This instrument utilizes (1) a whisk broom scanner system in nadir direction to map trace gas distributions of the overflown area at high spatial resolution. In addition, (2) a forward-looking system, observes the vertical trace gas distribution in 31 different viewing directions simultaneously (push broom scanning). Both viewing directions are equipped with digital cameras, enabling the creation of aerial maps and the comparison of spectral data with background features. This system was used for measurements of the horizontal and vertical distribution of bromine monoxide (BrO) and other gases over a wide variety of sea, ice and land surface conditions (first-year sea ice, frost flowers, open leads, nilas, and arctic tundra). Preliminary data will be presented, including maps putting trace gases in the context of surface features.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFM.A31D0055Z
- Keywords:
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- 0365 ATMOSPHERIC COMPOSITION AND STRUCTURE / Troposphere: composition and chemistry;
- 0368 ATMOSPHERIC COMPOSITION AND STRUCTURE / Troposphere: constituent transport and chemistry;
- 0750 CRYOSPHERE / Sea ice;
- 3360 ATMOSPHERIC PROCESSES / Remote sensing