Abstract. During polar spring, the presence of reactive bromine in the polar boundary
layer is considered to be the main cause of ozone depletion and mercury
deposition. However, many uncertainties still remain regarding understanding the
mechanisms of the chemical process and source of the bromine. As Arctic
sea ice has recently been dramatically reduced, it is critical to investigate
the mechanisms using more accurate measurements with higher temporal and
spatial resolution. In this study, a typical process of enhanced bromine and
depleted ozone in the Ny-Ålesund boundary layer in late April 2015 was
observed by applying ground-based multi-axis differential optical absorption
spectroscopy (MAX-DOAS) technique. The results showed that there were bromine monoxide
(BrO) slant columns as high as 5.6 × 1014 molec cm−2 above the
Kings Bay area on 26 April. Meanwhile, the boundary layer ozone and gaseous
elemental mercury (GEM) were synchronously reduced by 85 and 90 %,
respectively. Based on the meteorology, sea ice distribution and air mass
history, the sea ice in the Kings Bay area, which emerged for only a very
short period of time when the enhanced BrO was observed, was considered to be
the major source of this bromine enhancement event. The oxidized GEM may be
directly deposited onto snow/ice and thereby influence the polar ecosystem.
Naval submarine base Kings Bay and Bangor soil evaluations.