ALBERT

Description: Surface snow samples were collected daily, at several sites representing distinct environments: sea ice, inland close to sea level, and a hilltop ~600 m above sea level (asl), from a Canadian high Arctic location at Eureka, Nunavut (80°N, 86°W) from the end of February to the end of March in 2018 and 2019. Snow samples were under ionic and salinity analysis. The aim of this study is to explore the role of snowpack in polar spring boundary layer chemistry, especially as a direct source of reactive bromine (BrO〈sub〉X〈/sub〉=BrO+Br) and nitrogen (NO〈sub〉X〈/sub〉=NO+NO〈sub〉2〈/sub〉). We find that surface snow bromide at sea level is significantly enriched, indicating a net sink of atmospheric bromine. Both surface snow bromide and nitrate at sea level have an increasing trend over the measurement time period. Using these trends, we derive an integrated net deposition flux of bromide of 1.01×10〈sup〉7〈/sup〉 molecules cm〈sup〉-2〈/sup〉 s〈sup〉-1〈/sup〉 and of nitrate of 2.6×10〈sup〉8〈/sup〉 molecules cm〈sup〉-2〈/sup〉 s〈sup〉-1〈/sup〉. In addition, nitrate and bromide in the morning samples are significantly higher than the afternoon samples, indicating a strong photochemistry effect, however the bromide loss rate is smaller than the nitrate loss rate by more than an order of magnitude. Also, surface snow nitrate and bromide at inland sites are significantly correlated (R=0.48-0.76), with a [NO〈sub〉3〈/sub〉〈sup〉-〈/sup〉]/[Br〈sup〉-〈/sup〉] ratio of 4-7 indicating a possible acceleration effect of reactive bromine in atmospheric NO〈sub〉X〈/sub〉-to-nitrate conversion. This is the first time we see such an effect from snow chemistry data obtained with a sampling frequency as short as one day.