Tropospheric bromine atom measurements at Utqiagvik (Barrow), Alaska, March 2012

The 2012 Bromine, Ozone, and Mercury Experiment (BROMEX) occurred during March 2012 with the overarching goal being to study the origin and propagation of bromine chemistry in the springtime Arctic. Chemical ionization mass spectrometry measurements of trace halogen gases were conducted at approximately one meter above the snowpack on the Barrow Environmental Observatory tundra near Utqiagvik (Barrow), AK (71 deg. 16.500 N, 156 deg 38.426 W). These measurements resulted in a highly comprehensive dataset of trace halogen gases that aid in our understanding of springtime ozone and mercury depletion events. Our previous dataset reported one hour average mole ratios of Br 2 , Cl 2 , BrO, HOBr, BrO, and O 3 (Paul Shepson. 2014. Studies of the Production of Molecular Halogens in Arctic Snowpacks and on Sea Ice Surfaces. Arctic Data Center. urn:uuid:cf8576c7-595a-4774-b275-0e979152f7eb). Here we report one hour average mole ratios of bromine atoms (Br), which, to our knowledge, represent the first tropospheric measurement and quantitation of ambient bromine atom levels.