Frost Flower Chemistry and Physics: a Hudson Bay Field Study

Frost flowers are an important part of air-ice surface exchange in the polar regions and play a role in halogen chemistry in the troposphere. Their presence affects our ice core interpretation, understanding of past atmospheric circulation and climate modeling. Frost flowers were observed and collected in areas of differing salinity from sea ice on the Hudson Bay, Quebec in March 2008. Specific surface areas of the frost flower samples were obtained using CH4 adsorption at 77K in a volumetric apparatus, followed by Brunuaer- Emmett-Teller analysis. The enrichment or depletion in certain ions in frost flowers helps us understand their contributions to atmospheric chemistry. Chemical analysis was performed on the frost flower melt and on local seawater and brine, and we examine sulfate and bromide enrichment factors (with respect to chloride). We present this data together with photomicrographs of frost flowers from the area to illustrate the effects of temperature and salinity on frost flower morphology and composition.