Snow-air fluxes of gaseous elemental mercury during the spring snowmelt period, 2017-2018

The overarching objective of this research is to improve current understanding of Arctic snowpack Hg dynamics during the spring melt period and the physical mechanisms that govern partitioning of the spring snowpack Hg burden between emission vs meltwater output pathways. The key question posed in this study is: How do short-term variations in weather conditions (e.g. over periods of days to weeks) during arctic spring affect the relative fractions of meltwater Hg outputs versus Hg re-emission to the atmosphere, from the end-of-winter snowpack. The specific, short-term objectives are to: (1)Produce a point-scale snowpack Hg mass balance estimate, resolved at a daily time step, for the entire spring snowmelt period, by monitoring surface-air Hg fluxes and meltwater Hg outputs over time; (2)Produce detailed, vertically resolved snowpack water and energy balance estimates using hydrometric and micrometeorological techniques; and (3) Use results from 1 and 2 to interpret daily patterns of snowpack Hg losses via surface-air emission and meltwater output pathways in relation to weather/climate variables, snowpack physical and chemical characteristics and snowmelt rates.