Fluxes of gaseous elemental mercury (GEM) in the High Arctic during atmospheric mercury depletion events (AMDEs)

摘要

Measurements of gaseous elemental mercury (GEM) fluxes over snowsurfaces using a relaxed eddy accumulation (REA) system are carriedout at the High Arctic site at the Villum Research Station, Station Nord, inNorth Greenland. Simultaneously, CO2 fluxes are determinedusing the eddy covariance (EC) technique. The REA system withdual inlets and dual analyzers is used to measure fluxes directlyover the snow. The measurements were carried out from 23 April to12 May during spring 2016, where atmospheric mercury depletionevents (AMDEs) took place. The measurements showed a net emission of8.9 ng m−2 min−1, with only a few minor episodes ofnet depositional fluxes, from a maximum deposition of8.1 ng m−2 min−1 to a maximum emission of179.2 ng m−2 min−1. The data support the theory thatgaseous oxidized mercury (GOM) is deposited during AMDEs followed byformation of GEM on surface snow and is re-emitted as GEM shortlyafter the AMDEs. Furthermore, observation of the relation betweenGEM fluxes and atmospheric temperature suggests that GEM emissionpartly could be affected by surface heating. However, it is alsoclear that the GEM emissions are affected by many parameters.