Computation, accuracy and applications of trajectories—A review and bibliography

Recent climate change in the Arctic and its impact on contaminant pathways and interpretation of temporal trend data.

Contaminants in the Canadian Arctic: 5 years of progress in understanding sources, occurrence and pathways.

Arctic contaminants : sources, occurrence and pathways

It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM) occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere; however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg). This phenomenon is termed atmospheric mercury depletion events (AMDEs) and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review Hg research taken place in Polar Regions pertaining to AMDEs, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made but the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the role that the snow pack and the sea ice play in the cycling of Hg is presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the deposited Hg does not remain in the same form in the snow. Kinetic studies undertaken have demonstrated that bromine is the major oxidant depleting Hg in the atmosphere. Modeling results demonstrate that there is a significant deposition of Hg to Polar Regions as a result of AMDEs. Models have also shown that Hg is readily transported to the Arctic from source regions, at times during springtime when this environment is actively transforming Hg from the atmosphere to the snow and ice surfaces. The presence of significant amounts of methyl Hg in snow in the Arctic surrounding AMDEs is important because this species is the link between the environment and impacts to wildlife and humans. Further, much work on methylation and demethylation processes has occurred but these processes are not yet fully understood. Recent changes in the climate and sea ice cover in Polar Regions are likely to have strong effects on the cycling of Hg in this environment; however more research is needed to understand Hg processes in order to formulate meaningful predictions of these changes.

/pdf/a-synthesis-of-atmospheric-mercury-depletion-event-chemistry-25nq37zth4.pdf

A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow

Trajectory analysis has been successfully applied as an analysis tool for atmospheric transport problems on scales ranging from 100’s to 1000’s of kilometers. A modeled trajectory is an estimate of the transport pathway of an infinitesimally small air parcel. This pathway represents an estimate of the centerline of an advected air mass subject to dispersion in the horizontal and vertical directions. These estimates are based on raw or analyzed data which have spatial and temporal gaps of up to several hundred kilometers and 12 hours, respectively. Trajectories corresponding to individual transport events thus provide, at best, an approximate indication of the mean motion of an advected air parcel.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0889.1989.tb00139.x

Intercomparison of three long-range trajectory models applied to Arctic haze

The flux of anthropogenic sulphur into the arctic from mid-latitudes in 1979/80

http://deepblue.lib.umich.edu/bitstream/handle/2027.42/31953/0000906.pdf?sequence=1

M.P. Olson

Papers

Intercomparison of three long-range trajectory models applied to Arctic haze

The flux of anthropogenic sulphur into the arctic from mid-latitudes in 1979/80

The flux of anthropogenic trace metals into the arctic from the mid-latitudes in 1979/80

Trajectory analysis of source regions influencing the south Greenland Ice Sheet during the Dye 3 Gas and Aerosol Sampling Program

A comparison of box and plume model calculations for sulphur deposition and flux in Alberta, Canada