Long range transport of mercury to the Arctic and across Canada

Durnford, Dorothy; Dastoor, Ashu; Figueras-Nieto, D.; Ryjkov, Andrei

doi:10.5194/acp-10-6063-2010

Cited by 138 publications

(104 citation statements)

References 47 publications

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“…GEM-MACH-Hg is a new chemical transport model for mercury that is based on the GRAHM model developed by Environment and Climate Change Canada (Dastoor and Larocque, 2014;Dastoor et al, 2008Dastoor et al, , 2015Durnford et al, 2010Durnford et al, , 2012Kos et al, 2013) GEM-MACH-Hg uses a newer version of the Environment and Climate Change Canada's operational meteorological model. The horizontal resolution of the model is 1 • × 1 • .…”

Section: Gem-mach-hgmentioning

confidence: 99%

Multi-model study of mercury dispersion in the atmosphere: vertical and interhemispheric distribution of mercury species

et al. 2017

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Abstract. Atmospheric chemistry and transport of mercury play a key role in the global mercury cycle. However, there are still considerable knowledge gaps concerning the fate of mercury in the atmosphere. This is the second part of a model intercomparison study investigating the impact of atmospheric chemistry and emissions on mercury in the atmosphere. While the first study focused on ground-based observations of mercury concentration and deposition, here we investigate the vertical and interhemispheric distribution and speciation of mercury from the planetary boundary layer to the lower stratosphere. So far, there have been few model studies investigating the vertical distribution of mercury, mostly focusing on single aircraft campaigns. Here, we present a first comprehensive analysis based on various aircraft observations in Europe, North America, and on intercontinental flights.The investigated models proved to be able to reproduce the distribution of total and elemental mercury concentrations in the troposphere including interhemispheric trends. One key aspect of the study is the investigation of mercury oxidation in the troposphere. We found that different chemistry schemes were better at reproducing observed oxidized mercury patterns depending on altitude. High concentrations of oxidized mercury in the upper troposphere could be reproduced with oxidation by bromine while elevated concentrations in the lower troposphere were better reproduced by OH and ozone chemistry. However, the results were not always conclusive as the physical and chemical parameterizations in the chemistry transport models also proved to have a substantial impact on model results.

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Section: Gem-mach-hgmentioning

confidence: 99%

Multi-model study of mercury dispersion in the atmosphere: vertical and interhemispheric distribution of mercury species

et al. 2017

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“…GEM-MACH-Hg is an online model: the meteorology is simulated in-step with the chemistry, and includes representation of physicochemical processes of mercury based on the ECCC's previous mercury model, GRAHM (Global/Regional Atmospheric Heavy Metals model, Dastoor and Larocque, 2004;Dastoor et al, 2008Dastoor et al, , 2015Durnford et al, 2010Durnford et al, , 2012Kos et al, 2013). We use the model with a horizontal resolution of 10 km in a nested grid over North America.…”

Section: Gem-mach-hg Is the Mercury Version Of The Eccc's Current Opementioning

confidence: 99%

“…A dynamic multilayer snowpack/meltwater mercury parameterization allowing the representation of deposition and re-emission of mercury is used (Durnford et al 2010). Oceanic evasion of GEM is activated if there is open water and the temperature at the air-sea interface is -4ºC or greater and depends on the distribution of primary production and atmospheric deposition (Dastoor 10 and Durnford, 2014).…”

Section: Gem-mach-hg Is the Mercury Version Of The Eccc's Current Opementioning

confidence: 99%

How important is biomass burning in Canada to mercury contamination?

Fraser¹,

Dastoor²,

Ryjkov³

2017

Preprint

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Abstract.Wildfire frequency has increased in past four decades in Canada, and is expected to increase in future as a result of climate change (Wotton et. al. 2010). Mercury (Hg) emissions from biomass burning are known to be significant; however, the impact of biomass burning on air concentration and deposition fluxes in Canada has not been previously quantified. We use 10 estimates of burned biomass from FINN (Fire Inventory from NCAR) and vegetation-specific Emission Factors (EFs) of mercury to investigate the spatiotemporal variability of Hg emissions in Canada. We use Environment and Climate Change Canada's GEM-MACH-Hg (Global Environmental Multi-scale, Modelling Air quality and Chemistry model, mercury version) to quantify the impact of biomass burning in Canada on spatiotemporal variability of air concentrations and deposition fluxes of mercury in Canada. We use North American gaseous elemental mercury (GEM) observations (2010)(2011)(2012)(2013)(2014)(2015), 15 and an inversion technique to optimize the emission factors for GEM for five vegetation types represented in North American fires to constrain the biomass burning impacts of mercury. We use three biomass burning Hg emissions scenarios in Canada to conduct three sets of model simulations for 2010-2015: two scenarios where Hg is emitted only as GEM using literature or optimized EFs, and a third scenario where Hg is emitted as GEM using literature EFs and particle bound mercury (PBM) emitted using the average GEM/PBM ratio from lab measurements. The three biomass burning emission scenarios represent the range of 20 possible values for the impacts of Hg emissions from biomass burning in Canada on Hg concentration and deposition.We find total biomass burning Hg emissions to be highly variable from year to year, and estimate average 2010-2015 total atmospheric biomass burning emissions of Hg in Canada to be between 6-14 t during the biomass burning season (i.e., from May to September), which is 3 -7 times the mercury emission from anthropogenic sources in Canada for this period. On average, 65% of the emissions occur in the provinces west of Ontario. We find that while emissions from biomass burning have a small 25 impact on surface air concentrations of GEM averaged over individual provinces/territories, the impact at individual sites can be as high as 95% during burning events. We estimate average annual mercury deposition from biomass burning in Canada to be between 0.3 -2.8 t, compared to 0.14 t of mercury deposition from anthropogenic sources during the biomass burning season in Canada. Compared to the biomass burning emissions, the relative impact of fires on mercury deposition is shifted eastward, with on average 54% percent of the deposition occurring in provinces west of Ontario. While the relative contribution of Canadian 30 biomass burning to the total mercury deposition over each province/territory is no more than 9% between 2010-2015, the local contribution in some locations (including areas downwind of biomass burning) can be as high as...

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“…Fu et al, 2015a;Wang et al, 2016), approximately 1/6 of the global Hg emissions into the atmosphere Song et al, 2015). The large emissions in China not only have an impact on the domestic Hg pollution (Fu et al, 2015b), but also have the potential to enhance atmospheric Hg concentration and deposition elsewhere (Seigneur et al, 2004;Strode et al, 2008;Durnford et al, 2010). To construct the mass budget of Hg in China, measurements of atmospheric Hg wet and dry deposition are essential.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric wet and litterfall mercury deposition at urban and rural sites in China

Yang

Lang

et al. 2016

Atmos. Chem. Phys.

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Abstract. Mercury (Hg) concentrations and deposition fluxes in precipitation and litterfall were measured at multiple sites (six rural sites and an urban site) across a broad geographic area in China. The annual deposition fluxes of Hg in precipitation at rural sites and an urban site were 2.0 to 7.2 and 12.6 ± 6.5 µg m −2 yr −1 , respectively. Wet deposition fluxes of Hg at rural sites showed a clear regional difference with elevated deposition fluxes in the subtropical zone, followed by the temporal zone and arid/semi-arid zone. Precipitation depth is the primary influencing factor causing the variation of wet deposition. Hg fluxes through litterfall ranged from 22.8 to 62.8 µg m −2 yr −1 , higher than the wet deposition fluxes by a factor of 3.9 to 8.7 and representing approximately 75 % of the total Hg deposition at the forest sites in China. This suggests that uptake of atmospheric Hg by foliage is the dominant pathway to remove atmospheric Hg in forest ecosystems in China. Wet deposition fluxes of Hg at rural sites of China were generally lower compared to those in North America and Europe, possibly due to a combination of lower precipitation depth, lower GOM concentrations in the troposphere and the generally lower cloud base heights at most sites that wash out a smaller amount of GOM and PBM during precipitation events.

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Long range transport of mercury to the Arctic and across Canada

Cited by 138 publications

References 47 publications

Multi-model study of mercury dispersion in the atmosphere: vertical and interhemispheric distribution of mercury species

Multi-model study of mercury dispersion in the atmosphere: vertical and interhemispheric distribution of mercury species

How important is biomass burning in Canada to mercury contamination?

Atmospheric wet and litterfall mercury deposition at urban and rural sites in China

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