ECHMERIT V1.0 – a new global fully coupled mercury-chemistry and transport model

Jung, Gerlinde; Hedgecock, Ian M.; Pirrone, Nicola

doi:10.5194/gmd-2-175-2009

Cited by 51 publications

(48 citation statements)

References 91 publications

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“…ECHMERIT is a global online meteorological chemistry transport model, based on the ECHAM5 global circulation model, with a highly flexible chemistry mechanism designed to facilitate the investigation of atmospheric mercury chemistry (Jung et al, 2009;De Simone et al, 2014. The model uses the same spectral grid as ECHAM.…”

Section: Echmeritmentioning

confidence: 99%

“…In the BASE case only O 3 and OH chemistry are used. Chemical initial and boundary conditions were taken from the ECHMERIT model (Jung et al, 2009;De Simone et al, 2014) for Hg species, while boundary conditions for other chemical species were taken from MOZART-4 (Emmons et al, 2010). Dry deposition of gas-phase species is treated using the approach developed by Wesely (1989), multiplying the concentrations in the lowest model layer by the spatially and temporally varying deposition velocity, which is proportional to aerodynamic, sublayer, and surface resistances.…”

Section: Wrf-chemmentioning

confidence: 99%

“…ECHMERIT uses a parameterization of dynamic air-seawater exchange as a function of ambient parameters, but using a constant value of mercury concentration in seawater (De Simone et al, 2014). Emissions from soils and vegetation were calculated offline and derived from the EDGAR/POET emission inventory (Granier et al, 2005;Peters and Olivier, 2003) that includes biogenic emissions from the GEIA inventories (http://www.geiacenter.org), as described by Jung et al (2009). Prompt re-emission of a fixed fraction (20 %) of wet and dry deposited mercury is applied in the model to account for reduction and evasion processes which govern mercury short-term cycling between the atmosphere and terrestrial reservoirs .…”

Section: Echmeritmentioning

confidence: 99%

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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: Echmeritmentioning

confidence: 99%

Section: Wrf-chemmentioning

confidence: 99%

Section: Echmeritmentioning

confidence: 99%

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

et al. 2017

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“…Wet deposition (in-cloud and below-cloud scavenging) of Hg species has been implemented by adapting an already available module in WRF/Chem, based on the approach described by Neu and Prather (2012). Chemical initial and boundary conditions (IC/BC) were taken from the ECHMERIT model (Jung et al, 2009;De Simone et al, 2014 for Hg species, while boundary conditions for other chemical species were taken from MOZART-4 (Emmons et al, 2010).…”

Section: Models Description and Set-upmentioning

confidence: 99%

Sensitivity model study of regional mercury dispersion in the atmosphere

et al. 2017

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Abstract. Atmospheric deposition is the most important pathway by which Hg reaches marine ecosystems, where it can be methylated and enter the base of food chain. The deposition, transport and chemical interactions of atmospheric Hg have been simulated over Europe for the year 2013 in the framework of the Global Mercury Observation System (GMOS) project, performing 14 different model sensitivity tests using two high-resolution three-dimensional chemical transport models (CTMs), varying the anthropogenic emission datasets, atmospheric Br input fields, Hg oxidation schemes and modelling domain boundary condition input. Sensitivity simulation results were compared with observations from 28 monitoring sites in Europe to assess model performance and particularly to analyse the influence of anthropogenic emission speciation and the Hg 0 (g) atmospheric oxidation mechanism. The contribution of anthropogenic Hg emissions, their speciation and vertical distribution are crucial to the simulated concentration and deposition fields, as is also the choice of Hg 0 (g) oxidation pathway. The areas most sensitive to changes in Hg emission speciation and the emission vertical distribution are those near major sources, but also the Aegean and the Black seas, the English Channel, the Skagerrak Strait and the northern German coast. Considerable influence was found also evident over the Mediterranean, the North Sea and Baltic Sea and some influence is seen over continental Europe, while this difference is least over the north-western part of the modelling domain, which includes the Norwegian Sea and Iceland. The Br oxidation pathway produces more Hg II (g) in the lower model levels, but overall wet deposition is lower in comparison to the simulations which employ an O 3 / OH oxidation mechanism. The necessity to perform continuous measurements of speciated Hg and to investigate the local impacts of Hg emissions and deposition, as well as interactions dependent on land use and vegetation, forests, peat bogs, etc., is highlighted in this study.

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“…Methylmercury concentrations in fish in an ecosystem are strongly linked to the local Hg deposition rate (Hammerschmidt and Fitzgerald, 2006;Harris et al, 2007). Dry deposition and wet deposition are both significant contributors to the global deposition flux of Hg (e.g., Bergan et al, 1999;Seigneur et al, 2001;Dastoor and Larocque, 2004;Jung et al, 2009;Amos et al, 2012). Models suggest that the global dry deposition…”

Section: Introductionmentioning

confidence: 99%

Subtropical subsidence and surface deposition of oxidized mercury produced in the free troposphere

Shah

Jaeglé

2017

Atmos. Chem. Phys.

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Abstract. Oxidized mercury (Hg(II)) is chemically produced in the atmosphere by oxidation of elemental mercury and is directly emitted by anthropogenic activities. We use the GEOS-Chem global chemical transport model with gaseous oxidation driven by Br atoms to quantify how surface deposition of Hg(II) is influenced by Hg(II) production at different atmospheric heights. We tag Hg(II) chemically produced in the lower (surface-750 hPa), middle (750-400 hPa), and upper troposphere (400 hPa-tropopause), in the stratosphere, as well as directly emitted Hg(II). We evaluate our 2-year simulation (2013)(2014) against observations of Hg(II) wet deposition as well as surface and free-tropospheric observations of Hg(II), finding reasonable agreement. We find that Hg(II) produced in the upper and middle troposphere constitutes 91 % of the tropospheric mass of Hg(II) and 91 % of the annual Hg(II) wet deposition flux. This large global influence from the upper and middle troposphere is the result of strong chemical production coupled with a long lifetime of Hg(II) in these regions. Annually, 77-84 % of surface-level Hg(II) over the western US, South America, South Africa, and Australia is produced in the upper and middle troposphere, whereas 26-66 % of surface Hg(II) over the eastern US, Europe, and East Asia, and South Asia is directly emitted. The influence of directly emitted Hg(II) near emission sources is likely higher but cannot be quantified by our coarse-resolution global model (2 • latitude × 2.5 • longitude). Over the oceans, 72 % of surface Hg(II) is produced in the lower troposphere because of higher Br concentrations in the marine boundary layer. The global contribution of the upper and middle troposphere to the Hg(II) dry deposition flux is 52 %. It is lower compared to the contribution to wet deposition because dry deposition of Hg(II) produced aloft requires its entrainment into the boundary layer, while rain can scavenge Hg(II) from higher altitudes more readily. We find that 55 % of the spatial variation of Hg wet deposition flux observed at the Mercury Deposition Network sites is explained by the combined variation of precipitation and Hg(II) produced in the upper and middle troposphere. Our simulation points to a large role of the dry subtropical subsidence regions. Hg(II) present in these regions accounts for 74 % of Hg(II) at 500 hPa over the continental US and more than 60 % of the surface Hg(II) over high-altitude areas of the western US. Globally, it accounts for 78 % of the tropospheric Hg(II) mass and 61 % of the total Hg(II) deposition. During the Nitrogen, Oxidants, Mercury, and Aerosol Distributions, Sources, and Sinks (NOMADSS) aircraft campaign, the contribution of Hg(II) from the dry subtropical regions was found to be 75 % when measured Hg(II) exceeded 250 pg m −3 . Hg(II) produced in the upper and middle troposphere subsides in the anticyclones, where the dry conditions inhibit the loss of Hg(II). Our results highlight the importance the subtropical anticyclones as the primary conduits for t...

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ECHMERIT V1.0 – a new global fully coupled mercury-chemistry and transport model

Cited by 51 publications

References 91 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

Sensitivity model study of regional mercury dispersion in the atmosphere

Subtropical subsidence and surface deposition of oxidized mercury produced in the free troposphere

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