Nested-grid simulation of mercury over North America
| Autor: | Peter Weiss-Penzias, Qiaoqiao Wang, Robert W. Talbot, Kevin D. Perry, Yanxu Zhang, Steven Brooks, Thomas M. Holsen, Dirk Felton, Christopher D. Holmes, H. M. Amos, R. Zsolway, A. van Donkelaar, R. Tordon, Alexandra Steffen, Randall V. Martin, Richard S. Artz, Lyatt Jaeglé, Winston T. Luke, David Schmeltz, Eric K. Miller |
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| Rok vydání: | 2012 |
| Předmět: |
Atmospheric Science
Chemical transport model united-states chemistry.chemical_element Atmospheric sciences power-plant plumes Latitude oxidized mercury lcsh:Chemistry dry deposition Physical Sciences and Mathematics wet deposition Emission inventory elemental mercury atmospheric mercury measurement network camnet lcsh:QC1-999 Nested set model Mercury (element) Deposition (aerosol physics) lcsh:QD1-999 chemistry Climatology total gaseous mercury Spatial variability spatial variability Longitude lcsh:Physics |
| Zdroj: | Zhang, Y.; Jaegle, L.; van Donkelaar, A.; Martin, R. V; Holmes, C. D; Amos, H. M; et al.(2012). Nested-grid simulation of mercury over North America. Atmospheric Chemistry and Physics, 12(14), 6095-6111. doi: 10.5194/acp-12-6095-2012. UC Irvine: Retrieved from: http://www.escholarship.org/uc/item/1nw7s07s Atmospheric Chemistry and Physics, Vol 12, Iss 14, Pp 6095-6111 (2012) |
| DOI: | 10.5194/acpd-12-2603-2012 |
| Popis: | We have developed a new nested-grid mercury (Hg) simulation over North America with a 1/2° latitude by 2/3° longitude horizontal resolution employing the GEOS-Chem global chemical transport model. Emissions, chemistry, deposition, and meteorology are self-consistent between the global and nested domains. Compared to the global model (4° latitude by 5° longitude), the nested model shows improved skill at capturing the high spatial and temporal variability of Hg wet deposition over North America observed by the Mercury Deposition Network (MDN) in 2008–2009. The nested simulation resolves features such as higher deposition due to orographic precipitation, land/ocean contrast and and predicts more efficient convective rain scavenging of Hg over the southeast United States. However, the nested model overestimates Hg wet deposition over the Ohio River Valley region (ORV) by 27%. We modify anthropogenic emission speciation profiles in the US EPA National Emission Inventory (NEI) to account for the rapid in-plume reduction of reactive to elemental Hg (IPR simulation). This leads to a decrease in the model bias to −2.3% over the ORV region. Over the contiguous US, the correlation coefficient (r) between MDN observations and our IPR simulation increases from 0.60 to 0.78. The IPR nested simulation generally reproduces the seasonal cycle in surface concentrations of speciated Hg from the Atmospheric Mercury Network (AMNet) and Canadian Atmospheric Mercury Network (CAMNet). In the IPR simulation, annual mean gaseous and particulate-bound Hg(II) are within 140% and 11% of observations, respectively. In contrast, the simulation with unmodified anthropogenic Hg speciation profiles overestimates these observations by factors of 4 and 2 for gaseous and particulate-bound Hg(II), respectively. The nested model shows improved skill at capturing the horizontal variability of Hg observed over California during the ARCTAS aircraft campaign. The nested model suggests that North American anthropogenic emissions account for 10–22% of Hg wet deposition flux over the US, depending on the anthropogenic emissions speciation profile assumed. The modeled percent contribution can be as high as 60% near large point sources in ORV. Our results indicate that the North American anthropogenic contribution to dry deposition is 13–20%. |
| Databáze: | OpenAIRE |
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