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Summertime Influence of Asian Pollution in the Free Troposphere over North AmericaWe analyze aircraft observations obtained during INTEX-A (1 July 14 - August 2004) to examine the summertime influence of Asian pollution in the free troposphere over North America. By applying correlation analysis and Principal Component Analysis (PCA) to the observations between 6-12 km, we find dominant influences from recent convection and lightning (13 percent of observations), Asia (7 percent), the lower stratosphere (7 percent), and boreal forest fires (2 percent), with the remaining 71 percent assigned to background. Asian airmasses are marked by high levels of CO, O3, HCN, PAN, acetylene, benzene, methanol, and SO4(2-). The partitioning of reactive nitrogen species in the Asian plumes is dominated by peroxyacetyl nitrate (PAN) (approximately 600 pptv), with varying NO(x)/HNO3 ratios in individual plumes consistent with different plumes ages ranging from 3 to 9 days. Export of Asian pollution in warm conveyor belts of mid-latitude cyclones, deep convection, and lifting in typhoons all contributed to the five major Asian pollution plumes. Compared to past measurement campaigns of Asian outflow during spring, INTEX-A observations display unique characteristics: lower levels of anthropogenic pollutants (CO, propane, ethane, benzene) due to their shorter summer lifetimes; higher levels of biogenic tracers (methanol and acetone) because of a more active biosphere; as well as higher levels of PAN, NO(x), HNO3, and O3 (more active photochemistry possibly enhanced by injection of lightning NO(x)). The high delta O3/delta CO ratio (0.76 mol mol(exp -1)) of Asian plumes during INTEX-A is due to a combination of strong photochemical production and mixing with stratospheric air along isentropic surfaces. The GEOS-Chem global chemical transport model captures the timing and location of the Asian plumes remarkably well. However, it significantly underestimates the magnitude of the enhancements.
Document ID
20080008383
Acquisition Source
Langley Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Liang, Q. (Washington Univ. Seattle, WA, United States)
Jaegle, Lyatt (Washington Univ. Seattle, WA, United States)
Hudman, Rynda C. (Harvard Univ. Cambridge, MA, United States)
Turquety, Solene (Harvard Univ. Cambridge, MA, United States)
Jacob, Daniel J. (Harvard Univ. Cambridge, MA, United States)
Avery, Melody A. (NASA Langley Research Center Hampton, VA, United States)
Blake, Donald R. (California Univ. Irvine, CA, United States)
Browell, Edward V. (NASA Langley Research Center Hampton, VA, United States)
Sachse, Glen W. (NASA Langley Research Center Hampton, VA, United States)
Brune, W. H. (Pennsylvania State Univ. University Park, PA, United States)
Ren, Xinrong (Pennsylvania State Univ. University Park, PA, United States)
Clarke, A. (Hawaii Univ. Honolulu, HI, United States)
Cohen, R. (California Univ. Berkeley, CA, United States)
Dibb, Jack (New Hampshire Univ. Durham, NH, United States)
Fried, Alan (National Center for Atmospheric Research Boulder, CO, United States)
Fuelberg, Henry (Florida State Univ. Tallahassee, FL, United States)
Porter, M. (Florida State Univ. Tallahassee, FL, United States)
Heikes, Brian (Rhode Island Univ. Narragansett, RI, United States)
Huey, Greg (Georgia Inst. of Tech. Atlanta, GA, United States)
Singh, H. B. (NASA Ames Research Center Moffett Field, CA, United States)
Wennberg, Paul (California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2007
Subject Category
Environment Pollution
Funding Number(s)
CONTRACT_GRANT: NSF ATM 0238530
WBS: WBS 281945.02.39.01.04
Distribution Limits
Public
Copyright
Public Use Permitted.

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