Impact of Asian emissions on observations at Trinidad Head, California, during ITCT 2K2

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Read Full Article (file size: 505508 bytes) Cited by JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, D23S17, doi:10.1029/2003JD004406, 2004 Impact of Asian emissions on observations at Trinidad Head, California, during ITCT 2K2 Allen H. Goldstein Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA Dylan B. Millet Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA Megan McKay Department of Environmental Science, Policy, and Management, University of California, Berkeley, California, USA Lyatt Jaeglé Department of Atmospheric Science, University of Washington, Seattle, Washington, USA Larry Horowitz National Oceanic and Atmospheric Administration, Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey, USA Owen Cooper Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, USA National Oceanic and Atmospheric Administration, Aeronomy Laboratory, Boulder, Colorado, USA Rynda Hudman Division of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA Daniel J. Jacob Division of Engineering and Applied Sciences and Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts, USA Sam Oltmans National Oceanic and Atmospheric Administration, Aeronomy Laboratory, Boulder, Colorado, USA Andrew Clarke National Oceanic and Atmospheric Administration, Aeronomy Laboratory, Boulder, Colorado, USA Abstract Field measurements of a wide suite of trace gases and aerosols were carried out during April and May 2002, along with extensive chemical transport modeling, as part of the NOAA Intercontinental Transport and Chemical Transformation study. Here, we use a combination of in-situ ground-based measurements from Trinidad Head, CA, chemical transport modeling, and backward trajectory analysis to examine the impact of long-range transport from Asia on the composition of air masses arriving at the California coast at the surface. The impact of Asian emissions is explored in terms of both episodic enhancements and contribution to background concentrations. We find that variability in CO concentrations at the ground site was largely driven by North American emissions, and that individual Asian plumes did not cause any observable pollution enhancement episodes at Trinidad Head. Despite this, model simulations suggest that Asian emissions were responsible for 33% of the CO observed at Trinidad Head, providing a larger mean contribution than direct emissions from any other region of the globe. Surface ozone levels were found to depend primarily on local atmospheric mixing, with surface deposition leading to low concentrations under stagnant conditions. Model simulations suggested that on average 4 ± 1 ppb of ozone (10% of observed) at Trinidad Head was transported from Asia. Received 1 December 2003; accepted 19 March 2004; published 9 July 2004. Keywords: Asian emission; carbon monoxide; ozone. Index Terms: 0322 Atmospheric Composition and Structure: Constituent sources and sinks; 0345 Atmospheric Composition and Structure: Pollution—urban and regional (0305); 0365 Atmospheric Composition and Structure: Troposphere—composition and chemistry; 0368 Atmospheric Composition and Structure: Troposphere—constituent transport and chemistry; 1610 Global Change: Atmosphere (0315, 0325). Read Full Article (file size: 505508 bytes) Cited by Citation: Goldstein, A. H., D. B. Millet, M. McKay, L. Jaeglé, L. Horowitz, O. Cooper, R. Hudman, D. J. Jacob, S. Oltmans, and A. Clarke (2004), Impact of Asian emissions on observations at Trinidad Head, California, during ITCT 2K2, J. Geophys. Res., 109, D23S17, doi:10.1029/2003JD004406. Copyright 2004 by the American Geophysical Union.

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