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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D20, 8801, doi:10.1029/2002JD003094, 2003

Influence of regional-scale anthropogenic emissions on CO₂ distributions over the western North Pacific

S. A. Vay

NASA Langley Research Center, Hampton, Virginia, USA

J.-H. Woo

Center for Global and Regional Environmental Research, University of Iowa, Iowa City, Iowa, USA

B. E. Anderson

NASA Langley Research Center, Hampton, Virginia, USA

K. L. Thornhill

Science Applications International Corporation, Hampton, Virginia, USA

D. R. Blake

Department of Chemistry, University of California, Irvine, California, USA

D. J. Westberg

Science Applications International Corporation, Hampton, Virginia, USA

C. M. Kiley

Department of Meteorology, Florida State University, Tallahassee, Florida, USA

M. A. Avery

NASA Langley Research Center, Hampton, Virginia, USA

G. W. Sachse

NASA Langley Research Center, Hampton, Virginia, USA

D. G. Streets

Decision and Information Sciences Division, Argonne National Laboratory, Argonne, Illinois, USA

Y. Tsutsumi

Atmospheric Environment Division, Japan Meteorological Agency, Tokyo, Japan

S. R. Nolf

Computer Sciences Corporation, Hampton, Virginia, USA

Abstract

We report here airborne measurements of atmospheric CO₂ over the western North Pacific during the March–April 2001 Transport and Chemical Evolution over the Pacific (TRACE-P) mission. The CO₂ spatial distributions were notably influenced by cyclogenesis-triggered transport of regionally polluted continental air masses. Examination of the CO₂ to C₂H₂/CO ratio indicated rapid outflow of combustion-related emissions in the free troposphere below 8 km. Although the highest CO₂ mixing ratios were measured within the Pacific Rim region, enhancements were also observed further east over the open ocean at locations far removed from surface sources. Near the Asian continent, discrete plumes encountered within the planetary boundary layer contained up to 393 ppmv of CO₂. Coincident enhancements in the mixing ratios of C₂Cl₄, C₂H₂, and C₂H₄ measured concurrently revealed combustion and industrial sources. To elucidate the source distributions of CO₂, an emissions database for Asia was examined in conjunction with the chemistry and 5-day backward trajectories that revealed the WNW/W sector of northeast Asia was a major contributor to these pollution events. Comparisons of NOAA/CMDL and JMA surface data with measurements obtained aloft showed a strong latitudinal gradient that peaked between 35° and 40°N. We estimated a net CO₂ flux from the Asian continent of approximately 13.93 Tg C day⁻¹ for late winter/early spring with the majority of the export (79%) occurring in the lower free troposphere (2–8 km). The apportionment of the flux between anthropogenic and biospheric sources was estimated at 6.37 Tg C day⁻¹ and 7.56 Tg C day⁻¹, respectively.

Received 30 October 2002; accepted 24 April 2003; published 12 September 2003.

Index Terms: 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.

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Citation: Vay, S. A., et al. (2003), Influence of regional-scale anthropogenic emissions on CO₂ distributions over the western North Pacific, J. Geophys. Res., 108(D20), 8801, doi:10.1029/2002JD003094.

Copyright 2003 by the American Geophysical Union.