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Correction to "Asian chemical Outflow to the Pacific in Spring: Origins, Pathways, and Budgets" by Isabelle Bey et al.We analyze the Asian outflow of CO, ozone, and nitrogen oxides (NOx) to the Pacific in spring by using the GEOS-CHEM global three-dimensional model of tropospheric chemistry and simulating the Pacific Exploratory Mission-West (PEM-West B) aircraft mission in February-March 1994. The GEOS-CHEM model uses assimilated meteorological fields from the NASA Goddard Earth Observing System (GEOS). It reproduces relatively well the main features of tropospheric ozone, CO, and reactive nitrogen species observed in PEM-West B, including latitudinal and vertical gradients of the Asian pollution outflow over the western Pacific although simulated concentrations of CO tend to be too low (possibly because biogenic sources are underestimated). We use CO as a long-lived tracer to diagnose the processes contributing to the outflow. The highest concentrations in the outflow are in the boundary layer (0-2 km), but the strongest outflow fluxes are in the lower free troposphere (2-5 km) and reflect episodic lifting of pollution over central and eastern China ahead of eastward moving cold fronts. This frontal lifting, followed by westerly transport in the lower free troposphere, is the principal process responsible for export of both anthropogenic and biomass burning pollution from Asia. Anthropogenic emissions from Europe and biomass burning emissions from Africa make also major contributions to the Asian outflow over the western Pacific; European sources dominate in the lower troposphere north of 40 degrees N, while African sources are important in the upper troposphere at low latitudes. For the period of PEM-West B (February-March) we estimate that fossil fuel combustion and biomass burning make comparable contributions to the budgets of CO, ozone, and NO, in the Asian outflow. We find that 13% of NO, emitted in Asia is exported as NO, or PAN, a smaller fraction than for the United States because of higher aerosol concentrations that promote heterogeneous conversion of NOx to HNO3. Production and export of ozone from Asia in spring is much greater than from the United States because of the higher photochemical activity.
Document ID
20040111410
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Bey, Isabelle
(Harvard Univ.)
Jacob, Daniel J.
(Harvard Univ.)
Logan, Jennifer A.
(Harvard Univ.)
Yantosca, Robert M.
(Harvard Univ.)
Date Acquired
August 21, 2013
Publication Date
March 11, 2003
Publication Information
Publication: Journal of Geophysical Research
Publisher: American Geophysical Union
Volume: 108
Issue: D5
ISSN: 0148-0227
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NAG1-2307
Distribution Limits
Public
Copyright
Other

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