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Transport and Chemical Evolution over the Pacific (TRACE-P)Aircraft Mission: Design, Execution, and First ResultsThe NASA Transport and Chemical Evolution over the Pacific (TRACE-P) aircraft mission was conducted in February-April 2001 over the NW Pacific (1) to characterize the Asian chemical outflow and relate it quantitatively to its sources and (2) to determine its chemical evolution. It used two aircraft, a DC-8 and a P-3B, operating out of Hong Kong and Yokota Air Force Base (near Tokyo), with secondary sites in Hawaii, Wake Island, Guam, Okinawa, and Midway. The aircraft carried instrumentation for measurements of long-lived greenhouse gases, ozone and its precursors, aerosols and their precursors, related species, and chemical tracers. Five chemical transport models (CTMs) were used for chemical forecasting. Customized bottom-up emission inventories for East Asia were generated prior to the mission to support chemical forecasting and to serve as a priori for evaluation with the aircraft data. Validation flights were conducted for the Measurements Of Pollution In The Troposphere (MOPITT) satellite instrument and revealed little bias (6 plus or minus 2%) in the MOPITT measurements of CO columns. A major event of transpacific Asian pollution was characterized through combined analysis of TRACE-P and MOPITT data. The TRACE-P observations showed that cold fronts sweeping across East Asia and the associated warm conveyor belts (WCBs) are the dominant pathway for Asian outflow to the Pacific in spring. The WCBs lift both anthropogenic and biomass burning (SE Asia) effluents to the free troposphere, resulting in complex chemical signatures. The TRACE-P data are in general consistent with a priori emission inventories, lending confidence in our ability to quantify Asian emissions from socioeconomic data and emission factors. However, the residential combustion source in rural China was found to be much larger than the a priori, and there were also unexplained chemical enhancements (HCN, CH3Cl, OCS, alkylnitrates) in Chinese urban plumes. The Asian source of CCl4 was found to be much higher than government estimates. Measurements of HCN and CH3CN indicated a dominant biomass burning source and ocean sink for both gases. Large fractions of sulfate and nitrate were found to be present in dust aerosols. Photochemical activity in the Asian outflow was strongly reduced by aerosol attenuation of UV radiation, with major implications for the concentrations of HOx, radicals. New particle formation, apparently from ternary nucleation involving NH3, was observed in Chinese urban plumes.
Document ID
20040110725
Acquisition Source
Headquarters
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Jacob, Daniel J.
(Harvard Univ. Cambridge, MA, United States)
Crawford, James H.
(NASA Langley Research Center Hampton, VA, United States)
Kleb, Mary M.
(NASA Langley Research Center Hampton, VA, United States)
Connors, Vickie S.
(NASA Langley Research Center Hampton, VA, United States)
Bendura, Richard J.
(NASA Langley Research Center Hampton, VA, United States)
Raper, James L.
(NASA Langley Research Center Hampton, VA, United States)
Sachse, Glen W.
(NASA Langley Research Center Hampton, VA, United States)
Gille, John C.
(National Center for Atmospheric Research Boulder, CO, United States)
Emmons, Louisa
(National Center for Atmospheric Research Boulder, CO, United States)
Heald, Colette L.
(Harvard Univ. Cambridge, MA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2003
Publication Information
Publication: Journal of Geophysical Research
Publisher: American Geophysical Union
Volume: 108
Issue: D20
ISSN: 0148-0227
Subject Category
Geophysics
Funding Number(s)
CONTRACT_GRANT: NAG1-2328
Distribution Limits
Public
Copyright
Other

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