HR: 16:15h
AN: A54C-02    [Abstracts]
TI: A multi-platform analysis of the North American reactive nitrogen budget during the ICARTT summer intensive
AU: * Hudman, R C
EM: hudman@fas.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street G3G, Cambridge, MA 02138 United States
AU: Jacob, D J
EM: djacob@fas.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street G3G, Cambridge, MA 02138 United States
AU: Turquety, S
EM: stu@io.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street G3G, Cambridge, MA 02138 United States
AU: Murray, L
EM: ltm@io.harvard.edu
AF: Division of Engineering and Applied Sciences, Harvard University, 29 Oxford Street G3G, Cambridge, MA 02138 United States
AU: Avery, M
EM: Melody.A.Avery@nasa.gov
AF: NASA Langley Research Center, Chemistry and Dynamics Branch, Hampton, VA 23681 United States
AU: Bertram, T H
EM: tbertram@berkeley.edu
AF: Department of Chemistry, University of California Berkeley, B45 Hildebrand Lab, Berkeley, CA 94720-1460 United States
AU: Browell, E
EM: Edward.V.Browell@.nasa.gov
AF: NASA Langley Research Center, Chemistry and Dynamics Branch, Hampton, VA 23681 United States
AU: Brune, W
EM: brune@meteo.psu.edu
AF: Department of Meteorology, Pennsylvania State University, Department of Meteorology 504 Walker Building, University Park, PA 16802 United States
AU: Cohen, R C
EM: cohen@cchem.berkeley.edu
AF: Department of Chemistry, University of California Berkeley, B45 Hildebrand Lab, Berkeley, CA 94720-1460 United States
AU: Dibb, J E
EM: jack.dibb@unh.edu
AF: Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 39 College Road, Durham, NH 03824-352
AU: Flocke, F M
EM: ffl@ucar.edu
AF: Atmospheric Chemistry Division, NCAR, PO Box 3000, Boulder, CO 80305 United States
AU: Holloway, J
EM: jholloway@al.noaa.gov
AF: Aeronomy Laboratory, NOAA, 1850 Table Mesa Drive, Boulder, CO 80303 United States
AU: Newman, A
EM: Andy.Neuman@noaa.gov
AF: Aeronomy Laboratory, NOAA, 1850 Table Mesa Drive, Boulder, CO 80303 United States
AU: Ren, X
EM: xur1@psu.edu
AF: Department of Meteorology, Pennsylvania State University, Department of Meteorology 504 Walker Building, University Park, PA 16802 United States
AU: Ryerson, T B
EM: thomas.b.ryerson@noaa.gov
AF: Aeronomy Laboratory, NOAA, 1850 Table Mesa Drive, Boulder, CO 80303 United States
AU: Sachse, G W
EM: Glen.W.Sachse@nasa.gov
AF: NASA Langley Research Center, Chemistry and Dynamics Branch, Hampton, VA 23681 United States
AU: Singh, H B
EM: Hanwant.B.Singh@nasa.gov
AF: NASA Ames Research Center, MS 245-5, Moffett Field, CA 94035 United States
AU: Wooldridge, P J
A54C-02 AF: Department of Chemistry, University of California Berkeley, B45 Hildebrand Lab, Berkeley, CA 94720-1460 United States
AB: Model studies suggest that export of NO_y (NO_x and its oxidation products) from North America makes a significant contribution to the global tropospheric ozone reservoir. The ICARTT campaign of summer 2004, including two instrumented aircraft with extensive coverage over eastern North America and North Atlantic, provided the opportunity to better understand this NO_y export and relate it to its sources. We present here a global 3-D model (GEOS-Chem) analysis of the ICARTT observations to quantify the NO_x sources from combustion and lightning, the chemical evolution of NO_x in the boundary layer, and the export and subsequent evolution into the free troposphere over the North Atlantic. The observed NO_y partitioning in the boundary layer among its major components (NO_x, HNO₃, PAN) shows significant differences between the Northeast/Midwest (28%, 54%, 18%), Southeast (19%, 59%, 22%), and Offshore (13%,77%,10%). The elevated NO_x fraction in the Northeast/Midwest is attributed to the density of sources and the relatively rapid ventilation. The Southeast is less efficiently ventilated. Such differences in NO_y partitioning result in significant differences in the observed NO_y export efficiencies to the free troposphere (2-8 km) between the Southeast (7-11%), the Northeast/Midwest (12-16%), and offshore (~9%). The GEOS-Chem model reproduces well these observed partitionings and export efficiencies, implying a good understanding of the boundary layer NO_y budget. Lightning was the dominant source of NO_x in the upper troposphere during ICARTT, implying much larger emissions than presently estimated in GEOS-Chem as well as a preferential release at the tropopause. Adjusting the model lightning source to match the constraints of the ICARTT NO_x data has a 5-10 ppbv impact on upper tropospheric ozone and corrects a previous low bias in the model.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005