HR: 08:00h
AN: A51E-01 INVITED    [Abstracts]
TI: Using satellite composites to examine transport of gases and aerosols in mid-latitude cyclones
AU: * Jaegle, L
EM: jaegle@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington, BOX 351640, Seattle, WA 98195, United States
AU: Wood, R
EM: robwood@atmos.washington.edu
AF: Department of Atmospheric Sciences, University of Washington, BOX 351640, Seattle, WA 98195, United States
AB: Mid-latitude cyclones have been recognized as an important mechanism for venting polluted air from the continental boundary layer to the free troposphere. Warm conveyor belts, rising airstreams originating at the surface in the warm sector of mid-latitude cyclones, are particularily efficient at transporting pollutants to the middle and upper troposphere. In this study we examine the transport of gases and aerosols in mid-latitude cyclones by using multi-platform remote sensing observations of aerosol optical depth, CO, O3, and NO2 from the MODIS, MLS, OMI, and TES instruments. These atmospheric composition observations are complemented by satellite observations of QuickSCAT surface winds, MODIS clouds, AMSR-E surface rain rate and column water vapor. We first identify mid-latitude cyclones using NCEP sea level pressure, and then composite satellite observations over a 4000 km x 4000 km grid centered over each cyclone. Composites generated over clean regions (South Pacific and South Atlantic) are contrasted to composites downwind of polluted regions (western North Pacific and western North Atlantic). We find a strong signature of surface wind-induced sea-salt generation for each of these regions. The observations downwind of polluted regions exhibit enhanced CO, NO2, and aerosols in the lower troposphere behind the surface cold front, as well as enhanced CO and aerosols at high altitudes ahead of the surface warm front, especially downwind of Asia. In addition, when the warm conveyor belt originates in the clean subtropics, it has a significant dilution effect on the polluted continental outflow. We will use these observations to provide quantitative constraints on the role of mid-latitude cyclones in exporting pollution to the free troposphere.
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0305 Aerosols and particles (0345, 4801, 4906)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting