2.1
Tropospheric ozone over the Atlantic and Indian oceans (1): Views from satellite and SHADOZ (Southern Hemisphere Additional Ozonesondes) soundings
Anne M. Thompson, NASA/GSFC, Greenbelt, MD; and J. C. Witte, R. B. Chatfield, and H. Guan
Two datasets have been used to characterize interannual and seasonal variability in tropospheric ozone in the tropics during the period 1998-2002. Satellite data, the modified-residual TTO (tropical tropospheric ozone) product from the TOMS instrument (http://www.atmos.umd.edu/~tropo), give column tropospheric ozone amounts in Dobson Units over the entire tropical band. The SHADOZ ozone sounding data (http://croc.gsfc.nasa.gov/shadoz) gives weekly profiles at a dozen stations distributed zonally throughout the southern tropics [Thompson et al., 2003]. Data from early 1999 campaigns (Aerosols99 and INDOEX) augment coverage over the Atlantic and Indian Ocean regions. The most robust features of ozone detected in these data are: (1) a zonal tropospheric wave-one pattern that varies in magnitude over the course of the year; (2) considerable variability at all SHADOZ sites, week-to-week and day-to- day as well as in the expected seasonal timescale; (3) an Atlantic "paradox" in December-January-February, ie higher tropospheric ozone is seen south of the equator than to the north, where the biomass burning pollution source of ozone is concentrated; (4) interaction of ozone with convection which is especially pronounced in areas affected by the Asian winter monsoon. Examples of ozone, primarily from SHADOZ data, will be shown along with analyses that illustrate regional influences and intercontinental-range transport.
Session 2, Atmospheric chemistry of gases, aerosols, and clouds in urban, regional, and global scales: OZONE (Room 612)
Wednesday, 14 January 2004, 8:30 AM-2:15 PM, Room 612
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