Wednesday, 14 January 2004: 8:30 AM
Tropospheric ozone over the Atlantic and Indian oceans (1): Views from satellite and SHADOZ (Southern Hemisphere Additional Ozonesondes) soundings
Room 612
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.
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