Monday, 10 February 2003: 9:15 AM
Insights into tropical tropospherc ozone from the SHADOZ (Southern Hemisphere ADditional OZonesondes) sounding network
The first view of lower stratospheric and upper tropospheric structure from
sondes is provided by a 3-year, 10-site record from the Southern Hemisphere
ADditional OZonesondes (SHADOZ) network:
http://code916.gsfc.nasa.gov/Data_services/shadoz. Observations covering
1998-2000 were made over Ascension Island; Nairobi, Kenya; Irene, South
Africa; La Reunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa;
San Cristobal, Galapagos; Natal, Brazil. Taking the UT/LS (upper
troposphere-lower stratosphere) as the region between 12 and 17 km, we
examine ozone variability in this region on a week-to- week and seasonal
basis. The tropopause is lower in September-October-November than in
March-April- May, when ozone is a minimum at most SHADOZ stations. A zonal
wave-one pattern (referring to ozone mixing ratios greater over the
Atlantic and adjacent continents than over the Pacific and eastern Indian
Ocean), persists all year. The wave, predominantly in the troposphere and
with variable magnitude, appears to be due to general circulation - with
subsidence over the Atlantic and frequent deep convection over the Pacific
and Indian Ocean. The variability of deep convection - most prominent at
Java, Fiji, Samoa and Natal - is explored in time-vs-altitude ozone
curtains. Stratospheric incursions into the troposphere are most prominent
in soundings at Irene and Reunion Island.
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