Amazon basin ozone and aerosol: Wet season observations
- NASA Langley Research Center, Hampton, VA (USA)
The tropical environment is recognized as having a major impact on global tropospheric chemistry. The data show that the wet season Amazon Basin is an effective sink for ozone and a net source for aerosols. Mixed layer ozone at 150-m altitude averaged 8.5 ppbv compared to about 18 ppbv at 3-km altitude. In addition, a negative ozone gradient (decreasing value to the surface) was observed within the mixed layer. The averaged wet season mixed layer ozone was about 7 ppbv lower than observed during the dry season. This is attributed to the enhanced convective activity associated with the wet season and the change in mixed layer photochemistry from net ozone production (dry season) to a net destruction (wet season). The net sink characteristics of the wet season mixed layer are seen throughout the troposphere of the Amazon Basin in that ozone (3- to 4-km altitude) is typically 15-25 ppbv as compared to dry season values of 30-35 ppbv. In terms of the aerosol source characteristics of the Amazon Basin, mixed layer aerosols (0.1- to 0.4-{mu}m diameter) are a factor of 5-10 higher than observed in the troposphere with mixed layer values of 100-200 aerosols/cm{sup 3}. Analyses of both tropospheric and mixed layer aerosol samples show aerosols which are multisource. Tropospheric samples have size distributions which are trimodal and show modes at aerosol diameters which suggest the aerosols are (1) of lifetimes <1 hour, (2) of lifetimes of days, and (3) mechanically generated elements (e.g., wind-blow dust). Mixed layer data show two of the three modes with no mode which represent aerosols with lifetimes of days.
- OSTI ID:
- 6061831
- Journal Information:
- Journal of Geophysical Research; (USA), Vol. 95:D10; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AEROSOLS
ECOLOGICAL CONCENTRATION
BRAZIL
AIR POLLUTION MONITORING
OZONE
AIR-BIOSPHERE INTERACTIONS
AMAZON RIVER
ATMOSPHERIC CHEMISTRY
BOUNDARY LAYERS
CONVECTION
EARTH ATMOSPHERE
FORESTS
GLOBAL ASPECTS
HYDROXYL RADICALS
MIXING
MOISTURE
PARTICLE SIZE
PHOTOCHEMICAL REACTIONS
POLLUTION SOURCES
SEASONAL VARIATIONS
SINKS
TROPOSPHERE
CHEMICAL REACTIONS
CHEMISTRY
COLLOIDS
DEVELOPING COUNTRIES
DISPERSIONS
ENERGY TRANSFER
HEAT TRANSFER
LATIN AMERICA
LAYERS
MASS TRANSFER
RADICALS
RIVERS
SIZE
SOLS
SOUTH AMERICA
STREAMS
SURFACE WATERS
VARIATIONS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)