Photochemical ozone production in tropical squall line convection during NASA Global Tropospheric Experiment/Amazon Boundary Layer Experiment 2A

Journal Article · Wed Feb 20 00:00:00 EST 1991 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/90JD02284· OSTI ID:5401257

Pickering, K E ^[1]; Thompson, A M; Tao, Weikuo; Simpson, J ^[2]; Scala, J R; Garstang, M ^[3]

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1. Applied Research Corp., Landover, MD (USA)
2. NASA Goddard Space Flight Center, Greenbelt, MD (USA)
3. Univ. of Virginia, Charlottesville (USA)

The authors have examined the role of convection in trace gas transport and ozone production in a tropical dry season squall line sampled on August 3, 1985, during NASA Global Tropospheric Experiment/Amazon Boundary Layer Experiment 2A (NASA GTE/ABLE 2A) in Amazonia, Brazil. Two types of analyses were performed. (1) Transient effects within the cloud are examined with a combination of two-dimensional cloud and one-dimensional photochemical modeling. Tracer analyses using the cloud model wind fields yield a series of cross sections of NO{sub x}, CO and O{sub 3} distribution during the lifetime of the cloud; these fields are used in the photochemical model to compute the net rate of O{sub 3} production. At noon, when the cloud was mature, the instantaneous ozone production potential in the cloud is between 50 and 60% less than in no-cloud conditions due to reduced photolysis and cloud scavenging of radicals. (2) Analysis of cloud inflows and outflows is used to differentiate between air that is undisturbed and air that has been modified by the storm. These profiles are used in the photochemical model to examine the aftereffects of convective redistribution in the 24-hour period following the storm. Total tropospheric column O{sub 3} production changed little due to convection because so little NO{sub x} was available in the lower troposphere. However, the integrated O{sub 3} production potential in the 5- to 13-km layer changed from net destruction to net production as a result of the convection. The conditions of the August 3, 1985, event may be typical of the early part of the dry season in Amazonia, when only minimal amounts of pollution from biomass burning have been transported into the region.

• OSTI ID: 5401257
• Journal Information: Journal of Geophysical Research; (United States), Vol. 96:D2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
OZONE
SYNTHESIS
TROPOSPHERE
ATMOSPHERIC CHEMISTRY
AIR POLLUTION
BIOMASS
BOUNDARY LAYERS
BRAZIL
CARBON MONOXIDE
COMBUSTION
CONVECTION
ENVIRONMENTAL TRANSPORT
LIFETIME
MATHEMATICAL MODELS
NITROGEN OXIDES
ONE-DIMENSIONAL CALCULATIONS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
STORMS
TRANSIENTS
TWO-DIMENSIONAL CALCULATIONS
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
DEVELOPING COUNTRIES
DISASTERS
EARTH ATMOSPHERE
ENERGY SOURCES
ENERGY TRANSFER
HEAT TRANSFER
LATIN AMERICA
LAYERS
MASS TRANSFER
NITROGEN COMPOUNDS
OXIDATION
OXIDES
OXYGEN COMPOUNDS
POLLUTION
RENEWABLE ENERGY SOURCES
SOUTH AMERICA
THERMOCHEMICAL PROCESSES
540110*