Heterogeneous physicochemistry of the polar ozone hole

Journal Article · Thu Nov 30 00:00:00 EST 1989 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JD094iD14p16493· OSTI ID:7222561

Turco, R P ^[1]; Toon, O B ^[2]; Hamill, P ^[3]

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1. Univ. of California, Los Angeles (United States)
2. NASA Ames Research Center, Moffett Field, CA (United States)
3. San Jose Univ., CA (United States)

The heterogeneous physical and chemical processes that occur in the presence of and involve polar stratospheric clouds (PSCs) are investigated. The theory developed here is guided by, and compared for consistency with, the extensive observations from the Airborne Antarctic Ozone Experiment. The authors first describe the characteristics of PSCs that affect chemical processes, such as particle composition, cloud surface area and mass, and aerosol mechanical time constants. The vapor pressures of trace compounds measured over ice in laboratory settings are discussed and shown to be consistent with in situ observations and simple thermodynamics. The mechanism for the formation of nitric acid haze (type I PSC) is elucidated. To estimate key chemical time constants, they derive expressions for the rates of mass transfer to PSC particles and reaction rates on surfaces; here, laboratory measurements of sticking coefficients are related to the fundamental parameters of surface physics and chemistry. They reach several important conclusions. The HCL + ClONO{sub 2}, ClONO{sub 2} + H{sub 2}O, N{sub 2}O{sub 5} + HCl, and N{sub 2}O{sub 5} + H{sub 2}O reactions can occur on early forming type I PSC (haze) particles, converting inert chlorine to active chlorine (Cl{sub 2}, HOCl, and ClONO{sub 2}) and active nitrogen to HNO{sub 3} relatively quickly. Denitrification occurs somewhat later in the winter season with the formation of type II PSC (ice cirrus) clouds, which can absorb HNO{sub 3} in solid solution and remove the HNO{sub 3} by sedimentation; the degree of denitrification is sensitive to the cooling rate and the time constant for condensation of nitric acid haze. Dechlorination does not occur as efficiently as denitrification because the HCl reservoir is effectively depleted by conversion into active chlorine before the onset of type II cloud formation and denitrification.

• OSTI ID: 7222561
• Journal Information: Journal of Geophysical Research; (United States), Vol. 94:D14; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
29 ENERGY PLANNING
POLICY AND ECONOMY
ANTARCTIC REGIONS
OZONE LAYER
ATMOSPHERIC CHEMISTRY
AEROSOLS
CHEMICAL COMPOSITION
CHEMICAL REACTION KINETICS
CHLORINE NITRATES
CHLOROFLUOROCARBONS
CLOUDS
DECHLORINATION
DEHALOGENATION
DENITRIFICATION
HOLES
HYDROCHLORIC ACID
HYDROFLUORIC ACID
ICE
LOSSES
MASS TRANSFER
MATHEMATICAL MODELS
NITRIC ACID
NITROGEN OXIDES
PHOTOCHEMICAL REACTIONS
RECYCLING
STRATOSPHERE
SURFACE AREA
VAPOR PRESSURE
VORTICES
WATER VAPOR
WEIGHT
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CHLORINE COMPOUNDS
COLLOIDS
DISPERSIONS
EARTH ATMOSPHERE
FLUIDS
FLUORINE COMPOUNDS
GASES
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETICS
LAYERS
NITRATES
NITROGEN COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLAR REGIONS
REACTION KINETICS
SOLS
SURFACE PROPERTIES
THERMODYNAMIC PROPERTIES
VAPORS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)
290301 - Energy Planning & Policy- Environment
Health
& Safety- Regional & Global Environmental Aspects- (1992-)