Barotropic simulation of large-scale mixing in the Antarctic Polar Vortex

Journal Article · Wed Sep 01 04:00:00 EDT 1993 · Journal of the Atmospheric Sciences; (United States)

DOI:https://doi.org/10.1175/1520-0469(1993)050<2901:BSOLSM>2.0.CO;2· OSTI ID:5638626

Bowman, K P ^[1]

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1. Texas A M Univ., College Station, TX (United States)

Theory and observations suggest that the Antarctic polar vortex is relatively isolated from midlatitudes, although others have interpreted the observations to indicate that there is substantial mixing from the interior of the vortex into middle latitudes. The equivalent barotropic model of Salby et al. is used to study quasi-horizontal mixing by the large-scale flow in the lower stratosphere during Southern Hemisphere spring, which is when the Antarctic ozone hole appears and disappears. The model is forced by relaxation to observed climatological monthly mean zonal-mean winds and by an idealized wave 1 or 2 forcing at the lower boundary. Mixing and transport and diagnosed primarily through Lagrangian tracer trajectories. For September, October, and November basic states, there is little or no mixing in the interior of the vortex. Mixing occurs near the critical lines for the waves: in the tropics and subtropics for a stationary wave 1, and in midlatitudes on the equatorward flank of the jet for an eastward-moving wave 2. For the December basic state, the wave 2 forcing rapidly mixes the interior of the vortex. Mixing of Lagrangian tracer particles can be significant even when the waves do not [open quotes]break,[close quotes] as evidenced by the potential vorticity field. In the model there does not appear to be any significant transport of air out of the interior of the polar vortex prior to the vortex breakdown. The principal factor that leads to the vortex breakdown and mixing of the vortex interior is the deceleration of the jet to the factor that leads to the vortex breakdown and mixing of the vortex interior is the deceleration of the get to the point where winds in the interior of the vortex are close to phase velocity of the wavenumber 2 forcing. The tracer transport is very similar to many aspects of the behavior of the total ozone field during the spring season. 37 refs., 14 figs., 1 tab.

• OSTI ID: 5638626
• Journal Information: Journal of the Atmospheric Sciences; (United States), Journal Name: Journal of the Atmospheric Sciences; (United States) Vol. 50:17; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110
540120* -- Environment
Atmospheric-- Chemicals Monitoring &amp; Transport-- (1990-)
ANTARCTIC REGIONS
ANTARCTICA
ATMOSPHERIC CHEMISTRY
ATMOSPHERIC CIRCULATION
CHEMISTRY
CRYOSPHERE
EARTH ATMOSPHERE
EARTH PLANET
FLUID FLOW
LAYERS
MATHEMATICAL MODELS
METEOROLOGY
MIXING
OZONE LAYER
PLANETS
POLAR REGIONS
SEASONAL VARIATIONS
SOUTHERN HEMISPHERE
STRATOSPHERE
VARIATIONS
VORTEX FLOW