Interannual variability of the Antarctic ozone hole in a GCM. Part 2: A comparison of unforced and QBO-induced variability

Journal Article · Tue Jun 15 04:00:00 EDT 1999 · Journal of the Atmospheric Sciences

DOI:https://doi.org/10.1175/1520-0469(1999)056<1873:IVOTAO>2.0.CO;2· OSTI ID:6169796

Shindell, D T; Rind, D; Balachandran, N ^[1]

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1. Columbia Univ., New York, NY (United States)

Simulations were performed with the Goddard Institute for Space Studies GCM including a prescribed quasi-biennial oscillation (QBO), applied at a constant maximum value, and a physically realistic parameterization of the heterogeneous chemistry responsible for severe polar ozone loss. While the QBO is primarily a stratospheric phenomenon, in this model the QBO modulates the amount and propagation of planetary wave energy in the troposphere as well as in the stratosphere. Dynamical activity is greater in the easterly than in the unforced case, while westerly years are dynamically more quiescent. By altering zonal winds and potential vorticity, the QBO forcing changes the refraction of planetary waves beginning in midwinter, causing the lower-stratospheric zonal average temperatures at Southern Hemisphere high latitudes to be [approximately]3--5 K warmer in the easterly phase than in the westerly during the late winter and early spring. Ozone loss varies nonlinearly with temperature, due to the sharp threshold for formation of heterogeneous chemistry surfaces, so that the mean daily total mass of ozone depleted in this region during September was 8.7 [times] 10[sup 10] kg in the QBO easterly maximum, as compared with 12.0 [times] 10[sup 10] kg in the westerly maximum and 10.3 [times] 10[sup 10] kg in the unforced case. Through this mechanism, the midwinter divergence of the Eliassen-Palm flux is well correlated with the subsequent springtime total ozone loss (R[sup 2] = 0.6). The chemical ozone loss differences are much larger than QBO-induced transport differences in the authors' model. Inclusion of the QBO forcing also increased the maximum variability in total ozone loss from the [approximately]20% value found in the unforced runs to [approximately]50%. These large variations in ozone depletion are very similar in size to the largest observed variations in the severity of the ozone hole. The results suggest that both random variability and periodic QBO forcing are important components, perhaps explaining some of the difficulties encountered in previous attempts to correlate the severity of the ozone hole with the QBO phase.

• OSTI ID: 6169796
• Journal Information: Journal of the Atmospheric Sciences, Journal Name: Journal of the Atmospheric Sciences Vol. 56:12; ISSN 0022-4928; ISSN JAHSAK
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring &amp; Transport-- (1990-)
AIR POLLUTION
ANNUAL VARIATIONS
ANTARCTIC REGIONS
ANTARCTICA
COMPARATIVE EVALUATIONS
CRYOSPHERE
EVALUATION
GENERAL CIRCULATION MODELS
LAYERS
MATHEMATICAL MODELS
OZONE LAYER
POLAR REGIONS
POLLUTION
VARIATIONS