Spatial patterns and mechanisms of the quasi-biennial oscillation–annual beat of ozone
An idealized two-dimensional chemistry and transport model is used to investigate the spatial patterns of, and mechanism for, the quasi-biennial oscillation–annual beat (QBO-AB) signal in ozone in the tropics and subtropics. Principal component analysis is applied to the detrended, deseasonalized, and filtered total column ozone anomaly from the standard model. The first two empirical orthogonal functions (EOFs) capture over 98.5% of the total variance. The first EOF, accounting for 70.3% of the variance, displays a structure attributable to the approximately symmetric QBO with a period of 28 months. The second EOF, capturing 28.2% of the variance, is related to the QBO-AB around 20 months. An extended EOF analysis reveals the characteristic pattern of the downward propagation of QBO and upward propagation of QBO-AB. The model results are compared to those from the merged ozone data. Sensitivity experiments indicate that the QBO-AB is produced primarily as a result of the dynamical QBO-AB in the mean meridional circulation and by the interaction between the QBO and the annual cycle in transport, each contributing roughly equally to the forcing of QBO-AB. The interaction between the QBO in the transport fields and the annual cycle in chemistry plays a minor role.
Additional Information© 2005 American Geophysical Union. Received 7 April 2005; revised 19 July 2005; accepted 31 August 2005; published 13 December 2005. We thank A. Ruzmaikin, J. Feynman, V. Natraj, and M. Gerstell for their helpful comments. This work was supported in part by NASA grants NAG1-1806 and NNG04GN02G to the California Institute of Technology. The fourth author was supported by the Human Resources Development Fund at the Jet Propulsion Laboratory.
Published - jgrd12235.pdf
Supplemental Material - jgrd12235-sup-0001-t01.txt
Supplemental Material - jgrd12235-sup-0002-t02.txt
Supplemental Material - jgrd12235-sup-0003-t03.txt
Supplemental Material - jgrd12235-sup-0004-t04.txt