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A data study of the influence of the equatorial upper stratosphere on northern-hemisphere stratospheric sudden warmings


Gray, LJ and Phipps, SJ and Dunkerton, TJ and Baldwin, MP and Drysdale, EF and Allen, MR, A data study of the influence of the equatorial upper stratosphere on northern-hemisphere stratospheric sudden warmings, Royal Meteorological Society. Quarterly Journal, 127, (576) pp. 1985-2003. ISSN 1477-870X (2001) [Refereed Article]

Copyright Statement

Copyright 2001 Royal Meteorological Society

DOI: doi:10.1002/qj.49712757607


Equatorial winds in the stratosphere are known to influence the frequency of stratospheric midwinter sudden warmings. Sudden warmings, in turn, influence the Earth's climate both through their direct influence on polar temperatures and through the temperature dependence of ozone depletion in the lower stratosphere. The conventional (Holton-Tan) explanation for the equatorial influence on sudden warmings is in terms of the equatorial winds in the lower stratosphere (∼20-30 km) acting as a waveguide for midlatitude planetary wave propagation. This study employs stratospheric-temperature analyses and equatorial rocketsonde wind data extending to 58 km to diagnose the relationship between the northern-hemisphere polar temperatures and equatorial zonal winds at all height levels in the stratosphere. In addition to the recognized Holton-Tan relationship linking the polar temperatures to the quasi-biennial oscillation in equatorial winds in the lower stratosphere, a strong correlation of polar temperatures with equatorial winds in the upper stratosphere is found. We suggest that this may be associated with the strength and vertical extent of the westerly phase of the semi-annual oscillation in the upper stratosphere, although the observations alone cannot provide a conclusive, causal relationship. The main diagnostic tools employed are correlation studies and composite analysis. The results underline the need for continued high quality, equatorial wind measurements at all stratospheric levels.

Item Details

Item Type:Refereed Article
Keywords:interannual variability, Northern-hemisphere winter, quasi-biennial oscillation, semiannual oscillation, stratosphere, stratospheric sudden warming
Research Division:Earth Sciences
Research Group:Atmospheric sciences
Research Field:Atmospheric dynamics
Objective Division:Environmental Management
Objective Group:Air quality, atmosphere and weather
Objective Field:Atmospheric processes and dynamics
UTAS Author:Phipps, SJ (Dr Steven Phipps)
ID Code:104705
Year Published:2001
Web of Science® Times Cited:92
Deposited By:IMAS Research and Education Centre
Deposited On:2015-11-18
Last Modified:2016-01-20

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