Sudden stratospheric and stratopause warmings: Observations of temperatures in the middle atmosphere above Eureka

Duck, T. J., J. A. Whiteway, and A. I. Carswell, Atmospheric Science Across the Stratopause, Geophysical Monograph, 123, American Geophysical Union, Washington, 207 - 212, 2000.

Abstract. Wintertime observations of strato-mesospheric temperatures have been obtained in the High Arctic at Eureka (80N, 86W) since 1993 by using a lidar and meteorological balloons. Several minor sudden stratospheric warmings (i.e., large-scale stratospheric circulation disturbances) have been observed since that time. With respect to the measurements obtained at Eureka, the disturbances are associated with lower stratospheric warming and stratopause cooling. In contrast, when the circulation is relatively undisturbed, lower stratospheric cooling and stratopause warming are observed above Eureka. These temperature changes are associated primarily with movements of the wintertime stratospheric vortex, which implies that single station measurements are best examined against the backdrop of the actual three-dimensional circulation rather than the more traditional sudden warming diagnostics. Furthermore, because warming at the stratopause is observed when the circulation is relatively undisturbed, a contribution in addition to planetary wave drag and vortex-vortex interactions is likely important for the dynamics of the upper stratosphere.

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