Measurements of gravity waves and thermal structure in the stratospheric polar vortex

Whiteway, J. A., T. J. Duck, and A. I. Carswell, In Mesoscale Processes in the Stratosphere, ISBN 92-828-4629-6, European Commission, Environment and Climate Research Programme, Belgium, 271 - 274. Proceedings of the European Workshop on Mesoscale Processes in the Stratosphere and Their Effect on Stratospheric Chemistry and Microphysics, 8-11 November 1998, Bad Toelz, Bavaria, Germany, K. S. Carslaw and G. T. Amanatidis, editors, 1999.

Abstract. Lidar measurements of stratospheric thermal structure and gravity wave activity have been conducted at Eureka in the Canadian High Arctic since 1993. It has been found that the amount of wave activity in the upper stratosphere is related to the position of the polar vortex: the wave activity is a maximum in the jet and a minimum inside the core of the vortex. The measurements also reveal that the warmest part of the upper stratosphere is in the core of the polar vortex. It is observed that a warming of the upper stratospheric vortex core starts in late December and descends as it is sustained throughout the winter. The commencement of this warming is coincident with the onset of enhanced gravity wave activity in the vortex jet. This suggests that the vortex core warming may be the result of adiabatic warming associated with airflow into the vortex that is induced by the breaking of gravity waves above the jet of the vortex.



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