Recorded presentationJ4.2
Stratosphere-troposphere coupling and links with Eurasian land-surface variability
Judah Cohen, AER, Lexington, MA; and M. Barlow, P. Kushner, and K. Saito
A diagnostic of Northern-Hemisphere winter extratropical stratosphere-troposphere interactions is presented to facilitate the study of stratosphere-troposphere coupling and to examine what might influence these interactions. The diagnostic is a multivariate EOF combining lower-stratospheric planetary wave activity flux in December with sea-level pressure in January. This EOF analysis captures a strong linkage between the vertical component of lower stratospheric wave activity over Eurasia and subsequent development of hemispheric-wide surface circulation anomalies, which are strongly related to the Arctic Oscillation. Wintertime stratosphere-troposphere events picked out by this diagnostic often have a precursor in autumn: years with large October snow extent over Eurasia feature strong wintertime upward-propagating planetary wave pulses, a weaker wintertime polar vortex, and high geopotential heights in the wintertime polar troposphere. This provides further evidence for predictability of wintertime circulation based on autumnal snow extent over Eurasia. Recorded presentation
Joint Session 4, Land-Atmosphere Interactions, Part IV
Wednesday, 23 January 2008, 8:30 AM-10:00 AM, 224
Previous paper Next paper