ESRL/PSL Seminar Series

Atmospheric jet stream regime transitions and possible implications for weather and climate

Nili Harnik
Dept of Geophysical, Atmospheric & Planetary Sciences Tel Aviv University

Abstract


The global atmospheric circulation in its simplest form arises from the interaction of three main components- the mean meridional circulation (Hadley and Ferrel cells), the zonal jet streams, and synoptic scale eddies. This three-way interaction gives rise to different dynamical regimes, which are characterized by the type of jet stream - a subtropical jet which is thermally driven, and eddy driven jet, and a merged thermally and eddy driven jet. We will present a study of the different dynamical regimes, their maintenance and variability, using the simplest global circulation model which resolves these three components, and discuss the relevance to the observed circulation and its variability patterns. In particular we will argue that the unusually persistent negative NAO winter of 2009-10 resulted from the dynamical transition of the Atlantic jet from an eddy driven jet, to a merged jet, which is more like the Pacific.


1D-403

Brown Bag Seminar
NOON, Tuesday Feb 24th
(NOTE: THIS IS A TIME CHANGE FROM THE ORIGINAL ANNOUNCEMENT)

Seminar Coordinator: Barbara.S.Herrli@noaa.gov


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