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Blocking Precursors to Stratospheric Sudden Warming Event

Martius, O.; Davies, H. C.; Polvani, Lorenzo M.

The primary causes for the onset of major, midwinter, stratospheric sudden warming events remain unclear. In this paper, we report that 25 of the 27 events objectively identified in the ERA-40 dataset for the period 1957–2001 are preceded by blocking patterns in the troposphere. The spatial characteristics of tropospheric blocks prior to sudden warming events are strongly correlated with the type of sudden warming event that follows. Vortex displacement events are nearly always preceded by blocking over the Atlantic basin only, whereas vortex splitting events are preceded by blocking events occurring in the Pacific basin or in both basins contemporaneously. The differences in the geographical blocking distribution prior to sudden warming events are mirrored in the patterns of planetary waves that are responsible for producing events of either type. The evidence presented here, suggests that tropospheric blocking plays an important role in determining the onset and the type of warmings.

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Title
Geophysical Research Letters
DOI
https://doi.org/10.1029/2009GL038776

More About This Work

Academic Units
Applied Physics and Applied Mathematics
Earth and Environmental Sciences
Published Here
November 1, 2013
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