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Traveling planetary‐scale Rossby waves in the winter stratosphere: The role of tropospheric baroclinic instability
Author(s) -
Domeisen Daniela I. V.,
Plumb R. Alan
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl053684
Subject(s) - baroclinity , stratosphere , rossby wave , troposphere , atmospheric sciences , climatology , instability , northern hemisphere , atmospheric wave , geology , gravity wave , geophysics , physics , gravitational wave , mechanics , astrophysics
The Southern Hemisphere winter stratosphere exhibits prominent traveling planetary‐scale Rossby waves, which generally are not able to induce Stratospheric Sudden Warmings. A series of runs of a simplified general circulation model is presented, aimed at better understanding the generation of these waves. While the generation of planetary‐scale traveling waves through the interaction of synoptic‐scale waves is observed in a control run, when the model is truncated to permit only waves with zonal wave number 1 or 2, the long waves are found to increase in strength, leading to a considerably more active stratosphere including Sudden Warmings comparable in strength to Northern Hemisphere winter. This finding suggests that the role of tropospheric synoptic eddies is two‐fold: while generating a weak planetary‐scale wave flux into the stratosphere, their main effect is to suppress baroclinic instability of planetary‐scale waves by stabilizing the tropospheric mean state.