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Teleconnections and low‐frequency variability in idealized experiments with two storm tracks
Author(s) -
Franzke Christian,
Fraedrich Klaus,
Lunkeit Frank
Publication year - 2001
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49712757411
Subject(s) - teleconnection , storm track , baroclinity , storm , geology , barotropic fluid , climatology , eddy , rossby wave , northern hemisphere , divergence (linguistics) , jet stream , atmospheric sciences , geophysics , meteorology , physics , oceanography , jet (fluid) , turbulence , mechanics , el niño southern oscillation , linguistics , philosophy
Low‐frequency variability and teleconnection patterns induced by two storm tracks in idealized experiments depend on their zonal distance. A separation of about 150°, which resembles the northern hemisphere storm‐track distribution, reveals teleconnection patterns which are similar to the Pacific North American (PNA) pattern and the North Atlantic Oscillation (NAO). The NAO‐like structure is associated with retrograde travelling Rossby waves; barotropic stream‐function tendencies show that the interaction of the stationary eddies with the low‐frequency flow and the high‐frequency eddies contribute to the amplification of the pattern. Its decay is due to their interaction with the zonal‐mean flow, and the low‐frequency contribution to the divergence term. The PNA‐like pattern has a longer memory and is linked to a quasi‐stationary wave. The stationary‐wave activity flux shows the dominating influence of baroclinic processes and the other storm track further upstream. The correlation between the teleconnection indices is significant for storm‐track distances between 180° and 160°, and vanishes between 150° and 130°.