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contributor authorFranzke, Christian
contributor authorFeldstein, Steven B.
date accessioned2017-06-09T16:52:28Z
date available2017-06-09T16:52:28Z
date copyright2005/09/01
date issued2005
identifier issn0022-4928
identifier otherams-75723.pdf
identifier urihttp://onlinelibrary.yabesh.ir/handle/yetl/4218091
description abstractThis study presents an alternative interpretation for Northern Hemisphere teleconnection patterns. Rather than comprising several different recurrent regimes, this study suggests that there is a continuum of teleconnection patterns. This interpretation indicates either that 1) all members of the continuum can be expressed in terms of a linear combination of a small number of real physical modes that correspond to basis functions or 2) that most low-frequency patterns within the continuum are real physical patterns, each having its own spatial structure and frequency of occurrence. Daily NCEP?NCAR reanalysis data are used that cover the boreal winters of 1958?97. A set of nonorthogonal basis functions that span the continuum is derived. The leading basis functions correspond to well-known patterns such as the Pacific?North American teleconnection and North Atlantic Oscillation. Evidence for the continuum perspective is based on the finding that 1) most members of the continuum tend to have similar variance and autocorrelation time scales and 2) that members of the continuum show dynamical characteristics that are intermediate between those of the surrounding basis functions. The latter finding is obtained by examining the streamfunction tendency equation both for the basis functions and some members of the continuum. The streamfunction tendency equation analysis suggests that North Pacific patterns (basis functions and continuum) are primarily driven by their interaction with the climatological stationary eddies and that North Atlantic patterns are primarily driven by transient eddy vorticity fluxes. The decay mechanism for all patterns is similar, being due to the impact of low-frequency (period greater than 10 days) transient eddies and horizontal divergence. Analysis with outgoing longwave radiation shows that tropical convection is found to play a much greater role in exciting North Pacific patterns. A plausible explanation for these differences between the North Atlantic and North Pacific patterns is presented.
publisherAmerican Meteorological Society
titleThe Continuum and Dynamics of Northern Hemisphere Teleconnection Patterns
typeJournal Paper
journal volume62
journal issue9
journal titleJournal of the Atmospheric Sciences
identifier doi10.1175/JAS3536.1
journal fristpage3250
journal lastpage3267
treeJournal of the Atmospheric Sciences:;2005:;Volume( 062 ):;issue: 009
contenttypeFulltext


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