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Sukyoung Lee

1. Introduction The theory of β -plane turbulence ( Rhines 1975 , 1977 ) motivated the search for multiple jets in both barotropic ( Williams 1978 ; Yoden and Yamada 1993 ; Huang and Robinson 1998 ; Huang et al. 2001 ) and shallow water ( Cho and Polvani 1996 ) models. Multiple-jet states are also found in baroclinic flows where disturbances are spontaneously generated by baroclinic instability ( Williams 1979 ; Panetta and Held 1988 ; Vallis and Maltrud 1993 ; Panetta 1993 ; Lee 1997

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Walter A. Robinson

1. Introduction It has been known for half a century that in the time and zonal mean eddies in earth’s atmosphere transport angular momentum poleward and to a lesser extent equatorward into the midlatitude jets (cf. Lorenz 1967 ; Starr 1968 ). What has been less clear is the overall effects of the eddies on the jet. These include the direct effects of eddy transports of heat and momentum and the effects of secondary circulations induced by these eddy transports. Transient eddies in the

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Sukyoung Lee and Hyun-kyung Kim

1. Introduction Among the major features of the planetary-scale atmospheric general circulation, the quasi-zonal jets in the upper troposphere are of primary interest. It is well known that there are two different types of atmospheric jets: the subtropical jet and the polar-front or eddy-driven, jet. The subtropical jet is driven by angular momentum transport from the deep Tropics. This transport is accomplished through the Hadley cell, which, in part, is driven by thermal convection and

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Brian F. Farrell and Petros J. Ioannou

recent studies of storm track statistics ( Whitaker and Sardeshmukh 1998 ; Zhang and Held 1999 ; DelSole 2001a ). In this work we extend this stochastic turbulence theory to study the sensitivity of storm track statistics to changes in mean jet structure and parameters. Such an extension of stability theory to address the sensitivity of statistically steady quadratic quantities is natural to the point of view taken in GST, which directs attention to transient growth supported by the nonnormality of

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R. M. Endlich and G. S. McLean

APRIL 1960R. M. ENDLICH AND G. S. McLEAN135GEOSTROPHIC AND GRADIENT DEPARTURE- HN JET STREAMS R. M. Endlich and G. S. McLeanGeophysics Research Directorate, Air Force Cambridge Research Center (Manuscript received 4 May 1959)ABSTRACTWind measurements made by aircraft of Project Jet Stream during forty-eight flights are compared withgeostrophic and gradient winds (computed on upper-air charts) in order to determine geostrophic andgradient departures. Due to random errors in

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Orli Lachmy and Nili Harnik

1. Introduction One of the most prominent features of the zonal mean flow in the atmosphere is the upper-tropospheric jet, which is a local maximum of the zonal wind. Two different processes may be responsible for creating jets in the atmosphere: one is advection of planetary angular momentum by the mean meridional circulation (MMC) and the other is convergence of eddy momentum flux ( Lee and Kim 2003 ). Since the MMC in the tropics is driven mainly by thermal processes, the term “thermally

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Baruch Ziv and Nathan Paldor

expected to be found near jet streams. Both Palmen and Newton (1969 , PN69 hereafter) and Shapiro and Kennedy (1981) have shown that this hypothesis is supported by observations and that the ageostrophic wind component in the vicinity of jets attains the same order of magnitude as that of its geostrophic counterpart. Studies of the ageostrophic circulations associated with jets distinguish between straight jets (e.g., KS86; Nakamura 1993 ) and curved ones (e.g., KS86; Cammas and Ramond 1989 ). The

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T. N. Krishnamurti

172JOURNAL OF METEOROLOGYVOLUMK 18THE SUBTROPICAL JET STREAM OF WINTER'T. N. Krishnamurti University of Chicago(Manuscript received 7 July 1960)ABSTRACTDaily upper-wind analysis at 200 nib was carried out between the equator and 45N, around the globe,for December 1955 to February 1956 to map the subtropical jet stream. It turned out that this currentformed a pattern of three standing long waves which maintained nearly a steady state. This made possibleiin analysis of the meteorological

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Sukyoung Lee

1. Introduction From theoretical ( Rhines 1975 ) and numerical ( Williams 1978 ) studies, it is well known that in the presence of the meridional planetary vorticity gradient β , an upscale energy cascade generates zonal jets in two-dimensional turbulence. Numerical simulations of quasigeostrophic (QG) turbulence show that if the width of the baroclinically unstable region of the initial flow is greater than the inverse of Rhines’s cascade-arrest scale, ( β /2 u rms ) 1/2 , multiple zonal jets

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R. Bradley Pierce, T. Duncan Fairlie, William L. Grose, Richard Swinbank, and Alan O'Neill

15OCTOBER 1994 PIERCE ET AL. 2957Mixing Processes within the Polar Night Jet R. BRADLEY PIERCENASA Langley Research Center, Hampton, Virginia T. DUNCAN FAIRLIEScience and Technology Corporation, Hampton, Virginia WILLIAM L. GROSENASA Langley Research Center, Hampton, Virginia RICHARD SWINBANKU.K. Meteorological Office, Bracknell

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