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Navid C. Constantinou, Brian F. Farrell, and Petros J. Ioannou

1. Introduction Spatially and temporally coherent jets are a common feature of turbulent flows in planetary atmospheres with the banded winds of the giant planets constituting a familiar example ( Vasavada and Showman 2005 ). Fjørtoft (1953) noted that the conservation of both energy and enstrophy in dissipationless barotropic flow implies that transfer of energy among spatial spectral components results in energy accumulating at the largest scales. This argument provides a conceptual basis

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Noboru Nakamura and Da Zhu

1. Introduction Starting with the work of Rhines (1975) , it is now well known that macroturbulence on a rotating sphere is fundamentally different from isotropic 2D turbulence. Eddies become anisotropic as the inverse cascade of energy makes them aware of the meridional gradient in the background potential vorticity (PV), at which point zonal jets begin to form. On the beta plane, this occurs when the energy-containing eddy reaches the Rhines scale L β ≈ (EKE) 1/4 β −1/2 , where EKE denotes

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Yoshi-Yuki Hayashi, Seiya Nishizawa, Shin-ichi Takehiro, Michio Yamada, Keiichi Ishioka, and Shigeo Yoden

mean flows and recognized its persistent characteristics. A peculiar feature found by Yoden and Yamada (1993) is that, in addition to the appearance of the banded structure of zonal mean flows, intense easterly (retrograde) circumpolar jets tend to emerge especially at large rotation rate. The appearance of an easterly circumpolar jet has been confirmed as a robust feature in decaying turbulence, while in forced turbulence, its appearance seems to depend on the forcing scale. When the forcing

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Yuji Kitamura and Keiichi Ishioka

fundamentals for examining large-scale structures of atmospheric motions. Two-dimensional turbulence and its rotational effects have been studied to investigate the nonlinear dynamics in the atmosphere and ocean by many authors. Rhines (1975) first found that a zonal structure spontaneously becomes dominant in 2D turbulence on a β plane. The meridional scale of the zonal jet is characterized by the scale L β = 2 U 0 / β ( U 0 stands for a representative velocity), which is called the Rhines scale

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Shuguang Wang and Fuqing Zhang

1. Introduction Atmospheric jets are known to generate gravity waves. Gravity wave emission in the exit region of jets has been documented in many studies, such as those based on observations (e.g., Uccellini and Koch 1987 ; Koch and Dorian 1988 ; Schneider 1990 ; Hertzog et al. 2001 ; Zhang et al. 2001 ; Plougonven and Teitelbaum 2003 ; Wu and Zhang 2004 ; Koch et al. 2005 ) and on numerical simulations of gravity waves within baroclinic life cycles ( O’Sullivan and Dunkerton 1995

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Mark D. Fruman, Bach Lien Hua, and Richard Schopp

1. Introduction Understanding the formation and evolution of zonally symmetric zonal flows is a central problem in the theory of atmospheric and oceanic circulation. Examples include the equatorial jets on Jupiter ( Vasavada and Showman 2005 ) and the zonal jets in the circulations of all three equatorial oceans ( Ollitrault et al. 2006 ; Richards et al. 2006 ). In the latter case, the jets have a rich latitudinal and vertical structure not easily explained by traditional arguments. The

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Dave Broutman, Stephen D. Eckermann, and James W. Rottman

1. Introduction Mountain waves propagate to great heights in the atmosphere (see the review by Fritts and Alexander 2003 ), at times reaching the mesosphere and lower thermosphere ( Bacmeister 1993 ; Eckermann et al. 2007 ). The propagation can be interrupted by wind jets, which produce evanescent layers that partially reflect and partially transmit the waves (e.g., Nault and Sutherland 2008 , hereafter NaSu ). Above the wind jet, the partially transmitted waves can continue to grow with

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Sukyoung Lee

central assumption of weakly nonlinear theory. However, the assumption of homogeneous turbulence is at odds with the prominence of westerly jets and attendant nonzero time-mean turbulent eddy vorticity fluxes ( Robinson 2006 ); to use the nonlinear stability theorem, Shepherd (1988) assumed that the flow in question is subject to potential vorticity damping, which implies that the top of the atmosphere is subject to the same Ekman damping rate as the bottom of the atmosphere. Although these papers

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Thomas R. Parish and Larry D. Oolman

1. Introduction The summertime Great Plains low-level jet (LLJ) of the central United States is one of the most intensely studied mesoscale features of the past 50 years (e.g., Lettau and Davidson 1957 ; Hoecker 1963 ; Bonner 1968 ). Wind profiles at Great Plains sites during the daytime show weak southerly winds, often less than 5 m s −1 . Speeds increase significantly in the hours after sunset with an LLJ developing at levels 300–800 m above the ground. LLJ wind speeds reach a maximum

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Jie Song, Wen Zhou, Xin Wang, and Chongyin Li

storm track in observations and in ideal model simulations ( Vallis et al. 2004 ). In the zonal direction, a more zonally “annular” (localized) AM is associated with a more zonally uniform (localized) storm track. Recently, some studies have also revealed that the zonal pattern of the AM is strongly influenced by the boundary topography and land–sea contrast ( Cash et al. 2005 ; Körnich et al. 2006 ; Gerber and Vallis 2009 ). In this study, we highlight the importance of the strong subtropical jet

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