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Yonghui Lin and Fuqing Zhang

and organize convection (e.g., Zhang et al. 2001 ), and they are identified as a possible source of clear-air turbulence (e.g., Koch et al. 2005 ). Mountains, convection, wind shear, and adjustment of unbalanced flows related to jet streams and frontal systems are the most important sources of gravity waves ( Hooke 1986 ). Uccellini and Koch (1987) conceptualized the synoptic pattern of gravity wave generation and found that mesoscale waves with amplitudes of 1–15 hPa, horizontal wavelengths of

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Joshua G. Gebauer, Evgeni Fedorovich, and Alan Shapiro

1. Introduction Wind maxima in the lowest levels of the atmosphere have been an intensively studied meteorological phenomenon. Often referred to in the literature as low-level jets (LLJs), these wind maxima can occur as low as 90 m above ground ( Banta et al. 2002 ). Such LLJs can play a role in pollutant mixing and transport ( Zunckel et al. 1996 ; Banta et al. 1998 ; Darby et al. 2006 ; Bao et al. 2008 ; Klein et al. 2014 ) and can affect wind energy production ( Cosack et al. 2007

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Olivia Martius

1. Introduction a. Rationale The subtropical jet is a salient feature of the subtropical upper-level flow and a key player in the dynamical processes that link the tropics with the subtropics and the extratropics. Of central importance is the role that the subtropical jet (STJ) plays in governing Rossby wave dynamics. The STJ is coaligned with a band of strong potential vorticity (PV) gradients and therefore acts as a waveguide for synoptic-scale Rossby waves ( Hoskins and Ambrizzi 1993

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P. B. Rhines

1. Introduction and potential vorticity background Solar radiation bathes the earth, varying smoothly with latitude, and yet the circulations it produces are filled with small-scale transient eddies, jet streams, and boundary currents. Zonal jet stream generation occurs with thermally forced circulations on a simple, smooth globe. Instability of zonally symmetric, baroclinic circulations is often given as a primary reason for these synoptic-scale features, which are amplified or generated ab

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Adam H. Monahan and John C. Fyfe

general circulation models (e.g., Fyfe et al. 1999 ) and is related to (but not identical with; cf. Monahan and Fyfe 2008 , hereafter MF08 ) the leading mode of zonal-mean geopotential height variability (the annular mode). As noted in Wittman et al. (2005) , the ubiquity of this dipolar structure suggests that it reflects some generic feature of variability of the extratropical atmosphere—in particular, the existence of a jet in zonal-mean zonal winds characterized by fluctuations in position

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Junjun Liu and Tapio Schneider

1. Introduction Among the most striking features of the giant planets are the alternating zonal jets. As shown in Fig. 1 , Jupiter and Saturn have prograde equatorial jets (superrotation) that peak at ∼100 m s −1 and ∼200–400 m s −1 , depending on the vertical level considered. Uranus and Neptune have retrograde equatorial jets (subrotation) that peak at ∼100 m s −1 and ∼150–400 m s −1 . Jupiter and Saturn have multiple off-equatorial jets in each hemisphere; Uranus and Neptune have only a

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Brian F. Farrell and Petros J. Ioannou

1. Introduction Coherent jets are often observed in turbulent flows, with the banded winds of Jupiter constituting a familiar and frequently studied example ( Ingersoll 1990 ; Vasavada and Showman 2005 ; Sánchez-Lavega et al. 2008 ). This phenomenon of spontaneous jet formation in turbulence has been studied observationally and theoretically ( Rhines 1975 ; Williams 1979 , 2003 ; Panetta 1993 ; Nozawa and Yoden 1997 ; Huang and Robinson 1998 ; Manfroi and Young 1999 ; Vallis and

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Matthew H. Hitchman and Amihan S. Huesmann

1. Introduction The stratospheric quasi-biennial oscillation (QBO; Reed et al. 1961 ; Wallace 1973 ; Baldwin et al. 2001 ), with its irregular (22–32 months) periodic reversal in zonal wind, creates long-lasting anomalies that influence the globe. In 1980, Holton and Tan (1980) discovered a significant correlation between QBO westerlies (W) at 50 hPa and the strength of the boreal polar night jet (PNJ). They suggested that sudden stratospheric warmings are less likely during QBO W, when

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Cegeon J. Chan, R. Alan Plumb, and Ivana Cerovecki

1. Introduction In this paper, we describe some characteristics of zonal jets in a model of a zonally reentrant ocean, bounded by zonal walls at the equator and 50°S, driven by a steady eastward wind stress that peaks in middle latitudes. The model simulation was run as a test bed for ideas on eddy transport, and its major, climatological, characteristics are described elsewhere (Cerovecki et al. 2007, manuscript submitted to J. Phys. Oceanogr. , hereafter CPH). Here we focus on the time

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Stephanie Leroux and Nicholas M. J. Hall

African easterly jet (AEJ). Many studies have focused on these African synoptic-scale perturbations since the 1970s and the Global Atmospheric Research Program (GARP) Atlantic Tropical Experiment (GATE) campaign (e.g., Burpee 1972 ; Reed et al. 1969). Motivations for a better understanding of easterly waves are strong because these waves are associated with modulation of convection and rainfall over West Africa (e.g., Duvel 1990 ; Fink and Reiner 2003 ; Kiladis et al. 2006 ) and with the genesis

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