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Gloria L. Manney and Michaela I. Hegglin

1. Introduction The upper-tropospheric (UT) jet streams are a key component of the atmospheric circulation and are closely linked with weather and climate phenomena such as storm tracks, precipitation, and extreme events ( Koch et al. 2006 ; Harnik et al. 2016 ; Mann et al. 2017 , and references therein). The UT jets and the tropopause are themselves sensitive to climate change and ozone depletion (e.g., Seidel and Randel 2006 ; Lorenz and DeWeaver 2007 ; McLandress et al. 2011 ; WMO 2011

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Lionel Gourdeau, William S. Kessler, Russ E. Davis, Jeff Sherman, Christophe Maes, and Elodie Kestenare

). This latter pathway represents a principal water mass connection between the subtropical southwest Pacific and the equatorial ocean ( Tsuchiya 1981 ); the possibility that transport changes along this pathway influence climate on the equator motivates study of the regional circulation. Several sources of information have demonstrated that the broad westward flow feeding the Coral Sea is broken into several jets ( Fig. 1 ). Historical climatologies show zonal geostrophic jets extending west of the

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Andrew F. Thompson

1. Introduction Ocean flows are replete with coherent structures on scales ranging from the Rossby deformation radius λ , tens of kilometers, to the size of ocean basins, many thousands of kilometers. Ocean jets, defined as zonally elongated flows typically exhibiting banded structure with alternating eastward and westward velocities, are an example of coherent structures observed throughout this range of scales. The near-universal presence of jets in the ocean has been substantiated by

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Scott J. Weaver and Sumant Nigam

1. Introduction The Great Plains of North America extend from the interior Canadian provinces of Alberta, Saskatchewan, and Manitoba southward through the west-central United States into Texas. This area is a predominantly flat agricultural region in close proximity to the Rocky Mountains and the Gulf of Mexico. During spring and summer, large amounts of heat and moisture are transported northward from the Gulf of Mexico into the central United States by the Great Plains low-level jet (GPLLJ

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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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Emma J. D. Boland, Andrew F. Thompson, Emily Shuckburgh, and Peter H. Haynes

1. Introduction A number of studies have identified and noted the potential impact of zonal jet structure (alternating eastward and westward velocities) on ocean circulation ( Berloff et al. 2009 ; Maximenko et al. 2005 ), yet many instances of nonzonal jet orientation are also evident. Observations of sea surface height indicate jet cores at topographic gradient maxima ( Hughes and Ash 2001 ) and also reveal increased eddy forcing of jets near topographically complex regions ( Maximenko et al

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Wenbo Tang, Manikandan Mathur, George Haller, Douglas C. Hahn, and Frank H. Ruggiero

as DLE ridges, even though they do not induce exponential separation of particles. To distinguish these shear-type LCS from hyperbolic (i.e., attracting or repelling) LCS, we use stability results from Haller (2002) . Shear-type LCS turn out to play an important role in the present flow, as these LCS act as Lagrangian boundaries of a subtropical jet stream. The dataset we analyze here contains high-resolution three-dimensional numerical weather prediction simulations combined with in situ

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Serguei Sokolov and Stephen R. Rintoul

1. Introduction For geophysical flows of sufficient spatial scale, the meridional gradient of planetary vorticity (the β effect) provides a restoring force that helps to organize the flow into persistent, narrow zonal jets ( Rhines 1975 ). Well-known examples include the jets on Jupiter and the outer planets and the jet streams in the earth’s atmosphere. Oceanic flows also fall in a parameter range conducive to the formation of zonal jets, although the presence of land boundaries has been

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Brad E. Beechler, Jeffrey B. Weiss, Gregory S. Duane, and Joseph Tribbia

in errors of location. Models produce structures such as cyclones, storm fronts, and jet streaks but may not be able to predict all-important characteristics of these structures. Forecast model bias is a persistent problem in numerical modeling and data assimilation ( Dee and da Silva 1998 ). For instance, Alexander et al. (1998) show that the fifth-generation Pennsylvania State University–National Center for Atmospheric Research (NCAR) Mesoscale Model (MM5) model has trouble accurately

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Yoshi N. Sasaki, Shoshiro Minobe, and Niklas Schneider

1. Introduction The Kuroshio Extension (KE) jet, the western boundary current of the subtropical gyre in the North Pacific, transports warm water poleward and yields large heat release from the ocean to the atmosphere. The KE jet exhibits large fluctuations on interannual and decadal time scales (e.g., Deser et al. 1999 ; Schneider et al. 2002 ; Qiu and Chen 2005 ), so its variability has attracted much attention owing to its significant roles not only in the interior ocean structure of the

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