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Joseph Kidston, G. K. Vallis, S. M. Dean, and J. A. Renwick

1. Introduction a. Jet stream movement There is evidence of a poleward shift of the eddy-driven jet streams in recent decades, particularly in the Southern Hemisphere ( Feldstein 2002 ; Marshall 2003 ; Ostermeier and Wallace 2003 ; Thompson et al. 2000 ; Trenberth et al. 2007 ). A large portion of the observed mid- to high-latitude temperature trends bear the signature of such a shift ( Hurrell 1996 ; Thompson et al. 2000 ; Thompson and Solomon 2002 ; Trenberth et al. 2007 ). Events such

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Yazhou Zhang, Peiwen Yan, Zhijie Liao, Danqing Huang, and Yaocun Zhang

1. Introduction In general, there are two branches of westerly jet streams in the upper troposphere over East Asia around the year, the East Asian polar-front jet (EAPJ) and the East Asian subtropical jet (EASJ). The EAPJ is located in the baroclinic zone, which is mainly formed by the eddy momentum flux convergence ( Panetta 1993 ; Lee 1997 ). The EASJ is an important component of the global subtropical jet, which is driven by the angular momentum transport along the poleward shift of the

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Changhyun Yoo and Sukyoung Lee

1. Introduction Multiple zonal jets are ubiquitous not only in planetary atmospheres (e.g., Jupiter and Saturn), but also in the earth’s atmosphere and ocean. The satellite-derived total ozone data, analyzed by Hudson et al. (2003) , show three distinctive regions separated by two boundaries in the earth’s atmosphere. One boundary closely coincides with the subtropical jet and the other with the polar-front jet. Recently, high-resolution ocean models ( Nakano and Hasumi 2005 ; Richards et al

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Bing Pu and Kerry H. Cook

1. Introduction Two low-level westerly flow regimes are important for the moisture transport into West Africa. One is the well-known West African monsoon (WAM) flow, which is formed by the westward acceleration of the onshore flow across the Guinean coast. The other is the westerly flow near 10°N, directed from the eastern Atlantic onto the West African coast. Grodsky et al. (2003) first identified this westerly flow as a jet using high-resolution scatterometer measurements and studied its

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Kerry H. Cook and Edward K. Vizy

1. Introduction The Caribbean low-level jet (CLLJ) is an easterly jet located over the Caribbean Sea between the northern coast of South America (Venezuela and Columbia) and the Greater Antilles (Cuba, Haiti, Dominican Republic, and Puerto Rico). It is present throughout the year and transports large amounts of moisture from the tropical Atlantic into the Caribbean Sea, into the Gulf of Mexico, across Central America, and into the Pacific basin. In this paper, we build on results from previous

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Paul D. Williams and Christopher W. Kelsall

1. Introduction Zonal jets in planetary atmospheres and oceans affect the transport of heat, momentum, and tracers. Satellite observations show clear evidence of multiple alternating zonal jets extending from the equator to the polar regions in the atmospheres of Jupiter ( Limaye 1986 ) and Saturn ( Sanchez-Lavega et al. 2000 ). In numerical simulations of the atmospheres of Jupiter, Saturn, Uranus, and Neptune, jets are found to emerge spontaneously from random initial conditions, in good

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Douglas O. ReVelle and E. Douglas Nilsson

1. Introduction and overview a. AOE-96 and other Arctic Ocean expeditions Low-level jets (LLJs) are ubiquitous in the atmosphere and have been observed over numerous continental locations and over the Arctic and Antarctic Oceans in the atmospheric planetary boundary layer. Modeling of the Arctic Ocean atmospheric boundary layer (ABL) is in some ways similar to modeling of the nocturnal boundary layer over continental surfaces in middle and high latitudes. The key to understanding the Arctic

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Scott J. Eichelberger and Dennis L. Hartmann

1. Introduction The tropospheric zonal flow consists of two dynamically distinct jets: the subtropical jet and the midlatitude eddy-driven jet. To first order, the subtropical jet results from angular momentum transport by the Hadley circulation ( Held and Hou 1980 ), which is driven by thermal convection. The subtropical jet exists at the poleward boundary of the Hadley circulation. The eddy-driven jet results from the eddy-momentum flux convergence of baroclinic waves that develop in a region

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Bing Pu and Robert E. Dickinson

source that sets up a large-scale mountain–lowland circulation pattern with subsidence over the Great Plains—inhibiting convection during the afternoon.... Moist instabilities...initiate convection in rising air over the lee of the Rockies, propagating to the east.... The moisture supply for these storms the low-level jet, aiding in the setup of convective ‘corridors’ for intense storms” (p. 1231). Various authors have identified processes in models responsible for their lack of success in

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F. J. Beron-Vera, M. G. Brown, M. J. Olascoaga, I. I. Rypina, H. Koçak, and I. A. Udovydchenkov

1. Introduction In Rypina et al. (2007a) , it was argued that the transport barrier near the core of the austral polar night jet can be explained by a mechanism different from the potential vorticity (PV) barrier mechanism ( Juckes and McIntyre 1987 ). The new barrier mechanism, which was subsequently referred to as strong KAM stability ( Rypina et al. 2007b ), follows from an argument that does not make use of dynamical constraints on the streamfunction. This necessitates that dynamical

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