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Alan Shapiro, Evgeni Fedorovich, and Stefan Rahimi

1. Introduction The nocturnal low-level jet (LLJ) is a low-level maximum in the boundary layer wind profile common to the Great Plains of the United States ( Bonner 1968 ; Mitchell et al. 1995 ; Stensrud 1996 ; Whiteman et al. 1997 ; Arritt et al. 1997 ; Song et al. 2005 ; Walters et al. 2008 ) and other places worldwide ( Sládkovič and Kanter 1977 ; Stensrud 1996 ; Beyrich et al. 1997 ; Rife et al. 2010 ; Fiedler et al. 2013 ). Typically LLJs begin to develop around sunset in fair

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H. Luce, G. Hassenpflug, M. Yamamoto, S. Fukao, and K. Sato

the top of stratiform clouds, and less often, in the upper-tropospheric jet streams near the tropopause at 10–11 km (see the review by Gossard 1990 ). Owing to their high sensitivity, very high frequency (VHF; 30–300 MHz) stratosphere–troposphere (ST) pulsed Doppler radars can provide observations within the tropopause region, up to 20–25 km. Contrary to UHF (300–3000 MHz) radars, VHF ST radars are not only sensitive to turbulent irregularities but also to laminar and thin stable humidity and

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Clio Michel and Gwendal Rivière

eastward propagation, the eddies feed back onto the mean flow by accelerating the zonal wind at midlatitudes through Rossby wave breakings in the upper troposphere. This forms the so-called eddy-driven jet (EDJ), or polar-front jet, which has an equivalent barotropic structure and its position is well diagnosed by that of the maximum of the westerlies in the lower troposphere ( Woollings et al. 2010 ). At low latitudes, the conservation of the angular momentum along the high-altitude branch of the

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Mara Felici, Valerio Lucarini, Antonio Speranza, and Renato Vitolo

statistical inference on statistically stationary time series produced by a dynamical system providing a minimal model for the dynamics of the midlatitudes baroclinic jet. There reported is, from mathematical literature, a suitable, rigorous, universal setting for the analysis of the extreme events in stationary time series. This is based on Gnedenko’s theorem ( Gnedenko 1943 ) according to which the distribution of the block maxima of a sample of independent identically distributed variables converges

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Yu Du and Richard Rotunno

1. Introduction The warm-season nocturnal low-level jet (LLJ) over the Great Plains of the United States (Great Plains) has been extensively studied over the past 60 years through observations (e.g., Bonner 1968 ; Whiteman et al. 1997 ; Mitchell et al. 1995 ; Banta et al. 2002 ), numerical simulations (e.g., Zhong et al. 1996 ; Jiang et al. 2007 , hereinafter J07 ; Parish and Oolman 2010 , hereinafter P10 ; Rife et al. 2010 ), and theoretical models (e.g., Blackadar 1957 ; Holton

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Fay Luxford and Tim Woollings

skewness and kurtosis of flow variables are often used to characterize these non-Gaussian features. The basic structure of these statistics has been described by White (1980) , Trenberth and Mo (1985) , Nakamura and Wallace (1991) , and Holzer (1996) . The clearest signature is for geopotential height to be positively skewed on the poleward side of jet streams/storm tracks and negatively skewed on the equatorward side. This means that the distribution of geopotential height at a grid point poleward

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Brian F. Farrell and Petros J. Ioannou

1. Introduction Emergence of coherent jets from relatively incoherent background velocity fields occurs in both rotating and nonrotating fluids. Examples of steady jets include the banded winds of the gaseous planets ( Ingersol 1990 ); examples of orderly variation include the quasi-biennial oscillation (QBO) of the equatorial stratosphere ( Reed and Rogers 1962 ), and the torsional oscillations of the solar convection zone ( Vorontsov et al. 2002 ). Earth's midlatitude jets show a more

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Willis L. Webb

SEPTEMBER 1966 W I L L I S L. W E B B 531The Stratospheric Tidal Jet WilLiS L.U. S. Army Electronics Command, White Sands Missile Range, N. Mex. (Manuscript received 8 March 1966)ABSTRACT Rotation of the earth introduces a diurnal perturbation into the heating experienced by the ozonospherethrough absorption of solar ultraviolet radiant energy. This diurnal heat wave induces

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R. M. Endlich and G. S. McLean

DECEMBER 1957K. M. ENDLICH AND G. S. McLEAN543THE STRUCTURE OF THE JET STREA By R. M. Endlich and G. S. MckeanGeophysics Research Directorate, Air Force Cambridge Research Center (Manuscript received 8 April 1957)ABSTRACTTypical jet stream characteristics are illustrated by discussions of an average, a strong and a weak jetstream. The basic data were obtained by aircraft of Project Jet Stream in flights carried out mainly over thesoutheastern United States. An empirical model, based on

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S. J. Jacobs

954 JOURNAL OF 'THE ATMOSPHERIC SCIENCES VOLUME28Ageostrophic Stability of Divergent Jets S. J. JAC0~S~Dept. of Meteorology and Oceanography, The University of Michigan, Ann Arbor (Manuscript received 11 August 1969, in revised form 12 March 1971) The barotropic stability of divergent jets is studied under the condition of small but nonzero Rossby number. Small disturbances to the basic state

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