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Joseph A. Zehnder

VOL. 48, NO. 10 JOURNAL OF THE ATMOSPHERIC SCIENCES 15MAY1991The Interaction of Planetary-Scale Tropical Easterly Waves with Topography: A Mechanism for the Initiation of Tropical Cyclones JOSEPH A. ZEHNDERInstitute of Atmospheric Physics, University of Arizona, Tucson, Arizona(Manuscript received 29 June 1990, in final form 24 November 1990)ABSTRACT The interaction of a basic state flow consisting of a

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Akira Kasahara and Pedro L. da Silva Dias

15 SEPTEMBER 1986 AKIRA KASAHARA AND PEDRO L. DA SILVA DIAS1893Response of Planetary Waves to Stationary Tropical Heating in a Global Atmosphere with Meridional and Vertical ShearAIURA KASAHARANational Center for Atmospheric Research,* Boulder, CO 80307PEDRO L. DA SILVA DIASDepartment of Meteorology, Institute ofAstronomy and Geophysics, University of SZo Paulo, 0100O-Scio Paulo, Brazil(Manuscript received 14 October 1985, in final form 7 March 1986)ABSTRACTThe response of planetary

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Yoko Naito and Shigeo Yoden

), and a major SSW tends to occur in the easterly phase ( Labitzke 1982 ). The weaker polar vortex in the easterly phase of the QBO is associated with a larger upward component of the Eliassen–Palm (EP) flux from the troposphere to the stratosphere ( Dunkerton and Baldwin 1991 ). In the Holton–Tan relationship described above, modulation of the propagation route of planetary waves associated with the QBO, for example, latitudinal shifts of the zero-wind line (i.e., a critical line for stationary

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D. Y. Wang, W. E. Ward, G. G. Shepherd, and Dongs-Liang Wu

1. Introduction While there exists a number of studies on stationary planet waves (SPWs) in the stratosphere and mesosphere (for reviews, see Barnett and Labitzke 1990 ; Andrews et al. 1987 ), to date, their presence in the 90–120-km region of the mesosphere and lower thermosphere (MLT) for the most part has not been explored. The investigations of planetary waves in the region focus mostly on traveling modes, in particular, the two-day wave. This is because researchers interpreting

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T. R. Krismer, M. A. Giorgetta, J. S. von Storch, and I. Fast

. Research on the momentum transport by atmospheric waves got much attention in relation to the quasi-biennial oscillation (QBO). The dissipative processes are enhanced in the regions of strong vertical shear associated with the QBO jets, where the full spectrum of equatorial waves, from planetary Kelvin and Rossby waves to mesoscale gravity waves, is necessary to propagate the QBO jets against the resistance of the tropical upwelling ( Dunkerton 1997 ; Sato and Dunkerton 1997 ). How the stratospheric

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Masakazu Taguchi

forecasts to planetary wave forcing (PWF) from the troposphere. The present approach seeks a clean and straightforward examination of ensemble forecast data that has not been fully taken in existing studies of MSSW predictability. Examining these aspects will lead to improvements in forecast systems for better predictions in the extratropical stratosphere and troposphere. The rest of the paper is organized as follows. Section 2 documents the method, including the analyzed data, definition of MSSWs

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João Rafael Dias Pinto and Jonathan Lloyd Mitchell

high-Rossby-number regime, Dias Pinto and Mitchell (2014) demonstrated why idealized models in the statistically steady state tend to produce different regimes when either the parameters of rotation rate or the planetary radius are reduced to reproduce a condition of the higher-Rossby-number regime. In this high-Rossby-number regime, principal component analysis of the eddy geopotential height from a superrotating simulation in steady state suggested that a coupling involving only Rossby waves

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Izumi Saito and Keiichi Ishioka

velocity at the equator for (a) E8, (b) E9, and (c) E10 experiments. Solid black curves indicate the theoretical prediction as in Fig. 6 . Long-dashed red and short-dashed blue curves indicate the results of the nonlinear and quasi-linear models, respectively. The value of the velocity is normalized by the measure of the energy injection rate. REFERENCES Andrews , D. G. , and M. E. McIntyre , 1976 : Planetary waves in horizontal and vertical shear: The generalized Eliassen-Palm relation and the

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Richard S. Lindzen

1452 JOURNAL OF THE ATMOSPHERIC SCIENCES Vo~.ma~29Equatorial Planetary Waves in Shear: Part H RICHARD S. LnqDZENzDept. of th. Geophysical Sciences, Ths University of Chicago 60637(Manuscript received 12 May 1972, in revised form 10 July 1972)ABSTRACT The general problem of the vertical propagation of equatorial waves through mean fields with verticalshear is solved analytically for all meridional

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Richard S. Lindzen

formulas for the various wave fields are obtained, and the role ofdissipation and the behavior of momentum and energy fluxes are investigated. Results are compared withboth numerical calculations and with observations. From the latter, we are able to estimate the dissipativetime scale in the tropical stratosphere. On the basis of the above findings, the Lindzen-Holton model of the quasi-biennial oscillation is modified.1. Introduction For several years now, long-period (5-12 days),planetary

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