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Alison Ming, Peter Hitchcock, and Peter Haynes

1. Introduction The important role for wave forces (or “wave drag”) in the dynamics of the mean meridional circulation (e.g., the Brewer–Dobson circulation in the stratosphere) is now well understood. In particular, for a steady circulation that crosses angular momentum contours (which are to good approximation vertical outside of the tropics), there must be a corresponding wave force and the relation between the wave force and the circulation is expressed by the downward control principle

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Chidong Zhang

15 M^wCH 1993 ZHANG 807Laterally Forced Equatorial Perturbations in a Linear Model. Part II: Mobile Forcing CHIDONG ZHANG*Department of Meteorology, The Pennsylvania State University, University Park. Pennsylvania(Manuscript received 15 August 1991, in final form 20 April 1992)ABSTRACT Impacts of atmospheric mean zonal flows on equatorial perturbations laterally forced

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John W. Bergman and Harry H. Hendon

diabatic heating and to the individual components: latent heating and radiative heating. The role of clouds is quantified by the circulation driven by “cloud radiative forcing” (CRF), which is calculated by subtracting clear-sky radiative heating rates from the net radiative heating rates. We further diagnose the relative contributions by deep convective clouds, for example, in the intertropical convergence zone (ITCZ), and by shallow cloud fields at subtropical locations. This study is motivated by

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Brian H. Tang

amplitude near the center of the pre-Nuri disturbance. The negative virtual potential temperature anomalies in the lower troposphere must be eradicated in order for tropical cyclogenesis to occur ( Bister and Emanuel 1997 ). While thermal-wind balance is a useful starting point and will serve to motivate the framework that will be introduced, there are several limitations. The first limitation is that thermal-wind balance does not have any time dependence and therefore cannot give insight into forcing

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Amanda Gounou and Robin J. Hogan

longwave warming effect on climate (a positive radiative forcing) has been found to exceed the shortwave cooling effect (a negative radiative forcing) leading to a net warming effect ( Meerkötter et al. 1999 ; Strauss et al. 1997 ). Nonetheless, the two effects are of similar magnitude, and uncertainties in forcing have been found due to the various assumptions made, particularly regarding particle size, optical depth, and contrail cover. Fahey et al. (1999) estimate that the global mean net top

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A. M. Rogerson and R. M. Samelson

I Ju~E 1995 ROGERSON AND SAMELSON 2025Synoptic Forcing of Coastal-Trapped Disturbances inthe Marine Atmospheric Boundary Layer A. M. ROGERSON AND R. M. $AMELSONWoods Hole Oceanographic Institution, Woods Hole, Massachusetts(Manuscript received 25 July 1994, in final form 28 November 1994)ABSTRACT Motivated by recent observations along the west coast

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Timothy DelSole

1. Introduction In an important paper, Farrell and Ioannou (1995) showed that a quasigeostrophic model linearized about the time mean, forced by white noise on large scales, and dissipated at a uniform rate can produce realistic heat and momentum fluxes. The forcing and dissipation in this model parameterized the effect of nonlinear interactions. Whitaker and Sardeshmukh (1998) showed that a global version of this model also could produce realistic storm tracks. Despite these successes, the

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Xiaoqing Wu, Mitchell W. Moncrieff, and Kerry A. Emanuel

-standing problem concerns the collective effects of cloud systems rather than the detailed influence of any one process (i.e., microphysics, turbulence, surface fluxes, or radiation). The intensive observing periods conducted during major field campaigns provide independent datasets with which to evaluate the simulated cloud-scale and mesoscale response to large-scale forcing. These datasets include satellite-measured radiative fluxes, surface heat fluxes, and radar-derived rainfall data, among others

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R. L. Walterscheid and J. Boucher Jr.

1062 JOURNAL OF THE ATMOSPHERIC SCIENCES VOL. 41, No. 6A Simple Model of the Transient Response of' the Thermosphere to Impulsive Forcing R. L. WALTERSCHEID AND D. J. BOUCHER, JR.Space Sciences Laboratory, The Aerospace Corporation, Los .4ngeles, CA 90009(Manuscript received 7 March 1983, in final form 17 November 1983) Substantial variations in density, temperature and winds in the high.latitude thcrmospbem during

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M. J. Alexander and J. R. Holton

1. Introduction In their theory of the quasi-biennial oscillation (QBO) of the zonal mean winds in the equatorial stratosphere, Lindzen and Holton (1968, hereafter LH68) argued that zonal forcing induced by a continuous spectrum of long-period vertically propagating gravity waves was responsible for the downward propagating easterly and westerly mean wind regimes that characterize the QBO. In LH68 the wave-induced forcing of the mean flow was attributed to absorption of these vertically

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