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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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Chungu Lu and Gerald L. Browning

1. Introduction In recent years, a large number of studies have been devoted to the problem of four-dimensional variational (4DVAR) data assimilation when the constraining equations contain discontinuous forcing terms ( Verlinde and Cotton 1993 ; Bao and Warner 1993 ; Bao and Kuo 1995 ; Xu 1996a , b ; 1997a , b ; Zupanski 1993 ; Zou et al. 1993 ; Zou 1997 ). This problem arises in the implementation of the 4DVAR method for a typical atmospheric model, where the model physical

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James A. Anstey, John F. Scinocca, and Martin Keller

problem is the expectation that small-scale waves, which are the most difficult to observe, make a dominant contribution to the forcing ( Dunkerton 1997 ; Kawatani et al. 2010a ). In GCMs run at spatial resolutions typical of climate models, the effects of a significant portion of the small-scale wave spectrum must be parameterized, and many of the parameters used in these schemes are poorly constrained by observations. Although the situation is improving ( Geller et al. 2013 ), presently modelers

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R. K. Scott and L. M. Polvani

1. Introduction It is by now widely accepted that short-term variability of the extratropical stratosphere can arise from variability external to the stratosphere, in particular from variability of the tropospheric circulation, a principle source of planetary-scale wave forcing. The most dramatic example of such short-term stratospheric variability is the so-called sudden warming, during which the radiatively driven cyclonic circulation of the winter stratospheric polar vortex undergoes a rapid

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E. Källén

2150 JOURNAL OF THE ATMOSPHERIC SCIENCES Vo~.usl~38The Nonlinear Effects of Orographic and Momentum Forcing in a Low-Order~ Barotropic Model E. K~LLI~N1European Centre for Medium Range Weather Forecasts, Reading, England(Manuscript received 14 January 1981, in final form 19 May 1981)ABSTRACT An analysis of a low-order barotropic system with orographic and momentum forcing is presented

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Peter H. Stone and Giovanna Salustri

15DECEMBER 1984 PETER H. STONE AND GIOVANNA SALUSTRI 3527Generalization of the Quasi-Geostrophic Eliassen-Palm Flux to Include Eddy Forcing of Condensation Heating PETER H. STONE AND GIOVANNA SALUSTR!Center for Meteorology and Physical Oceanography, Massachusetts Institute of Technology, Cambridge, MA 02139(Manuscript received 15 September 1983, in final form 30 August 1984

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S. Garimella, D. A. Rothenberg, M. J. Wolf, C. Wang, and D. J. Cziczo

to be that of effective mineral dusts: S ice = 1.1 ( Hoose et al. 2008 ). The onset of immersion freezing is at water saturation ( Pruppacher and Klett 1997 ). As noted in the text, reported CFDC data more closely resemble (b) than (a) ( Garimella et al. 2016 ; DeMott et al. 2015 ). Here, we consider the effect of this bias on simulated cloud radiative forcing using the National Center for Atmospheric Research Community Earth System Model, version 1.2.2, with the Community Atmosphere Model

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Richard W. Zurek

652 JOURNAL 'OF THE ATMOSPHERIC SCIENCES VOL. 43, NO. 7Atmospheric Tidal .Forcing of the Zonal-Mean Circulation: The Martian Dusty Atmosphere RICHARD W. ZUREKJet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109(Manusedpt received 19 July 1985, in final form 21 October 1985) Classical atmospheric tidal theory hag been used to compute the bilinear

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S. K. Satheesh and J. Srinivasan

1. Introduction Radiative forcing due to aerosols is one of the largest sources of uncertainties in estimating anthropogenic climate perturbations ( Charlson et al. 1992 ; Houghton et al. 1995 ). Aerosols are produced by various sources that are highly inhomogeneous in both time and space ( Shaw et al. 1973 ; Prospero et al. 1983 ; Bates et al. 1998 ; Russell et al. 1999 ; Quinn et al. 2000 ). Thus, estimating aerosol radiative forcing is much more complicated than estimating radiative

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Jeffrey D. Wilson and Mankin Mak

1 APRIL 1984 JEFFREY D. WILSON AND MANKIN MAK 1187Tropical Response to Lateral Forcing with a Latitudinally and Zonally Nonuniform Basic State JEFFREY D. WILSONI AND MANKIN MAKDepartment of Atmospheric Sciences, University of lllinois at Urbana-Champaign, Urbana, IL 61801(Manuscript received 22 June 1983, in final form 28 November 1983)ABSTRACT The tropical response to a lateral forcing is investigated with a quasi

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