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Donal J. O'Sullivan and Matthew H. Hitchman

fromrotational to divergent modes. The interplay between inertial and gravitational instabilities and their role incausing irreversible mixing in the winter subtropics is explored. The effects of inertial instability on the seasonalevolution of PV is discussed from the point of view of "PV thinking."1. Introduction Extratropical planetary Rossby waves arc known topropagate energy upward and equatorward from theirtropospheric source region. Much of this wave activityreaches the equatorial middle atmosphere

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J. D. Opsteegh and H. M. Van Den Dool

seasonal mean circulation, caused by persistent SST anomalies, are investigated by testing the hypothesis that a persistentheating will have different effects in differentmonths or seasons. The response of the model iscomputed for each of the four seasons, using aheating distribution that is the same in each season.We have carried out two experiments, one with aheating in middle-latitudes and one with a heating inthe tropics. The differencesbetween the eight modelruns are carefully studied.2

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Todd D. Ringler and Kerry H. Cook

contains a description of the model developed for this study and the place of this model in the hierarchy of models that have been applied to this problem. In section 4 a critical height is defined and applied to characterize the influence of various parameters on the degree of linearity of the solution. In section 5 the spatial structure of a prototypical nonlinear response is compared to the linear response. The effects of surface wind and meridional temperature gradient on the amplitude of the

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C-P. Chang and Tim Li

monsoon rainfall, either by reducing the intensity and life cycle of the monsoon disturbances, or by producing a displacement of the seasonal-mean rainfall pattern. The combination of these two opposite effects will determine the net effect of ENSO on the monsoon at a given time. Therefore, depending on the phase of the biennial mode at that time, the otherwise regular biennial cycle may be disturbed. The present theory predicts a robust TBO mode from northern summer through northern winter because of

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Qingyuan Han, William B. Rossow, Jian Zeng, and Ronald Welch

: Global, seasonal cloud variations from satellite radiance measurements. Part I: Sensitivity of analysis. J. Climate , 2 , 419 – 458 . Rotstayn , L. D. , 1999 : Indirect forcing by anthropogenic aerosols: A global climate model calculation of the effective-radius and cloud-lifetime effects. J. Geophys. Res , 104 , 9369 – 9380 . Twohy , C. H. , P. A. Durkee , R. J. Huebert , and R. J. Charlson , 1995 : Effects of aerosol particles on the microphysics of coastal stratiform clouds

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Richard T. Wetherald and Syukuro Manabe

2044 JOURNAL OF THE ATMOSPHERIC SCIENCES VOLUME32The Effects of Changing the Solar Constant on the Climate of a General Circulation Model Rmmmv T. WETHERALD AND SYUKURO MANABEGeophysical Fl~dd Dyrmmics Laboratory/NOAA, Princeton University, Princeton, N.J. 08540(Manuscript received 5 May 1975, in revised form 2 July 1975)ABSTRACT A study is conducted to evaluate the response of a simplified

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Akira Kasahara and Warren M. Washington

incorporating into the NCAR global circulation model the dynamiceffect of mountains, the prediction of cloudiness for radiation calculations, and the calculation of groundsurface temperature using a heat balance equation. Other aspects of the physics of the model and thefinite-difference schemes are very similar to those discussed by the authors in 1967 and 1970. For the simulation of seasonal climate we specify two parameters: the sun's declination and the distribution of oceansurface temperatures. Since

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Mingfang Ting and Ngar-Cheung Lau

University, Princeton, New Jersey(Manuscript received 9 June 1992, in final form 21 December 1992) ABSTRACT The nature of simulated atmospheric variability on monthly time scales has been investigated by analyzingthe output from a 100-year integration of a spectral GCM with rhomboidal wavenumber 15 truncation. In thisexperiment, the seasonally varying, climatological sea surface temperature was prescribed throughout the worldoceans. The principal modes of variability in the model

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Tim Li, Bin Wang, C-P. Chang, and Yongsheng Zhang

, the cold SSTA and the anomalous anticyclone develop. A similar feedback mechanism has been discussed previously by Wang et al. (2000) with regard to air–sea interactions in the western North Pacific. Because of its dependence on the basic-state wind, the nature of this TAS feedback is season dependent (see discussions in Wang et al. 2003 ). The positive feedback is only efficient in boreal summer when the southeasterly flow is pronounced. With the seasonal change of the background flows from

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P. H. Haynes, M. E. McIntyre, T. G. Shepherd, C. J. Marks, and K. P. Shine

below). This "downward control" principle expresses a critical part of the dynamical chain of causeand effect governing the average rate at which photochemical products like ozone become available for foldinginto, or otherwise descending into, the extratropical troposphere. The dynamical facts expressed by the principleare also relevant, for instance, to understanding the seasonal-mean rate of upwelling of water vapor to thesummer mesopause, and the interhemispheric differences in stratospheric

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