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Rongcai Ren, Xin Xia, and Jian Rao

using simple models to perform idealized numerical experiments, early investigators identified the important dynamical roles of topographic forcing in modulating the stratosphere. For example, early simulations by Manabe and Terpstra (1974) indicated that topographic forcing serves to amplify the amplitudes of the stratospheric planetary waves of very low wavenumber, by transporting energy from the troposphere to the stratosphere. Later studies further demonstrated the varying dynamical roles of

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Shinya Shimokawa and Tomonori Matsuura

that stable antisymmetric inertial subgyres appeared for some wind stress strengths and can be explained by an analytical modon solution. Thus far, most studies of double gyres using middle-range complexity have been conducted under constant (time independent) wind forcing. In the real atmosphere and oceans, seasonal wind forcing with westerly and trade winds generates subtropical and subpolar gyres arising from western boundary currents and internal currents. Recently, Sakamoto (2006) showed

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Karen L. Smith, Christopher G. Fletcher, and Paul J. Kushner

character and because they are modulated by multiple influences, including interactions with the ocean surface, the land surface, and the stratosphere ( DeWeaver and Nigam 2004 ; Limpasuvan and Hartmann 2000 ; Czaja and Frankignoul 2002 ; Gong et al. 2002 ; Baldwin et al. 2003 ). In simulations, the response of the modes to a prescribed forcing is model dependent because many details, including the characteristics of the modes, the temporal and spatial structure of the forcing, the background flow

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Clara Deser and Adam S. Phillips

; Trenberth and Hurrell 1994 ; Deser et al. 2004 ). The latter may also play a contributing role to circulation trends over the North Atlantic ( Hoerling et al. 2004 ; Hurrell et al. 2004 ), although intrinsic variability due to nonlinear atmospheric dynamics is also important ( Schneider et al. 2003 ; Hurrell et al. 2004 ; Bracco et al. 2004 ). Thus, there is evidence that both SST changes and atmospheric radiative forcing due to changes in greenhouse gas and ozone concentrations have contributed to

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Zhili Wang, Junyu Mu, Meilin Yang, and Xiaochao Yu

forcing has been identified as a primary driver of long-term changes in the East Asian summer monsoon (EASM) since the 1950s ( Song et al. 2014 ; Liu et al. 2019 ). Several studies showed different impacts of aerosol forcing on the monsoon system through a regional climate model approach (e.g., Ji et al. 2011 ; Zhuang et al. 2018 ) compared to the results from a global climate model because of the high resolution and lack of nonlocal aerosol effects. Aerosols emitted from local sources generally

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Shayne McGregor, Neil J. Holbrook, and Scott B. Power

. (2003a , b ) went one step further and combined off-equatorial wind stress forcing with ENSO theory to produce a unified theory for decadal variability and ENSO modes. However, the manner in which the changes in Pacific Ocean background state induced by extratropical Rossby waves actually interact with and affect ENSO variability in a more complex setting has not been studied extensively to date. In this study we use a stochastically forced (SF), intermediate-complexity, coupled ENSO model to

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V. Ramaswamy, W. Collins, J. Haywood, J. Lean, N. Mahowald, G. Myhre, V. Naik, K. P. Shine, B. Soden, G. Stenchikov, and T. Storelvmo

describing the agents driving Earth’s climate change since preindustrial times (1750) and the formulation of the “radiative forcing” (RF) (see section 2 ) of climate change. The central purpose of this paper is to trace the progression in the RF concept leading to our current knowledge and estimates of the major agents known to perturb climate. Below, we give a perspective into the key milestones marking advances in the knowledge of RF. Subsequent sections of the paper focus on the evolution of the

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Isaac M. Held, Michael Winton, Ken Takahashi, Thomas Delworth, Fanrong Zeng, and Geoffrey K. Vallis

1. Introduction It is informative to take a simulation of the future climate and, at several times along this trajectory, abruptly return to preindustrial forcing. Matthews and Caldeira (2007) describe calculations of this type using a climate model of intermediate complexity, motivated by geoengineering proposals. Similar calculations with comprehensive climate models have the potential to increase our understanding of the variety of time scales involved in the climate response. In this work

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Yuki Hayashi and Kaoru Sato

2009 ; Kohma and Sato 2013 ; Hirano et al. 2016 ). Lagrangian-mean middle-atmospheric circulation is mainly driven by the remote redistribution of momentum by atmospheric waves. Most previous studies have examined the middle atmosphere in terms of zonal-mean features. An approximate form of Lagrangian-mean circulation was derived as the residual circulation of transformed Eulerian-mean (TEM) equations by Andrews and McIntyre (1976) . Wave forcing is described as the Eliassen–Palm (EP) flux

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David B. Mechem, Yefim L. Kogan, Mikhail Ovtchinnikov, Anthony B. Davis, K. Franklin Evans, and Robert G. Ellingson

arising from MD effects may also influence convective dynamics. Instead of these predominantly indirect influences of MD radiative transfer (MDRT) on cloud dynamics, we are concerned with identifying direct impacts of MD effects on the cloud dynamics themselves. As such, we choose to focus on cloud types for which radiative forcing contributes significantly to the system energetics. For boundary layer stratocumulus, cloud top longwave radiational cooling is most frequently the primary engine driving

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