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Jason M. Keeler, Brian F. Jewett, Robert M. Rauber, Greg M. McFarquhar, Roy M. Rasmussen, Lulin Xue, Changhai Liu, and Gregory Thompson

an understanding of GC dynamics is important to understanding winter cyclone precipitation processes. In recent years, it has been suggested that the dynamics of GCs could be analogous to that of stratocumulus clouds ( Syrett et al. 1995 ; Kumjian et al. 2014 ; Rauber et al. 2014a , b ), where radiative forcing favors destabilization at cloud top and development of convection ( Wood 2012 ). Keeler et al. (2016 , hereafter Part I) directly addressed this hypothesis by performing idealized

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Hye-Yeong Chun and Jong-Jin Baik

VOL. 51, NO. 21 JOURNAL OF THE ATMOSPHERIC SCIENCES 1 NOVEMBER 1994Weakly Nonlinear Response of a Stably Stratified Atmosphere to Diabatic Forcing in a Uniform Flow HYE-YEONG CHUNAtmospheric and Environmental Research Institute and Department of Atmospheric Sciences, Seoul National University, Seoul, Korea JONG-JIN BAIKGlobal Environment Laboratory and Department of

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M. J. Alexander and T. J. Dunkerton

their global properties difficult to quantify in currently available meteorological data and difficult to resolve in most global models. Gravity waves carry momentum and energy vertically in the atmosphere leading to important forcing terms in the momentum and energy budget equations in global models. These forcing terms are accounted for via parameterizations of gravity wave effects that use the information on the larger-scale wind and stability fields. Lindzen (1981) developed a successful

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Adiv Paradise, Cesar B. Rocha, Pragallva Barpanda, and Noboru Nakamura

characteristics. Many indices have been proposed, and while most produce consistent climatologies, they often disagree in identifying individual events and in evaluating the effects of climate change on the statistics of blocking ( Barnes et al. 2012 , 2014 ). The difficulty stems partly from the lack of definitive theory for the onset of persistent jet anomalies. Proposed theories for block formation and maintenance include resonance between stationary Rossby waves and forcing ( Charney and DeVore 1979

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S. K. Satheesh and J. Srinivasan

. Hence, the claim by R08 is unsustainable and unfortunate. SS06 proposed a novel means to estimate aerosol radiative forcing (at locations where detailed aerosol characterization is not possible due to various constraints), based on spectral aerosol optical depth measurements. Even though SS06 used OPAC for sensitivity analysis, the proposed method is not dependent on OPAC, as SS06 state, “The assumed initial composition has no impact on the final result, but minimizes the number of iterations

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Peter M. Norris and Arlindo M. da Silva

source of uncertainty in GCM studies of future climate. Part of the historical problem has been that, in the face of these complexity and scale mismatch problems, simple empirical cloud parameterizations have been devised and then just tuned to give reasonable top-of-atmosphere radiative forcing in a globally or zonally averaged sense. Sufficient attention has not generally been given to the validation of the predicted cloud properties. In the NWP community even less attention has historically been

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Alain Lahellec and Jean-Louis Dufresne

the literature (e.g., Dessler 2010 ; Lindzen and Choi 2009 , and comment articles). The methodological difficulty in separating climate forcing and rapid adjustment from feedback is also addressed in Stocker et al. (2014) . 1 It is mathematically difficult to justify a linear behavior from high-dimensional, nonlinear systems, because this calls for integro-differential functional techniques. In the first of these two papers ( Lahellec and Dufresne 2013 , hereafter Part I ), we approached the

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L. L. Hood and B. E. Soukharev

warmings of the polar winter stratosphere, tropical ozone and temperature variations correlate inversely with those at high latitudes ( Fritz and Soules 1972 ; Chandra 1986 ). Consistently, the rate of planetary wave absorption at northern middle to high latitudes, has been shown to correlate inversely with temporal tendencies in tropical column ozone ( Randel 1993 ). A recent analysis by Randel et al. (2002a) has further quantified the influence of extratropical wave forcing on tropical upwelling

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Alvaro de la Cámara, François Lott, Valérian Jewtoukoff, Riwal Plougonven, and Albert Hertzog

(GW) forcing in the southern stratosphere, particularly around 60°S ( McLandress et al. 2012 ), but the orographic or nonorographic origin of the missing GW drag is still controversial. In present-day climate models, this is unavoidably related to how GW parameterizations are constructed. On the one hand, parameterized orographic gravity waves (OGWs) usually break in the troposphere and stratosphere (e.g., Palmer et al. 1986 ; Lott et al. 2005 ). This is in contrast to nonorographic gravity

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Riwal Plougonven and Fuqing Zhang

forcing due to nonlinear terms linked to the vortical (balanced) motions on the right-hand side. It was shown that this could provide an efficient way to predict large-scale waves emitted in the far field ( Ford 1994a , b ; Plougonven and Zeitlin 2002 ). In a context more comparable with the atmosphere, a similar approach was applied to the problem of IGWs excited by 2D frontogenesis by Reeder and Griffiths (1996) . One notable difference with the work of Ford (1994a) was that the wave equation

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