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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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Guoxing Chen, Wei-Chyung Wang, and Jen-Ping Chen

consistent with the biases found in the smaller simulated shortwave cloud radiative forcing in these regions ( Calisto et al. 2014 ; Flato et al. 2014 ). It is also known that these regions have been affected by aerosols emitted from the continents. For instance, the southeast Pacific (SEP), where the largest and most persistent stratocumulus deck in the world resides, is exposed to anthropogenic aerosols produced by copper smelters in South America ( Huneeus et al. 2006 ). The increased aerosols not

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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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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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Long Li and Terrence R. Nathan

1. Introduction The major goal of this study is to examine the role of time-varying tropical forcing on the generation and maintenance of atmospheric low-frequency variability (LFV) during the Northern Hemisphere (NH) winter. Emphasis is placed on timescales that exceed deterministic predictability but which are less than seasonal; we will focus on intraseasonal timescales within the 10–60 day range. Phenomena associated with LFV on the intraseasonal timescale have been well documented for both

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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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Jason K. S. Ching and J. A. Businger

time and height. The special case for which the direction of the pressure gradient force is aperiodic function of time is studied in detail. The nondimensional number F = z (4Kt)-I is seen to be the properscale which describes the flow response to the boundary layer.1. Introduction As a first step towards improving our understandingof the time dependent planetary boundary layer (PBL),a simple model assuming horizontal uniformity and aconstant eddy viscosity has been investigated. Thesteady

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