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Joseph Egger and Klaus-Peter Hoinka

investigation of Fig. 1 has to start from the PV equation with three-dimensional velocity v = ( u , υ , w ), where the overbar denotes the time mean state and the prime deviations from the mean. It is assumed in (1.2) that the flow is incompressible and that dissipative effects can be represented by a simple damping term. Forcing by heating is excluded. The deviations contain all available time scales. Multiplication of (1.2) by yields, after simple manipulations and after taking expectations

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Jeffrey M. Chagnon

of momentum flux [see review by Fritts and Alexander (2003) and references therein]. A problem that is complimentary to the wave–mean flow interaction problem is the wave–forcing interaction problem. The latter has received relatively less scrutiny in the literature (exceptions noted below) but may be of significance to mesoscale dynamics in the troposphere. The wave–forcing interaction problem is of particular relevance to convectively generated waves that, unlike topographically forced waves

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K. M. Markowicz, P. J. Flatau, J. Remiszewska, M. Witek, E. A. Reid, J. S. Reid, A. Bucholtz, and B. Holben

and middle-troposphere subsidence are responsible for the mostly clear-sky conditions; thus, it was a good site to study the direct aerosol radiative forcing. The purpose of this study is to extend previous knowledge about the aerosol optical properties in the Middle East region. We investigate the influence of aerosol on the surface radiation budget. The results are based on the data collected during 6 weeks of measurements performed at the MAARCO site, including surface and columnar observations

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Meelis J. Zidikheri and Jorgen S. Frederiksen

1. Introduction The attribution of climate change to a particular forcing agent (e.g., greenhouse gases, aerosols, volcanic activity, land use) is a problem of great significance in climate science. The most established systematic methodology of climate change detection and attribution is the “fingerprint” method ( Hasselmann 1993 ; Hegerl et al. 1996 ; Hasselmann 1997 ), which is a statistical method of relating the observed climate response to model responses. In this approach, one needs

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Adam R. Edson and Peter R. Bannon

1. Introduction Rossby’s (1938) introduction of the adjustment problem used a momentum forcing to represent a sudden deposition of horizontal momentum into an infinite strip of the ocean by a surface wind stress. The Coriolis force associated with this flow would initially not be in balance with the pressure field and an adjustment would ensue. The original reduced-gravity shallow-water problem has been thoroughly examined [ Cahn (1945) ; Mihaljan (1963) ; see Blumen (1972) for a review

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Edwin K. Schneider and Meizhu Fan

1. Introduction A mechanism for explaining low-frequency SST variability is that the ocean is forced stochastically by fluxes representing weather noise ( Hasselmann 1976 ). Weather noise is the part of the atmospheric variability that is not the response to the boundary or external forcing. In Hasselmann’s one-point slab ocean linear model, which is closely related to the theory of Brownian motion ( Einstein 1905 ), the weather noise forcing is taken to be random noise independent of the

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Michael J. Ring and R. Alan Plumb

Polvani 2004 ; Song and Robinson 2004 ; Thompson et al. 2005 , 2006 ). Thus, the patterns appear both as unforced natural variability and as a forced response to perturbations of the climate system. In a previous study ( Ring and Plumb 2007 , hereafter RP07 ), using a simple atmospheric general circulation model, we investigated the extent to which the annular modes constitute such a preferred response of the climate system to forcing by prescribed torques [modeled on those used by Song and

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R. K. Scott, L. M. Polvani, and D. W. Waugh

1. Introduction In a companion paper ( Scott and Polvani 2006 , hereafter Part I ) it was demonstrated that a realistic stratosphere (considered in isolation) possesses its own natural or internal variability, in the sense that, in the absence of any time dependence in the external forcing, the stratospheric flow evolves into a time-dependent regime consisting of quasi-periodic vacillations resembling stratospheric sudden warmings. By external forcing, we refer to forcing by processes external

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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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L. J. Gray, S. T. Rumbold, and K. P. Shine

discrepancy between the 11-yr SC estimates from the SSU/MSU and the National Centers for Environmental Prediction (NCEP)–National Center for Atmospheric Research (NCAR) and 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) reanalyses. An additional output from the above calculations is the radiative forcing at the tropopause, which includes the so-called instantaneous radiative forcing due to the changes in irradiance and ozone, and also the effect of the FDH

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