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Alexander Ruzmaikin, Hartmut H. Aumann, and Evan M. Manning

( Waliser et al. 1993 ), the moisture of the upper troposphere and cloud-ice increase, driven by tropical deep convection. This effect greatly enhances the water vapor feedback ( Su et al. 2006 ), although no specific measure of its dependence on the surface temperature and humidity has been suggested. Clear-sky OLR data from the Earth Radiation Budget Experiment (ERBE) in 1985–88 were compared with outputs of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4

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Lyubov G. Chumakova, Rodolfo R. Rosales, and Esteban G. Tabak

nonetheless the dynamical backbone of the troposphere. Yet discrete modes are the signature of systems of finite extent: a semi-infinite stratified atmosphere yields a continuum spectrum of modes, much as the Fourier transform in the infinite line, as opposed to the discrete Fourier series associated with finite intervals. This has led to arguments by R. Lindzen that these discrete tropospheric modes are just a fallacy of overly simplified theoretical models, and that the atmosphere “is characterized by a

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David M. Romps and Zhiming Kuang

1. Introduction Despite decades of inquiry, the role of undiluted moist-adiabatic ascent in tropical oceanic deep convection remains a point of debate. Key aspects of the ongoing debate can be captured by four unanswered questions. The first is a simple question of existence: outside of tropical cyclones, do parcels of oceanic boundary layer air convect to the upper troposphere undiluted? The key word here is “undiluted,” as in not having entrained environmental air. Since this is a simple

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Judah Cohen, Mathew Barlow, Paul J. Kushner, and Kazuyuki Saito

1. Introduction In this report we examine the tropospheric precursors and horizontal structure of the multiple-week extratropical stratosphere–troposphere interaction events highlighted by Baldwin and Dunkerton (1999 , 2001 ) and numerous follow-on studies (e.g., Cohen et al. 2002 ; Baldwin et al. 2003 ; Polvani and Waugh 2004 ; Limpasuvan et al. 2004 , 2005 ; Reichler et al. 2005 ). These events consist of an annular-mode ( Thompson and Wallace 2000 ) signature that starts in the

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Marie Lothon, Frédérique Saïd, Fabienne Lohou, and Bernard Campistron

convergence zone (ITCZ) that follows the apparent latitudinal movement of the sun ( Hastenrath 1995 ). This convergence and the differential surface heating between ocean and continent trigger and maintain the low-level humid monsoon flux from the Guinea Gulf. In opposition to the low-level southwesterly flow, a northeasterly advection (Harmattan) of a dry and warm Saharan air layer (SAL) develops in the mean troposphere sloping up the monsoon layer. The conflict of these two air masses of different

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Robert X. Black, Brent A. McDaniel, and Walter A. Robinson

subject of considerable debate in the recent literature (e.g., Manzini et al. 2003 ). A robust bidirectional dynamical coupling between the stratosphere and troposphere has been observed in the boreal extratropics during winter ( Thompson and Wallace 1998 ; Baldwin et al. 2003 ; McDaniel and Black 2005 ) in association with intraseasonal variability in the northern annular mode (NAM). The NAM is the primary mode of circulation variability in the Northern Hemisphere extratropics and its lower

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Shu-Peng Ho, Ying-Hwa Kuo, and Sergey Sokolovskiy

1. Introduction Temperature and water vapor play a crucial role in weather and climate. Accurate global water vapor and temperature estimates, particularly in the middle and lower troposphere (LT), are extremely important for understanding the physics of convective cloud systems, precipitation, the hydrological cycle, and the energy balance of the earth ( Crook 1996 ; Lee et al. 1991 ; Mueller et al. 1993 ; Weckwerth et al. 1996 ; Webster and Stephens 1984 ). To more accurately assess

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Robert X. Black and Brent A. McDaniel

1. Introduction It is now well established that robust stratosphere–troposphere coupling occurs during boreal winter in connection with intraseasonal variations in the northern annular mode (NAM; see Thompson and Wallace 1998 ; Baldwin and Dunkerton 2001 ; McDaniel and Black 2005 ). This coupling is associated with a vertically coherent zonal wind anomaly pattern extending from the earth’s surface upward into the middle stratosphere. At stratospheric altitudes the NAM is manifested by

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Kevin M. Grise, David W. J. Thompson, and Piers M. Forster

1. Introduction Observations and numerical simulations both suggest that variability in the extratropical stratosphere has a demonstrable impact on the extratropical troposphere. The coupling between stratospheric and tropospheric flow is observed in the context of Northern Hemisphere (NH) sudden stratospheric warmings ( Baldwin and Dunkerton 1999 , 2001 ; Limpasuvan et al. 2004 ), Southern Hemisphere (SH) sudden stratospheric warmings ( Thompson et al. 2005 ), and recent trends in the SH

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Fabien Gibert, Pierre H. Flamant, Juan Cuesta, and Didier Bruneau

al. 2003 ). Nevertheless, the intrinsic limitations in space and time call for a significant improvement of the overall global observational capability. Global monitoring, ultimately from space, is foreseen as a means to quantify sources and sinks on a regional scale and to better understand the links between the various components of the carbon cycle. A vertical profile would be ideal, but a column-integrated amount or column-weighted amount is also valuable, provided that the lower troposphere

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