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Jainn J. Shi, Simon W. Chang, Teddy R. Holt, Timothy F. Hogan, and Douglas L. Westphal

hazardous natural and anthropogenic contaminants, such as fine sand particulates, soot from the oil well fires, smoke from explosives, unique bacteria specific to the region, and possible weaponized chemical agents. Ongoing investigative studies require accurate atmospheric transport and dispersion (T&D) modeling in order to assess the relative impacts of all of these contaminants. This in turn requires an analysis of the complicated, time-dependent mesoscale structure of the atmosphere at frequent

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B. G. Hunt

lower stratosphere, and also climate sensitivity experiments, for which consideration of thewater vapor concentration is, in many cases, vital. This paper is concerned with the effects of increasingvertical resolution in a hemispheric model. The effectof increasing the horizontal resolution in a 9 levelhemispheric model has been investigated by Manabe333334 MONTHLY WEATHER REVIEW VOLUME104TABLE 1. Q

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Stephen D. Nicholls and Karen I. Mohr

. Because aerosol optical depth and the occurrence of intense convective systems were closely tied to regional dynamics, it was not possible at the scale and level of this study to separate the effects of high dust loads from a generally unfavorable low-level environment. The AEW-associated percentages in Fig. 6 are consistent with the seasonal cycle but should be considered conservative, particularly in the Sahel ( Fink and Reiner 2003 ), because of the difficulty of associating snapshots of

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Daran L. Rife, Thomas T. Warner, Fei Chen, and Elford G. Astling

1. Introduction There is plentiful evidence that regional landscape variability and the adequacy with which its effects are represented in atmospheric models have a potentially strong impact on simulated mesoscale weather and climate. Many sources of such local landscape forcing, such as associated with terrain and coastlines, are fairly well understood and have been thoroughly studied. Specifically, numerous modeling and empirical studies document mesoscale impacts of surface variability

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Evelyn D. Grell, Jian-Wen Bao, David E. Kingsmill, and Sara A. Michelson

. 10.1002/qj.416 Lim , K.-S. S. , and S.-Y. Hong , 2010 : Development of an effective double-moment cloud microphysics scheme with prognostic cloud condensation nuclei (CCN) for weather and climate models . Mon. Wea. Rev. , 138 , 1587 – 1612 , . 10.1175/2009MWR2968.1 Lohmann , U. , 2008 : Global anthropogenic aerosol effects on convective clouds in ECHAM5-HAM . Atmos. Chem. Phys. , 8 , 2115 – 2131 , . 10

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Retha Matthee Mecikalski, Anthony L. Bain, and Lawrence D. Carey

and transport of natural and anthropogenic atmospheric constituents throughout the depth of the troposphere. Cloud electrification is also known to play a pivotal role in the production of nitrogen oxides (NO x ). The electrical characteristics of DMC during DC3 were documented via very high-frequency (VHF) lightning mapping arrays (LMA) and low-frequency (LF) to very low-frequency (VLF) sensors. The motivation behind the careful documentation of lightning during DC3 was twofold: 1) it is

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Massimiliano Burlando, Djordje Romanić, Giovanni Solari, Horia Hangan, and Shi Zhang

, is a unique facility designed to physically simulate downbursts ( Hangan 2014 ). It also offers the unique opportunity to clarify the crucial role of scale effects ( Xu et al. 2008 ; McConville et al. 2009 ) through comparison with results obtained in other laboratories. Computational fluid dynamics (CFD) simulations have been applied through full-cloud, subcloud, and impinging wall jet models. The full-cloud model ( Orf et al. 2012 ) offers a comprehensive representation of the whole phenomenon

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Barry H. Lynn, David R. Stauffer, Peter J. Wetzel, Wei-Kuo Tao, Pinhas Alpert, Nataly Perlin, R. David Baker, Ricardo Muñoz, Aaron Boone, and Yiqin Jia

very much more cloud than the HIR runs (see below), it seems most likely that the MM5 cloud transmittance functions caused too little solar radiation to reach the surface. This problem has been reported by other researchers as well; and the cloud shortwave radiation scheme in the most recent version of MM5 (version 3) has been modified to reduce the cloud effects on shortwave radiation, particularly from cirrus clouds, and to a lesser extent from rainwater (J. Dudhia 2000, personal communication

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Thomas Milewski and Michel S. Bourqui

the atmosphere . Tellus , 61A , 97 – 111 . Bourqui , M. S. , C. P. Taylor , and K. P. Shine , 2005 : A new fast stratospheric ozone chemistry scheme in an intermediate general-circulation model. II: Applications to effects of future increases in greenhouse gases . Quart. J. Roy. Meteor. Soc. , 131 , 2243 – 2261 . Brasseur , G. P. , X. Tie , P. J. Rasch , and F. Lefèvre , 1997 : A three-dimensional simulation of the Antarctic ozone hole: Impact of anthropogenic chlorine

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Yi Huang, Steven T. Siems, Michael J. Manton, and Gregory Thompson

), were implemented to test the model sensitivity to different physical treatments. An overview of the MP and PBL schemes tested in this study is given in Table 1 . As the atmosphere over the SO is essentially free of terrestrial and anthropogenic aerosol emissions (e.g., Yum and Hudson 2005 ; Gras 1995 ), simulations with lower cloud condensation nuclei (CCN) concentration were also examined. Table 1. A list of microphysical (MP) schemes and planetary boundary layer (PBL) schemes used for the

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