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R. A. Hansell, S. C. Tsay, Q. Ji, N. C. Hsu, M. J. Jeong, S. H. Wang, J. S. Reid, K. N. Liou, and S. C. Ou

important implications for their potential to modulate the heat and moisture surface budgets ( Solomon et al. 2007 ), surface–air exchange processes, and the general circulation of the atmosphere (e.g., Lau et al. 2006 ). It is necessary to understand these regional effects before a comprehensive understanding of its global-scale impact can be achieved. In this paper, the DRE LW of airborne mineral dust during the NASA African Monsoon Multidisciplinary Analysis (NAMMA) 2006 field campaign is

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Oreste Reale, William K. Lau, Kyu-Myong Kim, and Eugenia Brin

enhanced shear tend to suppress convection, and that SAL’s dust-induced warming can strengthen the temperature inversion at the SAL base. However, microphysical effects were not clearly known at the time of their study. The more recent study by Jenkins et al. (2008) is focused on microphysical effects and shows that the microphysical effects of SAL’s dust can enhance convection by acting on condensation nuclei. The two studies are not incompatible but they do serve to highlight the great complexity

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Gerald M. Heymsfield, Lin Tian, Andrew J. Heymsfield, Lihua Li, and Stephen Guimond

hurricanes. Previous observations have stimulated our interest in gathering further statistics about hurricanes versus mesoscale convective system (MCS) hot towers, especially at higher altitudes, where data are scarce to nonexistent. Section 2 will describe the cases sampled and the methodology both for estimation of vertical velocities and for deriving statistical information from the data. Section 3 presents characteristics of the updrafts to learn more about the regional variation of reflectivity

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Edward K. Vizy and Kerry H. Cook

reasons. Further examination of this issue utilizing a regional model that includes the effects of aerosols is needed. Finally, the focus here has been on evaluating the synoptic-scale environmental conditions associated with the passage of the two waves. The influence of smaller, mesoscale processes that may also influence cyclogensis (e.g., Holland 1995 ; Simpson et al. 1997 ; Reasor et al. 2005 ) are not explored since they are not resolved sufficiently at 30-km resolution. The next step is to

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Andrew J. Heymsfield, Aaron Bansemer, Gerald Heymsfield, and Alexandre O. Fierro

1. Introduction Cirrus clouds at a given time cover about 20% of tropical latitudes and contribute significantly to regional and global radiation budgets ( Rossow and Schiffer 1999 ). Optically thick tropical cirrus are produced primarily through deep convection and generate as much as 25% of the earth’s net cloud radiative forcing ( Hartmann et al. 1992 ). The primary impact of thin versus thick cirrus is on the shortwave energy budget, and the albedo of these ice clouds depends on their

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Chuntao Liu, Earle R. Williams, Edward J. Zipser, and Gary Burns

the Americas over Africa in the Carnegie curve, with the maximum near 1900 UTC when afternoon South American storms are most active. This finding serves to resolve one of the inconsistencies set forth in Fig. 1 (and discussed further in Williams 2009 ), an important motivation for this study. Two effects serve to flatten the UTC diurnal variation of electrified shower clouds ( Fig. 6 ) relative to the Carnegie curve: 1) the frequent predominance of the Maritime Continent (among the three

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Syed Ismail, Richard A. Ferrare, Edward V. Browell, Gao Chen, Bruce Anderson, Susan A. Kooi, Anthony Notari, Carolyn F. Butler, Sharon Burton, Marta Fenn, Jason P. Dunion, Gerry Heymsfield, T. N. Krishnamurti, and Mrinal K. Biswas

and decent and by signal saturation/attenuation effects. The SAL sits atop the MBL at about 1 km and appears prominently in the altitude range of 1–6 km in orange, green, and blue colors. Note that as the SAL emerges from the African coast it is undercut by a cool marine layer causing its base to gradually rise as it is advected further to the west. A good example of this feature can be seen in Fig. 1 of Twohy et al. (2009) . As was seen in Fig. 3a , low-level convection in the southern region

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Jonathan Zawislak and Edward J. Zipser

line just south of Dakar and the second is an MCS originating off the coast of Guinea. The intensity (based on minimum 85-GHz PCT) of the MCSs is within the strongest 1% of TRMM precipitation features (defined in Liu et al. 2008 ) within 5° of vorticity maxima tracks in the NAMMA focus region for June–September (JJAS) 1998–2007. An overpass 10 h later ( Fig. 10 , 6 h prior to classification) contains MCSs of slightly less intensity, but still in the top 1% of the regional climatology, and much

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Robert Cifelli, Timothy Lang, Steven A. Rutledge, Nick Guy, Edward J. Zipser, Jon Zawislak, and Robert Holzworth

circulation in close proximity to the oceanic site (Praia). This change in the wave structure provided an increasing influx of moisture over the Cape Verdes and preconditioned the environment for an extended period of precipitation activity (more than 36 h). Although the signatures of events 2 and 3 were discernable from satellite data, from the TOGA radar perspective the activity was continuous from the time event 2 arrived at the oceanic site. Similar to the coastal site, the combined effects of large

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