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Sarah J. Arnup and Michael J. Reeder

change in moisture accompanied by a relatively small change in temperature and is another example of an airmass boundary ( Cohen and Kreitzberg 1997 ; Cohen and Schultz 2005 ). In the Australian region, a dryline forms inland from the northern coastlines from the diffuse moisture gradient across the tropical and continental air masses. Despite the prominence of the dryline in the climatology of northern Australia, there have been few investigations of its structure, daily evolution, or seasonal

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Scott D. Rudlosky and Henry E. Fuelberg

1. Introduction Cloud-to-ground (CG) lightning distributions are strongly influenced by seasonal and regional variations in atmospheric conditions. Thus, analysis of CG characteristics and their relation to specific changes in atmospheric conditions can help to better define the CG threat. Many studies have described CG variability on both the seasonal and regional scales; however, ambiguity still remains in the relationships between atmospheric conditions, storm-scale processes, and CG

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T. Jung, T. N. Palmer, M. J. Rodwell, and S. Serrar

Atlantic region is governed by internal atmospheric processes (e.g., Kushnir et al. 2002 ; Rowell 1998 ), especially on seasonal and interannual time scales. This suggests that predictability of such anomalies is limited to a few weeks. There is observational and modeling evidence, however, that the atmosphere in the North Atlantic region is also affected (i) locally by North Atlantic sea surface temperature (SST) anomalies (e.g., Czaja and Frankignoul 1999 ; Rodwell and Folland 2002 ; Rodwell et

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Scott D. Rudlosky and Katrina S. Virts

researchers and operational users. Section 2 defines the instrument, data, and analysis methods. Section 3 describes the overall annual distributions along with insights gained through examining observations in the region of overlapping coverage. Seasonal distributions illustrate both natural variability and evolving instrument performance. Diurnal variability highlights the usefulness of continuous GLM observations throughout the combined FOV. As the number and variety of operational GLM users

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G. W. Reuter and N. Aktary

JANUARY 1995 REUTER AND AKTARY 153Convective and Symmetric Instabilities and Their Effects on Precipitation: Seasonal Variations in Central Alberta during 1990 and 1991 G. W. REUTER AND N. AKTARYDivision of Meteorology, Department of Geography, University of Alberta, Edmonton, Alberta, Canada(Manuscript received 25 August 1993, in final form 6 May 1994)ABSTRACT Sounding

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Changhai Liu and Mitchell W. Moncrieff

et al. (2004b) reported that the precipitation amount from simulated multicell and supercell storms could vary by a factor of 3–4 due to changes in intercept parameters defining the hail/graupel distribution. The effects of cloud microphysics have also been investigated in real-data simulations using mesoscale numerical models. However, all previous studies have concentrated on cold-season orographic events. For instance, Reisner et al. (1998) evaluated three options of increasing complexity

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Jean-Philippe Duvel

) and that develop in the lee of Hoggar and Aïr Mountains are also certainly related in part to AEWs of the north path. A detailed description of the objective vortex tracking approach and of the datasets is given in section 2 . Different aspects of the origin, the merging, and the cyclogenesis of the vortices are analyzed in the following sections: initiation and track density in section 3 , seasonal and interannual variations in section 4 , and longitudinal variations in section 5 . Section 6

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Katrina S. Virts and Steven J. Goodman

total lightning available from ENGLN to analyze individual lightning clusters, with a focus on the seasonal and diurnal variations in the initiation of prolific, high-impact thunderstorms over Lake Victoria and the surrounding region. Lightning in these storms represents both a direct danger to the local population as well as an indicator of storm depth and updraft intensity ( Cecil 2005 ; Deierling and Petersen 2008 ) that relate to the other threats such as storm outflow gusts, wind-driven waves

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JEROME SPAR

UDC 551.509.333:551.528.6:551.513.1:551.465.83Supplementary Notes on Sea-Surface TemperatureAnomalies and Model-GeneratedMeteorological Histories'JEROME SPAR Z-Departrnent of Meteorology and Oceanography,New York University, Bronx, N.Y.ABSTRACT-In seasonal computations, the Mints-Arakawa two-level model is found to be sensitive to aminor alteration in the computational program. Effects ofthe program change on monthly mean sea level pressurefields are small in the first month but large in the

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Claire L. Vincent and Todd P. Lane

regions. For example, Qian (2008) attributed the nighttime maxima in precipitation over the seas around Java to the interaction of land breezes and topographic effects such as land-breeze convergence near concave coastlines. Similar conclusions were made for offshore convection near Darwin, Australia, by Wapler and Lane (2012) . Zhou and Wang (2006) used satellite observations and numerical modeling to study the offshore propagation of precipitation on a cross section through New Guinea, and

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