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Stephen R. Guimond, Gerald M. Heymsfield, and F. Joseph Turk

1. Introduction a. Instruments for tropical cyclone observation Advancements in the field of atmospheric science (and science in general) often arise because of new and innovative observations of the entity being studied. Such is the case with the problem of tropical cyclone (TC) intensification. In recent years, the plethora of instruments (e.g., dropsondes, aircraft Doppler radars, microwave satellite imagers and sounders) has led to an increase in the frequency and quality of TC inner core

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Jonathan Zawislak and Edward J. Zipser

regarding the difference between developing and nondeveloping easterly waves; the composition, distribution, and microphysics of the Saharan air layer (SAL); and the role of the SAL in cyclogenesis. The NAMMA dataset provides a valuable high temporal and spatial resolution dataset in the east Atlantic. Data include dropsonde observations from the NASA DC-8 medium-altitude research aircraft, rawinsondes, and ground observations at Praia, Cape Verde, and Dakar, Senegal, as well as data from the Tropical

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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

during NAMMA showed the occurrence of rapid enhancements and subsequent decreases in aerosol content of the SAL every few days. Episodic SAL events with distinctive boundaries and sudden intensity enhancements as seen in satellite imagery (and confirmed by lidar backscatter observations) are termed “SAL events” in this paper. The SAL is a synoptic-scale feature containing warm, dust-laden air transported from the Sahel and Saharan regions of northern Africa ( Carlson and Prospero 1972 ). The layers

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

1. Introduction Measurements of updraft characteristics are important for understanding fundamental kinematic and microphysical processes in deep convection. These measurements are often difficult to obtain from in situ observations because of the transient nature of updrafts and the safety concerns arising from aircraft penetrating convective cores. Consequently, there have been relatively few comparisons between numerically simulated and measured vertical motions through the full depth of

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

; Thorncroft et al. 2008 ). Observations of these processes are central to the objectives of NAMMA ( Zipser et al. 2009 ). All three radar sites are located between 13° and 15°N latitude (see Fig. 1 ), which for the continental and coastal sites lies in the Sahel region where AEWs have a pronounced impact on squall-line MCS generation ( Fink and Reiner 2003 ). A recent study by Rickenbach et al. (2009) noted that more than half of the squall line MCSs observed by the radar in Niamey, Niger, during AMMA

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Scott A. Braun, Michael T. Montgomery, Kevin J. Mallen, and Paul D. Reasor

observations. In this study, results are shown for two simulations. The primary simulation (designated the Control run) is started at 0600 UTC 22 July 2005 and run for 66 h until 0000 UTC 25 July. This simulation verifies well against observations but produces a weaker surface pressure minimum at landfall than is observed. A second simulation (designated the Sim2 run) is started at 1200 UTC 21 July and is discussed in section 5 . This simulation produces a stronger vortex and more active convection at

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Zhaoxia Pu, Xuanli Li, and Juanzhen Sun

tropical cyclogenesis and intensity change. During TCSP, many remotely sensed datasets were collected, including regular satellite and aircraft observations. With multiple types of observational data, TCSP offered an opportunity to study not only tropical cyclone development in detail but also the impact of remotely sensed and in situ data on mesoscale forecasts of tropical cyclones. A previous study by Pu et al. (2008) proved that aircraft dropsonde and satellite wind data have improved the large

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Jonathan L. Vigh and Wayne H. Schubert

-like vortex in section 5 . The results of calculations from these solutions are shown in section 6 to illustrate how the temperature tendency depends on the eyewall geometry and the radial distribution of inertial stability. In section 7 we discuss observations of the radial distribution of heating and inertial stability in real storms; the implications of the impact of subsequent structure change on intensification rate are also considered. Some concluding remarks are presented in section 8 . 2

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Robert Rogers

(sometimes referred to as convective bursts) within the inner core (e.g., Reasor et al. 2009 ; Squires and Businger 2008 ; Hennon 2006 ; Kelley et al. 2004 ; Rodgers et al. 1998 ; Gentry et al. 1970 ). Convective bursts are recognized in many ways, with cloud tops getting colder and expanding in infrared (IR) measurements, very low brightness temperatures due to ice scattering in the passive microwave channels, an increase of lightning flash rates, and towers of high radar reflectivity ( Cecil et

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Chanh Q. Kieu and Da-Lin Zhang

, following a period of little convective activity, and then they merged into the monsoon low with one becoming the eye and the other forming a spiral rainband of the storm. In both cases, the large-scale cyclonic flows appear to set up favorable environments, but it is the mesoscale processes that determine the timing and location of TCG. Reasor et al. (2005) documented the existence of even smaller-scale (meso γ ) vortices from radar observations during the early development of Hurricane Dolly (1996

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