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Zhuo Wang, M. T. Montgomery, and T. J. Dunkerton

cumulus convection in the two outer grids; in the two inner grids (9-km and 3-km resolution), cumulus convection was calculated explicitly at the grid scale. Other physics parameterizations used include WRF single-moment, six-class microphysics ( Hong and Lim 2006 ) and the Yonsei University (YSU) planetary boundary layer scheme ( Noh et al. 2003 ), Rapid Radiative Transfer Model (RRTM) longwave radiation scheme ( Mlawer et al. 1997 ), and the Dudhia (1989) shortwave radiation scheme. Sensitivity

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Edward K. Vizy and Kerry H. Cook

the underlying ocean temperature. Studies (e.g., Palmen 1948 ; Gray 1968 , 1988 ) suggest that average SSTs in the ocean mixed layer of at least 26°C are required for development of deep convection associated with tropical cyclones to occur. Another condition needed for tropical development is a synoptic low-level cyclonic vorticity maximum stronger than the background planetary vorticity (e.g., Gray 1968 , 1988 ). Off the West African coast such a cyclonic relative vorticity maximum can be

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Zhaoxia Pu, Xuanli Li, and Juanzhen Sun

Jindo, South Korea, were assimilated for the prediction of the landfalling Typhoon Rusa (2002). A noticeable improvement in the short-range prediction of the precipitation was produced by the radar data assimilation. Zhao and Jin (2008) assimilated observations from five Weather Surveillance Radar-1988 Doppler (WSR-88D) radars for Hurricane Isabel (2003). With the Navy’s Coupled Ocean–Atmosphere Mesoscale Prediction System (COAMPS), they assimilated radar reflectivity and radial velocity data

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

variation in thunder area for the world ( Whipple 1929 ). The Carnegie curve represents the integration of thousands of measurements of the earth’s fair weather electric field in universal time over the world’s oceans where the planetary boundary layer is relatively free of pollution. The approximate representativeness of the Carnegie curve for individual days is substantiated by measurements of the ionospheric potential ( Markson et al. 1999 ; Markson 2007 ), a quantity generally regarded as the most

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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

that deficiencies in the modeling of moisture and diabatic processes are due in part to the lack of knowledge of the tropical humidity fields. Model forecasts are very sensitive to the surface layer moisture. Krishnamurti and Oosterhof (1989) showed that models that incorporated an explicitly resolved surface layer were able to more accurately compute the strong moisture flux between the ocean and atmosphere, resulting in more accurate prediction of the formation of hurricanes. Results from the

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Wallace Hogsett and Da-Lin Zhang

KE, w 2 /2, is excluded because it is one to two orders of magnitude smaller than the horizontal component. We start from a prognostic equation for LE, which is essentially the available water vapor contained in the atmosphere, to account for the most crucial component for TC development and maintenance. It is obtained by multiplying the water vapor budget equation from Zhang et al. (2002) by the latent heat of vaporization, L υ : where the three rhs terms represent sources and sinks of LE

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Wei Zhong, Da-Lin Zhang, and Han-Cheng Lu

the potential vorticity (PV) field might become more circular, with its highest values at the TC center, and then the radial PV gradient would provide a basic state on which VRWs can propagate. By invoking an analogy between radial gradients of the basic-state absolute vorticity in TCs and meridional gradients of the planetary vorticity in large-scale weather systems, Montgomery and Kallenbach (1997 , hereafter MK97) advanced the VRW theory by obtaining the following local dispersion relation

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

Kakar at NASA Headquarters with funds from the NASA TCSP program. M. T. Montgomery was supported through Multi-Interagency Procurement Request NNG07HU17I. K. Mallen was supported through a fellowship from the Center for Earth–Atmosphere Studies, a cooperative agreement between NASA and CSU. The simulations were conducted on NASA Center for Computational Sciences facilities. REFERENCES Bister , M. , and K. A. Emanuel , 1997 : The genesis of Hurricane Guillermo: TEXMEX analyses and a modeling

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Robert Rogers

: Sensitivity of high-resolution simulations of Hurricane Bob (1991) to planetary boundary layer parameterizations. Mon. Wea. Rev. , 128 , 3941 – 3961 . Braun , S. A. , M. T. Montgomery , and Z. Pu , 2006 : High-resolution simulation of Hurricane Bonnie (1998). Part I: The organization of eyewall vertical motion. J. Atmos. Sci. , 63 , 19 – 42 . Cangialosi , J. , and S. S. Chen , 2004 : A numerical study of the topographic effects on structure and rainfall in Hurricane Georges (1998

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

strongest 10% of updrafts and downdrafts in hurricanes had averages of 4.2 and 2.6 m s −1 , respectively, and peak updrafts of ∼8 m s −1 . Anderson et al. (2005) examined updrafts in tropical convective storms using measurements from the higher-altitude Citation jet aircraft. They examined similarities between tropical oceanic and land cases from TRMM Large-Scale Biosphere–Atmosphere Experiment in Amazonia (LBA) and the Kwajalein Experiment (KWAJEX). Unlike earlier studies that used flight level data

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