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Jonathan L. Vigh and Wayne H. Schubert

.2) and (2.5) below, for an inviscid axisymmetric vortex the azimuthal wind tendency depends on the radial and vertical advection of angular momentum, whereas the temperature tendency depends on the diabatic heating, in addition to the radial and vertical advection terms. If the vortex is balanced (in the sense that it is continuously evolving from one gradient-balanced state to another), then the transverse circulation is determined by the solution of a second-order partial differential equation in

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Chanh Q. Kieu and Da-Lin Zhang

processes accounting for the vortex-merging scenarios and the roles of CGVs embedded in the ITCZ in the genesis of TS Eugene through the PV budget analysis. a. Dynamical framework In this study, we choose to examine the PV budgets in a quasi-Lagrangian framework following the storm. We start from the nonhydrostatic PV equation of Haynes and McIntyre (1987) : where u is the 3D wind field, H is the 3D diabatic-heating rate, and F is the 3D frictional force. It is clear that diabatic heating and

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

lower troposphere provides a favorable environment for vorticity aggregation leading to TC formation; hypothesis 2 (H2) that the cat’s eye is a region of quasi-closed Lagrangian circulation, where air is repeatedly moistened by convection and protected to some degree from dry air intrusion, which favors a predominantly convective type of heating profile; and hypothesis 3 (H3) that the parent wave is maintained and possibly enhanced by diabatically amplified mesoscale vortices within the cat’s eye

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

surface in the lower troposphere provides a favorable environment for vorticity aggregation for TC formation; in the second (H2) the cat’s eye is a region of quasi-closed Lagrangian circulation, where air is repeatedly moistened by convection and protected to some degree from dry air intrusion, which favors a predominantly convective type of heating profile; and in the third (H3) the parent wave is maintained and possibly enhanced by diabatically amplified mesoscale vortices within the cat’s eye. The

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Robert Rogers

importance has been extended to RI. The role of diabatic heating associated with convective bursts in RI is likely dependent on the magnitude, duration, horizontal and vertical distributions, and the orientation of the heating relative to the radius of maximum winds ( Schubert and Vigh 2008 ; Nolan et al. 2007 ). The morphology of the precipitation, for example, the distribution of convective precipitation and whether the precipitation is organized into a predominantly convective or stratiform mode

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Joël Arnault and Frank Roux

), the thermodynamic equation of Bannon (2002) becomes In (25) , the tendency of H m C is equal to the sum of flux divergence BH C and source terms: the pressure tendency G p C ; the total pressure work (CP C + CPV C ); the term associated with changes of water phase ; the heating rate due to other diabatic processes (e.g., radiative heating and turbulent dissipation) ; the opposite of the total heating rate of hydrometeors (this term appears because we consider the variation of moist

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Chanh Q. Kieu and Da-Lin Zhang

.g., Krishnamurthi et al. 1994 ; Zhang and Kieu 2006 ), the mass and moisture convergence in the PBL or the transverse circulation can be decomposed into separate contributions of the friction and diabatic heating in deep convection. The two different scenarios just indicate that the PBL friction plays a more important role than diabatic heating in converging the mass and high- θ e air from the ITCZ during the present TCG stage. The opposite is true during the hurricane stage in which the latent heating could

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

measurements (J. Knaff and C. Velden 2008, personal communication). Although HTs are not resolvable by the AMSU, it is expected that the collective effects of multiple HTs (i.e., a convective burst) will be discernable in the data because of the large amount of diabatic heating, subsidence, and attendant falling surface pressure that both theory and observations show following convective burst episodes ( Shapiro and Willoughby 1982 ; Montgomery and Enagonio 1998 ; Heymsfield et al. 2001 ; Kelley et al

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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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Jonathan Zawislak and Edward J. Zipser

correlated. An important relationship between diabatically generated subsynoptic-scale potential vorticity (PV) anomalies from rainfall (maximum during September and October) over the Guinea Highlands and tropical cyclogenesis has, however, been identified previously ( Berry and Thorncroft 2005 ; Hopsch et al. 2007 ). Furthermore, Thorncroft and Hodges (2001) , Hopsch et al. (2007) , and Kerns et al. (2008) note the relative unimportance of the low-level northern track vorticity maxima in tropical

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