the roles of vortex rossby waves in hurricane secondary eyewall formation abstract a high resolution full physics model initiated with an idealized tropical cyclone like vortex is used to simulate and investigate the secondary eyewall formation the beta skirt axisymmetrization bsa hypothesis previously proposed is examined and the roles of axisymmetrizing vortex rossby waves vrws in the secondary eyewall formation are further investigated during the formation period convection outside the inner core region is organized into an outer spiral rainband the pv dipoles that are persistently generated by convective updrafts through tilting effect move along the rainband and inward toward inner core region and are finally axisymmetrized in the preexisting beta skirt region the formation of the secondary eyewall is preceded by a rapid intensification period during which vortical hot towers discrete vrws and sheared vrws dominate the inner core asymmetric structures sheared vrws are repeatedly emanated from the outer edge of the eyewall and become more concentric when propa

concentric eyewall formation in typhoon sinlaku 2008 part iii horizontal momentum budget analyses abstract this is a follow up work to two prior studies examining secondary eyewall formation sef in typhoon sinlaku 2008 this study shows that in the sef region the majority of the elevated

the kinematic structure of hurricane gloria 1985 determined from nested analyses of dropwindsonde and doppler radar data abstract a set of three dimensional filtered multiply nested objective analyses has been completed for the wind field of hurricane gloria for 0000 utc 25 september 1985 at this time gloria was one of the most intense hurricanes ever observed in the atlantic basin with a minimum sea level pressure of 919 mb the nested analyses based on observations from airborne doppler radar and omega dropwindsondes simultaneously describe eyewall and synoptic scale features and are the most comprehensive analyses of a single hurricane constructed to date the analyses have been used to document the multiscale kinematic structure of gloria and to investigate the relationship between the kinematic fields and the motion of the vortex the analyses indicate that the vortex was unusually barotropic the radius of maximum wind rmw was nearly vertical below 500 mb with a slight inward slope with height between 750 and 550 mb the strongest azimuthal mean tangential winds were found well above the boundary layer near

rapid filamentation zones in intense tropical cyclones intense tropical cyclones often possess relatively little convection around their cores in radar composites this surrounding region is usually echo free or contains light stratiform precipitation while subsidence is typically quite pronounced in this region it is not the only mechanism suppressing convection another possible mechanism leading to weak echo moats is presented in this paper the basic idea is that the strain dominated flow surrounding an intense vortex core creates an unfavorable environment for sustained deep moist convection strain dominated regions of a tropical cyclone can be distinguished from rotationdominated regions by the sign of s 2 s 2 2 where s1 ux y and s2 x uy are the rates of strain and x uy is the relative vorticity within the radius of maximum tangential wind the flow tends to be rotation dominated 2 s 2 s 2 so that coherent structures such as mesovortices can survive for long periods of time outside the radius of maximum tangential wind the flow tends to be strain dominated s 2 s 2 2 resulting in filaments of anomalous vorticity in the regions of strain dominated flow the filamentation time is defined as fil 2 s 2 s 2 2 1 2 in a tropical cyclone an approximately 30 kmwide annular region can exist just outside the radius of maximum tangential wind where fil is less than 30 min and even as small as 5 min this region is defined as the rapid filamentation zone since the time scale for deep moist convective overturning is approximately 30 min deep convection can be significantly distorted and even suppressed in the rapid filamentation zone a nondivergent barotropic model illustrates the effects of rapid filamentation zones in category 1 5 hurricanes and demonstrates the evolution of such zones during binary vortex interaction and mesovortex formation from a thin annular ring of enhanced vorticity

observations of the distribution of ice in hurricanes abstract observations of the type and distribution 0 c isotherm in three atlantic hurricanes are presented supercooled drops graupel columns and aggregated snowflakes were observed the supercooled drops were found only in convective updrafts stronger than 5 m s 1 but not all updrafts 5 m s 1 contained appreciable liquid graupel was found in all updrafts at temperatures 2 c and small columns were sometimes found in downdrafts nonconvective rainbands contained 15 30 l 1 of snow composed of columns and what appeared to be large aggregates other stratiform regions contained 1 15 l 1 of medium and large aggregates columns were occasionally found there also but only within about 15 km of convection hurricane convection is almost completely glaciated at the 5 c level it is suggested that the ice particles observed at 6 0 km inside the convection result primarily from downward mixing on both sides of the eyewall updraft of ice formed in the convective areas at higher colder levels the ice in t

the concentric eyewall cycle of hurricane gilbert abstract hurricane gilbert of 1988 formed an outer eyewall as it intensified rapidly toward a record minimum pressure of 888 hpa in the western caribbean the outer eyewall strengthened and contracted while the inner eyewall showed some signs of weakening before landfall on the yucatan peninsula remarkably both eyewalls survived passage over land but the storm was much weaker when it entered the gulf of mexico although the primary cause of weakening was passage over land the effect of the contracting outer eyewall may have contributed later the outer eyewall completely replaced the inner eyewall subsequently it contracted steadily but slowly as gilbert maintained nearly constant intensity over the cooler waters of the gulf before final landfall on the mainland of mexico

eastern pacific hurricanes jimena of 1991 and olivia of 1994 the effect of vertical shear on structure and intensity abstract shear is a key inhibitor of tropical cyclone intensification although its signature is readily recognized in satellite imagery and theoretical or modeling studies provide some insight detailed observations have been limited airborne radar and in situ observations in hurricanes jimena of 1991 and olivia of 1994 are a step toward better understanding each storm was observed on two consecutive days initially both had small eyes 16 18 km radius and maximum winds of 57 m s 1 over sea surface temperatures sst 28 c in easterly environmental shear jimena maintained constant intensity or weakened gradually for 2 days in 13 20 m s 1 easterly shear olivia intensified in 8 m s 1 shear on the first day overnight the shear diminished to reverse and became westerly on the second day olivia weakened as the shear increased to 15 m s 1 from the west the storm moved over cooler sst and became surrounded by dryer air as convection weakened and the outer rainbands ceased to be effective barriers

monsoon convection in the himalayan region as seen by the trmm precipitation radar three dimensional structure of summer monsoon convection in the himalayan region and its overall variability are examined by analyzing data from the tropical rainfall measuring mission trmm precipitation radar over the june september seasons of 2002 and 2003 statistics are compiled for both convective and stratiform components of the observed radar echoes deep intense convective echoes 40 dbz echo reaching heights 10 km occur primarily just upstream south of and over the lower elevations of the himalayan barrier especially in the northwestern concave indentation of the barrier the deep intense convective echoes are vertically erect consistent with the relatively weak environmental shear they sometimes extend above 17 km indicating that exceptionally strong updraughts loft graupel to high altitudes occasionally scattered isolated deep intense convective echoes occur over the tibetan plateau wide intense convective echoes 40 dbz echo 1000 km2 in horizontal dimension also occur preferentially just upstream of and over the lower elevations of the himalayas most frequently in the northwestern indentation of the barrier the wide intense echoes have an additional tendency to occur along the central portion of the himalayas and they seldom if ever occur over the tibetan plateau the wide intense echoes exhibit three mesoscale structures amorphous areas lines parallel to the mountain barrier and arc shaped squall lines perpendicular to and propagating parallel to the steep himalayan barrier the latter are rare generally weaker than those seen in other parts of the world and occur when a midlevel jet is aligned with the himalayan escarpment deep and wide intense convective echoes over the northwestern subcontinent tend to occur where the low level moist layer of monsoon air from the arabian sea meets dry downslope flow in a manner reminiscent of severe convection leeward of the rocky mountains in the central usa as the low level layer of moist air from the sea moves over the hot arid northwestern subcontinent it is capped by an elevated layer of dry air advected off the afghan or tibetan plateau the capped low level monsoonal airflow accumulates instability via surface heating until this instability is released by orographically induced lifting immediately adjacent to or directly over the foothills of the himalayas broad 50 000 km2 in area stratiform echoes occur in the eastern and central portions of the himalayan region in connection with bay of bengal depressions their centroids are most frequent just upstream of the himalayas in the region of the concave indentation of the barrier at the eastern end of the range the steep topography apparently enhances the formation and longevity of the broad stratiform echoes monsoonal depressions provide a moist maritime environment for the convection evidently allowing mesoscale systems to develop larger stratiform echoes than in the western himalayan region copyright 2007 royal meteorological society

inner core structure of hurricane alicia from airborne doppler radar observations abstract airborne doppler radar measurements are used to determine the horizontal winds vertical air motions radar reflectivity and hydrometer fallspeeds over much of the inner core region within 40 km of the eye of hurricane alicia 1983 the reconstructed flow field is more complete and detailed than any obtained previously the data show both the primary azimuthal and secondary radial height circulations the primary circulation was characterized by an outward sloping maximum of tangential wind the secondary circulation was characterized by a deep layer of radial inflow in the lower troposphere and a layer of intense outflow above 10 km altitude the rising branch of the secondary circulation was located in the eyewall and sloped radially outward discrete convective scale bubbles of more intense upward motion were superimposed on this mean rising current and convective scale downdrafts were located throughout and below the core of maximum precipitation in the eyewall precipitation particle

dynamics of the stratiform sector of a tropical cyclone rainband abstractairborne doppler radar documented the stratiform sector of a rainband within the stationary rainband complex of hurricane rita the stratiform rainband sector is a mesoscale feature consisting of nearly uniform precipitation and weak vertical velocities from collapsing convective cells upward transport and associated latent heating occur within the stratiform cloud layer in the form of rising radial outflow beneath downward transport is organized into descending radial inflow in response to two regions of latent cooling in the outer upper regions of the rainband sublimational cooling introduces horizontal buoyancy gradients which produce horizontal vorticity and descending inflow similar to that of the trailing stratiform region of a mesoscale convective system within the zone of heavier stratiform precipitation melting cooling along the outer rainband edge creates a midlevel horizontal buoyancy gradient across the rainband that drives air farther inward beneath the brightband the organi

gravity waves in mexico city ii coupling between an anelastic solid and a fluid layer abstract this paper completes a previous study of the role of gravity during the 19 september 1985 michoacan earthquake at mexico city it is assumed as suggested by lomnitz 1989 1990 that nonlinear mechanisms could bring the rheology of the mexico city soft clay layer nearer to a fluid than to a solid in order to test whether gravity waves in a viscous fluid could provide an explanation of exceedingly long duration observed at mexico city we have studied the motion on the surface of an irregular viscous fluid layer overlaying an elastic half space our formulation takes into account vertical displacement at the free surface of the fluid layer but requires a linearization of the corresponding boundary condition a decomposition of diffracted fields in terms of plane waves allows the use of aki larner9s method excitation is given by vertically incident sv waves we present results both for nonviscous and viscous fluids and show that an adequate free boundary condition is essential for this problem lacking data we have performed several simulations for values of viscosity going from 300 to 30 000 pa s in the case of a nonviscous fluid gravity surface waves are generated efficiently by diffraction of elastic waves on the irregular interface but attenuate rapidly when including viscosity and are not significant for viscosities above 3000 pa s the results presented in our companion paper and here allow us to conclude that gravity is not a likely explanation to the long duration of ground motion observed at mexico city in a more general context our model may be useful to study the interaction of seismic waves with water reservoirs such as dams

crustal structure in the southern apennines from teleseismic receiver functions while the upper crustal structure of the southern apennines is known lack of control on the deep structure allows competing thin skinned and thick skinned models of the orogen in thin skinned models the detachment decouples a stack of rootless nappes from the basement in thick skinned models basement is involved in the most recent phase of thrusting to examine crustal structure we use teleseismic data from the calabria apennine tyrrhenian subductionaccretion collision network cat scan array in southern italy we use receiver functions rf processed into a common conversion point stack to generate images of the crust interpretation and correlation to geological structure are done using inversions of individual station rfs we focus on a shallow discontinuity where p to s conversions occur in the foreland it corresponds to velocity jumps between carbonate and clastic strata with basement a similar interpretation for the apennines provides the most parsimonious explanation and supports a thick skinned interpretation in a thick skinned reconstruction the amount of shortening is much smaller than for a thin skinned model this implies considerably less pliocene pleistocene shortening across the apennines and suggests an east southeast motion of the calabrian arc subparallel to the southern apennines rather than a radial expansion of the arc

three dimensional kinematic and microphysical evolution of florida cumulonimbus part ii frequency distributions of vertical velocity reflectivity and differential reflectivity abstract high resolution radar data collected in florida during the convection and precipitation electrification experiment are used to elucidate the microphysical and kinematic processes occurring during the transition of a multicellular storm from convective to stratiform stages a statistical technique is employed to examine the evolving properties of the ensemble small scale variability of radar reflectivity vertical velocity and differential reflectivity over the entire storm differential radar reflectivity data indicate that the precipitation at upper levels was nearly glaciated early in the storm s lifetime dual doppler radar data show that throughout the storm s lifetime both updrafts and down drafts were present at all altitudes and that most of the volume of the radar echo contained vertical velocities incapable of supporting precipitation size particles thus the ensemble microphysical properties of the storm were increasingly dominated by particles falling in an environment of weak vertic

convectively generated potential vorticity in rainbands and formation of the secondary eyewall in hurricane rita of 2005 abstracteyewall replacements in mature tropical cyclones usually cause intensity fluctuations one reason for eyewall replacements remaining a forecasting challenge is the lack of understanding of how secondary eyewalls form this study uses high resolution full physics model forecast fields of hurricanes katrina and rita 2005 to better understand potential vorticity pv generation in the rainbands and the role that convectively generated pv played in the formation of a secondary eyewall in hurricane rita previous studies have focused on dynamic processes in the inner core and or the effects of certain specified pv distributions however the initial development of a concentric pv ring in the rainband region has not been fully addressed katrina and rita were extensively observed by three research aircraft during the hurricane rainband and intensity change experiment rainex which was designed to study the interaction of the rainbands and the inner core rita developed a secondary eyewall and went

clouds in tropical cyclones abstract clouds within the inner regions of tropical cyclones are unlike those anywhere else in the atmosphere convective clouds contributing to cyclogenesis have rotational and deep intense updrafts but tend to have relatively weak downdrafts within the eyes of mature tropical cyclones stratus clouds top a boundary layer capped by subsidence an outward sloping eyewall cloud is controlled by adjustment of the vortex toward gradient wind balance which is maintained by a slantwise current transporting boundary layer air upward in a nearly conditionally symmetric neutral state this balance is intermittently upset by buoyancy arising from high moist static energy air entering the base of the eyewall because of the radial influx of low level air from the far environment supergradient wind in the eyewall zone and or small scale intense subvortices the latter contain strong erect updrafts graupel particles and large raindrops produced in the eyewall fall out relatively quickly while ice splinters left

intensity and structure changes during hurricane eyewall replacement cycles abstracta flight level aircraft dataset consisting of 79 atlantic basin hurricanes from 1977 to 2007 was used to develop an unprecedented climatology of inner core intensity and structure changes associated with eyewall replacement cycles ercs during an erc the inner core structure was found to undergo dramatic changes that result in an intensity oscillation and rapid broadening of the wind field concentrated temporal sampling by reconnaissance aircraft in 14 of the 79 hurricanes captured virtually the entire evolution of 24 erc events the analysis of this large dataset extends the phenomenological paradigm of ercs described in previous observational case studies by identifying and exploring three distinct phases of ercs intensification weakening and reintensification in general hurricanes intensify sometimes rapidly when outer wind maxima are first encountered by aircraft the mean locations of the inner and outer wind maximum at the start of an erc are 35 and 106 km from storm center respe

effects of vertical wind shear and storm motion on tropical cyclone rainfall asymmetries deduced from trmm abstract vertical wind shear and storm motion are two of the most important factors contributing to rainfall asymmetries in tropical cyclones tcs global tc rainfall structure in terms of azimuthal distribution and asymmetries relative to storm motion has been previously described using the tropical rainfall measuring mission microwave imager rainfall estimates the mean tc rainfall distribution and the wavenumber 1 asymmetry vary with storm intensity and geographical location among the six oceanic basins this study uses a similar approach to investigate the relationship between the structure of tc rainfall and the environmental flow by computing the rainfall asymmetry relative to the vertical wind shear the environmental vertical wind shear is defined as the difference between the mean wind vectors of the 200 and 850 hpa levels over an outer region extending from the radius of 200 800 km around the storm center the wavenumber 1 maximum rainfall asymmetry is downshear left right in the northern

the kinematic structure of a hurricane with sea level pressure less than 900 mb abstract a national oceanic and atmospheric administration aircraft recorded the first doppler radar data in a tropical cyclone with a minimum sea level pressure mslp 50 m s 1 extended to 12 km higher than has been reported in previous hurricanes the inner eyewall contained weak

vertical structure of tropical cyclones with concentric eyewalls as seen by the trmm precipitation radar ten years of data from the tropical rainfall measurement mission satellite s precipitation radar are analyzed to determinethe typical vertical structure of the concentric eyewalls of tropical cyclones undergoing eyewall replacement the vertical structure of the secondary outer eyewall is different from the primary inner eyewall and also different from the eyewall of single eyewall storms the upper troposphere portions of the outer eyewalls are like the rainbands from which they evolve their lower tropospheric portions are more intense and more uniform than rainbands of single eyewall storms suggesting that these secondary eyewalls are forming from rainbands undergoing axisymmetrization and building from below the inner concentric eyewalls are more strongly affected by shear than are the eyewalls of single eyewall storms while the outer eyewalls are relativelyunaffectedby shear which suggeststhe outereyewall is amplifyingthe shearinduced asymmetry of the inner eyewall

vertical structure of hurricane eyewalls as seen by the trmm precipitation radar abstractstatistical analysis of the vertical structure of radar echoes in the eyewalls of tropical cyclones shown by the tropical rainfall measurement mission trmm precipitation radar pr shows that the eyewall contains high reflectivities and high echo tops with deeper and more intense but highly intermittent echo perturbations superimposed on the basic structure the overall echo strength height of echo top and presence of intense echo perturbations all increase with vortex strength intense echo perturbations decrease in frequency with low sea surface temperatures when the pr data are normalized by the amount of radar echo in each sample and examined quadrant by quadrant relative to the direction of the environmental shear the nature of convective processes in different parts of the eyewall becomes apparent the normalized statistics of the echo intensity brightband structure and maximum echo top height show that processes generating convective precipitation are generally favored in the dow

concentric eye walls secondary wind maxima and the evolution of the hurricane vortex abstract research aircraft observations in recent hurricanes support the model of shapiro and willoughby 1982 for the tropical cyclone s response to circularly symmetric convective heat sources convective rings in both nature and the numerical model the tangential wind commonly increases rapidly just inside the radius of maximum wind and decreases inside the eye near the central axis of the vortex thus both secondary outer wind maxima and eyewall wind maxima often contract as they intensify this response is independent of the horizontal spatial scale of the maximum an outer maximum is frequently observed to constrict about a pre existing eye and replace it this chain of events often coincides with a weakening or at least a pause in intensification of the vortex as a whole the concentric eye phenomenon is a common but by no means universal feature of tropical cyclones it is most frequently observed in intense highly symmetric systems

kinematics of the secondary eyewall observed in hurricane rita 2005 abstractairborne doppler radar data collected from the concentric eyewalls of hurricane rita 2005 provide detailed three dimensional kinematic observations of the secondary eyewall feature the secondary eyewall radar echo shows a ring of heavy precipitation containing embedded convective cells which have no consistent orientation or radial location the axisymmetric mean structure has a tangential wind maximum within the reflectivity maximum at 2 km altitude and an elevated distribution of its strongest winds on the radially outer edge the corresponding vertical vorticity field contains a low level maximum on the inside edge which is part of a tube of increased vorticity that rises through the center of the reflectivity tower and into the midlevels the secondary circulation consists of boundary layer inflow that radially overshoots the secondary eyewall a portion of this inflowing air experiences convergence and supergradient forces that cause the air to rise and flow radially outward back into th

on the structure of the eyewall of hurricane diana 1984 comparison of radar and visual characteristics abstract features seen in aerial and satellite photographs of the inside edge of the eyewall of hurricane diana 1984 are compared with features seen in digitized three dimensional airborne radar reflectivity data the photographs show regularly spaced upwind and downshear tilted striations in the northeast east and southeast sectors of the eyewall that are nearly collocated with upwind tilted axes of relative reflectivity maxima of approximately 15 dbz

western north pacific typhoons with concentric eyewalls abstract this study examines the intensity change and moat dynamics of typhoons with concentric eyewalls using passive microwave data and best track data in the western north pacific between 1997 and 2006 of the 225 typhoons examined 55 typhoons and 62 cases with concentric eyewalls have been identified the data indicate that approximately 57 of category 4 and 72 of category 5 typhoons possessed concentric eyewalls at some point during their lifetime while major typhoons are most likely to form concentric eyewalls the formation of the concentric structure may not be necessarily at the lifetime maximum intensity approximately one third of concentric eyewall cases are formed at the time of maximum intensity the moat is known to be heavily influenced by the subsidence forced by the two eyewalls rozoff et al proposed that the rapid filamentation dynamics may also contribute to the organization of the moat this paper examines the possibility of rapid filamentation dynamics by devising a filamentati

vertical structure of tropical cyclone rainbands as seen by the trmm precipitation radar abstractten years of data from the tropical rainfall measurement mission satellite s precipitation radar trmm pr show the vertical structure of tropical cyclone rainbands radar echo statistics show that rainbands have a two layered structure with distinct modes separated by the melting layer the ice layer is a combination of particles imported from the eyewall and ice left aloft as convective cells collapse this layering is most pronounced in the inner region of the storm and the layering is enhanced by storm strength the inner region rainbands are vertically confined by outflow from the eyewall but nevertheless are a combination of strong embedded convective cells and robust stratiform precipitation both of which become more pronounced in stronger cyclones changes in rainband coverage vertical structure and the amount of active convection indicate a change in the nature of rainbands between the regions inward and outward of a radius of approximately 200 km beyond this radius rainbands consis

hurricane intensity and eyewall replacement observations made during the historic 2005 hurricane season document a case of eyewall replacement clouds outside the hurricane eyewall coalesce to form a new eyewall at a greater radius from the storm center and the old eyewall dies the winds in the new eyewall are initially weaker than those in the original eyewall but as the new eyewall contracts the storm reintensifies understanding this replacement mechanism is vital to forecasting variations in hurricane intensity processes in the moat region between the new and old eyewall have been particularly unclear aircraft data now show that the moat becomes dynamically similar to the eye and thus is converted into a region inimical to survival of the inner eyewall we suggest that targeting aircraft to key parts of the storm to gain crucial input to high resolution numerical models can lead to improvements in forecasting hurricane intensity

some dynamical aspects of tropical cyclone concentric eyewalls the intensification of tropical cyclones is often interrupted by an eyewall replacement cycle a process in which an outer eyewall forms contracts and replaces an inner eyewall the radial distributions of inertial stability and diabatic heating change during such events impacting the transverse circulation to examine the effects of such changes an analytical solution of the transverse circulation equation associated with a balanced vortex model is derived using a parameterization that distinguishes five radial regions subdividing the domain by each region s values of inertial stability and diabatic heating these regions define the eye inner eyewall moat outer eyewall and far field in mature concentric eyewall situations the solutions do not support the hypothesis that the inner eyewall collapses as a direct result of subsidence from the outer eyewall however the results suggest subsidence and warming temperatures in the moat are governed by enhanced inertial stability associated with a strengthening outer eyewall the model solutions also illustrate how the diabatic heating in the inner eyewall imbedded in a region of high inertial stability induces larger temperature tendencies than the diabatic heating in the outer eyewall which borders the far field region of low inertial stability thus as the inner eyewall dies the storm temporarily loses its ability to produce an intense localized warm region this ability is restored during the contraction and intensification of the outer eyewall these results provide a partial dynamical explanation of how an eyewall replacement cycle can act as a temporary brake on tropical cyclone intensification copyright 2008 royal meteorological society

temporal changes of the primary circulation in tropical cyclones abstract more than 900 radial profiles of in situ aircraft observations collected in 19 atlantic hurricanes and tropical storms over 13 years confirm that the usual mechanism of tropical cyclone intensification involves contracting maxima of the axisymmetric swirling wind radar shows that annuli of convective echoes accompany the wind maxima these features called convective rings exist and move inward because latent heat released in the rings leads to descent adiabatic warming and rapid isobaric height falls in the area they enclose the radial change in rate of isobaric height fall is concentrated at the inner edge of the wind maximum causing the gradient wind to increase there and the maximum to contract vigorous convection organized in rings invariably causes well defined inward moving wind maxima but when convection is weak the rings are also weak or even absent in this case the swirling wind may be nearly constant with radius and change slowly in time hurricanes that have a single vigor

airborne doppler observations of the inner core structural differences between intensifying and steady state tropical cyclones abstractdifferences in the inner core structure of intensifying in intensity increase of at least 20 kt 24 h 1 where 1 kt 0 51 m s 1 and steady state ss intensity remaining between 10 kt 24 h 1 tropical cyclones tcs are examined using composites of airborne doppler observations collected from noaa p 3 aircraft missions the in dataset contains 40 eyewall passes from 14 separate missions while the ss dataset contains 53 eyewall passes from 14 separate missions intensifying tcs have a ringlike vorticity structure inside the radius of maximum wind rmw lower vorticity in the outer core a deeper stronger inflow layer and stronger axisymmetric eyewall upward motion compared with steady state tcs there is little difference in the vortex tilt between 2 and 7 km and both in and ss tcs show an eyewall precipitation and updraft asymmetry whose maxima are located in the downshear and downshear left region the azimuthal coverage of eyewall and outer core precipitation is greater for in tcs