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Detailed analysis of concentric eyewall structures, vorticity patterns, and mesovortex dynamics during Hurricane Rita's eyewall replacement cycles. This study provides insights into the evolution and correlation of vorticity and wind patterns within the primary and secondary eyewalls.
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Vorticity Structures Accompanying Eyewall Replacement in Hurricane Rita (2005) R.A. Houze, Jr., and B.F. Smull Department of Atmospheric Sciences University of Washington AMS 28th Conf. on Hurricanes & Tropical Meteorology Orlando, Florida - 29 April 2007 Photo within Rita (CAT 4-->5) on 21 Sept 2005 courtesy M. Black, NOAA/AOML/HRD
Period of ELDORA Observations Documenting Concentric Eyewall Structure on 22 September 2005 Multi-day Intensity Trends for Hurricane Rita Best-track Central Pressure & Max Sustained Surface Winds
22 September 2005 - GOES Visible + P-3 TracksEyewall Replacement Phase
n o d c a e r S o a y M t m a i r r P y Concentric Eyewall Reflectivity Structure2.0 km MSL1801-1820 UTC NRL P-3/ELDORA Circumnavigation (Units: dBZ)
n o d c a e r S o a y M t m a i r r P y Double Wind Maximum - Horizontal Wind Speed2.5 km MSL1801-1820 UTC NRL P-3/ELDORA Circumnavigation (Units: m/s)
n o d c a e r S o a y M t m a i r r P y Double Wind Maximum - Horizontal Wind Speed0.5 km MSL1801-1820 UTC NRL P-3/ELDORA Circumnavigation (Units: m/s)
Patterns of Vertical Vorticity Accompanying Eyewall Replacement
Location of NW & SE Quadrant Analysis Domains NW Quadrant 80 x 80 km2 SE Quadrant 80 x 80 km2 ~Axisymmetrized Primary Eyewall z vs. High Wavenumber Secondary Eyewall Structures ( Units: 10-4 s-1)
NW Quadrant Marks and Houze 1983 Evidence of vorticity dipoles in region of secondary eyewall formation W E NW Quadrant Vorticity - 1.25 km MSLContrasting scale/orientation of primary vs. secondary eyewall Vorticity features ( Units: 10-4 s-1)
NW Quadrant Radial Section Eye Moat E W Radial Section - Reflectivity:Vertically coherent concentric eyewall/moat structure -Contrasting depth/tilt of primary & secondary eyewall features (Units: dBZ)
E W Radial Section - Horizontal Wind SpeedContrasting depth/slope of isotach patterns - Comparatively shallow, sloped secondary eyewall wind maxima (Units: m/s) NW Quadrant Radial Section Eye Moat
E W Radial Section - Vertical VorticityCorresponding contrasts in primary vs. secondary eyewall Tremendous vertical coherence of secondary eyewall dipoles ( Units: 10-4 s-1) NW Quadrant Radial Section Eye Moat
E W Radial Section - Vertical Vorticity& Doppler-Derived Air Motion VectorsTendency for & w to be correlated ( Units: 10-4 s-1) NW Quadrant Radial Section Eye Moat
Reproducibility of Observed Structures In Other Quadrants
WSW ENE Vertical Vorticity - 2.0 km MSLRadial section crosses intense primary eyewall mesovortex &high wavenumber secondary eyewall features beyond (Units: 10-4 s-1)
Radial Section - Vertical Vorticity SE Quadrant Radial Section ( Units: 10-4 s-1) Eye WSW ENE
Tangential SectionVorticity @ 2.0 km - Evidence of high wavenumber structures ( Units: 10-4 s-1) NE SW
Shear Flow x x x x x Corresponding Tilted VorticityStructures Structures within Secondary Eyewall SE Quadrant Tangential Section (Units: 10-4 s-1) SW NE
Shear Wind Speed in Secondary EyewallNear-sfc wind maxima at ~5 km spacingStructures within elevated (2-5 km) layer tilt downshear SE Quadrant Tangential Section (Units: m/s) x x x x x SW NE
Conclusions • Unprecedented high-resolution view of concentric eyewall structure & dynamics • Primary eyewall “triangular” with upright local vorticity maxima • Secondary eyewall • High wavenumber (~25) wind perturbations • Wind max strong but shallow & sloped • High wavenumber vorticity extrema • Tilt radially outward and tangentially downshear • Tend to correlate with w • Possibly associated with near-surface wind maxima
22 September 2005 - GOES Visible + P-3 TracksEyewall Replacement Phase
23 Sept 2005 - WSR-88D Composite + TracksStrongly-sheared Landfall Phase
Mesovortex along Primary Eyewall of RitaAssociated Reflectivity @ 0.5 km MSL (Units: dBZ)
Mesovortex along Primary Eyewall of RitaWind Speed @ 0.5 km MSL (Units: m/s)
Mesovortex Along Primary Eyewall of RitaVertical Vorticity @ 0.5 km MSL (Units: 10-4 s-1)
dBZ Vorticity () 3-D Exploration of Mesovortex StructureMap @ 0.5 km MSL & Radial Cross Section) ( Units: 10-4 s-1)
x x x x x Possible Convective Origins Suggested byAccompanying Precipitation Structures SE Quadrant Tangential Section (Units: dBZ)
Radial Section - Reflectivity SE Quadrant Radial Section (Units: dBZ) Eye Moat WSW ENE