1. February 5th, 20082008 TRMM Conference The 3-D Reflectivity Structure of Intense Atlantic Hurricanes as seen by the TRMM PR Deanna Hence, Robert Houze and Stacy Brodzik University of Washington

2. February 5th, 20082008 TRMM Conference Objectives of the Study To develop a three-dimensional climatology of precipitation structures within tropical cyclones To characterize the dynamics of the rainbands—are they more like ordinary convection or eyewall convection?

3. February 5th, 20082008 TRMM Conference Statistics of Precipitation Structure Suggest higher reflectivities aloft in eyewall and outer rainband region More intense brightband signature in inner rainband region Contoured Frequency by Altitude Diagrams (CFADS, Yuter and Houze 1995) Show frequency of occurrence of reflectivity values as a function of height Distinguishes precipitation type and vertical structure Yuter and Houze (1995) Cecil et al. (2002)

4. February 5th, 20082008 TRMM Conference Annuli and Quadrant Definition Based on eye diameter Ring 1 = R eye + 17 km Ring 2 = 2R1 Ring 3 = 3R1 Ring 4 = 4R1 Quadrants counted counterclockwise from storm track vector 180.4 Distance (km)  TRMM PR Vertical Slice 12 4 8 16 Height (km) 0 0.045.190.2135.3 48.6 43.2 37.8 32.4 27.0 21.6 16.2 10.8 5.4 dBZ eye TRMM PR Reflectivity at 03:36 on 28 August 2005 79°W 51 45 39 33 27 21 dBZ 15 9 3 8081908988878685848382 3 2 25 24 1 4 28°N 26 27 Storm motion

5. February 5th, 20082008 TRMM Conference TCSP and RAINEX Initial study includes Hurricanes Dennis, Emily, Katrina, and Rita of 2005 Analysis of overpasses when storms are hurricane strength Quadrant analysis revealed lack of consistent asymmetry

6. February 5th, 20082008 TRMM Conference Outer Region Broad distribution of reflectivities below melting level Bright band signature Relatively broad distribution above melting level reaching to 11 km Resembles ordinary buoyant convection Annulus 5

7. February 5th, 20082008 TRMM Conference Middle Region Narrower distribution of reflectivity below melting level Strong brightband signature Sharp dropoff of reflectivity above melting level reaching to just below 10 km Looks more like an eyewall CFAD Annulus 3

8. February 5th, 20082008 TRMM Conference Eyewall Relatively narrow but intense distribution below melting level Weak brightband signature Mostly narrow distribution above melting level Outliers suggest occasional intense convective towers reaching over 12 km Annulus 1

9. February 5th, 20082008 TRMM Conference Annulus 1 Annulus 3 Annulus 5 Initial Conclusions Outer region has distinct ordinary convective signature with some stratiform Middle region rainbands have structure more similar to eyewall than to ordinary convection Eyewall CFAD is not like that of classic stratiform or convective precipitation- it is intense, deep, AND uniform Eyewall has intermittent deep convective elements No distinctive quadrant asymmetry, but will further test with larger dataset

10. February 5th, 20082008 TRMM Conference Further Data First expansion is into the overpasses of all hurricanes between 1997-2007 that reach Category 4 and 5 intensity Overpasses are stratified into when the storm is Cat 1 or 2 and when Cat 3, 4, and 5 Category 5 overpasses are also looked at separately

11. February 5th, 20082008 TRMM Conference

12. February 5th, 20082008 TRMM Conference Further Data Generally consistent with the four 2005 storms, but differences between annuli are less when weaker storms are included. Eyewall distribution is broader when weaker storms are included Annulus 1Annulus 3Annulus 5

13. February 5th, 20082008 TRMM Conference Future work Continue expansion of database to all Atlantic Basin hurricanes, and eventually to all basins Stratify overpasses based on track speed, wind shear, and other factors known to influence storm structure and intensity Develop method of quantitatively sorting CFADs