1. Rainbands and Secondary Eye Wall Formation as Observed in RAINEX Derek Ortt and Shuyi S. Chen University of Miami-RSMAS

2. Motivation and Objective To examine the properties of rainbands in Hurricanes Katrina and Rita using RAINEX observations and model simulations To determine the physical processes that may be responsible for the formation of concentric eyewalls and eyewall replacement cycles in Hurricane Rita

3. Hurricanes Katrina and Rita KatrinaRita

4. Data and Analysis Method TMI water vapor data with a ¼ degree resolution P-3 GPS dropsonde data with a ½ s resolution (interpolated on to a 25m vertical resolution) from NOAA and NRL aircraft (47 in Katrina and 40 in Rita) G-IV dropsondes interpolated on a 100m resolution (56 in Katrina and 56 in Rita) Dropsondes are composited day by day Model data is from MM5 vortex following simulations with 3 nested domains at 15, 5, and 1.67km resolution Similar analysis methods are used the with the model as with the TMI and aircraft data

5. Observations

6. TMI Total Precipitable Water Katrina Rita 40 50 60 70 Black dots represent sample G-IV dropsonde locations

7. Storm outer environment

8. Storm outer environment

10. Sample P3 Dropsonde Locations Katrina Rita Black dots represent sample P3 dropsonde locations along the flight tracks

11. Sample Dropsonde Locations Red: NRL P-3 dropsondes Black: NOAA P-3 dropsondes G-IV dropsondes are released farther from the center than the drops depicted above. KatrinaRita

12. Rainband region

13. P-3 Dropsonde Composites KatrinaRita

14. Model Simulations

15. MM5 Total Precipitable Water KatrinaRita 40 50 60 70

16. Sample Model Vertical Profile Locations Magenta dots represent model simulated dropsonde locations Katrina Rita

18. MM5 Composite Vertical Profiles KatrinaRita

19. KatrinaRita

20. KatrinaRita

21. OTHER STORMS

22. 2004 Frances

24. EWRC

25. 2004 Ivan

27. NO EWRC

28. Conceptual Model of Moisture Gradient Affects to Rainbands Weak Gradient Strong Gradient Moist Dry

29. Conclusions The Rainbands in Rita were more symmetric about the storm than those in Katrina A sharp moisture gradient between the rainbands and surrounding environment was present in Rita, but not Katrina The rainbands in Rita were able to form into a secondary eye wall. A stable outer storm environment favor symmetric rainbands about the center, which may lead to the formation of concentric eyewalls

30. Aknowledgements Katrina and Rita track graphics courtesy of Unisys Weather TMI data from NRL and remote sensing systems NOAA P-3 and G-IV dropsonde data courtesy of AOML-HRD This work was funded by NSF grant ATM- 0432717 and this presenter has been funded by an AMS and University of Miami Fellowship