1. Shuyi S. Chen, Robert A. Houze Bradley Smull, David Nolan, Wen-Chau Lee Frank Marks, and Robert Rogers Observational and Modeling Study of Hurricane Rainbands and Intensity Change RAINEX Planning Meeting, Miami, Florida, 15-17 November 2004

2. Science Objectives  Use airborne observations to examine simultaneously the dynamic and thermodynamic structures of hurricane inner core and outer rainband regions where the positive potential vorticity associated with deep convective cores are located.  Use numerical model to investigate the interactions of the rainbands and primary hurricane vortex circulation and their role in hurricane intensity change.

3. Schematic Reflectivity Structure (Hugh Willoughby)

4. Hurricane Floyd (1999) 12 Sep 2230-2300 UTC13 Sep 2300-2330 UTC

5. Four characteristic tropical cyclone rainband/eyewall structures

6. Factors Controlling Intensity Change  Inner core (eyewall) dynamics  Environmental conditions, including vertical wind shear, moisture distribution, and sea surface temperature (upper ocean heat content), etc. Inner core Rainbands Environment

7. Evolution of a single primary eyewall (Kossin et al. 2000)

8. Primary + Secondary Eyewalls (Kossin et al. 2000)

9. In the convective rainband region outside of the hurricane inner core, convectively induced potential vorticity may be “axisymmetrized” by high wave number Rossby waves. Hypothesis:

10. Hurricane Floyd (1999) MM5 Floyd (1999)

14. Hurricane Floyd (1999) Eyewall Replacement

16. TRMM TMI

17. NOAA/HRD&AOC Radar Composites in Hurricane Isabel (2003) 9/12/03 1700 UTC9/12/03 2000 UTC9/13/03 1600 UTC 9/13/03 1800 UTC9/14/03 1600 UTC9/14/03 2000 UTC

20. Isabel (2003) Floyd (1999)

21. Isabel (2003) Floyd (1999)

22. What are the impacts of initial vortex scale on intensity and inner core structure of simulated tropical cyclones?

23. Surface Rain Rate

24. Wind at 3 km Level

25. Moist Potential Vorticity

26. Vertical wind shear Moisture distribution Environment Rainbands Inner Core

27. Track Chen&Desflots (UM/RSMAS)

28. Intensity (a) pressure(b) wind speed Chen&Desflots (UM/RSMAS)

29. NOAA/HRD&AOC Radar Composites in Hurricane Lili (2002) 10/02 0600 10/02 0900 10/02 1800 10/02 1900 10/02 1700 10/03 1500

30. Chen&Desflots (UM/RSMAS)

32. Eyewall Evolution in Lili (2002) pressure

33. Shear Analysis in Lili (2002) SLP : 943.9mb SHEAR:0.55m/s SLP : 943.9mb SHEAR:2.8m/s SLP : 944.4mb SHEAR:4.4m/s SLP : 948.9mb SHEAR:7m/s SLP : 953.1mb SHEAR:9m/s SLP : 955.1mb SHEAR:9.2m/s

34. Mean RH Profiles Derek and Chen (2004): NOAA/G-IV GPS dropsondes (49 flights and 1002 dropsondes, mostly taken in the TC environment outside of 300 km radius from TC centers)

35. Rainfall Moist simulationControl runDry simulation

36. Summary TC inner core PV structure seems to have a significant influence on the evolution of rainbands and eyewall replacements. Environmental moisture distribution and vertical wind shear affect TC inner core (and intensity) through rainbands in some cases. Future high-resolution hurricane prediction models (e.g., HWRF) must be able to resolve the rainbands and inner core as well as their interactions correctly. RAINEX will provide the 1st high-res 3-D wind data covering simultaneously both outer rainbands and inner core regions to validate/evaluate the model results and, ultimately, improve the TC intensity forecast.