1. Rosenstial School of Marine and Atmospheric Science
Shuyi S. Chen
Rosenstial School of Marine and Atmospheric Science
University of Miami
August-
September
NSF NOAA NRL NCAR UW UM
Houze et al. (2006, BAMS)

2. TC Internal Dynmaics and Interaction with Environment
Inner core and rainband internactions
Concentric eyewalls and eyewall replacement cycle
Environment Rainbands Inner Core
Vertical wind shear
Moisture distribution

3. RAINEX is the first experiment using three-Doppler-aircraft flying in hurricanes.
Approach:
Use airborne Doppler radar to observe both eyewall and rainband internal vorticity structures simultaneously
Use intensive dropsondes for thermodynamic environment of hurricane rainbands and eyewall to support both analysis and modeling/forecasting
Use model to determine how the vorticity features evolve and storm intensity changes

5. RAINEX Flight Coordination
Fig. 5 BAMS
ELDORA radar

6. RAINEX Operations

7. Plan--target dropsondes and Doppler
Fig. 7a BAMS

8. Hurricanes investigated in RAINEX
Katrina
Ophelia
Rita
Fig. 1 BAMS

9. High-Resolution Multi-nested Vortex-Following Numerical Models at University of Miami:
UM/RSMAS Coupled Atmos- Wave-Ocean Model
15 km
Mini ensemble MM5 and WRF forecasts using GFS, NOGAPS, CMC, and GFDL forecast fields as initial and lateral boundary conditions
5 km
1.6 km

10. NHC Fcst
Obs
MM5 (1.6km)
WRF (1.6km)

11. NHC Fcst
MM5&WRF
Obs
Global models

13. Model forecast of eyewall & rainbands at 1.6 km resolution
Katrina
Rita
Rain rate

14. Distance from vortex center
Katrina
Rain
Wind
Day
Day
Distance from vortex center

15. Distance from vortex center
Rita
Rain
Wind
Rain
Day
Distance from vortex center

16. ELDORA data in Katrina-28 August

17. RAINEX Flights in Hurricane Rita
Concentric
Eyewalls
Fig. 8 BAMS

18. Concentric eyewalls in Rita
Unprecedented

19. Question: How does the “moat form?”
ELDORA data show downward motion between the two eyewalls
dBZ

20. Dropwinsonde in Moat Region of Rita show “Eye-like sounding”

21. Eyewall Replacement in Hurricane Rita (2005)
22 September 2005
Inner
outer
N43 flight-level wind in Rita
Observed
MM5
WRF
Radar Reflectivity

22. ELDORA observations of the outer eyewall: Evidence of “filamentation”
Model Moist Pot. Vorticity
Vorticity
(10-4 s-1)

23. Rita
(1.6 km)
Katrina
(1.6 km)

24. Dots represent sample G-IV dropsonde locations
Effect of Environmental Humidity
TRMM TMI Total Precipitable Water 40 50 60 70
dry
humid
Katrina
Rita
Dots represent sample G-IV dropsonde locations

25. Dropsondes show stronger humidity gradient in eyewall replacement case
Storm outer
environment
Rainband region
Katrina
moist
Rita
moist
Katrina
dry
Rita
dry

26. Conceptual Model of How Moisture Gradient Affecting to Rainband Organizations
Weak Gradient in Katrina
Strong Gradient in Rita
Moist
Dry

27. Effect of vertical wind shear on Rita
Model 5-day forecast

28. CONCLUSIONS Three important storms observed
Katrina
Ophelia
Rita
Three important storms observed
Innovative satellite based flight control
First use of ELDORA in hurricanes
Future RAINEX studies
Try to connect all these structures in terms of rainband lifecycle
RAINEX dual-Doppler data & dropsondes -> vorticity maxima
High resolution model forecasts of RAINEX storms promising
Detailed vorticity patterns will be compared to model simulations
Data available via NCAR field catalog
Operations and data analysis aided by high-resolution modeling

29. CONCLUSIONS Eyewall replacement--formation of “moat” documented
Strong humidity gradient may favor concentric eyewalls
ELDORA confirms internal structure of rainband
ELDORA shows filamentation of vorticity in secondary eyewall
Future RAINEX studies
Try to connect all these structures in terms of rainband lifecycle
RAINEX dual-Doppler data & dropsondes -> vorticity maxima
High resolution model forecasts of RAINEX storms promising
Detailed vorticity patterns will be compared to model simulations
Formation of storm rotation in the convective burst phase
Dry air intrusion at midlevels