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)

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

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

RAINEX Flight Coordination Fig. 5 BAMS ELDORA radar

RAINEX Operations

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

Hurricanes investigated in RAINEX Katrina Ophelia Rita Fig. 1 BAMS

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

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

NHC Fcst MM5&WRF Obs Global models

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

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

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

ELDORA data in Katrina-28 August

RAINEX Flights in Hurricane Rita Concentric Eyewalls Fig. 8 BAMS

Concentric eyewalls in Rita Unprecedented

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

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

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

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

Rita (1.6 km) Katrina (1.6 km)

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

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

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

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

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

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