August-September

NSF NOAA NRL NCAR UW UM

AGU, San Francisco, 12 December 2006

Katrina Ophelia Rita

Hurricanes investigated in RAINEX

Motivation for RAINEX

Understanding Rapid Intensity Changes

How do interactions of environment, eyewalls & rainbands in the mature storm… …lead to intensity changes like these?

rain

ban

d

Intensity change problem:Intensity change problem:

Intensity of Katrina (2005)

Max Wind Speed (knots)

24 25 2826 2927August

Willoughby 88

High-Resolution Multi-nested Vortex-Following Numerical Models at University of Miami:

• UM/RSMAS Coupled Atmos-Wave-Ocean Model

15 km

1.6 km

5 km

Mini ensemble MM5 and WRF forecasts using GFS, NOGAPS, CMC, and GFDL forecast fields as initial and lateral boundary conditions

Courtesy S. Chen

RitaKatrina

Model forecast of eyewall & rainbandsat 1.6 km resolution

Rain rate

Courtesy S. Chen

Distance from vortex center

Day Day

Rain Wind

KatrinaKatrina

Courtesy S. Chen

RitaRita

Rain WindRain

Distance from vortex center

Day

Courtesy S. Chen

Targeted

RAINEX Flight CoordinationRAINEX Flight Coordination

ELDORA radar

KatrinaKatrina

Katrina-28 AugustKatrina-28 August

ELDORA data

Barnes et al. ‘83

NRL

Katrina-28 AugustKatrina-28 August

Confirms “Barnes” structure

RitaRita

RAINEX Flights in Hurricane RitaRAINEX Flights in Hurricane Rita

Cat. 5

ConcentricEyewalls

Sheared

Concentric eyewalls in RitaConcentric eyewalls in Rita

Unpreceden

ted

Sample cross section through eyewalls of RitaSample cross section through eyewalls of Rita

Horizontal Distance (km)

Hei

ght

(km

)

Eye

Dropsonde in the “moat” region

1802 UTC 22 September ‘05

Rita-22 SeptemberRita-22 September

ELDORA observations

of vorticity in the eyewalls

ELDORA observations

of vorticity in the eyewalls

Maybe first observation of “axisymmetrization”

VorticityVorticity

ELDORA observations of the inner eyewall

ELDORA observations of the inner eyewall

Eye

VorticityVorticity

This has been called“turbo-

boosting” of the eyewall

EyeHeitht (km)

warm air

Vortex on

eyewall

Inner eyewall Outer eyewall

Turbo-boostingTurbo-boosting

Eye

Moat formationMoat formation

2ndary eyewall

taking over

2ndary eyewall

taking overCourtesy Michael Bell

Composite of all ELDORA dataComposite of all ELDORA data

Data AvailabilityData Availability

Katrina Ophelia Rita

Three important storms observed

Innovative satellite-based flight control

First use of ELDORA in hurricanes

Data available via NCAR field catalog

Operations and data analysis aided by high-resolution modeling

RAINEX Technical AccomplishmentsRAINEX Technical Accomplishments

Formation of “moat” documented during eyewall replacement in Rita

ELDORA shows high wave no. vorticity pattern in 2ndary eyewall

ELDORA confirms internal structure of rainband in Katrina

High-res. model captures eyewall replacement in Rita

RAINEX Science DirectionsRAINEX Science Directions

ThanksThanks