Shuyi S. Chen Rosenstial School of Marine and Atmospheric Science University of Miami Overview of RAINEX Modeling of 2005 Hurricanes In the eye of Katrina

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

Inner core and rainband internactions Concentric eyewalls and eyewall replacement cycle Hurricane Internal Dynmaics Vertical wind shear Moisture distribution Environment Rainbands Inner Core

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 rain, wind, vorticity, features evolve and storm intensity changes

RSMAS Science Operation Center C130 / G-IV NRL/P3 Kermit Piggy NCAR/ATD NHC UCAR/JOSS air ground Simplified RAINEX Data Flow HRD IOP: August-September 2005

KatrinaOpheliaRita

High-Resolution Multi-nested Vortex-Following Numerical Models at University of Miami: UM/RSMAS Coupled Atmos- Wave-Ocean Model Weather Research and Forecast (WRF) 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

8/27 8/28

9/19 9/22 9/23 9/21 9/20

21-sep-2005, 19:00:00

ELDORA composite reflectivity in Rita on 22 Sept 05 MM5 Rainrate in Rita on 22 Sept 05

22 September 2005 Inner outer Inner outer N43 flight-level wind in Rita ObservedMM5 WRF Radar Reflectivity Eyewall Replacement in Hurricane Rita (2005)

Outer Rainband

How do concentric eyewalls (or secondary eyewall) form and how do they effect the storm intensity? Structures of primary eyewall and rainbands (i.e., internal dynamics) Initial conditions (e.g., background MPV field, etc.) Environmental influences (e.g., water vapor distribution that may influence rainband strength and orientation, etc.)

Rita Katrina 1.6 km “Rita” 5 km “Rita”Large init vortex1.6 km

Hurricane Rita

Hurricane Katrina 1.6 km 5 km Rapid intensification “Rita”

RitaKatrina(1.6 km)

Effect of vertical wind shear on Hurricane Rita structure and intensity Model 5-day forecast

TMI Total Precipitable Water Katrina Rita

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

Conclusions  RAINEX provided an unique, comprehensive dataset for evaluating and improving high-resolution models.  High-resolution (~1 km, fully resolving the inner core and rainband structures) forecasts in real-time are extremely valuable for mission planning and overall understanding of the storm structure, evolution, and intensity change.  Environmental moisture distribution can have a significant impact on rainband organizations, formation of concentric eyewalls, and eyewall replacement.  Accurate initial and lateral boundary conditions for high-res models are needed.  Need a good data assimilation system for high-resolution model forecasting in real-time.