Overview of RAINEX Modeling of 2005 Hurricanes

The Hurricane Rainband and Intensity Change Experiment (RAINEX) is a coordinated observational and modeling study of hurricane intensity changes in relation to inner-core vortex dynamics, formation of secondary wind maxima in the outer rainband region, eyewall replacement cycles, and dynamic/thermodynamic feedbacks of outer rainbands. The two main objectives are: 1) to examine structures (both dynamic and thermodynamic) of hurricane outer rainband and inner core regions simultaneously, and 2) to investigate the interactions of the rainbands and primary hurricane vortex circulation and the role of these interactions in hurricane intensity changes. The RAINEX field program took place from 15 August-30 September 2005, which is during the most active hurricane seasons in the Atlantic basin on record. RAINEX employs three aircraft equipped with dual-Doppler radar and the GPS dropsondes. It involves the NRL P3 with the NCAR ELDORA dual-Doppler system plus the two dual-Doppler equipped NOAA WP-3D aircraft. It was conducted in collaboration with the partners at NOAA. RAINEX conducted multi-day and multi-aircraft missions into Hurricanes Katrina, Ophelia, and Rita with well-designed fly patterns that target important features in both inner core and outer rainband regions. The data collected in RAINEX provides a unique opportunity for evaluating and validating high-resolution hurricane prediction models that are capable of resolving the eye, eyewall, and rainbands. An ensemble of high-resolution MM5 and WRF model forecasts was conducted in real-time during RAINEX. The models (at 1.6 km grid resolution) were able to capture the rapid intensification in Katrina and Rita as well as the formation of the secondary eyewall and eyewall replacement cycle in Rita. These forecasts were extremely valuable in the RAINEX mission planning in real-time. Detailed analysis of the dynamic and thermodynamic fields in the rainband and inner regions is underway. The goal is to provide an overview of the RAINEX modeling effort aimed to understand and better predict the storm structure and intensity changes.