IWRAP: the Imaging Wind and Rain Airborne Profiler for remote sensing of the ocean and the atmospheric boundary layer within tropical cyclones

The Imaging Wind and Rain Airborne Profiler (IWRAP) is the first high-resolution dual-band airborne Doppler radar designed to study the inner core of tropical cyclones (TCs). IWRAP is operated from a National Oceanic and Atmospheric Administration WP-3D aircraft during missions through TCs and severe ocean storms. The system is designed to provide high-resolution dual-polarized C- and Ku-band reflectivity and Doppler velocity profiles of the atmospheric boundary layer (ABL) within the inner core precipitation bands of TCs and to study the effects precipitation has on ocean wind scatterometry as it applies to TCs. IWRAP implements a very unique measurement strategy; it profiles simultaneously at four separate incidence angles (approximately 30°, 35°, 40°, and 50°) while conically scanning at 60 rpm. A summary of the principles of operation and the design of the instrument is given, followed by examples of IWRAP´s unique imaging capability. To our knowledge, these examples include the highest resolution measurements of the ABL winds in a hurricane ever obtained.