Development of the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP)

The focus of this paper is on a technology development currently in progress under the NASA IIP called High Altitude Wind and Rain Profiling Radar (HIWRAP). This radar is a dual-frequency (Kaand Ku-band), dual-beam (30 and 40 incidence angle), conical scan, solid-state transmitter-based system, designed for operation on the high-altitude (20 km) Global Hawk UAV. HIWRAP is a progression of technology from the current fixed-beam NASA highaltitude Doppler weather radars using tube technology, and the lower altitude solid-state IWRAP system. HIWRAP utilizes a solid state transmitter along with novel pulse compression scheme that will result in a system that is considerably more compact in size, requires less power, and ultimately costs significantly less than typical radars currently in use for precipitation and Doppler wind measurements. With the inclusion of Ka-band, HIWRAP will be able to image the winds through volume backscattering from clouds and precipitation, enabling it to measure the tropospheric winds above heavy rain at high levels. Further this effort and the HIWRAP prototype will potentially lead to a smaller, less expensive spaceborne instrument that provides wide swath coverage similar to the SeaWinds instrument and can image not only the surface winds but the 3D tropospheric winds and atmospheric boundary layer winds above and within precipitation systems and the precipitation itself.