High-altitude Airborne Radars - Past, Present, and Future

NASA has several high-altitude (>60,000 ft) aircraft that have been used for cloud and precipitation remote sensing with down looking Doppler radars. The ER-2 Doppler Radar (EDOP) X-band precipitation radar with two fixed beams has been used since the early 1990s to study convection, hurricanes, and for Tropical Rain Measuring Mission (TRMM) validation. Highlights of this radar include flights over the extremely intense Hurricane Emily convective burst. The Cloud Radar System (CRS) W-band radar flew for the first time in 2002 and for CloudSat, and it provided an excellent example for W-band multiple scattering in convection. CRS flew along with EDOP, and they provided dual-frequency capability that enabled particle size retrievals in light rain using W- and X-band measurements (e.g., Tian et al., 2007). More recently, NASA has moved into unmanned aircraft with the Global Hawk. In 2011, the High-altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) Ku- and Ka-band radar flew on the Global Hawk with emphasis on wind measurements in hurricanes. This radar also flew on the ER-2 in 2011 in a flight series for development of retrieval algorithms for the Global Precipitation Mission (GPM). A new ER-2 X-band radar (EXRAD) that is a scanning replacement for EDOP, performed its first flights in 2013. Currently, CRS is undergoing a major upgrade for improved performance and reliability. This presentation will highlight the capabilities of these radars and the research they have accomplished over the past few decades on storm structure and retrieval algorithms. Future plans for science campaigns and satellite algorithm development and validation will be discussed.