Airborne Aerosol Wind Profiler (AWP) Doppler Wind Lidar Observations Within The NOAA Joint Venture 3-D Wind Measurement Demonstration

The NASA Langley Research Center (LaRC) has recently completed development of the Aerosol Wind Profiler (AWP) airborne Doppler wind lidar (DWL) instrument. AWP was supported by the NASA Earth Science Technology Office and the Earth Science Division, a project that adapted the Wind-Space Pathfinder (Wind-SP) DWL transceiver onto a structure for flight aboard a variety of NASA research aircraft. Wind-SP, built in collaboration with Beyond Photonics, Inc., is a coherent-detection DWL operating at a 2.053 mm wavelength. It is an advancement over the LaRC Doppler Aerosol WiNd (DAWN) instrument that has recently flown on several NASA airborne campaigns, including the 2019 Aeolus Cal/Val, 2021 CPEX-Aerosol and Winds, and 2022 CPEX-Cabo Verde missions. Wind-SP included many technologies required for a space DWL mission. These include improved transmitters with high pulse energy (up to ~55 mJ) and repetition rate (200 Hz), auto-alignment sensors and actuators for long-term maintenance of optimal coherent DWL performance; electronic control of the beam path allowing for multiple viewing angles (allowing vector wind measurements) with no moving parts; compact highly-stable and tunable reference lasers allowing for high-precision measurement of velocity at long ranges while mitigating the impact of satellite platform velocity, and many others.

AWP laser pulses from the two beam paths are directed downward through parallel beam expanders that expand the beams from millimeter to a ~5 inch diameter. One beam is sent through a rotating scanner prism where it is directed 30° off-nadir, providing vertical profiles of horizontal winds at < 100 meter spacing between vertical levels. While the scanner is rotating from one azimuth angle to another, the second beam path becomes active which is directed in the nadir direction, providing vertical profiles of vertical wind speed. Aircraft angle-of-attack is compensated so that the beam is oriented as close to nadir as possible. AWP can derive high-precision (< 2 m/s RMS compared to dropsonde) vector wind profiles with 1-2 km spacing, data well suited for a variety of weather applications.

AWP will be used for its first science campaign in October 2023 and September 2024 as part of a NOAA Joint Venture Program 3-D Wind Measurement Demonstration suborbital campaign. The Joint Venture program is designed to work with the private sector, academia and other federal agencies to explore the feasibility and capability of emerging technologies spacecraft and other mission-specific tools to meet NOAA’s mission requirements. AWP will fly in October 2023 aboard the NASA DC-8 aircraft, piggybacking on flights during the NASA EcoDemonstrator mission based in Everett, Washington. Vaisala AVAPS dropsondes will also be released over ocean during transits between Palmdale, California and Everett. This presentation will summarize AWP datasets collected during these flights, AWP wind vector validation with AVAPS, and comparisons with NOAA weather prediction model and GOES-18 atmospheric motion vector products.