Cooperative Institute for Research in the Atmosphere

OAWL’s Journey Toward Space: A Doppler Lidar Approach for Global Wind Profiles from Space

Knowledge of weather patterns a day, three days, or even three weeks from now requires forecasts based on models initialized with accurate data. Vertically resolved wind profile data has been shown to have a high impact on forecast accuracy but measurements remain sparse, especially over areas such as the oceans or the Southern Hemisphere. This lack of wind profile data is a major limiting factor in numerical weather prediction’s ability to provide high-accuracy longer-term weather forecasts, to predicting hurricane storm tracks and intensity, and to understand aerosol transport.

To enable future space-based wind profile measurements, Ball Aerospace and NASA’s Earth Science Division Earth Science Technology Office funded development and demonstrations of Optical Autocovariance Wind Lidar (OAWL) technology. Recently NASA funded the build and demonstration of an airborne, Green-OAWL, or GrOAWL, a project to test a two-line-of-sight (LOS), 532 nm wavelength, aerosol Doppler wind lidar. While the LOS data can be directly assimilated into forecast models, by combining data from two orthogonal looks collected from a single instrument, this lidar can provides continuous, vertically-resolvedprofiles of horizontal wind speed and direction. Performance of the GrOAWL instrument was demonstrated and validated during a series of test flights on NASA’s WB-57 aircraft, during which GrOAWL measurements were compared with winds measured by dropsondes.

The GrOAWL instrument was designed to be an airborne demonstrator for ATHENA-OAWL, a mission concept to measure winds from the International Space Station proposed to NASA under the Earth Venture Instrument Program. Science goals of the mission included improving low and mid-latitude weather forecasts and reanalyses, investigating the interactions between aerosol radiative forcing and dynamics in tropical cyclone formation, and improving understanding of the impact of long range aerosol transport on global energy cycles, air quality, and climate. Although classified as selectable and well-reviewed, the mission was not funded. Currently, an upcoming Earth Venture Announcement of Opportunity provides the opportunity to improve and resubmit a proposal based on the ATHENA-OAWL concept.

During our talk we will describe the GrOAWL technique, show results from the airborne validation of the instrument, and discuss the ATHENA-OAWL mission parameters and science objectives.

Bios

Dr. Mike Hardesty has worked on development and application of Doppler lidars for measuring winds and atmospheric constituents for more than 30 years. He was a member of the science team for the Laser Atmospheric Wind Sounder, NASA’s original effort to implement space-based Doppler lidar. Since 1994 he has been a member of the Working Group on Space-based Lidar Winds, serving as co-chair since 2009. He has been a US visiting member of the European Space Agency’s Aeolus Mission Advisory Group since 2005 and is coordinating the US Calibration/Validation effort for Aeolus after launch of the instrument in Autumn of 2018.

Dr. Sara Tucker has worked for 18 years in industry and at NOAA designing, building, testing, and developing models and processing algorithms for multiple types of Doppler Wind lidars including two-micron coherent detection systems, a UV double-edge Fabry-Perot system and the dual-wavelength Optical Autocovariance Wind Lidar (OAWL). She has been Principal Investigator and technical lead on multiple OAWL related programs, including the HAWC-OAWL (HSRL, Aerosols Winds and Clouds using OAWL) IIP and the GrOAWL Earth Venture technology development effort. She is currently a lidar systems engineer at Ball Aerospace working under the Active Sensing Technology Initiative.