Photo credit: www.nasa.gov
Since the previous autumn, NASA scientists have been operating an advanced 3D Doppler wind lidar instrument across the United States, amassing nearly 100 hours of flight data, including a notable mission through a hurricane. The aim is to showcase the Aerosol Wind Profiler (AWP), which can deliver highly precise measurements of wind direction, wind speed, and aerosol concentration—essential components for enhancing weather forecasts.
Severe weather events, such as thunderstorms and hurricanes, can develop rapidly, underscoring the need for more reliable wind observations to improve prediction accuracy.
“There is a lack of global wind measurements above Earth’s surface,” stated Kris Bedka, the principal investigator for the AWP at NASA’s Langley Research Center in Hampton, Virginia. “Current methods involve data gathered by commercial aircraft en route to their destinations and by weather balloons launched up to twice a day from approximately 1,300 locations worldwide. Satellite images offer estimates of wind patterns by analyzing cloud and water vapor movements.”
Nonetheless, areas lacking cloud cover or easily trackable water vapor patterns often have few, if any, dependable wind measurements. The AWP aims to address these limitations by providing detailed 3D wind profiles.
Equipped on an aircraft with specialized viewing ports, AWP emits 200 laser energy pulses each second. These pulses scatter off various aerosol particles—such as pollutants, dust, smoke, seawater, and clouds—within the atmosphere. The movement of these particles alters the wavelength of the laser pulses, a phenomenon known as the Doppler effect.
The AWP sends out pulses in two directions, oriented 90 degrees apart. When combined, they generate a comprehensive 3D representation of wind vectors, detailing both speed and direction.
Kris Bedka
NASA Research Physical Scientist
“The Aerosol Wind Profiler can measure wind speed and direction simultaneously at multiple altitudes in the atmosphere with extraordinary precision,” Bedka elaborated. This capability can greatly enhance the understanding of weather patterns, allowing AWP’s data to play a crucial role in advancing weather modeling and forecasting techniques. Consequently, the instrument was selected as part of the National Oceanic and Atmospheric Administration’s (NOAA) Joint Venture Program, which seeks innovative data solutions to bridge gaps in existing weather forecasting systems. NASA also recognized the potential benefits of NOAA’s investments, contributing support to optimize the return on investment for both organizations.
Onboard NASA’s Gulfstream III (G-III) aircraft, AWP was paired with the High-Altitude Lidar Observatory (HALO), which assesses water vapor, aerosols, and cloud attributes using a combined differential absorption and high spectral resolution lidar.
This inaugural collaboration allowed AWP to measure winds while HALO collected aerosol and water vapor data, and NOAA dropsondes (small instruments deployed from the aircraft) gathered additional temperature and wind information.
“Deploying our instrument package on smaller, cost-effective aircraft grants us significant capabilities,” noted Bedka. “The combination of AWP and HALO represents NASA’s next-generation airborne weather remote sensing toolkit, which we aspire to adapt for satellite operation to benefit global weather monitoring.”
Kris Bedka
NASA Research Physical Scientist
Animation based on AWP data illustrates the intricate structure of aerosol layers in the atmosphere. According to Bedka, contemporary predictive models often fail to accurately depict aerosol organization throughout the atmospheric column.
“When we took off that day, I assumed we would encounter a clear atmosphere with minimal aerosol detection due to the onset of cool Canadian air,” Bedka recounted. “Surprisingly, we found ourselves in an aerosol-dense environment, enabling us to achieve remarkably detailed wind measurements.”
During the Joint Venture flights, Hurricane Helene was making landfall in Florida, prompting the AWP crew—comprising two pilots and five scientists—to hastily devise a flight path for collecting wind measurements along the storm’s outer bands.
“A 3D wind profile significantly enhances weather forecasting, especially for storm and hurricane prediction,” stated Harshesh Patel, acting manager of NOAA’s Joint Venture Program. “This AWP technology, developed at NASA Langley, presents promising capabilities that align well with NOAA’s requirements.”
The AWP lidar missions serve as a testing ground for potential integration into future satellite endeavors.
“To enhance global 3D wind models, a space-based platform is essential,” Patel added. “Instruments like the AWP have specific applications that could significantly support NOAA’s mission to deliver vital data for improved weather forecasts.”
Following the NOAA flights, AWP and HALO were directed to central California for the Westcoast & Heartland Hyperspectral Microwave Sensor Intensive Experiment and the Active Passive Profiling Experiment, supported by NASA’s Planetary Boundary Layer Decadal Survey Incubation Program and NASA Weather Programs. These investigations delve into atmospheric processes within the planetary boundary layer, the lowest atmospheric stratum influencing weather conditions at the surface.
For further information on NASA’s lidar initiatives, visit:
NASA Langley Research Center: Generations of Lidar Expertise
Source
www.nasa.gov