Since last fall, NASA scientists have flew advanced 3D Doppler wind pain instruments throughout the United States to collect nearly 100 hours of data, including flights through the hurricane. Target? To demonstrate the unique capabilities of the Aerosol Wind Profile (AWP) instrument to collect extremely accurate measurements of wind direction, wind speed and aerosol concentration – all key elements for accurate weather forecasts.

Weather phenomena such as severe thunderstorms and hurricanes are developing rapidly, so improving predictions requires more accurate wind observations.

“There is a lack of global wind measurements above the Earth’s surface,” explains Kris Bedka, principal investigator at the NASA Langley Research Center in Hampton, Virginia. “Wind is measured when commercial aircraft fly to destinations, with only 1,300 locations launching balloons twice a day. From space, wind is estimated by tracking satellite images of clouds and water vapor movements.”

However, in areas where there are no clouds or where water vapor patterns cannot be easily tracked, there are usually no reliable wind measurements. AWP instruments are designed to fill these gaps with detailed 3D wind profiles.

The AWP is mounted on the aircraft and has a viewing port under it, sending out 200 pulses of laser energy per second, which scatter and reflect aerosol particles (such as pollution, dust, smoke, smoke, sea salt and clouds). The movement of aerosols and cloud particles leads to changes in laser pulse wavelengths, a concept called the Doppler effect.

The AWP instrument sends these pulses in two directions, 90 degrees apart from each other. Combined together, they create a 3D outline of the wind vector, representing wind speed and direction.

"The aerosol wind profile is able to measure wind speed and direction, not just at a given point," Bedka said. "Instead, we are simultaneously measuring winds at different altitudes in the atmosphere with extremely high detail and accuracy."

Vectors help researchers and meteorologists understand the weather, so the measurements of AWP can greatly improve weather modeling and prediction. Therefore, the tool was selected as part of the National Oceanic and Atmospheric Administration (NOAA) joint venture program, which seeks from new technologies that can fill gaps in current weather forecasting systems. NASA's weather program also gains common benefits in NOAA's investments and provides additional support to increase the return on investment for both institutions.

AWP is paired with the agency's High Altitude LIDAR Observatory (HALO) on a NASA's Gulfstream III (G-III) aircraft, which measures water vapor, aerosol and cloud properties through a combined differential absorption and hyperspectral resolution lidar.

AWP collaborated for the first time to measure wind, Halo collected water vapor and aerosol data, and NOAA Dropsondes (a small musical instrument that fell from a tube at the bottom of the aircraft) collected temperature, water vapor and wind data.

“We have very powerful capabilities with small, affordable aircraft,” Bedka said. “The combination of AWP and Halo is NASA’s next-generation airborne weather remote sensing package, and we hope it will also be available for satellite rides, benefiting everyone around the world.”

The animation below is based on AWP data, showing the complexity and structure of the aerosol layer present in the atmosphere. Bedka said the current prediction model cannot accurately simulate how aerosols are organized over the entire atmospheric breadth.

“When we take off on this day, I think we’ll find a clear atmosphere with little to no aerosol back because we’re flying into the first real explosion of the cool Canadian air in autumn,” Bedka said. “What we’ve found is the opposite: an aerosol-rich environment that provides an excellent signal for accurately measuring wind.”

Hurricane Helen made landfall in Florida during a joint venture flight. Two pilots and five members of the AWP crew quickly developed a flight plan to perform wind measurements along the takeaway of severe storms.

"3D wind profiles can greatly improve weather forecasts, especially for storms and hurricanes," said Harshesh Patel, acting joint venture program manager at NOAA. "NASA Langley specializes in the development of coherent Doppler wind pain technology, and this AWP concept has the potential to provide better performance for NOAA's needs."

AWP LiDAR flights are the basis for exploring the integration of future satellite missions into possible integration.

“The need to improve global 3D wind models requires a space-based platform,” Patel added. “Instruments like AWP have specific space applications that may coincide with NOAA’s mission, which provides key data for improving weather forecasts.”

AWP and Halo are sent to Central California after NOAA flight Westcoast & Heartland hyperspectral microwave sensor intensive experiments and active passive analytical experiments supported by NASA's Planetary Boundary Inter-Stratigraphic Survey Incubation Program and NASA Weather Program. These tasks study atmospheric processes within the planet’s boundary layer, the lowest part of the atmosphere, which drives the weather conditions we experience on the ground.

Learn more about LiDAR instruments in a NASA visit:

NASA Langley Research Center: Generations of LiDAR expertise