Pilots of transoceanic flights currently get preflight briefings and, in certain cases involving especially intense storms, in-flight weather updates every four hours. They also have onboard radar, but that information is of limited value for strategic flight planning while en route.
"Turbulence is the leading cause of injuries in commercial aviation," said John Haynes, Applied Sciences Program manager at NASA Headquarters in Washington. "This prototype system is of crucial importance to pilots and is another demonstration of the practical benefit of NASA's Earth observations."
Pinpointing turbulence associated with storms over the oceans is far more challenging than it is over land because geostationary satellites, unlike ground-based radar, cannot see within the clouds. Thunderstorms may develop quickly and move rapidly, rendering the briefings and weather updates obsolete. Onboard radars lack the power to see long distances or through dense clouds.
As a result, pilots often must choose between detouring hundreds of miles around potentially stormy areas or flying directly through a region that may or may not contain intense weather. Storms may be associated with hazardous windshear and icing conditions in addition to lightning, hail and potentially severe turbulence.To create the forecasts, Kessinger and her colleagues first turned to geostationary satellite measurements to identify regions of the atmosphere that met two conditions: particularly high cloud tops and water vapor at high altitudes. These two conditions are a sign of powerful storms and strong updrafts that can buffet an aircraft. The scientists next used fuzzy logic and data fusion techniques to home in on storms of particular concern, and applied object tracking techniques and simulations of wind fields to predict storm locations at hourly intervals out to eight hours. Researchers verified the forecasts using a variety of data from NASA Earth observations, including the Tropical Rainfall Measuring Mission (TRMM) satellite.