Zeroing In on Hurricane Winds
Hurricane forecasting may get a boost from two new tools for measuring wind speed. A team of researchers at NASA Langley Research Center is using GPS signals to calculate wind speeds over large bodies of water. When a radio wave from a GPS satellite strikes the surface of the ocean, about 60 percent of the signal reflects back toward the sky. As winds build, wave heights increase and sea state grows rougher, which leads to more scattering of the returned signal. By comparing GPS signals coming directly from satellites above the aircraft with reflections from the sea below, an approximate wind speed can be calculated to within an accuracy range of about 11 mph.
KIMBRA CUTLIP is a freelance writer and former assistant editor for Weatherwise.