Early detection for tropical storms
A new instrument can detect tropical storms up to 46 hours sooner than conventional satellite photography.
The instrument uses a high frequency microwave scatterometer to detect wind speed and direction characteristic of tropical depressions at the ocean surface and is not inhibited by high-level cloud cover, which prevents satellite photography from detecting tropical storm cloud formations.
|IMAGE FROM QuikSCAT- January 31 2000. Yellow represents fastest winds - 35 knots, then orange (24), red (16), purple (12) and blue (0-6).|
Project scientist of SeaWinds at NASA's Jet Propulsion Laboratory in Pasadena, Timothy Liu says, "The ability of SeaWinds to see tropical depressions at their earliest stage provides the opportunity to identify and study the elements that create hurricanes".
During the 1999 Northern Hurricane season, SeaWinds data was used to identify 8 hurricanes. In those cases, it was able to detect the closed wind circulation well before it could be seen as cloud swirls on satellite image. The lead times ranged from three hours for Hurricane Irene to 46 hours for Hurricane Lenny.
During the current Northern hurricane season, scientists from the National Hurricane Centre and the Hurricane Research Division are comparing SeaWinds data with wind information from computer models, reconnaissance aircraft, satellites, and devices that measure temperature, moisture and relative humidity.
"This year the QuikSCAT data will be incorporated into a surface-wind analysis system of NOAA's Hurricane Research Division to produce the surface windfields in tropical storms in near real time," said Kastaros. "This will help the National Hurricane Centre in making decisions about warning the public when a storm threatens landfall."
SeaWinds, launched in June 1999 aboard the QuikSCAT satellite, travels over ninety percent of the Earth's ice-free oceans.