Weather Forecasting
Getting More Complex
August 25, 2005 — By Randolph E. Schmid, Associated Press
WASHINGTON — The outlook for
predicting the weather is improving. Beginning this month the complex
computer programs used by forecasters are getting more data on
temperatures, water vapor and gases in the air and on how the ground
affects the weather, the National Oceanic and Atmospheric Administration
said Wednesday.
"This advancement makes it possible for NOAA forecasters to produce more
skillful forecasts," said National Weather Service director David L.
Johnson. "When the GFS improves, nearly all of the National Weather
Service's operational forecasts improve."
GFS is the Global Forecast System, which is used to develop a variety of
forecasts up to 15 days in advance including hurricanes, heavy rain,
drought, snowstorms, icing and aviation outlooks. It forecasts wind,
temperature, humidity and air pressure from the ground up to 35 miles
above the Earth.
NOAA said the program now includes a better look at the physics of the
atmosphere, a clearer representation of the Earth's terrain and improved
satellite data as well as other technical changes.
"Our nation will have longer-ranging alerts and forecasts through these
improvements to the current system," said Conrad C. Lautenbacher, NOAA
administrator.
Among the improvements was adding data from NASA's Atmospheric Infrared
Sounder aboard the Aqua satellite.
With the improved forecast system the scientists say they expect a 12
percent to 15 percent reduction in hurricane track forecast errors at 24
through 36 hours and about a 20 percent reduction in track forecast
errors at four to five days.
Stephen Lord, director of the NOAA Environmental Modeling Center, said a
significant part of the change is an increase in the resolution of the
GFS.
The computer model can now look at areas as small as 22 miles across,
down from 35 miles previously.
Source: Associated Press |