August 24, 2005
3-D Science Improves Weather Forecasts
NASA -- 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.
NASA and the National Oceanic and Atmospheric Administration (NOAA) today outlined research that has helped to improve the accuracy of medium-range weather forecasts in the Northern Hemisphere.NASA and NOAA scientists at the Joint Center for Satellite Data Assimilation (JCSDA) in Camp Springs, Md., came up with procedures to improve forecasting accuracy. The scientists worked with experimental data from the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite.
They found incorporating AIRS data into numerical weather prediction models improves the accuracy range of experimental six-day Northern Hemisphere weather forecasts by up to six hours, a four percent increase. AIRS is a high-spectral resolution infrared instrument that takes 3-D pictures of atmospheric temperatures, water vapor and trace gases.
The instrument data have officially been incorporated into NOAA's National Weather Service's operational weather forecasts.
"NASA is assisting the world's weather prediction agencies by providing very detailed, accurate observations of key atmospheric variables that interact to shape our weather and climate," said Dr. Mary Cleave, associate administrator for NASA's Science Mission Directorate. "The forecast improvement accomplishment alone makes the AIRS project well worth the American taxpayers' investment."
"This AIRS instrument has provided the most significant increase in forecast improvement in this time range of any other single instrument," said retired Navy Vice Adm. Conrad C. Lautenbacher, Jr., Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator.
"Climate and weather forecasts are dependent upon our understanding current global ocean and atmosphere conditions. If we want to be able to predict what the weather will be like in the future, we must adequately define the global conditions today. Satellite data, like AIRS provides, is a vital link for NOAA to take the pulse of the planet continuously," added Lautenbacher.
"A four-percent increase in forecast accuracy at five or six days normally takes several years to achieve," said JSCDA Director, Dr. John LeMarshall. "This is a major advancement, and it is only the start of what we may see as much more data from this instrument is incorporated into operational forecast models at the NOAA's Environmental Modeling Center."
The European Center for Medium Range Weather Forecasts began incorporating data from AIRS into their operational forecasts in October 2003. The center reported an improvement in forecast accuracy of eight hours in Southern Hemisphere five-day forecasts.
AIRS is the result of more than 30 years of atmospheric research and is led by Dr. Moustafa Chahine of NASA's Jet Propulsion Laboratory, Pasadena, Calif. AIRS is the first in a series of advanced infrared sounders that will provide accurate, detailed atmospheric temperature and moisture observations for weather and climate applications.
The JCSDA is operated by NOAA, NASA, the U.S. Air Force and Navy. The goals of the center are to accelerate the use of observations from Earth-orbiting satellites to improve weather and climate forecasts, and to increase the accuracy of climate data sets.
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