AIRS and Weather Science
Weather
Overview
A major goal of the AIRS mission has been to improve weather forecasts by providing more complete atmospheric observations, especially over the oceans. Historically, measurement packages on weather balloons have been the most important source of information about Earth's atmosphere. But weather balloons have limitations. Most balloons are launched over land in select areas, which means the 75% of the world covered by ocean is not sampled. Economic differences between countries also influence coverage. Europe and North America have excellent coverage, while much of Africa, Asia and South America are sparsely sampled.
With it's vantage point from space, AIRS makes a total of 2.9M observations (or 324,000 retrievals) around the globe each day. Measurements derived from AIRS data rival the quality of US weather balloons, but offer a data set that is consistent, uniform, and accurate, and global.
AIRS data are assimilated at several national operational weather prediction centers (NWP) around the world, and the inclusion of AIRS data has been proven to increase forecast skill and improve hurricane path prediction. The National Oceanic and Atmospheric Administration (NOAA) assists in development of the AIRS data products and processes and distributes the AIRS data within 1-3 hours of acquisition to NWP centers worldwide.
AIRS data have been used to study long range transport of volcanic sulfur dioxide in order to provide better estimates of volcanic emissions and assist the Volcanic Ash Advisory Centers to locate these hazardous clouds. AIRS data are also being used by the U.S. Agency for International Development (USAID) and the USGS in support of the Famine Early Warning Systems Network.
Because of such notable advances from AIRS data, NOAA Administrator Conrad Lautenbacher stated in an August 24, 2005 press release:
"The AIRS instrument has provided the most significant increase in forecast improvement in this time range of any other single instrument".
Operational Weather Centers & Direct Broadcast
The polar-orbiting Aqua spacecraft, launched by NASA in May 2002, provides an X-band direct broadcast service where data from all science instruments is downlinked to the Earth in near real-time.
AIRS contributions to weather science are many. View a synopsis here:
Cyclone Nargis became the worst natural disaster in the recorded history of Burma, causing at least 138,000 fatalities in 2008. Tropical cyclones over the Bay of Bengal, just west of Burma, are difficult to predict because it is small and shallow. Cyclones there tend to have erratic tracks and short life spans.
To see if Nargis' path could have been better predicted, researchers used AIRS temperature measurements of the local atmosphere taken under partly cloudy conditions. Most forecast models rely on AIRS data collected in clear-sky conditions, but cloudy areas are more relevant to storms.
When AIRS data in cloudy regions were excluded, forecasts predicted that Nargis would not make landfall, or gave a location for landfall that was 300 kilometers, 186 miles, away from true landfall. Including AIRS data over partly-cloudy areas allowed researchers to pinpoint Nargis' landfall to within 50 kilometers, 31 miles, of the true location. This method showed similar improvements when applied to Atlantic hurricane forecasts.
Science Paper
Reale, O., W. K. Lau, J. Susskind, E. Brin, E. Liu, L. P. Riishojgaard, M. Fuentes, and R. Rosenberg (2009), AIRS impact on the analysis and forecast track of tropical cyclone Nargis in a global data assimilation and forecasting system, Geophys. Res. Lett., 36, L06812, doi:10.1029/2008GL037122.
NASA News Release
NASA Experiment Stirs Up Hope for Forecasting Deadliest Cyclones
Feature Article
An excellent summary of these findings is given on the NASA Global Climate Change Web Site, in a Cutting Edge Brief called "Breaking Through the Clouds". Take a look to find out how cloudy skies can actually help cyclone prediction.
Cyclone Nargis Image Archive
Views of Cyclone Nargis as the storm evolved can be found on the NASA Hurricane Resource Web Site.
Improving tropical cyclone forecasts using cloudy-sky data from the AIRS mission.
Credit: Dr. Oreste Reale, NASA/GSFC. Copyright 2009 American Geophysical Union
Weather Spotlight: Hurricane Path Prediction - Improving our estimation of landfall
AIRS infrared image of Cyclone Nargis, May 4, 2008 shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures in purple are high, cold cloud tops.
Credit: Dr. Edward Olsen, NASA/JPL
"The forecast improvement accomplishment alone makes the AIRS project well worth the American taxpayers' investment"
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- Dr. Mary Cleave, associate administrator of NASA's Science Mission Directorate
AIRS Contributions to
Weather Science