Supertyphoon Pongsona, December 2002
Human nature yearns to understand our planet's weather and how we affect it. In a pair of free lectures, Dr. Moustafa Chahine, science-team leader at NASA's Jet Propulsion Laboratory, Pasadena, Calif., will discuss NASA's Atmospheric Infrared Sounder instrument that is helping scientists understand Earth's weather and water cycle with unprecedented detail.

The instrument, along with its two companion instruments -- the Advanced Microwave Sounding Unit and the Humidity Sounder for Brazil -- launched in May 2002 on the NASA Aqua mission. JPL's Atmospheric Infrared Sounder measures Earth's atmosphere and surface, allowing scientists to improve weather prediction and observe changes in Earth's climate.

The three sounding instruments, with visible, infrared and microwave detectors, provide a three-dimensional look at Earth's weather. The three instruments can make simultaneous observations from space all the way to Earth's surface, even in the presence of heavy clouds. With more than 2,400 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases and other atmospheric phenomena.

"The accuracy of numerical weather prediction models is dependent upon the quality of today's weather information, which is largely based on weather balloons," Chahine said. "Our experiment will effectively multiply our existing global armada of 4,000 weather balloons 100 times, giving us global coverage over land and sea from space with the same data quality as ground-launched balloons. This additional data will dramatically reduce errors that have traditionally limited the range of current weather forecast models."

Chahine is a senior research scientist at JPL and science team leader for NASA's Atmospheric Infrared Sounder instrument. He received his Ph.D. in fluid physics in 1960 from the University of California at Berkeley, after which he came to JPL where he has served as founding manager of the Earth and Space Sciences Division and as laboratory chief scientist.

Both lectures begin at 7 p.m. Seating is on a first-come, first-served basis. The Thursday lecture will be webcast live and available after the event on the JPL Web site at: The lecture at JPL, located at 4800 Oak Grove Dr., Pasadena, off the Oak Grove Drive exit of the 210 (Foothill) Freeway, will be held in the von Karman Auditorium. The Friday lecture will be held in Pasadena City College's Vosloh Forum at 1570 E. Colorado Blvd. For more information, call (818) 354-0112.

Aqua is part of NASA's Earth Science Enterprise, a long-term research effort dedicated to understanding and protecting our home planet. Through the study of Earth, NASA will help provide sound science to policy and economic decision makers so as to better life here, while developing the technologies needed to explore the universe and search for life beyond our home planet.

JPL is a division of the California Institute of Technology in Pasadena.

News Media Contact

JPL/Colleen Sharkey
(818) 354-0372