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DC-8 departs for new mission
Public Affairs Specialist The world’s largest atoll will be the site of a two-month experiment that is part of a NASA-led effort utilizing Dryden’s DC-8 "Flying Laboratory" to better understand tropical rainfall, improving weather forecasting and long-term climate modeling. More than 200 experts from NASA, other government agencies, universities, research institutions and foreign nations are traveling to the remote atoll, Kwajalein, a chain of coral islands that surround a 1,000 square mile lagoon. The atoll is part of the Republic of Marshall Islands in the tropical Pacific Ocean. The experiment, called KWAJEX, is part of a bigger NASA Tropical Rainfall Measuring Mission (TRMM), during which scientists throughout the world are gathering detailed weather data on the ground, by airplane, ship and balloon. Researchers will calibrate instruments onboard the mission’s TRMM satellite and gather detailed weather data the satellite cannot obtain remotely. KWAJEX is the last of a series of experiments conducted as part of TRMM and is to continue through Sept. 15. "NASA and the Japanese National Space Development Agency launched the TRMM satellite from which we’ll get global precipitation measurements," said Steve Hipskind, Chief of the Atmospheric Chemistry and Dynamics Branch at NASA’s Ames Research Center, Moffett Field, Calif. By measuring tropical rainfall, scientists hope to get a better overall picture of how the Sun’s energy, concentrated in the tropics, is transferred from the ocean to the atmosphere. A better understanding of the energy transfer that drives the atmospheric motion will help scientists improve global computer models to better forecast weather and long-term climate change. The goals of the experiment are to better understand the exact nature of oceanic rainfall and how it differs from rain over land. "We know from the TRMM observations, for instance, that thunderstorms tend to be much weaker over oceans than over land," said TRMM Project Scientist Chris Kummerow of NASA Goddard Space Flight Center, Greenbelt, Md. "These differences in the clouds and possibly down to the raindrops themselves must be understood first and then accounted for in the satellite measurements if credible rainfall estimates are to be made around the globe. "When scientists first put together the plan for the satellite, they also made a ground observation plan," Hipskind said. The plan supplements satellite observations with detailed measurements of clouds. The plan included setting up long-term measuring stations at numerous locations around the globe. "Once you are able to establish the relationship between what the satellite is seeing and what is happening in detail in the atmosphere, then you can have confidence in the satellite measurements on a global scale," Hipskind said. The DC-8 serves two roles for the experiment. That aircraft simulates satellite overpasses by flying above clouds with the same instruments that are aboard the TRMM satellite – radar and radiometers. The DC-8 also collects data from within clouds, using cloud particle imager and sampling equipment to measure vapor, liquid, solid particle size, temperature, density and motion. Images from the TRMM mission are available on the Internet at URL: http://trmm.gsfc.nasa.gov/ For more information on Dryden’s DC-8, try this URL: /centers/dfrc/Projects/airsci/general/dc-8/dc8page.html |
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Responsible NASA Official: John Childress For questions, contact: Dryden Web Group Page Curator:WD-Team Modified: August 18, 1999 |
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