NASA News National Aeronautics and Space Administration Dryden Flight Research Center P.O. Box 273 Edwards, California 93523 AC 805-258-3449 FAX 805-258-3566 __________________________________________________________________________ For Release April 8, 1998 Kirsten Williams Dryden Flight Research Center, Edwards, Calif. (Phone: 805-258-2662) Allen Kenitzer Goddard Space Flight Center, Greenbelt, Md. (Phone: 301-286-2806) RELEASE NO: 98-18 EXPERIMENTS ABOARD NASA ER-2 VALIDATE SATELLITE RAINFALL MEASUREMENTS On Thursday April 9, a NASA Dryden Flight Research Center, Edwards, Calif., ER-2 Airborne Science aircraft is scheduled to deploy to Eglin Air Force Base, Fla., where it will help kick off a series of global field campaigns planned to validate measurements from NASA’s Tropical Rainfall Measuring Mission (TRMM) satellite, which was launched last November. The rainfall measuring satellite is slated to improve understanding of global climate change by providing more comprehensive information about rainfall. When clouds form, water vapor condenses, releasing what is know as “latent heat.” The release of latent heat energy in the atmosphere is the primary driver for atmospheric circulations in the tropics that can have vast global consequences, for example this year’s El Niño conditions. Because current rain measurements are inadequate, existing climate models do not accurately predict the amounts of heat being released. TRMM satellite data will help climate modelers in remedying one of their most serious deficiencies by providing more accurate rain and heat information. The month-long series of ER-2 flights are part of the two-phase Texas Florida Underflights (TEFLUN) experiment, which uses a combination of airborne and surface-based measurements, including ER-2 underflights of the satellite, to complement and verify the satellite data. This first phase of the experiment will concentrate on the southeast Texas region, while the second stage, planned for August-September 1998, will focus on Florida. ìThis is a very exciting field campaign in which we hope to obtain comprehensive data about precipitation systems,” said NASA TEFLUN Lead Scientist Gerry Heymsfield of NASA Goddard Space Flight Center, Greenbelt, Md. “This data will include TRMM satellite measurements and ER-2 remote measurements, as well as comparative ground-based and other airborne measurements. We use numerical models, which rely upon TRMM data inputs, to tell us about heating in the atmosphere. The TRMM field campaigns will provide important information for the validating these models.” “The ER-2 with its unique ability to carry a ton of scientific instruments for hours at altitudes above 60,000 ft. is a perfect match for this program,” said NASA ER-2 Pilot Jim Barrilleaux of the NASA Dryden Flight Research Center, Edwards, Calif. “We can loiter above the thunderstorm areas giving the scientists a full picture of the weather for use in comparison with ground radar and satellite data.” Two ER-2 aircraft are based at Dryden as part of NASA’s Airborne Science program. -more- During this phase of the experiment, the ER-2 will fly two different types of missions using a variety of highly specialized instruments. Sometimes the aircraft will “underfly” the satellite, which means it will follow the same path as the satellite, but at a much lower altitude. Scientists will compare measurements taken during these underflights directly with simultaneous satellite measurements. Since the TRMM satellite passes over any region in just a few minutes, however, the ER-2 , which is capable of cruising at altitudes as high as 70,000 feet, will more often “simulate” the satellite, gathering information by overflying precipitation systems within the experimental domain to provide comprehensive rainfall information. This phase of the program also includes measurements from the cloud physics aircraft, a Lear 24 jet owned and operated by SPEC, Inc. under contract with NASA which will fly at various altitudes up to 45,000 feet. In addition, the National Weather Service (NWS) operational Doppler radars (called WSR- 88Ds), the Texas A&M University Doppler Radar, the National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory’s X-band polarization radar and the NOAA Aeronomy dual-wavelength radar profiler system will gather information for the experiment. Information from the ground, special sounding systems and airborne sources, as well as the satellite, will provide a more complete and accurate precipitation picture for the region. Participating NASA centers for this experiment include NASA Headquarters, Washington, D.C.; the Dryden Flight Research Center; Goddard Space Flight Center; Ames Research Center, Moffett Field, Calif.; Jet Propulsion Laboratory, Pasadena, Calif.; and Marshall Space Flight Center, Huntsville, Ala. Other major partners include Texas A&M University, College Station, Texas; University of Alabama, Huntsville, Ala.; Massachusetts Institute of Technology, Cambridge, Mass., and the Environmental Research Laboratory and National Weather Service of NOAA. The lead scientists for the TEFLUN mission are Heymsfield and Ed Zipser of Texas A&M University. The Texas Florida Underflight experiment is the first of several field campaigns geared towards validating and complementing TRMM satellite data. Future field campaigns are scheduled for Brazil and the Marshall Island of Kwajalein. In addition, the satellite ground validation program includes routine collection of radar and rain gauge data around the globe, including Darwin, Australia; Marshall Island of Kwajalein; central Florida; southeast Texas; Phuket and Chaing Mai, Thailand; Israel; Taiwan and southern Brazil. Tropical Rainfall Measuring Mission Satellite The TRMM satellite, launched Nov. 27, 1997, is the first Earth Science observatory dedicated to studying the properties of tropical and subtropical rainfall. During its three-year lifespan, this joint NASA/Japanese Space Program satellite mission will obtain and study multi-year science data sets of tropical and subtropical rainfall measurements to understand how interactions between the sea, air and land masses produce changes in global rainfall and climate. Another important goal of TRMM is to study how El Niño-related rainfall anomalies correlate with other oceanic and atmospheric processes. The TRMM project is part of NASA’s Earth Science enterprise, a long-term coordinated research effort to study the total Earth system and the effects of natural and human-induced changes on the global environment. TRMM is managed by Goddard for the Office of Earth Science, Washington, D.C. NASA’s ER-2 High-Altitude Research Aircraft NASA’s ER-2s, manufactured by Lockheed Martin, are uniquely designed to carry high-altitude experiments at their cruising altitudes in the 70,000-foot range. The aircraft can carry scientific payloads of up to 2,600 pounds in a central fuselage bay, the nose and two wing pods. Although most missions last about six hours, including five hours at high altitude, the aircraft are capable of flying missions as long as eight hours over a 3,000-nautical-mile range. The ER-2s have been used on a wide variety of science missions, flying experiments related to Earth resources, celestial observations, atmospheric chemistry and dynamics, oceanic processes, electronic sensor research and development, satellite calibration and data validation, among others. They have flown atmospheric research missions from such far-flung spots as Punta Arenas, Chile; Bangor, Maine; Darwin, Australia; Stavanger, Norway; and the Fijian Islands. -more- -NASA- Videos and photos of the ER-2 are available from the Dryden Public Affairs Office to support this release. For photo prints or video footage, please call (805) 258-3449. Photos also are available on the Internet under NASA Dryden Research Aircraft Photo ArchiveURL: http://www.dfrc.nasa.gov/gallery/photo/ER-2/Small/index.html NASA Dryden news releases also are available on Dryden's website at: http://www.dfrc.nasa.gov/PAO/PressReleases/index.html TRMM satellite photos and information are available at Goddard’s Web site, URL: http://trmm.gsfc.nasa.gov -end- 3