March 1, 2006

The nation’s newest and most advanced research aircraft will participate in its first major mission March 1 through April 30, when it will study a severe type of atmospheric turbulence that forms near mountains and endangers airplanes. The $81.5 million HIAPER aircraft, owned by the National Science Foundation and operated by the National Center for Atmospheric Research (NCAR), will fly over treacherous whirlwinds, known as rotors, as they form above California’s Sierra Nevada mountain range.

HIAPER (High-performance Instrumented Airborne Platform for Environmental Research) will embark on a series of 10-hour flights that will take it from its base at Jefferson County Airport in Colorado to California’s Owens Valley during next month’s Terrain-Induced Rotor Experiment, or T-REX. The aircraft will explore the mountain waves that form over the Sierra Nevada and are associated with the rotors, as well as study the impacts of the waves on atmospheric regions as high as the stratosphere. The research will lead to better prediction of these aviation hazards.

Rotors, which form on the lee side of high, steep mountains beneath the cresting waves of air, have contributed to a number of aircraft accidents, but scientists know little about their structure and evolution. They are common in the Sierras because the area has the steepest topography in the continental United States. Owens Valley sits some 10,000 feet directly below the highest peaks of the adjacent mountains.

“From a scientific point of view, this will be a fantastic part of the atmosphere to be flying around in because of the mountain waves, the turbulence, and the movements of air masses,” says NCAR scientist Jorgen Jensen. “With our advanced instrument payload and our flight paths, the amount of data we will collect will be absolutely unprecedented for describing airflow over mountains.”

HIAPER, a highly instrumented Gulfstream V that is capable of reaching an altitude of 51,000 feet and cruising for 7,000 miles, is ideally suited for the experiment.

“HIAPER’s first science campaign, on the origin and evolution of rotors, could not have been done without the long-range capabilities of the aircraft,” says Margaret Leinen, NSF assistant director for geosciences. “In addition, the communications and data capabilities of HIAPER will allow the entire science team of T-REX to participate in the experiment, whether or not they are actually flying on board.”

James Huning, the program manager for HIAPER at the National Science Foundation, adds, “The project will help forecasters predict when and where rotors are most likely to occur and the degree of their intensity, as well as the nature of the mountain waves, or gravity waves that crest high above rotors and cause strong turbulence. Without HIAPER, this understanding would not be possible.”

NCAR’s Earth Observing Laboratory will oversee T-REX field operations from Bishop, California, and manage the resulting data.

“The results of this project should help pilots by enabling computer models to be more effective in forecasting turbulent conditions associated with mountain waves,” explains Richard Dirks, NCAR field operations director.

Project Details

The international research team of about 60 scientists, led by scientific project director Vanda Grubi

This text derived from http://www.ucar.edu/news/releases/2006/trex.shtml

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