The Terrain-Induced Rotor Experiment (T-REX) is a coordinated international project, composed of an observational field campaign and a research program, focused on the investigation of atmospheric rotors and closely related phenomena in complex terrain. The T-REX field campaign took place during March and April 2006 in the lee of the southern Sierra Nevada in eastern California. Atmospheric rotors have been traditionally defined as quasi-two-dimensional atmospheric vortices that form parallel to and downwind of a mountain ridge under conditions conducive to the generation of large-amplitude mountain waves. Intermittency, high levels of turbulence, and complex small-scale internal structure characterize rotors, which are known hazards to general aviation. The objective of the T-REX field campaign was to provide an unprecedented comprehensive set of in situ and remotely sensed meteorological observations from the ground to UTLS altitudes for the documentation of the spatiotemporal characteristics and internal structure of a tightly coupled system consisting of an atmospheric rotor, terrain-induced internal gravity waves, and a complex terrain boundary layer. In addition, T-REX had several ancillary objectives including the studies of UTLS chemical distribution in the presence of mountain waves and complex-terrain boundary layer in the absence of waves and rotors. This overview provides a background of the project including the information on its science objectives, experimental design, and observational systems, along with highlights of key observations obtained during the field campaign.

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Desert Research Institute, Reno, Nevada

Naval Research Laboratory, Monterey, California

National Center for Atmospheric Research* Boulder, Colorado

University of Leeds, Leeds, United Kingdom

Yale University, New Haven, Connecticut

University of Utah, Salt Lake City, Utah

National Weather Service, Las Vegas, Nevada

Met Office, Exeter, United Kingdom

DLR, Oberphaffenhoffen, Germany

University of Wyoming, Laramie, Wyoming

University of Virginia, Charlottesville, Virginia

University of California, Berkeley, Berkeley, California

*The National Center for Atmospheric Research is sponsored by the National Science Foundation