In this talk we will present plans for future activities related to the Terrain-induced Rotor Experiment ("T REX"), a new initiative to study mountain-wave induced rotors and low- as well as upper-level turbulence in airflow over complex terrain. Rotors, low-level horizontal vortices that form parallel to, and downstream of, the mountain crest can pose severe aeronautical hazards and have been cited as causing aircraft upsets and accidents of commercial, military and civilian aviation. The geographical focus area of T-REX is Owens Valley in the southern Sierra Nevada in California.

T-REX is envisioned as a two phase effort. Phase I (2003-2005), consisting of a ground-based observing program and a number of planned numerical theoretical studies, is planned to set the stage for Phase II (2006). A major field experiment in March-April 2006 featuring enhanced ground-based systems and airborne observing program is the hallmark of Phase II. The primary objectives of Phase I are to (1) establish quantitative characteristics of the rotor behavior including the rotor type and location as well as the frequency distribution of the mountain-wave events, (2) evaluate the extent to which current operational mesoscale models can reliably forecast the occurrence of rotors. The results from Phase I will be an invaluable resource in planning the deployment of ground-based and airborne instruments in Phase II of T-REX.

The core objectives of T-REX are the rotor flow dynamics, gravity-wave breaking, sensitivity of mountain-scale flow to upstream/downstream conditions, numerical predictability of mountain-wave induced flows as well as aviation safety under rotor flow conditions. A number of supporting objectives include rotor/wave climatology, orographic precipitation, stratospheric/tropospheric exchange, phase transition in lee wave clouds, and "layering" of humidity in lenticular clouds.

The presently envisioned ground-observing network for Phase I will be described as well as a preliminary organizational structure of the T-REX project.