The main scientific objective of T-REX is a comprehensive study of the coupled mountain-wave, rotor, and boundary-layer system. Some complimentary scientific issues include stratospheric-tropospheric exchange and structure and evolution of the complex terrain boundary layer in the absence of rotors. The comprehensive T-REX data sets will also represent a unique test bed for the validation of numerical models, and are expected to be instrumental in achieving further significant improvements in mesoscale and microscale modeling and in the prediction of aviation hazards, downslope windstorms, and aerosol transport and dispersion.
The observational thrusts are two-fold: 1) comprehensive ground-based and
airborne, in situ and remote sensing measurements during strongly perturbed conditions favoring rotor
formation, and 2) comprehensive observations of complex terrain broundary layer structure and
evolution from undisturbed to strongly perturbed conditions.

T-REX field activities will take place in Owens Valley in March and April 2006. Owens Valley lies
to the east of the southern Sierra Nevada, which is the tallest, steepest, quasi two-dimensional
topographic barrier in the contiguous United States. Mountain waves and attendant rotors are know to
reach particularly striking amplitude and strength there. Climatological studies, including results from
Phase I, show that the months of March and April have the highest frequency of rotor events. Ground-based and
airborne, in-situ and remote sensing measurements will be conducted both upwind and within Owens
Valley during the two month period.
