Atmosperhic rotors: Aircraft in situ and cloud radar measurements in T-REX

During the Terrain-induced Rotor Experiment in March and April 2006, highly turbulent flows in atmospheric rotors in the lee of the Sierra Nevada were probed by the University of Wyoming King Air aircraft. In situ thermodynamic and kinematic data were obtained on rotor circulations and wave structure over Owens Valley in a number of research missions under strong wave conditions. Sufficiently strong signal returns from the Wyoming Cloud Radar (WCR) were granted by the presence of ice particles within different types of clouds associated with the wave/rotor system, including mountain cap clouds over the Sierra crest, "spill over" clouds over the eastern Sierra slopes as well as wave and rotor clouds over Owens Valley. In a selected number of missions (IOP 3, IOP 4, IOP 11), returns from the rotor clouds allowed dual-Doppler analyses of air motions within the upper part of the rotor circulation.

In this study, we use the in situ data measured by the UW King Air and remote-sensing data from the WCR to address the causal relationship between waves and rotors, and to reveal fine-scale internal structures of the circulations within rotor clouds. High-resolution real-data COAMPS simulations are used to provide further insight into the overall evolution and structure of the flow field over the Sierra Nevada and Owens Valley, including waves and rotors.