Thursday,12 October, 3:00 pm, EN6085A

Exploration of Atmospheric Rotors in Terrain-induced Rotor Experiment (T-REX)

The Terrain-induced Rotor Experiment (T-REX) is the second phase of a coordinated effort to explore the structure and evolution of an atmospheric rotors and related phenomena in complex terrain.  Atmospheric rotors are intense low-level horizontal vortices that form along an axis parallel to, and downstream of, a mountain ridge crest. These vortices with rich, fine-scale internal structure are strongly coupled to both the overlying mountain waves as well as the underlying boundary layer. The field campaign of the Terrain-induced Rotor Experiment (T-REX) took place in March and April 2006 in Owens Valley, CA, which was also the location of the Sierra Rotors Project, the initial phase experiment in March and April 2004. Fifteen Intensive Observing Periods that documented the rotor coupled system were carried out during the two-month field campaign. The comprehensive T-REX data sets afford us with a unique opportunity to address basic scientific questions motivated by T-REX, and provide crucial observations for numerical model validation.

During T-REX, highly turbulent flows in atmospheric rotors in the lee of the Sierra Nevada were probed by the University of Wyoming King Air (UWKA) 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 and rotor 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. We will discuss in more detail the role of UWKA in T-REX, and the analysis of observations and high-resolution modeling of selected T-REX rotor events.