Multi-Doppler Measurements of Atmospheric Rotors and Turbulent Mountain Waves

Radar measurements of reflectivity and Doppler velocity for selected cases of rotors and turbulence associated with mountain waves from 2006 T-REX and NASA06 field campaigns are analyzed. The data were collected with the Wyoming Cloud Radar (WCR, http://atmos.uwyo.edu/wcr) on board the University of Wyoming King Air research aircraft (UWKA, https://atmos.uwyo.edu/n2uw). The retrieval of single-Doppler vertical velocity at 30 m resolution above and below the aircraft and two-dimensional (2-D), high-resolution (on the order of 40?40 m²) Dual-Doppler, vertical velocity fields below the aircraft are discussed. The results demonstrate complex dynamics occurring within mountain cap and roll/rotor clouds. Turbulent dynamics and small-scale vortices, without the presence of a larger-scale organized vortex, appear to be more prevalent below mountain wave crests at low levels. The analysis of radar data from consecutive passes during mountain wave events also suggests that while the terrain-induced waves exhibit both stationary and non-stationary behavior, there is a significant evolution in the turbulent dynamics under mountain wave crests and individual features/vortices have a variable life span (on the order of minutes to tens of minutes). The reflectivity fields reveal a disorganized and turbulent structure of the scatterers in the roll clouds. When scatterers are present below the roll cloud (e.g., due to precipitation) their distribution is highly non-uniform. Our radar data does not resolve the 3^rd dimension (across these flight tracks) and thus some 2-D assumptions are made.