Abstract : I.2
The nature of intermittent turbulent exchange in a complex terrain valley

Gregory Poulos, Juerg Schmidli
gsp@ucar.edu
National Center for Atmospheric Research, EOL-ISF

In March-April 2006 during the Terrain-Induced Rotors Experiment a series of relatively quiescent periods were studied. These EOPs (Enhanced Observing Periods) were marked by relatively slack synoptic pressure gradients, limited mountain wave activity, clear to nearly clear skies and more notable traditional valley circulations. During EOP-3 and the night that followed it - UTC nights of 19 and 20 April - conditions were particularly quiescent and clear and thereby likely candidates for the study of the stable boundary layer in the Owens Valley.

Herein data are presented from, primarily two tall towers that were placed near the north-south oriented valley center in nearly flat (slopes within 3 km < 0.5 degrees) areas. Adjacent are the Sierra Nevada which rise 3000 m to the west and the White Mountains which rise 1500 m to the east. Our data show that stably stratified conditions in this location are marked by intermittent turbulence, not unlike, but of different magnitude than similar conditions over non-mountainous flat terrain. These differences are quantified and their relevance to the behavior of turbulent exchange in complex terrain valleys is presented.