Synoptic flow interactions with Granite Mountain during MATERHORN

In the spring 2013, the Mountain Terrain Atmospheric Modeling and Observations Program (MATERHORN) conducted its second extensive field experiment at the Granite Mountain Atmospheric Science Testbed (GMAST), US Army Dugway Proving Grounds (DPG), Utah. Of particular interest to MATERHORN-X-2 were synoptically dominated conditions in which synoptic flows interacted with thermal circulation and with the topography, leading to modulations of thermal circulation and external-flow. Observed phenomena include eddies, large vortices, wakes, separated flows and lee and progressive waves. To capture these phenomena, a suite of remote sensors and in-situ instrumentation was used, which could characterize the upstream, unmodified synoptic approach flow and identify the synoptic flow/mountain interactions. In addition to meteorological towers, Doppler LiDARs placed at two locations to the east and in the lee of Granite Mountain were particularly useful, showing the horizontal spatial pattern and temporal evolution of synoptic-flow generated phenomena. To further investigate and provide guidance in analysis, WRF simulations were conducted.