Synoptic Flow Interactions with an Isolated Mountain in Complex Terrain

In the spring of 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 synoptic dominated conditions in which synoptic flows interacted with the topography leading to external-flow generated lee and progressive waves and if the Froude number was low; development of eddies, large vortices, wakes and waves in the lee of Granite Mountain. To capture these phenomena, a suite of advanced instrumentation was used, which could characterize the upstream unmodified synoptic approach flow and identify the synoptic flow / mountain interactions. In addition to meteorological towers, three 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 the synoptic generated phenomena. WRF simulations were used to provide analysis guidance. This research was funded by Office of Naval Research Grant # N00014-11-1-0709 and the Air Force Weather Agency.