Microscale Winds in Complex Terrain: Insights from the Perdigão Mega Project *

More than 70% of the Earth’s land surface is in complex terrain, and thus mountain meteorology has attracted the atten­tion of a wide range of constituencies, including meteorologists, fluid dynamists, and wind engineers. Most past research on winds in complex terrain has been on mesoscales (~1–100 km; hours to days), spurred by air pollution, aviation, warfare, and energy applications. Comprehensive field projects with mesoscale emphasis abound, some examples being VTMX, T-REX, MATERHORN and WFIP-2. More recently, however, microscale (1-500 m; seconds to hours) flows in complex terrain have received increasing interest owing to growing applications in wind engineering, urban modeling and firefighting. To this end, after a decade of preparation, the Perdigão mega-project came to fruition in 2017, participated by EU and US groups that included some 70+ research and technical personnel.  The terrain, instrumentation, and collaborative arrangements of the Perdigão project were all unique, for more information see: https://doi.org/10.1175/BAMS-D-17-0227.1.  This presentation describes the evolution of the project, its conduct, as well as selected results of flow through small topographic features and over heterogeneous surfaces relevant to wind energy prospecting.