Content area
Full Text
Comprehensive, multiscale, and multidisciplinar y obser vations allow scientists to discover novel flow physics, address current def iciencies of predictive models, and improve weather prediction in mountainous terrain.
Through woods and mountain passes the winds, like anthems, roll.
-Henry Wadsworth Longfellow
For centuries, humans have been both fascinated and awed by mountain weather, and its intriguing aberrancy continues to baffle weather forecasters. For instance, a clear morning on a tranquil mountain slope can swiftly change into violent storms within hours while a nearby valley remains calm. The variability of mountain weather spans a wide swath of space-time scales, contributing to a myriad of phenomena that stymie the predictability of mountain weather. Although isolated mountains are rare, about 20% of Earth's land surface is covered by mountainous areas (Louis 1975). Topography less than 600 m in height (<5% of the atmospheric-scale height) is referred to as hills, but demarcations between different topographic features remain ambiguous. Orographic mosaics that incorporate slopes, valleys, canyons, escarpments, gullies, and buttes (also known as complex terrain) cover about 70% of Earth's land surface (Strobach 1991). The majority of the world's urban areas have emerged in complex terrain because of accompanying water resources. Systematic studies of mountain weather date back to the 1850s, followed by a decline of scientific activity in the early 1900s owing to observational difficulties. A resurgence of research occurred in the midtwentieth century with the advent of aerological networks (Bjerknes et al. 1934) as well as groundbreaking advances of mountain-wave and slope-flow studies (Prandtl 1942; Queney 1948; Long 1953). Vivid applications in areas of urban air pollution (Ellis et al. 2000; Fernando and Weil 2010), dispersion in cities (Allwine et al. 2002), wind energy harvesting (Banta et al. 2013), aviation (Politovich et al. 2011), alpine warfare (Winters et al. 2001), and firefighting (Albini et al. 1982) have burgeoned mountain meteorology, but understanding of flow physics and fidelity of predictions leaves much to be desired. Reviews of relevant past research are found in Taylor et al. (1987), Blumen (1990), Baines (1998), Belcher and Hunt (1998), Whiteman (2000), Wood (2000), Barry (2008), Fernando (2010), and Chow et al. (2013).
Prompted by applications-driven overarching science questions, in 2011 the U.S. Department of Defense (DoD) funded a 5-yr Multidisciplinary University Research...