Upslope Flow Studies in Complex Terrain

Upslope (anabatic) flow in complex terrain contributes significantly to local and regional weather by transporting large amounts of heat and moisture, first along the slope and thereafter vertically upon flow separation. Upslope flow also transports air pollutants and contaminants effectively within an airshed. Previous studies have reported several parameterizations for the properties of upslope flow, which have been investigated using adventitious sets of data taken during field experiments and some laboratory experiments. This paper reports the results of a focused instrumentation deployment within the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) Program to study slope flows as well as analysis of associated laboratory studies. The aim is to investigate parameterizations for turbulent anabatic flows in complex terrain. The data from a series of heavily instrumented tall (~32m) towers installed on the mountain slopes of the MATERHORN field site are analyzed. The laboratory experiments consist of heating a simple slope with an approximately constant heat flux, and measuring the upslope velocity. Available limited data from the PAFEX [Pardyjak et al., Meteorologische Zeitschrift, 18(1), 85, 2009] and VTMX [Monti et al., J. Atmos. Sci., 57(17), 2513, 2001] experiments are also analyzed for upslope flow information. The data points to the efficacy of the parameterization proposed by Hunt et al. [J. Atmos. Sci., 60(17), 2169, 2003] for upslope flow velocity.