Evaluating Evaporative Fluxes in Complex Mountain Terrain

In mountains, the role of diurnal wind (i.e. valley, slope winds) due to differential heating and radiation and topography in controlling evaporative fluxes is not well understood. The Weather Research and Forecasting (WRF) model was applied in the complex terrain of the Kananaskis valley, Canadian Rockies, Alberta, to investigate the performance of the model for creating the surface driving data needed to calculate evaporative fluxes for fair-weather summer days. The model results were validated against measurements made using atmospheric sounding by SODAR and Wind-RASS profilers, and several micrometeorological stations located in both high altitude ridge top and valley bottom locations, providing regular measurements of the main atmospheric variables, such as air temperature, humidity, atmospheric pressure, solar irradiance, wind speed and direction. The use of PBL schemes and Large Eddy Simulations (LES) in WRF was examined by applying local filtering to alleviate the problems with steep terrain in the terrain-following vertical coordinate of WRF. The model was used to examine the temporal and spatial evolution of wind and fluxes with variability in topography and how this influences evaporation fluxes.