Daytime boundary layer structure and flows with interacting lake, valley, and urban circulations

As urban populations in the United States grow, it is becoming more important to understand the impacts of anthropogenic land cover change on local weather and air quality. Changes to surface temperatures and pollutant concentrations have consequences for human and environmental health. In this study, the structure and evolution of the daytime boundary layer and surface winds in the Salt Lake Valley were examined for the case of Intensive Observing Period (IOP) 6/7 during the Vertical Transport and Mixing Experiment (VTMX), a period with clear skies and light upper-level winds. The Pennsylvania State University - National Center for Atmospheric Research fifth generation Mesoscale Model (MM5) was used to simulate the case. Several features of interest were observed, including differential boundary layer growth across land cover boundaries, complex interactions between lake, slope, valley, and urban breezes, and a decrease in mid-valley boundary layer depth with the passage of the lake breeze front in the afternoon. The causes of these features were diagnosed using the MM5 output.