The VTMX 2000 Campaign

A month-long meteorological field campaign sponsored by the Department of Energy's Environmental Meteorology Program was conducted during October 2000 in the Salt Lake Valley to study vertical transport and mixing (VTMX) processes. The goals of the program are to increase the understanding of these processes, to improve the ability to measure and characterize them, and to incorporate that improved knowledge into conceptual and numerical models that can be used to describe and predict them. The program is currently concentrating on nocturnal stable periods and morning and evening transition periods, and it is further focused on urban areas located in valleys, basins, or other settings affected by nearby elevated terrain. Approximately 75 people participated in the campaign. The campaign featured a wide range of remote sensing and in situ measurements, including those from 6 radar wind profilers, 6 sodars, 5 radio acoustic sounding systems, a Doppler lidar, 2 aerosol lidars, and a water vapor lidar, as many as 22 rawinsonde soundings per intensive observing period (IOP), and the simultaneous release of up to 7 perfluorocarbon tracers. Preliminary results show the existence of strong cold pools forming over the valley center with significant wind shear aloft and intermittent turbulence close to the surface, a heat island over the downtown area at night and areas with substantially cooler temperatures nearby, regions of strong convergence and divergence affected by a narrow jet through a gap in the mountains to the south and flows out of the canyons to the east, and extensive wave activity.