The study was announced at a press conference in Salt Lake City yesterday. It is part of a four-year, $12 million effort to understand the vertical transport and mixing of the atmosphere. The study is sponsored by DOE's Office of Biological and Environmental Research.
Fourteen different research organizations are involved in the study, including several DOE labs, universities, government agencies and private industry.
Several research groups from Los Alamos National Laboratory will participate in observation and modeling activities as part of the URBAN/VTMX experiment. The URBAN experiment will measure air motion and tracer dispersion on scales encompassing the downtown area and buildings, while the VTMX experiment will look at larger urban and basin scales.
Los Alamos' Atmospheric and Climate Sciences Group is deploying volume imaging, scanning, high-resolution Raman lidar to measure water vapor and temperature in a large, open area on the lower slopes of the mountains on the west side of the Salt Lake basin. The goals of these measurements are to help characterize the evolution of the lower atmosphere at night, to reveal the fundamental mechanisms and characteristic scales of vertical transport and mixing in inversions and to provide data for models.
The group is also operating one of the radar wind profilers to measure wind speed and direction at various heights above the ground. The Los Alamos profiler is located at the mouth of one of the large canyons draining into the basin. It will measure cold air drainage flows out of the canyon and the mixing of these flows with the cold air pool in the basin.
Members of the Lab's Energy and Environmental Analysis Group will deploy six wind and temperature stations in downtown Salt Lake City.
"Our two-dimensional wind measurements, taken every second, will provide data to help us understand the complexities of air circulation around buildings and the turbulence generated as incoming winds impact buildings," said Jerry Streit. "We are also taking temperature measurements at two heights above rooftops to obtain data to help understand heat fluxes from urban surfaces," he said. "The heat fluxes affect the micrometeorology in cities."
The Los Alamos researchers are among sixty from around the country who will use more than 200 three-foot-diameter weather balloons, three laser systems, nine major instrument sites, dozens of meteorological ground stations and a research plane to gather data throughout the Salt Lake City valley, covering roughly 460 square miles.
"This study will focus on certain poorly understood atmospheric processes that affect how air mixes and moves vertically," said Chris Doran of DOE's Pacific Northwest National Laboratory, and lead scientist for the study, in a DOE news release. "Gaining a better understanding of how pollutant-trapping inversions form and break up has implications for improving air quality, weather forecasting and even aircraft operations."
The Los Alamos scientists' measurements are closely tied to a network of other meteorological instruments in downtown Salt Lake City, deployed by other study participants. There will be six intensive operation periods during October in which tracers will be released by the National Oceanographic and Atmospheric Agency and the plume sampled throughout the downtown area.
Scientists are particularly interested in gathering data on how the atmosphere mixes at nighttime and in the evening and early morning when the atmosphere is more stratified and there is less turbulence than in the daytime.
The Salt Lake City valley's topography is complex, providing a good setting to study how cold night air collects in mountain basins. Cold air pools below warmer air, creating a temperature inversion that can trap pollutants. Learning more about the nighttime pooling effect should help scientists predict the impacts of weather on an entire city in a basin region.
Los Alamos National Laboratory, a multidisciplinary research institution engaged in strategic science on behalf of national security, is operated by Los Alamos National Security, LLC, a team composed of Bechtel National, the University of California, The Babcock & Wilcox Company, and Washington Group International for the Department of Energy's National Nuclear Security Administration.
Los Alamos enhances national security by ensuring the safety and reliability of the U.S. nuclear stockpile, developing technologies to reduce threats from weapons of mass destruction, and solving problems related to energy, environment, infrastructure, health, and global security concerns.