RAPID: Cold Air Pool Exchange Processes during the Utah Wintertime Fine Particulate Study

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Persistent cold-air pools are a phenomena where air is effectively trapped in a basin or valley during high pressure events in wintertime. They are especially prevalent in high altitude basins in the western United States. One of the impacts of cold air pools is that particulate pollutants accumulate and affect the air quality for places like Salt Lake City, Utah. This award provides funding for researchers to take surface-based meteorological measurements during an existing aircraft-based air quality field campaign to better detail the processes that affect air movement within the cold air pools and impact the relevant chemical processes. In Salt Lake City alone there are over 1 million people affected by these events, and the research results may extend to other locations with similar topography such as Los Angeles and the Front Range of Colorado.The researchers will join the NOAA-led Utah Wintertime Fine Particulate Study which will take place in Jan-Feb 2017 in the Salt Lake City region. The NSF-funded researchers will augment the air quality focused study with meteorological measurements of the persistent cold pools that set up in the valleys and basins of Utah in the wintertime. In cold air pooling events vertical mixing is inhibited and particulate pollutants accumulate and affect human health. Multiple ceilometers, a lidar, sodar, temperature sensors, a surface flux station, and radiosonde launches will be deployed as ground-based assets to complement the NOAA aircraft campaign. The deployment will target key processes and questions regarding atmospheric mixing and airmass exchange that affect chemical composition and chemical pathways of particulate air pollution formation. The specific processes include: 1) vertical mixing within the persistent cold-air pool, 2) nighttime injections of clean, but oxidant-rich air along the basin sidewalls and through down-canyon flows, 3) daytime ventilation processes along the basin sidewalls, and 4) airmass exhanges with the lake boundary layer of the Great Salt Lake.