Weather Conditions During the 2013 SAS/SOAS Field Campaign: Providing Meteorological Context to the Extensive Project Measurements

The Southeast Atmosphere Study (SAS)/Southern Oxidant and Aerosol Study (SOAS) (url: http://www.eol.ucar.edu/projects/sas/) was a joint project supported by the National Science Foundation, the Environmental Protection Agency, Electric Power Research Institute and 30 US and International Research Institutions, and was the largest U.S. air quality study in decades. This collaborative project addressed various components of air quality, chemical and aerosol constituent evolution over the SE US. An international team of investigators brought an unprecedented suite of chemical species filter sampling equipment and in-situ sensors to characterize the atmosphere and the chemical processes occurring within it with specific emphasis on the characterization of the content, form and evolution of chemical and aerosol species in the humid Southeast US from 1 June-15 July during summer. The main ';super site' brought ~100 participants and ~50 specialized samplers and analyzers to the EPRI sponsored SouthEastern Aerosol and Atmospheric Characterization (SEARCH) Network site near Brent, Alabama. The purpose of this presentation is to provide the meteorological context to the observations that were made at the central Alabama ';super site' described above. The long-term climatology of the region suggested that the weather would be relatively quiet during the period with the occasional air mass change (frontal passage) and a few days of showers and/or windy conditions. What actually happened during the 45-day campaign was generally a much more unsettled period that included several frontal passages, a large number of rainy days and cooler than normal temperatures. Table 1 provides a preliminary summary of conditions during the campaign. The number of quiet or stagnant periods that might allow the buildup of various chemical constituents important to the study were infrequent and did not last for extended periods. Contact will be made with the Alabama State Climatologist to improve our perspective about the weather conditions that transpired during the 45-day project period. The wetter than normal conditions did result in several rainfall records in the region. We will also contact colleagues at the other ground sites (Look Rock, TN and Raleigh, NC) to compare and contrast their weather conditions during the SOAS deployment.Table 1. Preliminary summary of general weather conditions during the 45 day SOAS campaign during June-July, 2013