Extended Abstract (2.9M)J1.3
Variability of Georgia and Florida air quality as a function of radar derived aerosol coverage and height
Thomas A. Jones, Univ. of Alabama, Huntsville, AL; and S. A. Christopher
Substantial biomass burning occurred in the forested regions of southern Georgia during May 2007 due to abnormally low precipitation causing extreme drought conditions. Smoke and aerosols produced from these fires had large impacts on air-quality both near and over 1000 km away from the source fires. Surface air quality is a function of many parameters including intensity of burning, wind speed and direction, atmospheric stability, and ambient humidity. One very important parameter is the interaction between the vertical distribution of aerosols and the associated atmospheric stability. During periods of high stability, aerosols are trapped in the boundary layer, lower air quality greatest near the source regions. If stability is low, or aerosols are transported directly into the free atmosphere, air quality long distances downstream can be affected. However, the vertical distribution of aerosols is generally poorly sampled, and what data does exist is not continuous in space or time. Fortunately, many of the Georgia fires occurred within range of the Jacksonville, Florida WSR-88D radar (KJAX), which under certain conditions can be sensitive to soot in addition to precipitation. While the WSR-88D is not directly sensitive to sub-micron aerosol particles, it can detect carbonized blades of grass and leaves lofted into the atmosphere by the fire. Operational radar data also provides almost continuous observations of the fires with a spatial resolution of 1 km every 10 minutes. We compare the vertical distribution and areal coverage of the fire-lofted biomass with local and downstream air quality and meteorological conditions to examine the relationship between aerosol injection height and air quality. A preliminary investigation indicates the presence of a strong diurnal variability in injection height resulting from changes in fire intensity in coverage and boundary layer height. When fires were intense, and stability weak, large amounts out aerosols are transported high (~5 km) into the atmosphere, decreasing air quality large distances downstream.
Joint Session 1, Measurements and Modeling of Aerosols and Clouds-I
Tuesday, 22 January 2008, 1:30 PM-3:00 PM, 220
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