Observed Water Vapor Enhancement in Smoke Plumes

In situ measurements were obtained during multiple prescribed fires in a longleaf pine ecosystem at the Joseph W. Jones Ecological Research Center at Ichauway, Georgia in July 2008 and January 2009. Temperature and relative humidity data were obtained on a 10 m tower to capture fire front plume conditions, while radiosondes measured smoke plume characteristics aloft. As soon as a significant smoke from the fire was observed, radiosondes were launched downwind of the fire front and ascended directly into the smoke plumes. Radiosondes were also launched before and after each burn to obtain ambient background conditions. These two measurement platforms provide a unique dataset of smoke plume moisture to determine how moisture enhancement from fire smoke alters the dynamics of the plume. Preliminary analysis of results show moisture enhancement occurred in all smoke plumes with increased water vapor mixing ratios on the order of 2 to 11 g kg-1 at fire front passage, while plume moisture obtained by the radiosondes show an increase of 1 to 4 g kg-1. Understanding the moisture enhancement in prescribed fire smoke plumes will help determine the convective dynamics that occur in major wildland fires and convection columns.