89th American Meteorological Society Annual Meeting

Tuesday, 13 January 2009: 11:00 AM
Combined Lidar and Radar Observations of Smoke Plumes from Prescribed Burns
Room 122A (Phoenix Convention Center)
P.S. Tsai, University of Massachusetts, Amherst, MA; and S. J. Frasier, S. Goodrick, G. L. Achtemeier, and M. T. Odman
Poster PDF (927.7 kB)
The transport and dispersion of smoke plume from prescribed burns was studied using W-band radar (95 GHz) and a lidar ceilometer. The Microwave Remote Sensing Laboratory (MIRSL) at the University of Massachusetts observed prescribed burns conducted by the USDA Forest Service at Fort Benning Georgia during April 2008. The radar and lidar instruments, mounted on a single mobile platform, were located approximately 2 to 3 km downwind from the burn site. The lidar was a Vaisala CL31 ceilometer, operated with 10 m vertical resolution and 2 sec time averaging. The W-band radar operated with a range resolution of 30 m. The beamwidths of the radar and the lidar were both approximately 0.2 deg. Simultaneous data collections were obtained from the lidar, which was vertically pointed, and the radar which performed a mix of near-vertical observations, RHI, and PPI scans. These permitted observation of plume vertical extent, structure, and evolution. Results from two burns are highlighted. Observed reflectivities from the plumes were in the vicinity of -30 dBZ. Signal to noise ratio was sufficient to measure velocities and spectral widths from within the plume. Little or no lofted debris or large particulates were observed, and the smoke plume above the radar site was only faintly visible. It is hypothesized that for these 'moist' fires, the smoke particles serve as condensation nuclei permitting observation by the millimeter-wave radar.

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