Abstract
A thermal plume initiated by a ground-based artificial heat source was observed by radar, and some other remote and in-situ measurement techniques (lidar, photogrammetry, instrumented aircraft). In dry air, plume tracers for radar consisted of reflecting chaff released discontinuously in the plume from the bottom of the updraft and also in the nearby atmosphere by aircraft. Comparative evaluation of the remote sensing techniques for geometrical plume parameter measurements are presented. It is shown that radar and chaff techniques permit, in almost all atmospheric conditions, an accurate determination of lateral limits and maximum height of the plume. Air velocity and some other parameters concerning airflow conditions in the plume can be measured as well. Some aspects of the environmental plume circulation are also tentatively investigated.