Airborne visualization and quantification of discrete methane sources in the environment

Airborne thermal-infrared (TIR) imaging spectrometry techniques have been used to detect and track methane and other gaseous emissions from a variety of discrete sources in diverse environmental settings, and to enable estimation of the strength of each plume. The high spatial resolution (1-2 m) permits attribution of chemical plumes to their source, while the moderate spectral resolution (44 nm across the 7.5-13.5 mu m TIR band) enables identification and quantification of the gaseous plume constituents, even when one is present in considerably greater concentration than the others. Raw imagery was quantitatively analyzed using matched filtering and adaptive coherence techniques. Experiments under controlled conditions demonstrated successful detection of methane point sources at release rates as low as 2.2 kg/h (similar to 1 dm(3)/s at NTP). (C) 2014 Elsevier Inc. All rights reserved.