A scanning system for producing a path averaged concentration map of a leaking plume is provided. The system includes a tunable light source capable of tuning its wavelength over the absorption band of the specimen of interest, a lightweight mirror to scan the light, a lightweight collection optic, an array of detectors to measure reflected light, one or more processors configured to align the scanning with the detected signal and analyze the signal to produce a path averaged concentration map of the leaking plume, the one or more processors configured to use an analytical model of plume dynamics to compare the detected concentration map and calculate leak location and rate, and a flying platform that can fly in a control flight path.