Imaging Underground Leaks Below Pavement

Today we again explore ground-level leak plumes. This little guy (1 L/min), seen from a distance of 10m from the QLM gas imaging lidar camera, is what you’d typically see form an underground residential natural gas leak that is emerging from a crack in the sidewalk. What’s interesting though is that when you look at it from the side, with the camera pointing along (parallel to) the ground, the plume is only about 10cm tall, and it’s hugging the ground as it spreads out from the leak source. This is because at the surface, the wind speed goes to zero even though the wind was blowing ~2km/h in this case.