Lidar measurement of methane gas flow in complex wind

A gas detection system comprising:

• a lidar sensor comprising a tunable diode laser, a modulator, and a lidar detector;
• at least one processor configured to perform operations comprising:
• transmitting modulated diode laser light into a field of view;
• receiving data from the lidar detector, wherein the received data corresponds to modulated diode laser light that has been scattered from structures in the field of view;
• determining, from the received data, information relating to a gas concentration for a detected gas;
• determining, from the received data, lidar distance information relating to the structures in the field of view;
• determining local wind data for a location of the detected gas;
• and
• determining a rate of flow of the detected gas using the information relating to the gas concentration and the local wind data.

A method comprising:

• receiving gas detection data from a lidar sensor having a field of view,
• receiving distance information relating to structures within the field of view;
• determining a location for a detected gas based on the received gas detection data;
• receiving prevailing wind data for the location of the detected gas;
• determining local wind data for the location of the detected gas based on the prevailing wind data and the received distance information;
• determining a flow rate of the detected gas based on the received gas detection data and the local wind data;
• determining a gas concentration pathlength for one or more points in the field of view based on the received gas detection data and the received distance information,
• the gas concentration pathlength being gas concentration integrated along a laser beam path from the lidar sensor to a scattering object;
• wherein determining a location of the detected gas comprises
• determining a location of a source of the detected gas;
• wherein the location of the source of the detected gas is determined based on the determined gas concentration pathlength;
• and
• wherein the location of the source of the detected gas is determined based on a location of the lidar sensor and a lidar range from the lidar sensor to an area of the field of view in which the gas concentration pathlength exceeds a threshold.