A diode laser instrument for simultaneously measuring methane, nitrous oxide, carbon monoxide, and water vapor onboard an unmanned aerial vehicle will be developed in this project. Wavelength modulation absorption spectroscopy will be used to perform the measurements at a 10 Hz rate. The system will use a compact open path multipass cell to provide the necessary optical pathlength. Three mid-infrared lasers will be coupled to the cell. The Phase I project will emphasize development of the optical system and establishing of the sensitivity for ambient concentrations of the gases. These results will lead to the development of a light weight, low power, fast time response Phase II instrument suitable for deployment on a unmanned aerial vehicle.
The instrument will be useful for unmanned aerial vehicle measurements of two of the most important greenhouse gases, methane and nitrous oxide, and the leading man made pollutant, carbon monoxide. The system will be adaptable to use on balloons and ground based systems.
Measurements of methane are useful for identifying industrial leak sources as well as for pipeline monitoring. Nitrous oxide measurements are of interest to the agricultural community since it is a byproduct of crop planting.