The PI plans to develop a technique to measure changes in the oxygen concentration of the Earth's atmosphere. Specifically, the goal is to measure changes as small as 1 ppm in the O2 mole fraction of air, using differential-absorption spectroscopy. The research is motivated by the desire to obtain experimental data on the short and long-term variations in atmospheric oxygen for further understanding of the carbon cycle in the atmosphere, biosphere, and oceans; it is highly possible that such data would help answer the question of the missing carbon in the atmosphere, the missing oxygen in the oceans, and predict O2 and CO2 concentrations. The work will be split into three phases: 1) construction and testing of a diode laser and an electronic-noise canceller; 2) building the reference and sample cells, contructing the gas-handling system and incorporating the system for changing the optical path length through the sample oxygen cell; and 3) measurements to demonstrate the utility and robustness of the technique.
