High-Speed, WEide Dynamic Range Airborne Water Sensor

Physical Sciences Inc. proposes to demonstrate a flight qualifiable, wide dynamic range sensor for water vapor concentration measurements in the troposphere. The sensor is based on absorption measurements using a room temperature, tunable InGaAsP diode laser and a unique noise canceling detector system. The noise canceling detector permits near shot-noise limited absorption measurements without frequency modulation techniques, resulting in a simpler, less expensive, lighter weight, and easier to use instrument compared to frequency modulation (FM) techniques. Signal dynamic range in excess of 10 will be achieved using selected pairs of absorption transitions. The Phase I portion of the program will demonstrate quantitative absorption measurements of H20 vapor over the temperature range 190 K to 313 K in a pressure-controlled cryogenic environment chamber.