Ultralight, Low-power Probes of Carbon Dioxide

A wide range of practical instruments is needed for monitoring carbon dioxide concentrations of the land, air, and sea. Moderate accuracy of order 1 ppm (dry mole fraction) and temporal response of a few seconds will suffice. Expense, weight, size, and electrical power must be kept low to make the instrumentation applicable to a large number (~10,000) of one-way deployments per year. Accessible platforms include weather balloons, floater buoys for probing the ocean's surface, sky hooks (tethered, small blimps) for vertical profiling of the atmospheric boundary layer, and towers for monitoring the accumulation of nighttime transpiration and its dispersal as a transient flux. This project will use a variation of a proven electro-optical design to build and deploy solid-state probe detection systems. Manufacturability, as expressed by a fully integrated electrical/mechanical/optical design, will be a key consideration to make the Probe detection system inexpensive and robust. Phase I built and tested two kinds of nondispersive infrared probe technologies: photo-electronic and photo-acoustic. The functionality of the photo-acoustic probe was proven for the stable isotopes of CO2. Based on a wide range of laboratory tests, the photo-electronic probe proved advanced and robust enough to serve as the basis for Phase II. In Phase II, the photo-electronic probe will be upgraded and its observational capabilities will be demonstrated. Commercial Applications and other Benefits as described by the awardee: The new probes should serve as the basis for: (1) observational services, consisting of deployments of the probes from sky hooks, towers, weather balloons, and floater buoys, and of management of the data streams; (2) sales of the probes for use on these same platforms and also for monitoring leaks from geosequestration of carbon dioxide; and (3) improved measurements of the amounts of sequestration of carbon dioxide by natural ecosystems.