Advances in Shortwave Measurement Technology: An Isothermal Radiation Detector

23 Advances in Shortwave Measurement Technology: An Isothermal Radiation Detector--Yankee Environmental Systems, Inc., Airport Industrial Park, 101 Industrial Boulevard, Turners Falls, MA 01376-1608; (413) 863-0200 Dr. William O Jeffries, Principal Investigator Mrs. Cynthia A. Cote, Business Official DOE Grant No. DE-FG02-97ER82511 Amount: $75,000 Global climate, local weather, and human economic activity all depend on the balance of energy gained from the sun and lost to space. Because minute changes in this balance could cause dramatic shifts in climate, it is crucial to measure these radiation budgets accurately. Currently available atmospheric radiation instrumentation has limited stability and accuracy that prevent routine measurements having uncertainties of less than about +5 percent. This project seeks to develop a new approach to radiation measurement in which the energy received by the sensor surface is actively removed and measured in order to maintain the surface at a constant temperature instead of allowing the surface to heat up as in current instruments. The isothermal detector thus eliminates inaccuracies due to temperature differences and can potentially reduce uncertainties in routine field measurements by an order of magnitude beyond the current state of the art. Phase I work will demonstrate the validity of the isothermal detector concept and build a prototype having demonstrably improved performance. A mathematical model of the detector will be developed to predict performance and guide the design of a prototype. Results from the prototype will validate the modeling and give valuable experience with the technology. In Phase II any shortcomings of the prototype will be identified and corrected with the goal of producing a modest number of improved prototypes for beta testing and subsequent commercialization. A significant part of the effort will center on an improved calibration methodology. Commercial Applications and Other Benefits as described by the awardee: The new radiation detector, if successfully developed, represents a significant improvement in the performance of commercial radiometric instrumentation such as pyranometers and pyrheliometers. It should be valuable to scientific climate studies such as the Department of Energy's Atmospheric Radiation Measurement Program and NASA's Mission to Planet Earth. It would therefore have a significant commercial potential in the scientific instrumentation marketplace.