A Diode Laser Sensor for High Precision Measurement of Terrestrial CO₂ Sources and Sinks--Physical Sciences, Inc., 20 New England Business Center, Andover, MA 01810-1077; 978-689-0003
Dr. David M. Sonnenfroh, Principal Investigator
Dr. Byron David Green, Business Official
DOE Grant No. DE-FG02-99ER82858
Amount: $749,758

High precision measurements of the sequestration and emission of CO₂ and other greenhouse gases from various ecosystems, as well as from anthropogenic sources, are required for improved climate and climate change predictions. Existing instrumentation is insufficient to the need in sensitivity, temporal response, chemical selectivity, or ability to be routinely used in the field for large area survey measurements. This project will develop and test a new, room temperature diode-laser-based sensor for eddy covariance measurements of CO₂ and H₂O simultaneously and will be easily field deployable for extended periods. In addition, its unique air probe can be replicated to form networks of sensors, controlled by a single central processor, for gradient or large area surveys. The Phase I project designed and fabricated an in situ, open path, air sampling probe and combined it with an existing control system. A precision of 0.4 percent over 70 minutes while monitoring 333 ppmv CO₂ was demonstrated. Phase II will fabricate the field prototype laser sensor based on the design produced during Phase I, perform field tests, and then compare it with existing nondispersive infrared (NDIR) sensors.

Commercial Applications and Other Benefits as described by the awardee: The sensor should find application in atmospheric field research concerned with quantifying the increasing burden of greenhouse gases in the atmosphere and their impact on global climate change. The underlying high speed, high precision, multiple-trace gas measurement technology should also have commercial application in industrial process control, agricultural monitoring, fence line fugitive emissions monitoring, compliance monitoring, and combustion analysis.