Low Power Instrumentation for Measurement of Greenhouse Gas Emissions in Terrestrial-Aquatic Interfaces

Nitrous oxide is the third most important greenhouse trace gas after carbon dioxide and methane and is a dominant ozone depleting substance. Its emissions to the atmosphere are extremely heterogeneous in space and time. Novel approaches to characterize such heterogeneity for incorporation into models and to identify effective mitigation strategies are greatly needed. Commercial instruments for flux measurement of CH4 are available and have been deployed in global measurement campaigns such as FLUXNET. However, similar instruments for nitrous oxide do not exist, as it presents greater measurement challenges. Southwest Sciences, Inc. is addressing this need through an intensive program of further development, field testing, and commercialization of low power laser-based systems that measure nitrous oxide, methane, and carbon dioxide emissions. The instruments developed in this project will allow accurate, simultaneous measurements of greenhouse gas emissions at unprecedented spatial and temporal scales in a robust, low-power field package. The Phase I effort demonstrated that our nitrous oxide gas analyzer technology can be packaged into a compact, low power, light weight system that can run on battery power for extended times for use at remote study sites. Field tests demonstrated that the gas analyzer performance provides the speed and resolution required for eddy covariance flux determinations and, when combined with a sonic anemometer, provides data that can be processed to provide meaningful flux values. In Phase II, modifications that will allow the system to run unattended for longer periods of time while logging data to an onboard data storage device will be made. In addition, a new gas multigas analyzer that will simultaneously measure nitrous oxide, methane and carbon dioxide in a single instrument will be developed and field tested. Commercial instruments for measuring nitrous oxide fluxes and for measuring nitrous oxide, methane and carbon dioxide simultaneously are envisioned. The technology could be widely applied across existing and future FLUXNET, AmeriFlux, ARM and other atmospheric science networks. The instrument will allow researchers, regulators, and environmental consultants to accurately and effectively measure emissions at unprecedented spatial and temporal scales in a quick, efficient, and easy manner.