Issues are carbon dioxide and ozone. Model the interaction between trace gases, vegetation, and soil. To help managers develop air quality standards for ozone to protect vegetation. To learn more about tracking carbon storage in forests. Ameriflux GLEES

Eddy Covariance

AmeriFlux, a network of about 50 eddy covariance systems dispersed throughout the Americas, was initiated 7 years ago (primarily) to help quantify the North American carbon cycle. It is largely due to AmeriFlux that eddy covariance technology has been and is continuing to be advanced. One of my continuing research interests over the past 15 years of so has been the theory and practice of eddy covariance and I have made significant contributions to the AmeriFlux effort and to the scientific basis of modern eddy covariance systems. My current research plans in this area of research include two important aspects of eddy covariance and its application to the interpretation of carbon flux data gather using eddy covariance systems. The first is to continue investigations into the closed- and open-path CO2 flux systems. Although AmeriFlux has used closed-path systems extensively, there remain some aspects of this type of system that have not been fully documented. Most notably these include the proper application of spectral corrections and the Webb-Pearman-Leuning correction to CO2 flux estimation, the development of better methods of spectral corrections and a better understanding of the importance of the (usually ignored) pressure covariance term, <p’w’>, to the measured CO2 fluxes. More detailed comparisons between open- and closed-path estimates of CO2 fluxes are also planned. At present RWU-4452 is one of the few groups anywhere who have the capability of performing this type of experiment. Ultimately, the goal here is to apply the concepts of instrumentation physics to eddy covariance systems in order to improve our ability to make reliable and consistent measurements of CO2 fluxes and inferences about the terrestrial carbon cycle. The second research area is to begin a detailed analysis of the 3 years of the GLEES eddy covariance CO2 flux data. Initially the GLEES data will be used to test and extend newly developed methods of analyzing eddy covariance data to areas of complex terrain. Most notable among these new tools are the planar fit coordinate system and analytical approaches for investigating low frequency contributions to the measured fluxes. This is an area of research that has begun to receive much more attention than in the past. Nevertheless, there remain some significant issues about the usefulness of eddy covariance technology in complex terrain, and GLEES is an excellent site for testing some of these ideas. Here the ultimate goal is to document the contribution of Rocky Mountain subalpine forests to terrestrial carbon cycling.