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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 |
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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.
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