HR: 0830h
AN: B51D-0997    [PDF]
TI: Contribution of Climatic variables to Seasonal and Interannual Variability in Net Ecosystem Exchange at Eight AmeriFlux Forest Sites
AU: * Hui, D
EM: dafeng@ou.edu
AF: University of Oklahoma, Department of Botany and Microbiology, Norman, OK 73019 United States
AU: Luo, Y
EM: yluo@ou.edu
AF: University of Oklahoma, Department of Botany and Microbiology, Norman, OK 73019 United States
AU: Xu, T
AF: University of Oklahoma, Department of Botany and Microbiology, Norman, OK 73019 United States
AU: Wofsy, S
AF: Harvard University, Department of Earth and Planetary Sciences, Cambridge, MA 02138 United States
AU: Baldocchi, D
AF: University of California, Berkeley, Department of Environmental Sciences, Policy, and Management, Berkeley, CA 94720 United States
AU: Schmid, H
AF: Indiana University, Department of Geography, Bloomington, IN 47405 United States
AU: Katul, G
AF: Duke University, Nicholas School of the Environment and Earth Sciences, Dueham, NC 27708 United States
AU: Monson, R
AF: University of Colorado, Department of Environmental, Population and Organismic Biology, Boulder, CO 80301 United States
AU: Goldstein, A
AF: University of California, Berkeley, Department of Environmental Sciences, Policy, and Management, Berkeley, CA 94720 United States
AU: Curtis, P
AF: Ohio State University, Department of Evolution, Ecology, and Organismal Biology, Columbus, OH 43210 United States
AU: Hollinger, D
AF: USDA Forest Service, 271 Mast Rd., Durham, NH 03824 United States
AB: Seasonal and interannual variabilities in net ecosystem CO$_{2}$ exchange (NEE) have been well documented at many FluxNet sites. These variabilities have been linked to direct effect of climatic variations and climatic-induced functional changes. However, we still lack quantitative understanding of climatic effects on NEE variations. With a recently developed homogeneity-of-slopes model approach, variation in NEE can be partitioned into climatic variability and functional change. We applied this method to eight AmeriFlux forest sites with 37 site years eddy covariance measurements. Results showed that photosynthetic active radiation was the most important climatic variable at all sites. Climatic interannual variability contributed 5-10% of variations in NEE. Functional change contribution varied among sites from 0 to 10%. More than 50% of the variation in NEE could be explained by seasonal climatic variability. The considerable contributions by the functional change and climatic interannual variability in NEE necessitate long-term measurements to develop predictive understanding of ecosystem carbon exchange.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
DE: 1600 GLOBAL CHANGE (New category)
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting