COS 21-10 - Temperature acclimation effects on carbon dynamics of the conterminous UnitedStates forest in the 21st century

Tuesday, August 9, 2011: 11:10 AM
6A, Austin Convention Center
Min Chen, Earth & Atmospheric Sciences, Purdue University, West Lafayette, IN and Qianlai Zhuang, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN

The increasing air temperatures in the 21st century will alter forest ecosystem functioning and carbon dynamics. To date, how plant photosynthesis will acclimate to the rising temperature has not been well modeled and addressed in large-scale biogeochemical models. Here we present a study on regional ecosystem carbon dynamics under future climate scenarios by incorporating temperature acclimation effects into a large-scale ecosystem model, the Terrestrial Ecosystem Model (TEM). We incorporate a general formulation of the temperature acclimation of forest photosynthesis to TEM. We then apply the revised model to the conterminous United States forest ecosystems for the 21st century under the future Intergovernmental Panel on Climate Change (IPCC) climate scenarios A1FI, A2, B1 and B2.


We find that that there are significant differences between the estimates of carbon dynamics by the previous and the revised models. The largest differences occur under the A1FI scenario, in which the model that considers acclimation effects predicts the region acted as a carbon sink, and the accumulated carbon is 26 Pg C higher than the estimates with the model that has not considered the acclimation effects. Our results also indicate there are spatially different responses to the temperature acclimation effects in the region.  This study suggests that the future carbon quantification should take temperature acclimation effects into account so as to better quantify ecosystem carbon dynamics at regional scales.

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