Theory Of Climate Control On NEE Dynamics

Thursday, 18 December 2014
Chuixiang Yi, CUNY Queens College, School of Earth and Environmental Sciences, Flushing, NY, United States and Xiyan Xu, Lawrence Berkeley National Laboratory, Earth Sciences Division, Berkeley, CA, United States
We have investigated symmetry/asymmetry properties in climate-terrestrial carbon dynamics by conducting a literature review and a data analysis based on both existing field data and modeling data. We hypothesize that in bidirectional interactions of climate and carbon, the greenhouse effect of carbon on climate is symmetric and unconditional. On the other hand, climate controls on carbon exchanges between terrestrial ecosystems and atmosphere are asymmetric. Symmetry-breaking of climate control on photosynthesis occurs at temperature thresholds, while symmetry-breaking of climate control on terrestrial respiration occurs at soil-moisture thresholds. These climate thresholds switch climate control mechanism on NEE from one to another. Also these climate thresholds characterize optimal (or worst) climate conditions for transfer of atmospheric CO2 into terrestrial ecosystems. Taking climate thresholds as a reference climate, the impact of climate extremes on terrestrial carbon sequestration can be estimated by a perfect-deficit approach. This hypothesis has been testified by abundant observational data and modeling data.

Acknowledgements: This research was financially supported by PSC-CUNY Award (PSC-CUNY-ENHC-44-83).