Decadal trends in the seasonal-cycle amplitude of terrestrial CO2 exchange resulting from the ensemble of terrestrial biosphere models

• Published in: Tellus. Series B, Chemical and physical meteorology Vol. 68; no. 1; pp. 28968 - 20
• Main Authors: Ito, Akihiko, Inatomi, Motoko, Huntzinger, Deborah N., Schwalm, Christopher, Michalak, Anna M., Cook, Robert, King, Anthony W., Mao, Jiafu, Wei, Yaxing, Post, W. Mac, Wang, Weile, Arain, M. Altaf, Huang, Suo, Hayes, Daniel J., Ricciuto, Daniel M., Shi, Xiaoying, Huang, Maoyi, Lei, Huimin, Tian, Hanqin, Lu, Chaoqun, Yang, Jia, Tao, Bo, Jain, Atul, Poulter, Benjamin, Peng, Shushi, Ciais, Philippe, Fisher, Joshua B., Parazoo, Nicholas, Schaefer, Kevin, Peng, Changhui, Zeng, Ning, Zhao, Fang
• Format: Journal Article
• Language: English
• Published: Stockholm Taylor & Francis 01.01.2016; Ubiquity Press; Co-action Publishing; Stockholm University Press
• Subjects: Agricultural management; Amplitude; Atmosphere; atmospheric carbon dioxide; Atmospheric models; Biosphere; Biosphere models; carbon cycle; Carbon dioxide; Carbon dioxide atmospheric concentrations; Carbon dioxide concentration; Carbon dioxide exchange; Climate change; Climate models; Computer simulation; Data; Dynamics; Ecological monitoring; Ecosystem dynamics; Ecosystem models; Ecosystems; Emissions; Environment models; ENVIRONMENTAL SCIENCES; Factorial experiments; Intercomparison; Land use; Land use management; land-use change; Measurement techniques; Multiscale analysis; Nitrogen deposition; Photosynthesis; Remote sensing; Respiration; Scale (ratio); seasonal cycle; Seasonal variations; Seasonality; terrestrial ecosystem; Terrestrial ecosystems; Terrestrial environments; Trends
• ISSN: 0280-6509; 1600-0889
• DOI: 10.3402/tellusb.v68.28968

The seasonal-cycle amplitude (SCA) of the atmosphere-ecosystem carbon dioxide (CO 2 ) exchange rate is a useful metric of the responsiveness of the terrestrial biosphere to environmental variations. It is unclear, however, what underlying mechanisms are responsible for the observed increasing trend of SCA in atmospheric CO 2 concentration. Using output data from the Multi-scale Terrestrial Model Intercomparison Project (MsTMIP), we investigated how well the SCA of atmosphere-ecosystem CO 2 exchange was simulated with 15 contemporary terrestrial ecosystem models during the period 1901-2010. Also, we made attempt to evaluate the contributions of potential mechanisms such as atmospheric CO 2 , climate, land-use, and nitrogen deposition, through factorial experiments using different combinations of forcing data. Under contemporary conditions, the simulated global-scale SCA of the cumulative net ecosystem carbon flux of most models was comparable in magnitude with the SCA of atmospheric CO 2 concentrations. Results from factorial simulation experiments showed that elevated atmospheric CO 2 exerted a strong influence on the seasonality amplification. When the model considered not only climate change but also land-use and atmospheric CO 2 changes, the majority of the models showed amplification trends of the SCAs of photosynthesis, respiration, and net ecosystem production (+0.19 % to +0.50 % yr −1 ). In the case of land-use change, it was difficult to separate the contribution of agricultural management to SCA because of inadequacies in both the data and models. The simulated amplification of SCA was approximately consistent with the observational evidence of the SCA in atmospheric CO 2 concentrations. Large inter-model differences remained, however, in the simulated global tendencies and spatial patterns of CO 2 exchanges. Further studies are required to identify a consistent explanation for the simulated and observed amplification trends, including their underlying mechanisms. Nevertheless, this study implied that monitoring of ecosystem seasonality would provide useful insights concerning ecosystem dynamics.