@article {259, title = {China{\textquoteright}s terrestrial carbon balance: Contributions from multiple global change factors}, journal = {Global Biogeochemical Cycles}, volume = {25}, year = {2011}, month = {2011}, abstract = {

The magnitude, spatial, and temporal patterns of the terrestrial carbon sink and the underlying mechanisms remain uncertain and need to be investigated. China is important in determining the global carbon balance in terms of both carbon emission and carbon uptake. Of particular importance to climate-change policy and carbon management is the ability to evaluate the relative contributions of multiple environmental factors to net carbon source and sink in China{\textquoteright}s terrestrial ecosystems. Here the effects of multiple environmental factors (climate, atmospheric CO 2, ozone pollution, nitrogen deposition, nitrogen fertilizer application, and land cover/land use change) on net carbon balance in terrestrial ecosystems of China for the period 1961{\textendash}2005 were modeled with newly developed, detailed historical information of these changes. For this period, results from two models indicated a mean land sink of 0.21 Pg C per year, with a multimodel range from 0.18 to 0.24 Pg C per year. The models{\textquoteright} results are consistent with field observations and national inventory data and provide insights into the biogeochemical mechanisms responsible for the carbon sink in China{\textquoteright}s land ecosystems. In the simulations, nitrogen deposition and fertilizer applications together accounted for 61 percent of the net carbon storage in China{\textquoteright}s land ecosystems in recent decades, with atmospheric CO 2 increases and land use also functioning to stimulate carbon storage. The size of the modeled carbon sink over the period 1961{\textendash}2005 was reduced by both ozone pollution and climate change. The modeled carbon sink in response to per unit nitrogen deposition shows a leveling off or a decline in some areas in recent years, although the nitrogen input levels have continued to increase.

}, keywords = {China, ecosystem model, terrestrial carbon sink}, issn = {0886-6236}, doi = {10.1029/2010GB003838}, author = {TIAN, HANQIN and Melillo, Jerry M. and LU, CHAOQUN and Kicklighter, David W. and LIU, MINGLIANG and REN, WEI and XU, XIAOFENG and CHEN, GUANGSHENG and Zhang, Chi and Pan, Shufen and LIU, JIYUAN and Running, Steven} } @article {257, title = {Spatial and temporal patterns of CO2 and CH4 fluxes in China{\textquoteright}s croplands in response to multifactor environmental changes}, journal = {Tellus B}, volume = {63}, year = {2011}, month = {04/2011}, pages = {222 - 240}, abstract = {The spatial and temporal patterns of CO2 and CH4 fluxes in China{\textquoteright}s croplands were investigated and attributed to multifactor environmental changes using the agricultural module of the Dynamic Land Ecosystem Model (DLEM), a highly integrated process-based ecosystem model. During 1980{\textendash}2005 modelled results indicated that China{\textquoteright}s croplands acted as a carbon sink with an average carbon sequestration rate of 33.4 TgC yr-1 (1 Tg = 1012 g). Both the highest net CO2 uptake rate and the largest CH4 emission rate were found in southeast region of China{\textquoteright}s croplands. Of primary influences were land-cover and land-use change, atmospheric CO2 and nitrogen deposition, which accounted for 76\%, 42\% and 17\% of the total carbon sequestration in China{\textquoteright}s croplands during the study period, respectively. The total carbon losses due to elevated ozone and climate variability/change were equivalent to 27\% and 9\% of the total carbon sequestration, respectively. Our further analysis indicated that nitrogen fertilizer application accounted for 60\% of total national carbon uptake in cropland, whereas changes in paddy field areas mainly determined the variability of CH4 emissions. Our results suggest that improving air quality by means such as reducing ozone concentration and optimizing agronomic practices can enhance carbon sequestration capacity of China{\textquoteright}s croplands.}, keywords = {aerosol, air-sea gas exchanges, atmospheric 210pb, biomass burning emission, black carbon, breaking waves, CO2 FLUX, dynamical-chemical proxies, eddy covariance technique, equilibrium saturations, indo-gangetic plain, methane, multiple regression, oceanic co2 uptakes, open-path gas analyzer, satellite observations, siberia taiga, tower observation, west siberian lowland}, doi = {10.1111/j.1600-0889.2010.00522.x}, author = {REN, WEI and TIAN, HANQIN and XU, XIAOFENG and LIU, MINGLIANG and LU, CHAOQUN and CHEN, GUANGSHENG and Melillo, Jerry M. and J. Reilly and LIU, JIYUAN} }