TY - JOUR
T1 - Decreasing net primary production due to drought and slight decreases in solar radiation in China from 2000 to 2012
AU - Wang, J.
AU - Dong, J.
AU - Yi, Y.
AU - Lu, G.
AU - Oyler, J.
AU - Smith, W. K.
AU - Zhao, M.
AU - Liu, J.
AU - Running, S.
N1 - Funding Information:
This work was supported by National Natural Science Foundation of China (31270520), the Key Project in the National Science and Technology Pillar program of China (grant 2013BAC03B00), and U.S. National Science Foundation (NSF) EPSCoR program (NSF-IIA-1301789). S. Running was supported by NASA Earth Observing system MODIS grant (NNX08AG87A). This work used eddy covariance data acquired by the ChinaFLUX and AsiaFLUX, and we thank PIs for sharing the flux tower data. Especially, we appreciate Guirui Yu, Shaoqiang Wang, Honglin He, and Li Zhang of the Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, as well as the Associate Editor and two anonymous reviewers for their constructive suggestions and comments on this paper. The data used in this study will be available at http://www.cnern.org.cn/data/initDRsearch?classcode=DPAPER.
Publisher Copyright:
©2017. American Geophysical Union. All Rights Reserved.
PY - 2017/1/1
Y1 - 2017/1/1
N2 - Terrestrial ecosystems have continued to provide the critical service of slowing the atmospheric CO2 growth rate. Terrestrial net primary productivity (NPP) is thought to be a major contributing factor to this trend. Yet our ability to estimate NPP at the regional scale remains limited due to large uncertainties in the response of NPP to multiple interacting climate factors and uncertainties in the driver data sets needed to estimate NPP. In this study, we introduced an improved NPP algorithm that used local driver data sets and parameters in China. We found that bias decreased by 30% for gross primary production (GPP) and 17% for NPP compared with the widely used global GPP and NPP products, respectively. From 2000 to 2012, a pixel-level analysis of our improved NPP for the region of China showed an overall decreasing NPP trend of 4.65 Tg C a−1. Reductions in NPP were largest for the southern forests of China (−5.38 Tg C a−1), whereas minor increases in NPP were found for North China (0.65 Tg C a−1). Surprisingly, reductions in NPP were largely due to decreases in solar radiation (82%), rather than the more commonly expected effects of drought (18%). This was because for southern China, the interannual variability of NPP was more sensitive to solar radiation (R2 in 0.29–0.59) relative to precipitation (R2 < 0.13). These findings update our previous knowledge of carbon uptake responses to climate change in terrestrial ecosystems of China and highlight the importance of shortwave radiation in driving vegetation productivity for the region, especially for tropical forests.
AB - Terrestrial ecosystems have continued to provide the critical service of slowing the atmospheric CO2 growth rate. Terrestrial net primary productivity (NPP) is thought to be a major contributing factor to this trend. Yet our ability to estimate NPP at the regional scale remains limited due to large uncertainties in the response of NPP to multiple interacting climate factors and uncertainties in the driver data sets needed to estimate NPP. In this study, we introduced an improved NPP algorithm that used local driver data sets and parameters in China. We found that bias decreased by 30% for gross primary production (GPP) and 17% for NPP compared with the widely used global GPP and NPP products, respectively. From 2000 to 2012, a pixel-level analysis of our improved NPP for the region of China showed an overall decreasing NPP trend of 4.65 Tg C a−1. Reductions in NPP were largest for the southern forests of China (−5.38 Tg C a−1), whereas minor increases in NPP were found for North China (0.65 Tg C a−1). Surprisingly, reductions in NPP were largely due to decreases in solar radiation (82%), rather than the more commonly expected effects of drought (18%). This was because for southern China, the interannual variability of NPP was more sensitive to solar radiation (R2 in 0.29–0.59) relative to precipitation (R2 < 0.13). These findings update our previous knowledge of carbon uptake responses to climate change in terrestrial ecosystems of China and highlight the importance of shortwave radiation in driving vegetation productivity for the region, especially for tropical forests.
KW - China
KW - drought
KW - net primary production
KW - solar radiation
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U2 - 10.1002/2016JG003417
DO - 10.1002/2016JG003417
M3 - Article
AN - SCOPUS:85011277131
VL - 122
SP - 261
EP - 278
JO - Journal of Geophysical Research: Biogeosciences
JF - Journal of Geophysical Research: Biogeosciences
SN - 2169-8953
IS - 1
ER -