全球变化研究组知识库

Differences, arising from differences in gross primary production (GPP) model structures and driving forces, have fuelled arguments concerning interannual changes of GPP in China since 2000. To better investigate the interannual variability of GPP and its covariance with climate factors in China, this study adopted a multi-model analysis based on three GPP models (i.e., Terrestrial Ecosystem Carbon flux model [TEC], Breathing Earth System Simulator model [BESS], and MOD17 GPP model). The results show that annual GPP in China increased by 0.021-0.057 Pg C year(-1) from 2000 to 2015 attributable to atmospheric-CO2 fertilization effects and favourable climate change, that is, increasing precipitation (P-r) and temperature (T-a). However, northern China and southern China had a large difference in the amplitude of these GPP changes; annual GPP increased by 0.017-0.039 Pg C year(-1) in northern China but only 0.001-0.018 Pg C year(-1) in southern China. Northern China and southern China occupy contrasting climate zones and this contrast produced different interannual variability of GPP through different mechanisms. Northern China has a dry climate with GPP changes sensitive to P-r. As a result, more P-r along with higher T-a in northern China produced the strong uptrend of GPP from 2000 to 2015. In contrast, southern China has a wet climate with its GPP sensitive to solar radiation and T-a. For the interval of 2000-2015, decreasing radiation plus drought exerted a negative influence on GPP in southern China. This study highlights the diverse mechanisms in which climate change affects GPP in dry and wet climate zones. A robust multi-model analysis is preferred to reduce uncertainties arising from a single GPP model and its driving data.