Prediction of net primary productivity change pattern in China based on vegetation dynamic models

Six vegetation dynamic models, provided by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), are selected and verified for net primary productivity (NPP) in China based on remote sensing retrials. Then the goodness of fit of each model is used as the weight to synthesize a new sequence to estimate the future change pattern of China's NPP under the RCP2.6 and RCP6.0 scenarios. This study aims to solve inaccuracy of the estimation on the change pattern of China's NPP due to differences in data and methods. The results show that the single model has a poor fitting effect on NPP in most regions of China (R2 < 0.4), the average NPP is 33%-97% higher than the remotely sensed value, but it can well reflect the decreasing trend from southeast to northwest China. The overall goodness of fit of the proposed NPP data is 0.85, and the goodness of fit in most vegetation zones is basically greater than 0.3. In the future 30 years, China's average NPP will continue to decrease from southeast to northwest, and the average value will show a fluctuating growth, which is expected to reach 8.8 μg/(m2 s) in 2035 and 9.7 μg/(m2 s) in 2050. With the elaspe of time, the main growth area under the RCP2.6 scenario will shift from southern to northern China. This is reflected in the fact that NPP in north China will increase significantly at a rate greater than 0.15 μg/(m2 s) per year, but the growth rate will slow down and the area of significant growth will decrease in the southwestern and central-south regions. Under the RCP6.0 scenario, the main growth areas will retreat to the northeastern, southeastern and western regions, and the growth in the central and eastern regions will become insignificant. The high emission scenario will promote the growth of NPP before 2035 and inhibit the growth after 2035. The NPP will be extremely distributed under the RCP 6.0 scenario. For instance, the alpine desert grassland, temperate desert, shrub and semi-shrub desert in the northwest of Qinghai-Tibet Plateau will grow slowly or even stop growing. © 2022, Science Press. All right reserved.