Study on seasonal change of terrestrial net primary productivity (NPP) and its relationship with climate as well as, its variations in different land-use types is to help understand the responses of Chinese terrestrial ecosystem to global climate change and is important to carbon cycle research. In this study, time series dataset of Chinese terrestrial NPP from GLO-PEM model and corresponding information on climate and land use were used to explore the seasonal trends of terrestrial NPP in China from 1981 to 2000. As the result, seasonal NPP in China showed a significant increase for all four seasons (spring, summer, autumn and winter) during the past 20 years. The spring NPP indicated the largest increase rate, while the summer NPP was with the largest increase in magnitude. Seasonal NPP dynamics were different in different land-use types. Croplands had the largest NPP increase and increase rate in spring, summer and autumn, and woodland had the largest NPP increase in winter, while water had the largest NPP increase rate in winter. The regions with the largest increase in summer NPP occurred in most parts of eastern China, eastern Inner-Mongolia, Sichuan Basin, eastern Guizhou, southern Xizang and western Xinjiang, while the areas with the largest decrease in summer NPP appeared mainly in Hulun Buir Plateau, Ordos Plateau, Loess Plateau, eastern Qinghai-Tibet Plateau and northwestern Xinjiang.
Progress in Geography