Impacts of seasonal climate on net primary productivity (NPP) in Xinjiang, 1981-2000

This study presented the temporal and spatial variation patterns of the seasonal NPP, temperature and precipitation. The NPP simulated by using the GLO-PEM. A semi-mechanistic model of plant photosynthesis and respiration driven entirely by the satellite observations was combined with climate data in Xinjiang of China over the past 20 years to study the impact of seasonal climate changes on the seasonal NPP. The higher correlation coefficients between the seasonal NPP and the corresponding seasonal temperature and precipitation over the past 20 years happened in the areas covered with forest lands, grasslands, oasis and croplands in the northern and southern foothills of Tianshan Mountain, Iili River Valley, Tarim Basin and Junggar Basin. In these areas, the vegetation growth was greatly influenced by interannual changes of seasonal temperature and precipitation. The spatial patterns of the correlation coefficients in Xinjiang showed that the higher correlation coefficients between seasonal NPP and seasonal temperature and precipitation in 1990s than in 1980s. With the increased temperature and precipitation, the areas of grasslands and oasis in Xinjiang were expanded over the last 20 years.