The Impact of Precipitation and Temperature on Net Primary Productivity in Xinjiang, China from 1981 to 2000

Abstract

The response process and mechanism research of terrestrial ecosystem on global changes (including climate changes and human activities) are important components of research on global changes. The global warming and intensification of human activities over the past 100 years have aroused great attention of scientific communities and policymakers to the impact of climate changes on the internal process and feedback of terrestrial ecosystems, as well as research on ecological security under future climate scenarios (Cambridge University Press, 2000). The continuing rise in atmospheric CO2 is considered as a main cause of the future changes in global climate (Melillo et al., 1993; McGuire and Melillo, 1995; Cao and Woodward, 1998a). Predicted climate changes include an increase in mean annual air temperature and alterations in precipitation pattern and cloud cover. Elevated atmospheric CO2 and climate changes are expected to influence the ecosystems (Riedo et al., 2000). Terrestrial Net Primary Productivity (NPP) is regarded as the greatest annual carbon flux from the atmosphere to the biosphere and is considered as a main cause of seasonal fluctuations in atmospheric CO2 concentrations (Law and Waring, 1994; Runyon and Waring, 1994; Hall and Ojima, 1995; McGuire and Melillo, 1995; Churkina and Running, 1998). The terrestrial biospheric productivity plays a very important role to the life of humankind and all heterotrophic organisms on Earth (Melillo et al., 1993; Gilmanov and Walter, 1995).