Response Of Vegetation Net Primary Productivity (NPP) To Climate Change In China And Sensitivity Experiments

In order to understand the impact of the climate change on regional vegetation NPP, the author firstly analyzed the response of NPP to climate change in China from 1981 to 2000. Then CENTURY model was used to simulate the responses of vegetation NPP to the climate change. The relationships between vegetation NPP and the climatic factors were researched through sensitivity experiments using CENTURY model. It can be concluded as follows:(1) From analyzing the data set of AVHRR GLOPEM NPP in China from 1981-2000, vegetation in different regions of China had the diversity characteristics of the variations in annual and seasonal NPP. The relations between seasonal temperature and NPP showed a better distributional pattern than the relations between annual temperature and NPP. The relationships between NPP and temperature appeared a significant variation among each district in China. The key factor that influenced the relation between annual NPP and precipitation is the relationships between NPP and precipitation in spring, their patterns were very similar.(2) The variation of CO2 concentration did not has apparently effect on NPP annual coefficient of variation, while could cause an increase in the annual trend of NPP. Temperature had apparently effects on the NPP annual coefficient of variation; however, its influence was less significant than the variation caused by the variation of precipitation. The climatic factor held a predominant position in influencing the trend of NPP is precipitation, when the temperature and precipitation had combined impact on NPP, the response of NPP trend was similar to the variation caused by the variation of precipitation alone.(3) According to varied responses of NPP to different climatic contexts, it can be concluded that:on the same level of precipitation and CO2 concentration, vegetation NPP in most part of China decreased with the increasing of temperature, while the vegetation NPP showed the same trend as the variation of precipitation. When the vegetation was influenced by the variations of temperature and precipitation together, NPP in different parts of China showed diversity responses. The increasing of CO2 concentration could cause the rise in vegetation NPP of China, especially the vegetation NPP in Northeastern China and east-central China parts of the country.