A Study Of Phenological Change And The Relationship Between The Carbon Flux Of Forest Ecosystem In China For Nearly 30 Years (1982-2011)

At present, the study of terrestrial ecosystems respond to (past or future) climate change is one of the focus on global climate change research. Vegetation is the main body of terrestrial ecosystem. Phenology is the most sensitive indicator of climate change, it can quickly respond to climate change, and has negative feedback to climate change, but also affects the carbon cycle process. Phenology builts a bridge in the process of climate change and carbon cycle.Therefore how to use phenology to explore its response to climate change and the relationship between the carbon cycle more effectively are the targets of this.In this research, we explored the trend analysis and the differences of the main phenological phases of forest ecosystem obtained from NOAA-AVHRR and MODIS satellite remote sensing data and the meteorological data for nearly 30 years in China. The main phenological phases are the date of green-up, dormancy, and the length of growing season. At the same time, we used the improved model of Light Use Eifficiency (LUE) to simulate gross primary productivity (GPP). Analysis the relationship between the change of phenology and GPP.The main conclusions are:(1)The dates of green-up occurred in early April to the middle of May in various of vegetation types. They are advanced from north to south in our country. All the results of the dates of green-up are advanced in various of vegetation types, although they have different degrees. Northern has greater degree than southern in advance by contrast.(2) The dates of dormancy occurred in the middle to late September to early October in Cold Temperate Zone and Temperate Zone and occurred in the middle to late October to late November in subtropical and tropical zones. They are delayed from north to south in our country. All the results of the dates of dormancy are delayed in various of vegetation types, although they have different degrees. Southern has greater degree than northern in delay by contrast.(3) The lengths of growing season are extended from north to south in our country and they are longer than before in various of vegetation types. They have nearly same degrees in southern and northern in extend generally.The extension of the lengths of growing season by the combination of green-up and dormancy. The lengths of growing season are extended that is caused by green-up in advance in northern however that is caused by dormancy in delay in southern.(4) We explored the trend analysis and the differences of the main phenological phases of forest ecosystem obtained from satellite remote sensing data and meteorological data for nearly 30 years in China. We found that the change of phenological phases based on satellite remote sensing data and meteorological data are the same and that have extremely significant correlation. We found that the date of green-up obtained from meteorological data are less than 6.14d to the result of NDVI, dormancy are less than 6.49d, these lead to the length of growing season that shortened 0.34d. The phenological phases obtained from NDVI are later than the result of meteorological data.(5)A11 vegetation types showed that the lengths of growing season are longer than before and GPP are increasing in China for. nearly 30 years. The changing trends of phenophase and GPP also have highly consistency. The lengths of growing season are longer than before, that leaded to the increase of GPP. The dates of green-up are more important than dormancy in the influence of GPP.In this research, we explored the trend analysis and the differences of the main phenological phases of forest ecosystem obtained from satellite remote sensing data and meteorological data for nearly 30 years in China. We found that the change of phenological phases based on satellite remote sensing data and meteorological data are the same and that have extremely significant correlation. The changing trends of phenophase and GPP also have highly consistency.The lengths of growing season are longer than before, that leaded to the increase of GPP. It will be better to predict the responsed to global climate change by the cycle of carbon in terrestrial ecosystem.