Abstract:

The Terrestrial net primary productivity (NPP) is a crucial indicator of terrestrial ecosystem,and is closely related to the carbon cycle and global climate change.Nowadays it’s not only a hot issue in the field of geography,but also attached great importance by all the governments.Yangtze River Delta region is one of China′s most economically developed and most costeffective,most comprehensive regions,whose terrestrial ecosystem withstands dual impacts from the natural elements and human activities of high strength.Hence,in support of RS and GIS technology,we used CASA model to investigate the temporalspatial variation discipline of terrestrial net primary productivity in the Yangtze River Delta region over the past decade and figured out the main control factors of,it in order to provide the basis of the process parameters for further research on impact of high intensive human activities on terrestrial carbon cycle.The main conclusions of this study were as follows.(1) From 1999 to 2009,the net primary productivity of the Yangtze River Delta decreased from 283094 gC/(m2·a) to 223521 gC/(m2·a) with an average annual reduction of 234%.The Yangtze River Delta terrestrial net primary productivity showed a threeyear cycle type of wave decline over the past decade.(2) In terms of Jiangsu,Zhejiang and Shanghai,the sort of NPP value was Zhejiang,Jiangsu and Shanghai,showing the spatial distribution of high middle and low north and south groove shape.(3) The correlation coefficient of reduction in NPP and increase in urban construction land and nonagricultural population was respectively 0553 and 0447,indicating that urbanization was an important factor to NPP variation.The main natural factors controlling NPP variation were NDVI and solar radiation,whose correlation coefficient with NPP was 0750 and 0739;while  precipitation and temperature had a relatively weak impact on NPP,with the correlation coefficient of 0235 and 0159 respectively.NPP was the accumulation result of vegetation and heat.