Study On Temporal And Spatial Variation Of Vegetation Net Primary Productivity In Heilongjiang Province In1896and2009

Vegetation net primary productivity is the key parameter on reflecting theterrestrial vegetation carbon fixation capacity and terrestrial ecological processes,it’salso the indispensable part of the understanding of suface carbon cycle.NPP has specialsignificance to estinate the support ability of the earth and sustainable development ofterrestrial ecosystems.This study estimates vegetation net primary productivity using C-FIX model,combined with spatial analysis function of ArcGIS and ERDAS, based on CRUmeteorological data and the forest distribution map of Heilongjiang in1896. It takes theNDVI in2009and2000of MODIS as data source, with temperature, radiation andcloud resource. It refers the relevant conclusions to achieve control experiments.Someresults are as followed:(1)The net primary productivity of vegetation in Heilongjiang Province,1896is283.5307million tons,it’s not uniformly distributed throughout the year,the seasonalchange is very obvious.NPP production is mainly accumulated in the June,July andAugust,the highest values appears in the July.The NPP distribution has differences in theprovince,there are up to2times differences between the high value areas and thelow value areas.The distribution in the southwest is higher than the central andeastern,followed by southeastern and northwestern Daxinganling region.(2)The net primary productivity of vegetation in Heilongjiang Province,2009is124.3425million tons, it’s not uniformly distributed throughout the year,the seasonalchange is very obvious.NPP production is mainly accumulated in the June,July andAugust,the highest values appears in the July.The NPP distribution has differences in theprovince,there are up to10times differences between the high value areas and thelow value areas.The distribution of unit production in Daxinganling,Xiaoxinganling,Yichun and Mudanjiang region are higher than the Sanjiang plain andSongnen plain.(3)Analyze the NPP production and spatial distribution in Heilongjiang Province in1896and2009:Firstly, the NPP production in1896is2.28times of in2009,the differences of mothly production between the two years were in the range of1to3times,the monthly distribution trend is consistent.Visible,the net production capacity ofecosystem has decreased sighificantly today,the environment is deteriorating.Secondly,the spatial distribution change of NPP production is extremely sighificant in the hundredyears: The southwestern is the highest and the Daxinganling region is the lowest in1896,but in2009,the Daxinganling and Xiaoxinganling region are the highest,the lowestareas is southwestern.Thirdly, the highest area of NPP reduction is Songnen plain in thesouthwestern of Heilongjiang Province,followed by Sanjiang plain, central andsoutheastern,the Daxinganling region is the lowest.(4)Compare the control experiment and the simulation result of the real year hasshowed that,vegetation and meteorological factors affect the NPP production,especiallythe vegetation.Between the hundred years,the vegetation change is due to thedevelopment and utilization of the land with artificial reasons.It produces an importantimpact on the ecosystem balance of Heilongjiang Province and the surrounding area.