Estimate And Analysis Of Vegetation Net Primary Productivity Over The Sangjiang Plain

Sanjiang Plain was selected as study area in the study and the MODerate-resolutionImaging Spectroradiometer （MODIS） products, Tropical Rainfall Measuring Mission（TRMM）products and observed meteorological data were applied as the main datasource. A model based on remote sensing technology, Carnegie-Ames-StanfordApproach （CASA） used to calculate Net Primary Productivity （NPP）, adapt to theSanjiang Plain were package. The growing season NPP over the Sanjiang Plain （fromMay to September） of2000²008a by applying the model mentioned above. Finally, thespatial and temporal pattern of NPP was comprehensively analyzed, and the relationshipbetween key climate factor was disscussed. The research results were showed below:（1）NPP in the2000²008a growing season over the Sanjaing Plain was estimatedby using modified CASA model. When the estimated monthly NPP was compared withmonthly NPP measured by eddy covariance system during the growing season of2007²008a, it was found that both NPP were highly consistent with each other with thedetermination coefficient （R2） of0.76. At the same time, the estimation vegetation NPPand the findings of others with high consistency. Thus, this study was more reliable, itcan be used to Sanjiang Plain vegetation NPP analysis.（2）The NPP was different because of the environment, climatic factors andvegetation types. The land covered by forest had the largest NPP(493.34gC·m^-2) inSanjiang plain, then they were covered by wetland(401.09gC·m^-2), paddy field(360.09gC·m^-2) meadow(349.41gC·m^-2)and glebe(331.48gC·m^-2)in turn. From2000to2008a, the NPP over Sanjiang Plain showed non-obviously increased.（3） Overall, NPP non obviously correlated with temperature.NPP positivelycorrelated with precipitation. At the same time, the correlation between growing seasonNPP and precipitation and temperature were different along with the different vegetation.The NPP of forest non obviously correlated with precipitation, but notably correlatedwith temperature. However, the NPP of paddy field, glebe, meadow and wetland notablycorrelated with precipitation, but non-obviously correlated with temperature.（4）From2000to2008, Sanjiang plain vegetation net primary productivity stillmaintained a good growth trend. Therefore, it is useful to strengthen the resource management of Sanjiang plain, ban large-scale agricultural development activities andmaintain the characteristics of vegetation communities to promote the benigndevelopment of regional ecological environment.