1982～2010年中国东北地区植被NPP时空格局及驱动因子分析

应用逐像元线性回归模型方法,整合应用MODIS和AVHRR NDVI数据集,构建1982~2010年覆盖东北地区的8 km空间分辨率的NDVI数据集,进而应用CASA模型估算得到东北地区29 a NPP数据集,模拟精度在75%以上。29 a平均的东北地区植被NPP总量为6.5×108tC/a。植被NPP的分布受植被类型、气候、地形因素的综合影响。NPP地域差异明显,山地区植被>平原区植被>高原区植被,变化最大的植被类型为草地植被。过去29 a间,植被NPP呈显著上升趋势(P<0.01)。气候变化和土地利用变化均是影响植被时空格局的重要因素。

Spatio-temporal Pattern of Net Primary Productivity and Its Driven Factors in Northeast China in 1982-2010

AVHRR NDVI at 8 km spatial resolution and MODIS NDVI at 1 km spatial resolution were integrated using per pixel linear regression model method to construct NDVI dataset from 1982 to 2010 at 8 km spatial resolution and covering Northeast China.Based on the constructed NDVI dataset and meteorological data,monthly net primary productivity in Northeast China in1982-2010 were estimated using the CASA model.Simulation accuracy of net primary productivity was above 75% and through accuracy and consistency check.Annual total vegetation net primary productivity in Northeast China is 6.5×108 t/a(carbon),and the distribution of net primary productivity varied from vegetation types,climatic and topography differences.There are obvious difference and spatial heterogeneity for NPP in Northeast China.For the vegetation in different topography areas,net primary productivity decreased in the order of mountains,plains,plateaus.For different vegetation types,net primary productivity decreased in the order of broadleaved deciduous forest and evergreen coniferous forest,mixed coniferous and broadleaved forest and deciduous coniferous forest,crop,grass.Trend analysis at pixel extent showed that the pixels with decreased trends mainly distributed in the transitional zone between typical forest zone and plain,Hulun Buir grassland and Chifeng semi-aird region.Result of spatial variation analysis showed that the NPP of grassland vegetation had the highest changes compared with other vegetation types in the past 29 years.But net primary productivity of grassland have an obvious increase at a whole,this was maybe resulted from the conservative grazing and grassland protection.Net primary productivity exhibited obviously increasing trend in 1982-2010.Consequently,vegetation carbon fixation had enhanced as a whole acquired from the decade analysis.Climatic changes for different parameters are very important affecting factors on spatial pattern and annual dynamic of NPP.Land cover changes in Northeast China during the past 29 years influenced the spatial pattern and annual dynamic for net primary productivity of different vegetation types.Economic development in this region still makes a pressure for vegetation net primary productivity,especially the forest.