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植被净初级生产力(Net Primary Productivity,NPP)是评价陆地生态系统的重要参数,植被NPP的反演为全球碳循环的研究提供了重要的参考依据。本文基于2000-2014年的MODIS及气象站点数据,引入逐步线性回归、主成分回归、偏最小二乘回归以及岭回归分析,构建了多元逐步回归模型、主成分回归模型、偏最小二乘回归模型和岭回归模型,并对这4种模型进行了评估。结果表明:①多元逐步回归模型被认为是一种可以简单、高效、准确地反演西北干旱区植被NPP的模型,且模拟结果与MOD17A3产品及实测值具有很强的相关性;②西北干旱区多年平均植被NPP的分布具有明显的区域差异,山区增加,平原区减少,呈现出北部及西北部高,而南部及东南部低的特征;③西北干旱区NPP在年际变化上呈波动增加趋势,线性增长率为0.40g C/(m·a)。自2000年以来,58.66%区域的NPP呈现增长趋势,13.64%的地区保持不变,27.7%的地区表现为退化趋势。
Net Primary Productivity (NPP) is an important parameter for evaluating terrestrial ecosystems. The inversion of vegetation NPP provides an important reference for the research on global carbon cycle. Based on the MODIS and meteorological stations data from 2000 to 2014, this paper introduces stepwise linear regression, principal component regression, partial least-squares regression and ridge regression analysis to construct multiple stepwise regression models, principal component regression models, partial least-squares regression models And ridge regression model, and evaluated these 4 models. The results show that: ①Multiple stepwise regression model is considered as a model that can simply, efficiently and accurately reverse vegetation NPP in the arid region of northwestern China, and the simulation results have strong correlation with MOD17A3 products and measured values; ②Arid northwest arid region The distribution of NPP in many years had obvious regional differences, with the increase of mountainous area and the reduction of plain area, showing the characteristics of high in the north and northwest while low in the south and southeast; ③The NPP in the arid region of Northwest China showed an increasing trend in the interannual variation , Linear growth rate of 0.40g C / (m · a). Since 2000, the NPP in 58.66% of regions has shown an increasing trend, while 13.64% of regions have remained unchanged while 27.7% of regions have shown a trend of degeneration.