武汉地区植被NPP动态监测研究

Dynamic Monitoring of Vegetation NPP in Wuhan Based on MODIS

  • 摘要: 通过建立、比较多种区域性光合有效辐射(PAR)估算模型,对比分析了NDVI、EVI与光合有效辐射吸收系数(fPAR)之间的关系,根据不同植被最大光能利用率的不同,改进了植被净初级生产力(NPP)模拟算法。利用MODIS、气象辐射数据等,研究了武汉市2001~2011年间植被NPP季节、年际变化特征。结果表明,NPP季节变化明显,夏季高,春秋次之,冬季低,七月中旬最高,达到85 gCm-2month-1;年平均NPP呈现出一定的增长趋势,2008年最高562 gCm-2a-1;不同类型植被NPP差异较大,常绿阔叶植被年平均值最大1 028 gCm-2a-1,每年生阔叶植被NPP最低410 gCm-2a-1。

     

    Abstract: The net primary production (NPP) model was improved by developing and comparing different regional photosynthetically active radiation (PAR) models, studying the relationships between fraction of PAR and NDVI and EVI, and considering the difference in maximum light use efficiencies for different vegetation types. The seasonal and interannual variation patterns of vegetation NPP in Wuhan was studied with MODIS data and climatic materials. It is indicated that NPP changed greatly with seasons, high in summer, then the spring and autumn, low in winter, and the highest NPP value appeared in Mid July with about 85gCm 2month 1. There was an increasing trend in annual NPP from 2001 to 2011 for all kinds of vegetation, and the maximum value was observed in 2008 with 562gCm 2a 1. It was also found that NPP values of different vegetation types varied greatly at the same study period, evergreen broadleaf vegetation showed the highest annual NPP value, and the annual broadleaf vegetation displayed the smallest value due to the difference in light use efficiencies.

     

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