【摘要】 利用MODIS产品中分辨率为1 km的光合有效辐射吸收比例(FPAR)数据,结合植被功能型分类,分析2010—2012年北京植被FPAR的空间分布特征,以及各种植被类型FPAR的多年变化,并进一步探讨了FPAR与叶面积指数(LAI)之间的相关性.结果表明:研究期间,北京植被的FPAR空间分布均呈现出东北部、西南部高,并向中心城区逐渐递减的分布特征.通过FPAR的叠加分析还发现,各种植被类型FPAR年平均值的波动均较小,针叶树、阔叶树、草地、作物FPAR的年均值波动范围仅分别在0.42~0.44、0.38~0.39、0.32~0.33、0.21~0.22,但各种植被类型FPAR的年内变化范围均较大.各种植被类型的FPAR与LAI也具有较好的线性或对数关系.经过Timesat软件中的Savitzky-Golay平滑滤波后,各种植被类型FPAR的季节性变化特征更加明显.更多还原

【Abstract】 In this study,the spatial distribution of fraction of absorbed photosynthetically active radiation( FPAR) of vegetation in Beijing during 2010-2012 was analyzed based on the MODISFPAR data with a resolution of 1 km and the functional classification of vegetation.The yearly dynamics of FPAR of different vegetation types were also investigated.Furthermore,the correlation between FPAR and leaf area index( LAI) was explored.The results showed that,there was a spatially descended trend from the northeast mountains to the central urban area of Beijing.The annual average FPAR of different vegetation types changed little during 2010-2012.These values varied in the ranges of 0.42-0.44,0.38-0.39,0.32-0.33,and 0.21-0.22 for coniferous forest,broadleaf forest,grassland,and crop,respectively.However,the range of variation was big for each vegetation type within the year.There was significant linear or logarithm relationship between FPAR and LAI of each vegetation type.Additionally,the smooth time series of MODIS-FPAR of vegetation types could better reflect seasonal variation,which was generated by Savitzky-Golay filtering in software Timesat.更多还原