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利用光化学植被指数(PRI)反演区域尺度植被光能利用效率(LUE)的动态变化特征是当前生态系统生产力遥感研究的一个重要方向。基于2014年4月-2015年3月在广东省肇庆市鼎湖山森林生态试验站开展了植被冠层光谱和涡度相关通量同步观测,探讨亚热带常绿针阔混交林LUE与PRI的相关性及其调控因素。研究表明:(1)亚热带常绿针阔混交林LUE-PRI存在显著相关关系,但其相关性存在较大的季节性差异,冬季的相关性(R~2=0.40,P<0.01)明显优于夏季(R~2=0.04,P<0.01);(2)削弱植被自身的色素含量以及观测区内部的冠层结构、土壤背景、观测和光照条件影响后的?PRI难以有效表征亚热带常绿针阔混交林的LUE动态变化(表征程度为10%左右);(3)植被吸收的光合有效辐射(PAR)对LUE-PRI关系影响较大,饱和水汽压差(VPD)和日均温(Ta)对LUE-PRI相关性的影响较弱。需要进一步分析森林冠层结构、物候变化等因素对两者关系的影响,提高PRI作为亚热带森林LUE动态变化指示器的精度。
The use of photochemical vegetation index (PRI) to invert the dynamic characteristics of LUE at regional scale is an important direction of current research on remote sensing of ecosystem productivity. Based on the simultaneous observation of vegetation canopy spectrum and eddy covariance at Dinghushan Forest Ecological Experimental Station of Zhaoqing City, Guangdong Province from April 2014 to March 2015, the correlation between LUE and PRI in subtropical evergreen coniferous-broadleaf mixed forest And its regulatory factors. The results showed that: (1) There was a significant correlation between LUE-PRI and subtropical evergreen coniferous and broad-leaf mixed forest, but there was a big seasonal difference in the correlation between winter and autumn (R ~ 2 = 0.40, P <0.01) In the summer (R 2 = 0.04, P <0.01); (2) It is difficult to effectively characterize the subtropical evergreen with PRI, which weakens the pigment content of vegetation itself and the canopy structure, soil background, observation and illumination conditions in the observation area LUE-PRI dynamic changes in the coniferous-broad-leaved mixed forest (the degree of characterization is about 10%); (3) The photosynthetically active radiation (PAR) Ta) has a weaker effect on LUE-PRI correlation. Further analysis of the impact of forest canopy structure, phenological changes and other factors on the relationship between the two should be carried out to improve the accuracy of PRI as a dynamic indicator of LUE in subtropical forests.