Seasonal changes in camera-based indices from an open canopy black spruce forest in Alaska, and comparison with indices from a closed canopy evergreen coniferous forest in Japan
Seasonal changes in camera-based indices from an open canopy black spruce forest in Alaska, and comparison with indices from a closed canopy evergreen coniferous forest in Japan
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DOI：
10.1016/j.polar.2012.12.001
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发表时间：
2013-06
期刊：
影响因子：
1.8
通讯作者：
S. Nagai;T. Nakai;T. Saitoh;R. Busey;Hideki Kobayashi;R. Suzuki;H. Muraoka;Yongwon Kim
中科院分区：
文献类型：
--
作者：
S. Nagai;T. Nakai;T. Saitoh;R. Busey;Hideki Kobayashi;R. Suzuki;H. Muraoka;Yongwon Kim
评价万年青针叶林的碳、水和能量平衡需要精确的现场和卫星数据，以了解其时空动态。每日数码相机图像可用于确定物候、总初级生产力（GPP）和气象参数之间的关系，并用于地面实况卫星观测。在这项研究中，我们研究的季节性变化之间的关系，基于相机的冠层表面指数和涡协方差为基础的GPP来自实地研究，在阿拉斯加的开放式树冠黑云杉林和日本的封闭式树冠雪松林。绿色数码的总数码数，色调和GPP的比例在两个网站显示了钟形的季节性配置文件。黑云杉林和雪松林的冠层表面图像主要检测森林地面和树冠上植被的季节变化。与此相反，红色和蓝色的数字数字的比例，总数字的数量的季节性周期不同的两个网站之间，可能是由于森林结构和叶色的差异。这些结果表明，森林结构特征，如冠层开放度和季节性森林地面变化，应考虑在万年青针叶林的物候连续观测。
Evaluation of the carbon, water, and energy balances in evergreen coniferous forests requires accurate in situ and satellite data regarding their spatio-temporal dynamics. Daily digital camera images can be used to determine the relationships among phenology, gross primary productivity (GPP), and meteorological parameters, and to ground-truth satellite observations. In this study, we examine the relationship between seasonal variations in camera-based canopy surface indices and eddy-covariance-based GPP derived from field studies in an Alaskan open canopy black spruce forest and in a Japanese closed canopy cedar forest. The ratio of the green digital number to the total digital number, hue, and GPP showed a bell-shaped seasonal profile at both sites. Canopy surface images for the black spruce forest and cedar forest mainly detected seasonal changes in vegetation on the floor of the forest and in the tree canopy, respectively. In contrast, the seasonal cycles of the ratios of the red and blue digital numbers to the total digital numbers differed between the two sites, possibly due to differences in forest structure and leaf color. These results suggest that forest structural characteristics, such as canopy openness and seasonal forest-floor changes, should be considered during continuous observations of phenology in evergreen coniferous forests.