A note on the height variation of foliage clumping: comparison with remote sensing retrievals
A note on the height variation of foliage clumping: comparison with remote sensing retrievals
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DOI：
10.1080/2150704x.2012.742212
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发表时间：
2013-04
影响因子：
2.3
通讯作者：
J. Pisek;A. Oliphant
中科院分区：
文献类型：
--
作者：
J. Pisek;A. Oliphant
丛生指数（Clumping index，CI）是植物冠层的一个重要结构参数，它描述了不同冠层结构中相对于随机分布的叶群水平，在生态学和气象学模型中具有重要的应用价值。在这封信中，我们报告验证来自中分辨率成像光谱仪（MODIS）的数据在500米的分辨率，使用新的信息，在广泛的森林类型的立场树叶丛生的垂直剖面的全球树叶丛生地图。我们报告说，在中度到茂密的森林与发达的林下植被层，在地面附近的原位测量可能会大大低估了整体冠层丛生效应。这是因为，由于树枝下部植被的遮挡，树冠上层树冠之间的巨大间隙可能无法全部在地面附近测量。CI的高度变化的信息被证明是重要的正确估计和验证从航空/卫星遥感的树叶丛生。
Clumping index (CI), quantifying the level of foliage grouping within distinct canopy structures relative to a random distribution, is a key structural parameter of plant canopies and is very useful in ecological and meteorological models. In this letter, we report on validating the global foliage clumping map derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) data at 500 m resolution using new information about vertical profiles of foliage clumping in a wide range of forest type stands. We report that in moderate to dense forest stands with developed undergrowth layer, in situ measurements near the ground surface may considerably underestimate the overall canopy-level clumping effect. This is because the large gaps between tree crowns at upper levels of the canopy may not be all measured near the ground due to obscurity by lower vegetation of branches. This information about height variation of CI is shown to be important for correct estimating and validating the foliage clumping from airborne/satellite remote sensing.