Mapping Seasonal Tree Canopy Cover and Leaf Area Using Worldview-2/3 Satellite Imagery: A Megacity-Scale Case Study in Tokyo Urban Area
Mapping Seasonal Tree Canopy Cover and Leaf Area Using Worldview-2/3 Satellite Imagery: A Megacity-Scale Case Study in Tokyo Urban Area
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DOI：
10.3390/rs12091505
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发表时间：
2020-05-01
期刊：
影响因子：
5
通讯作者：
Tani, Akira
中科院分区：
文献类型：
--
作者：
Kokubu, Yutaka;Hara, Seiichi;Tani, Akira
本研究提出了一种在不同树木物候季节开发高分辨率（2 m）城市树冠叶面积清单的方法，并随后将该方法应用于东京 625 km(2) 的市区。卫星遥感具有同时对大面积区域进行成像的优势。然而，在高度异质的城市景观中，准确绘制树冠覆盖度和树叶面积仍然很困难。单棵树级别的 WorldView-2/3 卫星图像（2 m 分辨率）用于根据简单的基于像素的分类方法绘制城市树木地图。将我们的测绘结果与航空摄影获得的树冠覆盖度进行比较表明，误差范围在3.0 km(2)小区级别5.5%、60.9 km(2)直辖市级别5.0%和625 km(2)城市级别1.2%的可接受范围内。此外，我们研究了卫星数据（植被指数）和原位树木测量数据（树叶面积指数）之间的关系，以开发一个简单的模型来直接绘制 WorldView-2/3 图像中的树叶面积。东京市区在叶期的估计总叶面积（633 km(2)）是叶期（319 km(2)）的两倍。我们的结果还表明，东京市区的估计总叶面积是中等分辨率（30 m）卫星图像结果的 1.9-6.2 倍。
This study presents a methodology for developing a high-resolution (2 m) urban tree canopy leaf area inventory in different tree phenological seasons and a subsequent application of the methodology to a 625 km(2) urban area in Tokyo. Satellite remote sensing has the advantage of imaging large areas simultaneously. However, mapping the tree canopy cover and leaf area accurately is still difficult in a highly heterogeneous urban landscape. The WorldView-2/3 satellite imagery at the individual tree level (2 m resolution) was used to map urban trees based on a simple pixel-based classification method. The comparison of our mapping results with the tree canopy cover derived from aerial photography shows that the error margin is within an acceptable range of 5.5% at the 3.0 km(2) small district level, 5.0% at the 60.9 km(2) municipality level, and 1.2% at the 625 km(2) city level. Furthermore, we investigated the relationship between the satellite data (vegetation index) and in situ tree-measurement data (leaf area index) to develop a simple model to directly map the tree leaf area from the WorldView-2/3 imagery. The estimated total leaf area in Tokyo urban area in the leaf-on season (633 km(2)) was twice that of the leaf-off season (319 km(2)). Our results also showed that the estimated total leaf area in Tokyo urban area was 1.9-6.2 times higher than the results of the moderate-resolution (30 m) satellite imagery.