Mapping forest degradation in the Amazon region with Ikonos images
Mapping forest degradation in the Amazon region with Ikonos images
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使用 Ikonos 图像绘制亚马逊地区的森林退化地图
DOI：
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发表时间：
2005
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通讯作者：
Darren M Roberts
中科院分区：
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作者：
Carlos Souza;Darren M Roberts
Ikonos图像可以提供有关巴西亚马逊地区选择性伐木和森林表面火灾造成的森林退化的前所未有的信息。到目前为止，巴西雨林的损失是通过利用大地卫星图像制作的地图上的毁林统计数据定期估计的（国家空间研究所，2000年）。选择性砍伐的森林和烧毁的森林没有列入流域范围的统计数据，但也可以用大地卫星和地球观测卫星图像绘制地图（科克伦和Souza，1998年; Stone和列费夫尔，1998年; Souza和Barreto，2000年; Asner等人，2002年; Monteiro等人，2003年）。这些中等空间分辨率的图像不能提供关于退化森林的详细信息。例如，森林结构和组成（如树冠大小，藤本植物密度，树种等）不能在这些中等的空间分辨率（即20-30米像素大小）检索。此外，使用陆地卫星和SPOT图像很难将退化的古老森林（即0.2年）与完整的森林区分开来。这就是森林退化被报告为“神秘毁林”（Nepstad等人，1999年）的原因之一，并被认为对陆地卫星图像“不可见”（Laurence和Fearnside，1999年）。Ikonos图像的分辨率可以达到一米，为绘制亚马逊地区森林退化地图提供了新的能力。封面图像（图1）是Ikonos图像空间分辨率的一个独特例子，通过合并光谱带4（0.757-0.853 mm），3（0.632-0.698 mm）和2（0.506-0.595 mm）与全色带（0.45-0.90 mm）获得。在本例中，所有导致森林退化的进程都被捕获在一个快照中。我们将讨论Ikonos图像的潜力，以绘制退化的森林在巴西亚马逊和评估森林退化是否可能成为“神秘”的Ikonos传感器。
Ikonos images can provide unprecedented information about forest degradation caused by selective logging and forest surface fires in the Brazilian Amazon. Until now, the loss of the Brazilian rainforest has been estimated regularly through deforestation statistics from maps produced with Landsat images (INPE 2000). Selectively logged forests and burned forests have not been included in the basin wide statistics, but can be mapped with Landsat and SPOT images as well (Cochrane and Souza 1998, Stone and Lefebvre 1998, Souza and Barreto 2000, Asner et al. 2002, Monteiro et al. 2003). These moderate spatial resolution images do not provide detailed information about degraded forests. For example, forest structure and composition (e.g. crown size, liana density, tree species, etc) cannot be retrieved at these moderate spatial resolutions (i.e. 20–30 m pixel size). In addition, old degraded forests (i.e. .2 years) are difficult to distinguish from intact forests with both Landsat and SPOT images. This is one of the reasons forest degradation has been reported as ‘cryptic deforestation’ (Nepstad et al. 1999), and has been considered ‘invisible’ to Landsat images (Laurence and Fearnside 1999). Ikonos images, which can be acquired with resolution as fine as one metre, offer a new capability to map forest degradation in the Amazon region. The cover image (figure 1) is a unique example of the resolving spatial power of the Ikonos images, obtained by merging spectral bands 4 (0.757–0.853 mm), 3 (0.632–0.698 mm) and 2 (0.506–0.595 mm) with the panchromatic band (0.45–0.90 mm). In this example, all of the processes that cause forest degradation were captured in one snapshot. We will discuss the potential of the Ikonos images to map degraded forests in the Brazilian Amazon and evaluate whether forest degradation may become ‘cryptic’ to the Ikonos sensor.