Usability of noise-free daily satellite-observed green–red vegetation index values for monitoring ecosystem changes in Borneo
Usability of noise-free daily satellite-observed green–red vegetation index values for monitoring ecosystem changes in Borneo
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DOI：
10.1080/01431161.2014.978039
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发表时间：
2014-12
影响因子：
3.4
通讯作者：
S. Nagai;R. Ishii;A. Suhaili;Hideki Kobayashi;M. Matsuoka;T. Ichie;T. Motohka;J. J. Kendawang-J.;R. Suzuki
中科院分区：
文献类型：
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作者：
S. Nagai;R. Ishii;A. Suhaili;Hideki Kobayashi;M. Matsuoka;T. Ichie;T. Motohka;J. J. Kendawang-J.;R. Suzuki
我们研究了每日绿红植被指数（GRVI）观测的可用性，从Terra和Aqua中分辨率成像光谱仪卫星无云天监测生态系统变化在婆罗洲热带森林在500米的空间分辨率超过11年（2003-2013）。西南季风期（5 - 10月; 1-5天/月）无云GRVI数据的观测天数大于东北季风期（11 - 4月; 0-2天/月）。注意到观测频率的空间变化，Terra（上午）和Aqua（下午）数据显示无云数据的不同地理分布模式。加里曼丹西部山区（沙捞越和沙巴）的观测频率比东部山区（加里曼丹）的观测频率高1-2天/月。利用与卫星观测同时拍摄的天空图像和热带雨林冠层表面图像，对无云GRVI数据的质量进行了验证。在主要分布于沙捞越、加里曼丹西部和中部沿海地区的油棕和金合欢种植园和泥炭地，由于森林火灾造成的毁林和森林退化，无云日GRVI值降至零以下，并随着重新种植和植被恢复而增加。这些结果表明，需要在一天的不同时间从多颗卫星收集的每日无云GRVI数据，以准确监测热带生态系统中人类活动造成的气候条件变化和森林砍伐造成的年内和年际物候变化和森林退化。
We examined the usability of daily green–red vegetation index (GRVI) observations from the Terra and Aqua Moderate Resolution Imaging Spectroradiometer satellite on cloud-free days for monitoring ecosystem changes in Bornean tropical forests at a 500 m spatial resolution over 11 years (2003–2013). The number of observational days of cloud-free GRVI data in the southwest monsoon period (May–October; 1–5 days/month) was greater than that in the northeast monsoon period (November–April; 0–2 days/month). Spatial variation in the observation frequency was noticed, with Terra (morning) and Aqua (afternoon) data showing different geographic distribution patterns of cloud-free data. The observation frequency in the western Kalimantan mountains (Sarawak and Sabah) was 1–2 days/month greater than that in the eastern mountains (Kalimantan). The quality of cloud-free GRVI data was validated by using sky images taken at the same time as the satellite observations and canopy surface images in a tropical rainforest. In oil palm and acacia plantations and peatlands, which were mainly distributed in coastal regions of Sarawak and West and Central Kalimantan, the cloud-free daily GRVI value fell below zero owing to deforestation and forest degradation caused by forest fire and increased with replanting and vegetation recovery. These results indicate that daily cloud-free GRVI data from multiple satellites collected at different times of the day are required for accurate monitoring of intra- and interannual phenological variation and forest degradation attributed to changes in climatic conditions and deforestation caused by human activities in tropical ecosystems.