Remote detection of Trichodesmium blooms in optically complex coastal waters: Examples with MODIS full-spectral data
Remote detection of Trichodesmium blooms in optically complex coastal waters: Examples with MODIS full-spectral data
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DOI：
10.1016/j.rse.2010.04.011
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发表时间：
2010-09-15
影响因子：
13.5
通讯作者：
Hardy, Robert
中科院分区：
文献类型：
--
作者：
Hu, Chuanmin;Cannizzaro, Jennifer;Hardy, Robert
由于沉积物再悬浮、海岸径流和海底干扰造成的光学复杂性，对佛罗里达州西部陆架 (WFS) 上的毛藻蓝藻水华的远程检测一直存在问题。通过结合海洋波段和陆地波段测量的 MODIS 数据，开发了一种方法来识别 WFS 上毛藻的表面垫。该方法首先识别 MODIS FAI（浮藻指数）250 m 分辨率图像中可能的水华斑块，该图像源自 667、859 和 1240 nm 处的瑞利校正反射率。然后，光谱分析检查了 Trichodesmium 在 469、488、531、551 和 555 nm 处的独特反射特性，以了解 Trichodesmium 中不寻常色素的特定光学特性（吸收、反向散射和荧光）。这些光谱特征（即分别在 469-488-531-551-555 nm 处的高-低-高-低-高反射率）将木藻垫与 FAI 图像中观察到的其他特征（例如马尾藻属）明确区分开来。在其他沿海地区的测试表明，该方法是稳健的并且适用于其他光学复杂的水域。这里显示的结果可以帮助研究Trichodesmium水华动力学（例如，启动和水华形成），也可能有助于设计未来的传感器，以更好地检测和量化Trichodesmium（全球海洋中重要的N-2固定剂）。 (C) 2010 Elsevier Inc. 保留所有权利。
Remote detection of the Trichodesmium spp cyanobacteria blooms on the west Florida shelf (WFS) has been problematic due to optical complexity caused by sediment resuspension, coastal runoff, and bottom interference By combining MODIS data measured by the ocean bands and land bands, an approach was developed to identify surface mats of Trichodesmium on the WFS. The approach first identifies possible bloom patches in MODIS FAI (floating algae index) 250 m resolution imagery derived from the Rayleigh-corrected reflectance at 667, 859, and 1240 nm. Then, spectral analysis examines the unique reflectance characteristics of Trichodesmium at 469, 488, 531, 551, and 555 nm clue to specific optical properties (absorption, backscattering, and fluorescence) of the unusual pigments in Trichodesmium. These spectral characteristics (i.e., high-low-high-low-high reflectance at 469-488-531-551-555 nm, respectively) differentiate Trichodesmium mats unambiguously from other features observed in the FAI imagery, such as Sargassum spp. Tests in other coastal locations show that the approach is robust and applicable to other optically complex waters. Results shown here can help study Trichodesmium bloom dynamics (e.g., initiation and bloom formation) and may also help design future sensors to better detect and quantify Trichodesmium, an important N-2 fixer in the global oceans. (C) 2010 Elsevier Inc. All rights reserved.