Detecting massive green algae (Ulva prolifera) blooms in the Yellow Sea and East China Sea using Geostationary Ocean Color Imager (GOCI) data
Detecting massive green algae (Ulva prolifera) blooms in the Yellow Sea and East China Sea using Geostationary Ocean Color Imager (GOCI) data
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DOI：
10.1007/s12601-012-0034-2
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发表时间：
2012-09
影响因子：
1.3
通讯作者：
Y. Son;J. Min;J. Ryu
中科院分区：
文献类型：
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作者：
Y. Son;J. Min;J. Ryu
2008年6 - 8月在青岛、黄海、东海和日本沿岸发生的绿色大型海藻石莼（Ulva proliferated）的历史性大规模水华在相似的季节和区域再次发生。2011年6月13日，在中国青岛附近，世界上第一台地球同步海洋彩色成像仪（GOCI）探测到了一个巨大的漂浮绿色藻类水华，它起源于中国苏北海岸。2011年夏季，在黄海和东海的沿着和横隔海域，通过多个航次观测到了大型漂浮绿色藻类斑块。为了从太空探测大型藻类水华，我们分析了它们的光谱特征，从原位光学测量和卫星派生的绿色藻类光谱。利用三个波长（555、660、745 nm）的多光谱波段比，开发了“漂浮绿色藻类GOCI指数”（IGAG），绿色藻类在555、745和865 nm处反射，在660和680 nm处吸收。结果进行了比较，所获得的归一化差异植被指数（NDVI），增强植被指数（EVI），和韩国海洋卫星中心（KOSC）的方法。IGAG方法的一个优点是，漂浮绿色藻类的微弱或细微信号被增强并与周围复杂的水信号分离。虽然通过其他方法得出的漂浮绿色藻类地图描绘了密集的绿色藻类，但它们对细微（密度较低）特征以及附近多云或复杂水条件的情况不太敏感。来自IGAG的漂浮绿色藻类地图提供了比使用NDVI、EVI或KOSC方法得出的更可靠的宽漂浮绿色藻类水华估计。政府间咨询组的方法应有助于在区域和全球范围内追踪和监测绿色藻类大量繁殖的变化。
The historically massive bloom of the green macroalgaeUlva proliferareported in June–August 2008 around the Qingdao, Yellow Sea, East China Sea and Japan coasts has recurred in a similar season and region. On June 13, 2011, around Qingdao, China, the world’s first Geostationary Ocean Color Imager (GOCI) detected an enormous bloom of floating green algae, which originated from the nearshore Subei Bank, China. The large floating green algae patches were observed along and across the Yellow Sea and in the East China Sea during 2011 summer by various oceanic cruises. To detect the massive macroalgae blooms from space, we analyzed their spectral characteristics fromin situoptical measurements and satellite-derived green algae spectra. An “Index of floating Green Algae for GOCI” (IGAG) was developed from the multiple spectral band ratios using three wavelengths (555, 660, 745 nm), which the spectral response of green algae reflected at 555, 745, and 865 nm and absorbed at 660 and 680 nm. The results were compared with those obtained by the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and Korea Ocean Satellite Center (KOSC) approaches. An advantage of the IGAG method was that muted or subtle signals of floating green algae were enhanced and separated from surrounding complex water signals. Although maps of floating green algae derived by the other approaches delineated dense green algae, they were less sensitive to subtle (less dense) features and in cases of nearby cloudy or complex water conditions. The floating green algae maps from IGAG provided a more robust estimate of wide floating green algae blooms than those derived using NDVI, EVI, or KOSC approaches. The IGAG approach should be useful for tracing and monitoring changes in green algae blooms on regional and global scales.