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Optical sensing of plankton communities and dynamics
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High-frequency observation of floating algae from AHI on Himawari-8
P-B2-05-S
Xinrong Chen* , State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
Shaoling Shang, State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
Zhongping Lee, School for the Environment, University of Massachusetts Boston, Boston, MA 02125
Lin Qi, State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
Jing Yan, State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
Yonghong Li, State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China
Presenter Email: 1191088508@qq.com |
| Himawari-8 (H8) is a geostationary meteorology satellite launched and operated by Japan Meteorological Agency (JMA) and takes measurements at a temporal resolution of 10 minutes for its full disk view. Although designed as a meteorological satellite, the Advanced Himawari Imager (AHI) on board H8 has three visible (460, 510, and 640 nm), one near infrared (860 nm) and two shortwave infrared bands (1610 and 2257 nm) to observe the Earth system. In this study, the Floating Algae Index (FAI) developed for ocean color satellites (Hu, 2009) is adapted to process AHI data for the first time and applied for waters of Taihu Lake, China. The distribution of floating algae derived from AHI FAI was compared with that derived from concurrent GOCI AFAI (alternative FAI) and MODIS FAI. For a total of 18 near-cloud-free images, a correlation coefficient of 0.92 between the algae area derived from AHI FAI and MODIS FAI was found, with the mean percentage difference of ~5% in algae coverage. More concurrent images (n = 80) were collected for a comparison of FAI between AHI and GOCI as GOCI is also a geostationary satellite, resulting in a correlation coefficient of 0.91 and percentage deviation of ~8% in observed algae coverage. These results indicate that H8/AHI can obtain reliable observations of floating algae at ultrahigh temporal resolutions (10 minutes). In particular, such high-frequency measurements show that part of the Taihu Lake (e.g., the Meiliang Bay, Gong Bay) experienced more frequent cover of floating algae (mostly > 60%) than that observed by GOCI (generally < 40%). High-frequency measurements are thus important not only for efficient environmental monitoring, but also for scientific understanding of algae dynamics. |
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