Performance evaluation of operational atmospheric correction algorithms over the East China Seas

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• 作者：Shuangyan He 贺双颜 ; Mingxia He 贺明霞…
• 关键词：validation ; remote sensing reflectance ; aerosol optical thickness ; ocean color ; atmospheric correction ; remote sensing
• 刊名：Chinese Journal of Oceanology and Limnology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：35
• 期：1
• 页码：1-22
• 全文大小：
• 刊物主题：Oceanography;
• 出版者：Science Press
• ISSN：1993-5005
• 卷排序：35

文摘

To acquire high-quality operational data products for Chinese in-orbit and scheduled ocean color sensors, the performances of two operational atmospheric correction (AC) algorithms (ESA MEGS 7.4.1 and NASA SeaDAS 6.1) were evaluated over the East China Seas (ECS) using MERIS data. The spectral remote sensing reflectance R_rs(λ), aerosol optical thickness (AOT), and Ångström exponent (α) retrieved using the two algorithms were validated using in situ measurements obtained between May 2002 and October 2009. Match-ups of R_rs, AOT, and α between the in situ and MERIS data were obtained through strict exclusion criteria. Statistical analysis of R_rs(λ) showed a mean percentage difference (MPD) of 9%–13% in the 490–560 nm spectral range, and significant overestimation was observed at 413 nm (MPD>72%). The AOTs were overestimated (MPD>32%), and although the ESA algorithm outperformed the NASA algorithm in the blue-green bands, the situation was reversed in the red-near-infrared bands. The value of α was obviously underestimated by the ESA algorithm (MPD=41%) but not by the NASA algorithm (MPD=35%). To clarify why the NASA algorithm performed better in the retrieval of α, scatter plots of the α single scattering albedo (SSA) density were prepared. These α-SSA density scatter plots showed that the applicability of the aerosol models used by the NASA algorithm over the ECS is better than that used by the ESA algorithm, although neither aerosol model is suitable for the ECS region. The results of this study provide a reference to both data users and data agencies regarding the use of operational data products and the investigation into the improvement of current AC schemes over the ECS.