Validation of MERIS ocean-color products in the Bohai Sea: A case study for turbid coastal waters

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• 作者：Tingwei Cui ; Jie Zhang ; Steve Groom ; Ling Sun ; Timothy Smyth ; Shubha Sathyendranath
• 关键词：Ocean-color ; Validation ; MERIS ; Bohai Sea ; Remote-sensing
• 刊名：Remote Sensing of Environment
• 出版年：2010
• 出版时间：15 October 2010
• 年：2010
• 卷：114
• 期：10
• 页码：2326-2336
• 全文大小：1894 K

文摘

An extensive in situ data set in the Bohai Sea of China was collected to assess radiometric properties and concentrations of ocean constituents derived from Medium Resolution Imaging Spectrometer (MERIS). The data collected include spectral normalized water-leaving radiance L_wn(λ) and concentrations of suspended particulate matter (SPM) and chlorophyll a (Chl-a). A strict spatio-temporal match-up method was adopted in view of the complexity and variability of the turbid coastal area, resulting in 13, 48 and 18 match-ups for MERIS L_wn(λ), SPM and Chl-a estimates, respectively. For MERIS L_wn(λ), the match-ups showed mean absolute percentage differences (APD) of 17 % –20 % in the 412, 443, 620 and 665 nm bands, whereas L_wn(λ) at bands from 490 and 560 nm had better APD of 15–16 % . The band ratio of L_wn(490) to L_wn(560) of the satellite data was in good agreement with in situ observations with an APD of 4 % . MERIS SPM and Chl-a products overestimated the in situ values, with the APD of approximately 50 % and 60 % , respectively. When match-up criteria were relaxed, the assessment results degraded systematically. Hence, in turbid coastal areas where temporal variability and spatial heterogeneity of bio-optical properties may be pronounced as the result of terrestrial influences and local dynamics, the strict spatio-temporal match-up is recommended.