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Research Fund","award":["30-H30C01-9004-19\/21"],"award-info":[{"award-number":["30-H30C01-9004-19\/21"]}]},{"name":"the State Key Laboratory of Tropical Oceanography Independent Research Fund","award":["202201010101"],"award-info":[{"award-number":["202201010101"]}]},{"name":"the State Key Laboratory of Tropical Oceanography Independent Research Fund","award":["133244KYSB20180029"],"award-info":[{"award-number":["133244KYSB20180029"]}]},{"name":"the State Key Laboratory of Tropical Oceanography Independent Research Fund","award":["ZDYF2020174"],"award-info":[{"award-number":["ZDYF2020174"]}]},{"name":"the State Key Laboratory of Tropical Oceanography Independent Research Fund","award":["LTOZZ2103"],"award-info":[{"award-number":["LTOZZ2103"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>An attention U-Net was proposed to reconstruct the missing chlorophyll-a concentration (Cchla) data. The U-Net is a lightweight full convolution neural network architecture consisting of an enccoder-decoder (i.e., down-sampling and up-sampling). The attention gates (AGs) were integrated into the U-Net. Training the U-Net with AGs could implicitly teach it to suppress irrelevant areas and highlight the salient features in the missing data areas, which would increase the network sensitivity and reconstruction accuracy. The neural network uses the satellite-derived Cchla anomalies and its variance as the input, and the reconstructed fields along with their variances as outputs. The trained network was applied to long-term daily MODIS\/Aqua Cchla products in the Pearl River estuary (PRE) and adjacent continental shelf area. The model performance was evaluated by using an independent test dataset from both satellite-derived and in-situ measurements. The results showed that the proposed neural network not only had good performance in the reconstruction of valid pixels, but also provided a more reasonable reconstruction compared to the standard U-Net without AGs. This study provided a feasible method for the reconstruction task in the field of ocean color, which should be helpful in producing a creditable dataset to study the ecological effects of extreme weather conditions such as typhoons on the upper ocean in the PRE waters. Based on the reconstructed Cchla products, the footprints of the typhoons were studied. An increase in surface Cchla near the typhoons\u2019 track and a decrease in estuary were found. The composite results illustrated that the Cchla increases occurred for almost the entire area within a radius of 100 km. The time series analysis showed that the Cchla peak appeared on the fifth day after the typhoon\u2019s passage.<\/jats:p>","DOI":"10.3390\/rs15030546","type":"journal-article","created":{"date-parts":[[2023,1,18]],"date-time":"2023-01-18T02:31:11Z","timestamp":1674009071000},"page":"546","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Reconstruction of Daily MODIS\/Aqua Chlorophyll-a Concentration in Turbid Estuarine Waters Based on Attention U-NET"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0906-9584","authenticated-orcid":false,"given":"Haibin","family":"Ye","sequence":"first","affiliation":[{"name":"State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China"},{"name":"Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China"}]},{"given":"Shilin","family":"Tang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China"},{"name":"Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510301, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4361-5297","authenticated-orcid":false,"given":"Chaoyu","family":"Yang","sequence":"additional","affiliation":[{"name":"South China Sea Marine Prediction Center, State Oceanic Administration, Guangzhou 510300, China"},{"name":"Key Laboratory of Marine Environmental Survey Technology and Application, Ministry of Natural Resources (MNR), Guangzhou 510300, China"},{"name":"Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Guangzhou 510300, China"}]},{"given":"Chuqun","family":"Chen","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China"}]}],"member":"1968","published-online":{"date-parts":[[2023,1,17]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1016\/j.dsr.2011.02.003","article-title":"Inter-Annual Variations in the SeaWiFS Global Chlorophyll a Concentration (1997\u20132007)","volume":"58","author":"Vantrepotte","year":"2011","journal-title":"Deep. 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