{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T02:41:24Z","timestamp":1775097684774,"version":"3.50.1"},"reference-count":45,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2020,5,19]],"date-time":"2020-05-19T00:00:00Z","timestamp":1589846400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"The Environment Research and Technology Development Fund of the Ministry of the Environment and the Environmental Restoration and Conservation Agency","award":["2-1710"],"award-info":[{"award-number":["2-1710"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Paddy fields play very important environmental roles in food security, water resource management, biodiversity conservation, and climate change. Therefore, reliable broad-scale paddy field maps are essential for understanding these issues related to rice and paddy fields. Here, we propose a novel paddy field mapping method that uses Sentinel-1 synthetic aperture radar (SAR) time series that are robust for cloud cover, supplemented by Sentinel-2 optical images that are more reliable than SAR data for extracting irrigated paddy fields. Paddy fields were provisionally specified by using the Sentinel-1 SAR data and a conventional decision tree method. Then, an additional mask using water and vegetation indexes based on Sentinel-2 optical images was overlaid to remove non-paddy field areas. We used the proposed method to develop a paddy field map for Japan in 2018 with a 30 m spatial resolution. The producer\u2019s accuracy of this map (92.4%) for non-paddy reference agricultural fields was much higher than that of a map developed by the conventional method (57.0%) using only Sentinel-1 data. Our proposed method also reproduced paddy field areas at the prefecture scale better than existing paddy field maps developed by a remote sensing approach.<\/jats:p>","DOI":"10.3390\/rs12101622","type":"journal-article","created":{"date-parts":[[2020,5,20]],"date-time":"2020-05-20T02:48:24Z","timestamp":1589942904000},"page":"1622","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":50,"title":["Mapping Paddy Fields in Japan by Using a Sentinel-1 SAR Time Series Supplemented by Sentinel-2 Images on Google Earth Engine"],"prefix":"10.3390","volume":"12","author":[{"given":"Shimpei","family":"Inoue","sequence":"first","affiliation":[{"name":"Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan"},{"name":"Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8572, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Akihiko","family":"Ito","sequence":"additional","affiliation":[{"name":"Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chinatsu","family":"Yonezawa","sequence":"additional","affiliation":[{"name":"Graduate School of Agricultural Science, Tohoku University, 468-1 Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8572, Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"S50","DOI":"10.1038\/514S50a","article-title":"Rice by the numbers: A good grain","volume":"514","author":"Elert","year":"2014","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/S0065-2113(04)92004-4","article-title":"Rice and Water","volume":"Volume 92","author":"Sparks","year":"2007","journal-title":"Advances in Agronomy"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1023\/A:1011315214598","article-title":"Integrated Biodiversity Management in Paddy Fields: Shift of Paradigm from IPM toward IBM","volume":"5","author":"Kiritani","year":"2000","journal-title":"Integr. 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