| Project/Area Number |
17K02023
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Area studies
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| Research Institution | Toyama Prefectural University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2023-03-31
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| Project Status |
Completed (Fiscal Year 2022)
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| Budget Amount *help |
¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
Fiscal Year 2019: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2018: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2017: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
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| Keywords | 合成開口レーダ / 天水田 / 生産安定性 / 開墾 / 東北タイ / 後方散乱係数 / 湛水状況 / 合成開口レーダー / 生産力評価 / 偏波 / 天水農業 / 土壌含水率 / 土壌水分 / 土地利用変化 / 農村発展 / 水文条件 / 生存戦略 |
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| Outline of Final Research Achievements |
This study developed methodologies to classify the rainfed paddy fields in Northeast Thailand according to wetness (frequency and proportion of waterlogging) using synthetic aperture radar backscatter coefficients. Use of the cross-polarization backscatter coefficient effectively distinguished rice paddies in valleys and lowlands from upland-crop fields on hillsides that were once rice fields. Time-series backscatter coefficients in both co- and cross-polarizations throughout the rainy season resulted in accurate classifications of paddy fields into subcategories according to more detailed differences in wetness (differences in seasonal waterlogging patterns). OOB accuracy of Random Forests was more than 90%. No significant differences in classification accuracy were found between C-band and L-band.
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| Academic Significance and Societal Importance of the Research Achievements |
天水田の湿潤度（湛水の頻度や面積割合）は収量や生産安定性を規定する重要な要素である．東北タイにおいては，天水稲作の不安定性は地域住民の生存戦略や地域発展史に影響を与えてきたとされ，国内外の研究者により多くの研究がなされている．地域における水田の湿潤度を定量的に評価できれば，これまで東北タイにおいて積み重ねられてきた研究成果をより精緻化できる．ただし天水田の湿潤度は地形条件等により連続的に変化するため，広域にわたって把握・評価することが困難であった．本研究の成果は，天水田を広域的に評価する実用的な手法を提供するもので，東南アジアをはじめとする天水田地域を対象とした地域研究に大きく貢献しうる．
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