並列タイトル等Spatiotemporal changes in water quality in the Seto Inland Sea from 1981 to 2015: Analyses of public survey data
一般注記Long-term changes (from the 1980s to 2010s) in the water quality of the Seto Inland Sea, a semi-enclosed bay system in southwestern Japan consisting of 12 sea regions, were determined by analyzing public survey data. The average bottom water temperature (BWT) from 2010 to 2014 differed among the sea regions, for example, in January,it was lowest at Harima Nada and Bisan Seto (7.3-10.0℃) and highest in Kii Suido and Bungo Suido (11.5-14.4℃).BWT ranged from 15.0 to 23.3℃ in May and July, and from 22.5 to 25.2℃ in October. The spatial distribution of cold- or warm-water bodies corresponded well to those of high-salinity waters, indicating penetration of the Kuroshio Current from the Pacific Ocean. BWT increased significantly from the 1980s to 2010s in most sea regions and seasons.The overall mean increase in BWT was the largest in October (+5.82℃ 100-yr^<-1>), especially in Osaka Bay and Hibiki Nada (+9.25 and +9.10℃ 100-yr^<-1>, rspectively). Hypoxic bottom water (dissolved oxygen [DO] < 4.0 mg l^<-1>) occurred mainly in inner Osaka Bay in May, July, and October. From the 1980s to 2010s, the bottom DO gradually increased in five sea regions in July, but decreased in Kii Suido and Osaka Bay in October, which may partly be due to the rising BWT in autumn. The chlorophyll a concentration d creased significantly from the 1980s to 2010s in two to eight regions in January, May, July, and October. By contrast, chlorophyll a increased significantly in Harima Nada (January, July, and October), Bisan Seto (January and May), and Bingo Nada (January).
本報文は、過去の行政調査データを用いた1981～2015 年の瀬戸内海における水質項目の時空間変動解析結果をまとめたものであり、平成28 年度～平成30 年度に実施された環境省「閉鎖性海域における気候変動による影響把握等検討業務」 および令和元年度～令和3 年度に実施された環境省「閉鎖性海域における気候変動による影響評価及び適応策等検討業務」において実施された解析結果を含んでいる。
一次資料へのリンクURLhttps://nies.repo.nii.ac.jp/?action=repository_action_common_download&item_id=37&item_no=1&attribute_id=19&file_no=2
連携機関・データベース国立情報学研究所 : 学術機関リポジトリデータベース（IRDB）（機関リポジトリ）