{"title":"基于沿东经 138 度反复勘测的 2017 年黑潮大蜿蜒的时间变化","authors":"Daiki Ito, Yugo Shimizu, Takashi Setou, Akira Kusaka, Daisuke Ambe, Yutaka Hiroe, Kiyotaka Hidaka, Sayaka Sogawa, Tamaha Yamaguchi","doi":"10.1007/s10872-024-00718-8","DOIUrl":null,"url":null,"abstract":"<p>During August 2017, the Kuroshio began to follow its large meander (LM) path, and this was 12 years after the last LM event. Such LM events lead to the formation of an inshore cyclonic eddy (ICE) within the Kuroshio inshore region between the Kuroshio and the southern coast of Japan. We analyzed data from repeated seasonal surveys along a transect that followed 138°E, and from additional surveys, satellite observations, Argo floats, and a high-resolution reanalysis dataset to describe the temporal variation of the LM and ICE between 2017 and 2021. Cross sections from the repeated surveys highlighted the variations in the water mass structures. The time series of the indicators of the ICE intensity such as the Kuroshio volume transport and the planetary contribution of potential vorticity (<i>Q</i>) in the ICE revealed a maintenance trend in their intensity during the observation period. High-<i>Q</i> water was distributed in the ICE during the LM period compared to the non-LM period, and showed a clear seasonality within the shallower layers, suggesting the injection of <i>Q</i> via the advection from the upstream region in summer. Additional surveys captured an eddy that became detached from the ICE during summer 2020. This detached eddy had a <i>Q</i> value greater than the ICE and velocity similar to the Kuroshio, suggesting that the main stream had become temporarily separated. The structures and volume transport of warm water intrusions into the inshore region were also examined, and centrifugal instability was considered to be one of their generation mechanism.</p>","PeriodicalId":16640,"journal":{"name":"Journal of Oceanography","volume":null,"pages":null},"PeriodicalIF":1.3000,"publicationDate":"2024-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Temporal variation of the 2017 Kuroshio large meander based on repeated surveys along 138°E\",\"authors\":\"Daiki Ito, Yugo Shimizu, Takashi Setou, Akira Kusaka, Daisuke Ambe, Yutaka Hiroe, Kiyotaka Hidaka, Sayaka Sogawa, Tamaha Yamaguchi\",\"doi\":\"10.1007/s10872-024-00718-8\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>During August 2017, the Kuroshio began to follow its large meander (LM) path, and this was 12 years after the last LM event. Such LM events lead to the formation of an inshore cyclonic eddy (ICE) within the Kuroshio inshore region between the Kuroshio and the southern coast of Japan. We analyzed data from repeated seasonal surveys along a transect that followed 138°E, and from additional surveys, satellite observations, Argo floats, and a high-resolution reanalysis dataset to describe the temporal variation of the LM and ICE between 2017 and 2021. Cross sections from the repeated surveys highlighted the variations in the water mass structures. The time series of the indicators of the ICE intensity such as the Kuroshio volume transport and the planetary contribution of potential vorticity (<i>Q</i>) in the ICE revealed a maintenance trend in their intensity during the observation period. High-<i>Q</i> water was distributed in the ICE during the LM period compared to the non-LM period, and showed a clear seasonality within the shallower layers, suggesting the injection of <i>Q</i> via the advection from the upstream region in summer. Additional surveys captured an eddy that became detached from the ICE during summer 2020. This detached eddy had a <i>Q</i> value greater than the ICE and velocity similar to the Kuroshio, suggesting that the main stream had become temporarily separated. The structures and volume transport of warm water intrusions into the inshore region were also examined, and centrifugal instability was considered to be one of their generation mechanism.</p>\",\"PeriodicalId\":16640,\"journal\":{\"name\":\"Journal of Oceanography\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.3000,\"publicationDate\":\"2024-05-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Oceanography\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://doi.org/10.1007/s10872-024-00718-8\",\"RegionNum\":4,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q4\",\"JCRName\":\"OCEANOGRAPHY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Oceanography","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.1007/s10872-024-00718-8","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"OCEANOGRAPHY","Score":null,"Total":0}
Temporal variation of the 2017 Kuroshio large meander based on repeated surveys along 138°E
During August 2017, the Kuroshio began to follow its large meander (LM) path, and this was 12 years after the last LM event. Such LM events lead to the formation of an inshore cyclonic eddy (ICE) within the Kuroshio inshore region between the Kuroshio and the southern coast of Japan. We analyzed data from repeated seasonal surveys along a transect that followed 138°E, and from additional surveys, satellite observations, Argo floats, and a high-resolution reanalysis dataset to describe the temporal variation of the LM and ICE between 2017 and 2021. Cross sections from the repeated surveys highlighted the variations in the water mass structures. The time series of the indicators of the ICE intensity such as the Kuroshio volume transport and the planetary contribution of potential vorticity (Q) in the ICE revealed a maintenance trend in their intensity during the observation period. High-Q water was distributed in the ICE during the LM period compared to the non-LM period, and showed a clear seasonality within the shallower layers, suggesting the injection of Q via the advection from the upstream region in summer. Additional surveys captured an eddy that became detached from the ICE during summer 2020. This detached eddy had a Q value greater than the ICE and velocity similar to the Kuroshio, suggesting that the main stream had become temporarily separated. The structures and volume transport of warm water intrusions into the inshore region were also examined, and centrifugal instability was considered to be one of their generation mechanism.
期刊介绍:
The Journal of Oceanography is the official journal of the Oceanographic Society of Japan and open to all oceanographers in the world. The main aim of the journal is to promote understandings of ocean systems from various aspects including physical, chemical, biological, geological oceanography as well as paleoceanography, etc. The journal welcomes research focusing on the western North Pacific and Asian coastal waters, but the study region is not limited to the Asian Pacific. The journal publishes original articles, short contributions, reviews, and correspondence in oceanography and related fields.