Ocean and Polar Research

Korea Institute of Ocean Science & Technology (한국해양과학기술원)
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Distribution of Water Masses and Characteristics of Temperature Inversion in the Western Seas of Jeju Island in Spring

봄철 제주도 서부해역의 수괴 분포와 수온역전 특징

  • Kang, So-Young (Faculty of Earth and Marine Convergence, Earth and Marine Science Major, Jeju National University) ;
  • Moon, Jae-Hong (Faculty of Earth and Marine Convergence, Earth and Marine Science Major, Jeju National University)
  • 강소영 (제주대학교 지구해양융합학부 지구해양전공) ;
  • 문재홍 (제주대학교 지구해양융합학부 지구해양전공)
  • Received : 2022.05.04
  • Accepted : 2022.07.27
  • Published : 2022.09.30
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Abstract

Using the results of CTD casts made in Spring from 2017 to 2021, in this study we investigated the water mass distribution and occurrence of temperature inversion in the western seas of Jeju Island in spring. The distribution of water masses was characterized by cold and fresh water in the northwest and warm and saline water in the southeast, forming a strong thermohaline front running in the southwest-to-northeast direction. Strong temperature inversion mainly occurred in the frontal boundary when the cold water intrudes beneath the warm water at depths of 30-50 m. Analysis of the mixing ratio demonstrated that Jeju Warm Water is dominantly distributed in the western seas of Jeju Island, but its ratio can be modified depending on the southward extension of Yellow Sea Cold Water (YSCW). Results of in situ measurement showed that in 2020, the YSCW largely expanded to the western seas of Jeju Island, occupying approximately 40 % of the mixing ratio. Due to the expansion of YSCW, a strong thermohaline front was formed in the study area, thereby causing thick and strong temperature inversion. On the other hand, in 2018 the mixing ratio of YSCW was minimum (~18%) during the study period of 2017-2021, and thus a relatively weak frontal boundary was formed, without the occurrence of temperature inversion. The observational results also suggest that the interannual changes of water mass distribution and the associated temperature inversion in the western seas of Jeju Island are closely related with wind-driven Yellow Sea circulation in spring, which is the summer monsoon transition period.

Keywords

Acknowledgement

이 논문은 2022년도 제주대학교 교원성과지원사업에 의하여 연구되었습니다.

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