EC1 is a subsurface mooring that has been deployed in the Ulleung Interplain Gap (UIG) since 1996. The UIG is the only deep channel connecting the northern Japan Basin and the southwestern Ulleung Basin in the East Sea (Japan Sea). The EC1 provides continuous time series data at depths ranging from 150 to 2,250 meters, enabling scientific research on circulation and water properties. It equips current-meter, conductivity, temperature, pressure, and dissolved oxygen sensors. The EC1 mooring was recovered 3 times (26 times total) and redeployed 3 times (26 times total) from November 2020 to April 2023 (since 1996), with a typical turnover time of 1 year. The equipment has been upgraded since 1996 to continuously measure temperature, pressure, conductivity, dissolved oxygen, and the speed and direction of three-dimensional current, as well as to collect more and better time series data. The sampling intervals of all sensors are equal to or less than 60 minutes. The temperature, pressure, conductivity, and dissolved oxygen data collected from November 2020 to April 2023 were quality-assured and quality-controlled with typical procedures such as global and local range tests, spike tests, and gradient tests. The magnetic declination of 9 degrees west was applied to the current data for compass calibration.   Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.

Time-series data from subsurface moorings, U5 and UB2, and vertical profile data of conductivity-temperature-depth (CTD) were collected in the southwestern East Sea (Japan Sea). The moored current-meter data were collected using rotary-current meters (RCMs) at U5 at depths of 1000 and 2000 m from November 2002 to May 2006 and at UB2 at depths of 1000 and 1600 m from May 2006 to February 2010. Sampling intervals of the RCMs were 30 minutes or an hour. Six vertical profiles of temperature and salinity were collected using standard CTD instruments near U5 in August 1995, March 1997, June 1999, September 2005, August 2008, and October 2012. The data were quality controlled and quality assured before provision to the community via SEANOE. Important Note: This submission has been initially submitted to SEA scieNtific Open data Edition (SEANOE) publication service and received the recorded DOI. The metadata elements have been further processed (refined) in EMODnet Ingestion Service in order to conform with the Data Submission Service specifications.