An application of TrOCA to the East/Japan Sea

Abstract

The East/Japan Sea (hereafter EJS) is regarded as a Miniaure Ocean despite being a typical marginal sea, because it has an internal conveyor belt system, which comparises deep water formation, warm and cold currents at the surface, a sub-arctic polar front, and so on. Air-sea CO2 gas exchange is very activity in the EJS and, furthermore, anthropogenic CO2 has penetrated all the way to the bottom. A tracer, TrOCA (Tracer combining Oxygen, inorganic Carbon, and total Alkalinity), which is a composite of oxygen, dissolved inorganic carbon, and total alkalinity, has been proposed(Touratier and Goyet, 2004). Here we have applied TrOCA to the EJS as a tracer to understand basin-scale phenomena, using data obtained during the CREAMS (Circulation Research of the East Asian Marginal Seas) cruises in 1999. The CREAMS 1999 cruises were carried out on two research vessels (R/V Roger Revelle 24 June-17 July, R/V Professor Khromov 22 July-11 August) with almost full coverage of the EJS. The map of the surface distribution of TrOCA shows very well the boundary of the sub-arctic polar front. The vertical pofile of TrOCA has a peak in the central water at 200~1000m depth, where the East SEa central water (ESCW) is located, which may be evidence of recent ESCW formation. The RtOCA profile also shows the diffusion of the ESCW to the south. The potential application of TrOCA to the EJS as a tracer to understand basin scale phenomeb-arctic polar front, and so on. Air-sea CO2 gas exchange is very activity in the EJS and, furthermore, anthropogenic CO2 has penetrated all the way to the bottom. A tracer, TrOCA (Tracer combining Oxygen, inorganic Carbon, and total Alkalinity), which is a composite of oxygen, dissolved inorganic carbon, and total alkalinity, has been proposed(Touratier and Goyet, 2004). Here we have applied TrOCA to the EJS as a tracer to understand basin-scale phenomena, using data obtained during the CREAMS (Circulation Research of the East Asian Marginal Seas) cruises in 1999. The CREAMS 1999 cruises were carried out on two research vessels (R/V Roger Revelle 24 June-17 July, R/V Professor Khromov 22 July-11 August) with almost full coverage of the EJS. The map of the surface distribution of TrOCA shows very well the boundary of the sub-arctic polar front. The vertical pofile of TrOCA has a peak in the central water at 200~1000m depth, where the East SEa central water (ESCW) is located, which may be evidence of recent ESCW formation. The RtOCA profile also shows the diffusion of the ESCW to the south. The potential application of TrOCA to the EJS as a tracer to understand basin scale phenome