Journal of Oceanography, Vol. 55 (No. 2), pp. 157-169, 1999
Dong-Chan Oh1, Mi-Kyung Park1, Sang-Hwa Choi2, Dong-Jin Kang1, Sun Young Park1, Jeom Shik Hwang1, Andrey Andreev3, Gi Hoon Hong2 and Kyung-Ryul Kim1
1Department of Oceanography and Research Institute of Oceanography, Seoul National University, Seoul 151-742, Korea
2Korea Ocean Research & Development Institute, Ansan P.O. Box 29, Seoul 425-600, Korea
3Pacific Oceanological Institute, Russian Academy of Science, Vladivostok, Russia
(Received 8 October 1998; in revised form 5 December 1998; accepted 10 December 1998)
Abstract: During CREAMS expeditions, fCO2 for surface waters was measured continuously along the cruise tracks. The fCO2 in surface waters in summer varied in the range 320~440 matm, showing moderate supersaturation with respect to atmospheric CO2. In winter, however, fCO2 showed under-saturation of CO2 in most of the area, while varying in a much wider range from 180 to 520 matm. Some very high fCO2 values observed in the northern East Sea (Japan Sea) appeared to be associated with the intensive convection system developed in the area. A gas-exchange model was developed for describing the annual variation of fCO2 and for estimating the annual flux of CO2 at the air-sea interface. The model incorporated annual variations in SST, the thickness of the mixed layer, gas exchange associated with wind velocity, biological activity and atmospheric concentration of CO2. The model shows that the East Sea releases CO2 into the atmosphere from June to September, and absorbs CO2 during the rest of the year, from October through May. The net annual CO2 flux at the air-sea interface was estimated to be 0.032 (±0.012) Gt-C per year from the atmosphere into the East Sea. Water column chemistry shows penetration of CO2 into the whole water column, supporting a short turnover time for deep waters in the East Sea.