The Air-Sea Exchange of CO2 in the East Sea (Japan Sea)

Byline: Dong-Chan Oh (1), Mi-Kyung Park (1), Sang-Hwa Choi (2), Dong-Jin Kang (1), Sun Young Park (1), Jeom Shik Hwang (1), Andrey Andreev (3), Gi Hoon Hong (2), Kyung-Ryul Kim (1) Keywords: Surface fCO.sub.2 in the East (Japan) Sea; air-sea CO.sub.2 flux; seasonal variability of fCO.sub.2; solubility pump; gas-exchange model Abstract: During CREAMS expeditions, fCO.sub.2 for surface waters was measured continuously along the cruise tracks. The fCO.sub.2 in surface waters in summer varied in the range 320--440 Auatm, showing moderate supersaturation with respect to atmospheric CO.sub.2. In winter, however, fCO.sub.2 showed under-saturation of CO.sub.2 in most of the area, while varying in a much wider range from 180 to 520 Auatm. Some very high fCO.sub.2 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 fCO.sub.2 and for estimating the annual flux of CO.sub.2 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 CO.sub.2. The model shows that the East Sea releases CO.sub.2 into the atmosphere from June to September, and absorbs CO.sub.2 during the rest of the year, from October through May. The net annual CO.sub.2 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 CO.sub.2 into the whole water column, supporting a short turnover time for deep waters in the East Sea. Author Affiliation: (1) Department of Oceanography and Research Institute of Oceanography, Seoul National University, Seoul, 151-742, Korea (2) Korea Ocean Research &amp Development Institute, Ansan, P.O. Box 29, Seoul, 425-600, Korea (3) Russian Academy of Science, Pacific Oceanological Institute, Vladivostok, Russia Article History: Registration Date: 01/10/2004