TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 66 (No. 4), pp. 505-512, 2010

Estimating of Gas Transfer Velocity Using Triple Isotopes of Dissolved Oxygen

V. V. S. S. Sarma1,2*, Osamu Abe3, Makio Honda4 and Toshiro Saino1,4

1National Institute of Oceanography, Regional Centre, Council of Scientific and Industrial Research (CSIR), 176 Lawsons Bay Colony, Visakhapatnam 530 017, India
2SORST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
3Graduate School of Environmental Studies, Nagoya University, Nagoya 454-8601, Japan
4JAMSTEC, Natsushima, Yokosuka, Kanagawa 237-0061, Japan

(Received 4 August 2009; in revised form 25 March 2010; accepted 2 April 2010)

Abstract: The atmosphere-ocean exchange of climatically important gases is determined by the transfer velocity (k) and concentration gradient across the interface. Based on observations in the northwestern subarctic Pacific and Sagami Bay, we report here the results of the first ever application of the natural abundance of triple isotopes of dissolved oxygen (16O, 17O and 18O) for direct estimation of k and propose a new relationship with wind speed. The k values estimated from nighttime variations in oxygen isotopes are found to be higher than the direct estimations at low wind speed (<5 m s-1) and lower at high wind speeds (>13 m s-1) and showed significant spatial variability. The method presented here can be used to derive seasonal and spatial variations in k and the influence of surface conditions on the value, leading to improved estimates of biogenic/anthropogenic gas exchange at the air-sea interface.

*Corresponding author E-mail: sarmav@nio.org

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