TERRAPUB Journal of Oceanography
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Journal of Oceanography, Vol. 60 (No. 6), pp. 995-1000, 2004

CO2 Flux Measurements over the Sea Surface by Eddy Correlation and Aerodynamic Techniques

Toru Iwata1, Keiko Yoshikawa2, Katsutoshi Nishimura3, Yoshihisa Higuchi3, Takao Yamashita4, Shigeru Kato4 and Eiji Ohtaki1*

1Faculty of Environmental Science and Technology, Okayama University, Okayama 700-8530, Japan
2Matsushita Electric Industrial Co., Ltd., Panasonic System Solutions Company, Higashi-shinagawa, Shinagawa-ku, Tokyo 140-8587, Japan
3Japan Weather Association, Kansai Regional Office, Osaka 537-0011, Japan
4Disaster Prevention Research Institute, Kyoto University, Uji 611-0011, Japan

(Received 15 September 2003; in revised form 14 February 2004; accepted 19 February 2004)

Abstract: The measurements of the vertical transport of CO2 were carried out over the Sea of Japan using the specially designed pier of Kyoto University on September 20 to 22, 2000. CO2 fluxes were measured by the eddy correlation and aerodynamic techniques. Both techniques showed comparable CO2 fluxes during sea breeze conditions: -0.001 to -0.08 mg m-2s-1 with the mean of -0.05 mg m-2s-1. This means that the measuring site satisfies the fetch requirement for meteorological observations under sea breeze conditions. Moreover, the eddy diffusivity coefficient used in the aerodynamic technique is found to be consistent with the coefficient used in the eddy correlation technique. The present result leads us to conclude that the aerodynamic technique may be applicable to underway CO2 flux measurements over the ocean and may be used in place of the bulk technique. The important point is the need to maintain a measuring accuracy of CO2 concentration difference of the order of 0.1 ppmv on the research vessels or the buoys.


*Corresponding author E-mail: ohtaki@cc.okayama-u.ac.jp


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