Measurements of air-ice drag coefficient over the ice-covered Sea of Okhotsk

• Published in: Journal of oceanography Vol. 65; no. 4; pp. 487 - 498
• Main Authors: Fujisaki, Ayumi, Yamaguchi, Hajime, Toyota, Takenobu, Futatsudera, Akio, Miyanaga, Masaru
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.08.2009; Springer Netherlands; Springer Nature B.V
• Subjects: air-ice drag coefficient; Earth and Environmental Science; Earth Sciences; eddy correlation method; Fluid dynamics; Freshwater & Marine Ecology; Hydrodynamics; Ice; Marine; Ocean-atmosphere interaction; Oceanography; Original Articles; Sea ice; Sea of Okhotsk; Wind; INW, Okhotsk Sea; air-ice drag coefficient; Sea of Okhotsk; eddy correlation method; Sea ice
• ISSN: 0916-8370; 1573-868X
• DOI: 10.1007/s10872-009-0042-8

The air-ice drag coefficient under neutral stratification C DN was measured with the eddy correlation method in the southern Sea of Okhotsk. The disturbance of the wind field caused by the ship's structure was evaluated by computational fluid dynamics (CFD), and two types of correction methods were applied to estimate the error span of C DN : one is based on the results of CFD, and the other is based on the parameterization of C DN over open water suggested by Taylor and Yelland (2001). The C DN × 10³ values finally obtained ranged from 1.9 to 5.4 with a mean value of 2.7 by the CFD correction and from 1.5 to 5.0 with a mean value of 3.1 by the other method. This is somewhat larger than the value of 2.5 suggested by Shirasawa (1981), and in the same range as 2.2-4.0 over rough ice and 3.1-5.0 over very rough ice, values which were complied by Guest and Davidson (1991) for first year ice. Most of the ice conditions were characterized by broken floes with a diameter less than 100 m and raised rims, which made the surface rougher than flat, level ice. The relation between C DN and ice concentration was not clear, mainly because the contribution of the form drag caused at the freeboard was undetectable due to the great variation of ice surface condition. The roughness length z M was also evaluated using the model developed for snow covered ice in a previous study.