Journal of Tropical Oceanography ›› 2013, Vol. 32 ›› Issue (3): 9-15.doi: 10.11978/j.issn.1009-5470.2013.03.002cstr: 32234.14.j.issn.1009-5470.2013.03.002

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Correction of ship-based turbulent wind velocity and characterization of turbulence in the Northwest Pacific

WANG Jie1, DUAN Zi-qiang2, YAO Xiao-hong2, GAO Hui-wang2   

  1. 1. College of Physical and Environmental Oceanography, Ocean University of China, Qingdao 266100, China; 2. Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
  • Received:2012-02-27 Revised:2012-06-07 Online:2013-08-27 Published:2013-08-28
  • Contact: 高会旺。E-mail: hwgao@ouc.edu.cn

Abstract:

Ship-based turbulent wind velocities were measured in the Northwest Pacific from September to November in 2005. The analysis results of turbulent wind velocity power spectrum showed an unexpected peak in the frequency range of 0.06-0.26 Hz, which was believed to be caused by platform rocking. This study proposed a new approach, i.e., an improved filtering correction, to minimize the interference from platform rocking on the signal of turbulent wind velocity. In a dual-logarithm coordinates system, the power spectral densities in the whole range except that from 0.06 to 0.26 Hz were used to linearly fit the trend of the power spectra between 0.06 and 0.26 Hz. Combined the original power spectra and the trend inversion, the corrected power spectra were obtained. Through the inverse Fourier transform, the new turbulent wind velocity data was obtained. Using the corrected turbulent wind velocity data, we estimated a few turbulent parameters in the Northwest Pacific during the observational period. These results showed that the atmospheric thermal action was strong during the observational period, leading to weakly unstable and unstable stratifications. When the standard deviation of dimensionless velocity was plotted against the stability parameter, their relationship accorded with the 1/3 power law. Intensities of turbulence in u, v, and wdirection were estimated to be 0.091, 0.076, and 0.043, respectively. The drag coefficient was estimated to be (1.30±0.26)×10-3, which is similar to the values reported in this region by other investigators.

Key words: ship-based observation, wind fluctuation, eddy covariance technique, Northwest Pacific, turbulent characteristics

CLC Number: 

  • P732.15