东海东南陆架外缘冬、夏季实测海流FFT分析

使用FFT法首次将东海陆架冬、夏季2次定点ADCP测流资料在频率域内分解成3个部分：不随时间变化的定常海流、周期为6～25h的潮流和剩余流，再将潮流分解为垂向均匀的全流(也称正压潮流)和剩余的斜压潮流。结果表明：夏季测站定常海流、潮流和剩余流能量分别占总能量的5．3％，93．9％和0．9％，而冬季测站分别占10．8％，80．9％和8．4％。夏、冬季测站的斜压潮流与正压潮流能量之比分别为20．7％和4．1％。

FFT Analysis of the Observed Current Data in the Southeastern Shelf Edge Area of the East China Sea in Winter and Summer

In this paper, the fast Fourier transformation (FFT) method is used to decompose the current data observed at 2 acoustic Doppler current profiler(ADCP) fixed stations into 3 components, steady current, tidal current with a period of 6 to 25 hours and residual current, and the tidal current is then decomposed into vertically uniform barotropic tidal current and baroclinic tidal current. The method was used to decompose the current data observed at 2 ADCP stations in the southeastern shelf edge area of the East China Sea in winter and summer, and it is shown from the analysis results that the energies of steady current, tidal current and residual current account for 5.3 %, 93.9 % and 0.9 % of the total energy of observed current in summer and for 10.8 %, 80.9 % and 8.4 % of the total energy in winter, respectively, and the ratios between the energies of baroclinic and barotropic tidal current components in summer and winter are 20.7 % and 4.1 %,respectively.