太平洋北赤道流表层流速及分叉点位置

Surface Current Speed and Bifurcation of the North Equatorial Current in the Pacific Ocean

确定太平洋北赤道流表层流速及分叉点位置的变化是海洋环境研究中的1个重要问题。使用1987～1998年的WOCE浮标资料,通过估算得到了季节平均和年平均意义下北赤道流表层流速(1989～1998)。计算结果显示:北赤道流表层流的流速冬季最大,夏季最小,春秋两季相仿。在厄尔尼诺发生年的第2年,夏季平均流速往往较大。对浮标轨迹的逐年分析表明表层北赤道流分叉点的位置在11°N～14 .7°N之间,从轨迹较为密集的4年的分析可以看出,表层流分叉点的位置具有年际变化,其中,2个ElNino年分叉点偏北。

The seasonal and annual average surface speeds of the North Equatorial Current (NEC) are estimated from the WOCE SVP drifting buoy data of 1985～1998. From the results, we draw the conclusion that the surface current speed of the NEC reaches its maximum in winter and minimum in summer, and there is little difference in the other two seasons. The speed in summer seems larger in the year following an El Nino, A year-by-year analysis of the buoy tracks to the east of the Philippines indicates that the bifurcation latitude of the NEC is between 11°N～14.7°N. From an analysis of the buoy tracks in the 4 years when they were denser, we can see that the position of bifurcation shows interannual variations, in 1992 and 1994,when El Nino, the bifurcation latitudes were alidle higher than the other years.