Martinez Elodie, Maamaatuaiahutapu Keitapu, Taillandier Vincent
Laboratoire Terre-Océan, Université de la Polynésie Française, BP 6570 Faaa, Faaa 98702, Tahiti French Polynesia, France.
Mar Pollut Bull. 2009 Sep;58(9):1347-55. doi: 10.1016/j.marpolbul.2009.04.022. Epub 2009 May 21.
Whatever its origin is, a floating particle at the sea surface is advected by ocean currents. Surface currents could be derived from in situ observations or combined with satellite data. For a better resolution in time and space, we use satellite-derived sea-surface height and wind stress fields with a 1/3 degrees grid from 1993 to 2001 to determine the surface circulation of the South Pacific Ocean. Surface currents are then used to compute the Lagrangian trajectories of floating debris. Results show an accumulation of the debris in the eastern-centre region of the South Pacific subtropical gyre ([120 degrees W; 80 degrees W]-[20 degrees S; 40 degrees S]), resulting from a three-step process: in the first two years, mostly forced by Ekman drift, the debris drift towards the tropical convergence zone ( approximately 30 degrees S). Then they are advected eastward mostly forced by geostrophic currents. They finally reach the eastern-centre region of the South Pacific subtropical gyre from where they could not escape.
无论其来源如何，海面的漂浮粒子都会被洋流平流输送。表面洋流可以来自现场观测，也可以与卫星数据相结合。为了在时间和空间上获得更好的分辨率，我们使用1993年至2001年1/3度网格的卫星衍生海面高度和风应力场来确定南太平洋的表面环流。然后利用表面洋流来计算漂浮碎片的拉格朗日轨迹。结果表明，碎片在南太平洋亚热带环流的东部中心区域（[西经120度；西经80度]-[南纬20度；南纬40度]）积聚，这是一个三步过程的结果：在前两年，碎片主要受埃克曼漂流的影响，向热带辐合带（约南纬30度）漂移。然后，它们主要在地转流的作用下向东平流输送。它们最终到达南太平洋亚热带环流的东部中心区域，无法从那里逃脱。
