Poulain Pierre-Marie, Centurioni Luca, Özgökmen Tamay
NATO Science and Technology Organization, Centre for Maritime Research and Experimentation, 19126 La Spezia, Italy.
Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA.
Sensors (Basel). 2022 Jan 4;22(1):353. doi: 10.3390/s22010353.
Instruments drifting at the ocean surface are quasi-Lagrangian, that is, they do not follow exactly the near-surface ocean currents. The currents measured by three commonly-used drifters (CARTHE, CODE and SVP) are compared in a wide range of sea state conditions (winds up to 17 m/s and significant wave height up to 3 m). Nearly collocated and simultaneous drifter measurements in the southwestern Mediterranean reveal that the CARTHE and CODE drifters measure the currents in the first meter below the surface in approximately the same way. When compared to SVP drogued at 15 m nominal depth, the CODE and CARTHE currents are essentially downwind (and down-wave), with a typical speed of 0.5-1% of the wind speed. However, there is a large scatter in velocity differences between CODE/CARTHE and SVP for all wind and sea state conditions encountered, principally due to vertical and horizontal shears not related to the wind. For the CODE drifter with wind speed larger than 10 m/s and significant wave height larger than 1 m, about 30-40% of this difference can be explained by Stokes drift.
在海洋表面漂流的仪器是准拉格朗日型的，也就是说，它们并非精确地跟随近表层洋流。对三种常用漂流器（CARTHE、CODE和SVP）在大范围海况条件下（风速高达17米/秒，有效波高高达3米）所测量的洋流进行了比较。地中海西南部几乎在同一位置且同时进行的漂流器测量结果显示，CARTHE和CODE漂流器测量表层以下1米深处洋流的方式大致相同。与标称深度为15米的SVP拖曳式漂流器相比，CODE和CARTHE测量的洋流基本为顺风（和顺波）方向，典型速度为风速的0.5 - 1%。然而，在所有遇到的风和海况条件下，CODE/CARTHE与SVP之间的速度差异存在很大离散度，主要是由于与风无关的垂直和水平切变。对于风速大于10米/秒且有效波高大于1米的CODE漂流器，这种差异的约30 - 40%可由斯托克斯漂流来解释。
