中国近海中法海洋卫星波谱仪有效波高评估

Evaluation of Significant Wave Height for CFOSAT SWIM Wave Spectrometer in Chinese Offshore Waters

摘要:

研究有效波高（Significant Wave Height，SWH）的特征对海洋灾害预警和海洋生产安全具有重要意义。中法海洋卫星（China-France Oceanography SATellite，CFOSAT）上搭载的世界领先的 SWIM 波谱仪能够测量全球范围内的海浪参数。已有大量研究对 CFOSAT 海浪产品在全球范围内进行评估，然而对区域的研究相对较少。本研究采用中国近海 39 个浮标的海浪数据来评估 2020 年 SWIM 二级产品的数据质量，空间和时间匹配窗口分别为 100 km 和 5 min。结果表明：经过对陆地干扰施加不同程度的控制，SWIM 有效波高产品具有较高的精度。在完全去除陆地干扰后，星下点 SWH 与浮标观测的一致性较高，均方根误差为 0.346 m， 相关系数为 0.943，散射因子为 0.182。SWIM 数据与浮标观测数据之间的总体差异随着 SWH 的增加而增大。 6°、8°、10°入射角波束和合成波束 SWH 与浮标观测一致性良好，但精度略低于星下点 SWH。这些发现都有力地证明 SWIM 二级产品在中国近海具有很高的可信度。

Abstract:

Investigating the characteristics of significant wave height（SWH）is of great significance for early warning of marine disasters and the safety of marine production. The world-leading SWIM wave spectrometer onboard China-France Oceanography Satellite（CFOSAT）has the ability to provide wave properties on a global scale. However，there is a relative paucity on the coastal and regional assessments of the SWIM data. In this study，wave data from 39 buoys around Chinese offshore waters are employed to evaluate the quality of SWIM Level 2 products over 2020. Spatial and temporal matching criteria of 100 km and 5 min are applied. The results showed that after applying varying degrees of control to the land contaminations，there is a remarkable improvement in the accuracy of SWIM data. After completely filtering out the land contaminations，the nadir box SWH exhibits excellent consistency with buoy observations，where RMSE is 0.346 m，R is 0.943，and SI is 0.182. The overall difference between SWIM data and buoy observations increases with the SWH. Concerning the off-nadir observations，the spectrum SWH from 6°，8°，10° and combined SWH beams correlate well with the buoy observations，but the accuracy is slightly lower than the nadir box SWH. All these findings provide solid evidences that SWIM Level 2 products have strong credibility in Chinese offshore waters.