中法海洋卫星波谱仪有效波高中国近海评估

Evaluation of Significant Wave Height for CFOSAT SWIM Wave Spectrometer in the China Sea

摘要:

研究有效波高(Significant Wave Height, SWH)的特征对各种科学工程问题至关重要。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公里和5分钟。结果表明,经过严格的质量控制,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米,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。这些发现都有力的证明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 crucial for a wide range of scientific and industrial processes. 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 the present study, wave data from 39 buoys around Chinese 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 strict quality control, there has a remarkable improvement in the accuracy of SWIM data. After completely filtering out the land contaminations, the SWIM nadir box SWH exhibits excellent accordance with the buoy observations, where the RMSE is 0.346 m, R is 0.943, and SI is 0.182. The overall differences between SWIM data and buoy observations increases with the SWH. Concerning the off-nadir observations, the spectrum SWH from 6°, 8°, 10° and combined SWIM 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 the China Sea and may be of value to SWIM developers.