有效波高(SWH)的融合是随着海洋卫星数量的增加而产生的必然需求,融合产品的质量对有效波高的应用具有重要影响。卫星数量、融合时空窗口、结果时空分辨率及其准确度之间存在相互制约关系。本文基于时空反距离加权法,通过研究时空维度变化对误差水平的影响,提出了一种新的有效波高融合方法。使用9颗卫星观测的SWH数据进行了融合试验,并与哥白尼海洋环境监测服务(CMEMS)提供的网格化L4级产品以及NDBC浮标进行比对与验证；通过系统研究,确定了不同卫星个数对应的最佳时空窗口配置,给出了时间和空间反距离加权时对误差影响的等效关系。结果表明,新的融合方法在充分获取无缝隙SWH的基础上,也得到了更准确的SWH融合产品。本文的研究不仅为有效波高的全球应用提供了新的方法,也为多源遥感数据的处理和融合提供了重要参考。

Objective: Significant wave height (SWH) is a crucial parameter in the study of ocean wave fields. Since the launch of GEOSAT in 1985, satellite altimeters have been providing global observations of SWH. However, the limitations of individual satellite orbit intervals and operation cycles mean that only the fusion of multi-satellite observation data can meet the needs of mesoscale wave field research. Currently, methods for fusing SWH data at specific times include the spatiotemporal inverse distance weighting method and the time-weighted averaging method used in CMEMS L4 products. However, the spatiotemporal inverse distance weighting method does not objectively allocate weights for temporal and spatial distances. Additionally, the time-weighted averaging method employed in CMEMS L4 products cannot meet the fusion requirements for dense grids at high spatial resolutions. Methods: This study utilized along-track 1Hz significant wave height data from nine satellite observations. Initially, the multi-source satellite observation data were matched with buoy data from the National Data Buoy Center (NDBC). Calibration was then performed using least squares regression analysis. A filtering method based on empirical mode decomposition(EMD) was applied to the calibrated SWH data. By exploring the equivalence between spatial and temporal distances at the same error level, the influence of spatial and temporal dimensions on the fusion results was unified, leading to the development of a novel spatiotemporal fusion method for significant wave height. Results: Through a systematic study of the fusion process, we found that the spatial window size affects the proportion of blank grids. The error of the fusion results decreases initially and then increases with the enlargement of the temporal window. Compared to the CMEMS L4 products and traditional spatiotemporal weighting fusion methods, our fusion method demonstrates good consistency in global spatiotemporal distribution characteristics and reduces errors by 4.1 cm and 1.55 cm, respectively. Additionally, the proposed fusion method exhibits high-resolution fusion capabilities. Conclusion: This study proposes a new method for significant wave height fusion and conducts a detailed investigation into parameter selection within this method. The improvements not only demonstrate the potential of the new method in enhancing the accuracy of SWH fusion products but also increase the practicality and precision of SWH products in various ocean applications. Furthermore, this study provides valuable reference points for future applications in ocean wave observation and prediction. The research indicates that under the fusion of 4-9 satellites, selecting a 24-hour temporal window, and with 3 satellites, selecting a 30-hour temporal window, along with the optimal spatial window provided in this study, yields the highest accuracy in the final fusion results. However, there are areas that need improvement. Future research should incorporate more detailed and accurate sea ice datasets, considering factors such as sea ice concentration, ice edge, and ice type, to better account for the impact on grid masking in high-latitude regions.