Spatial Resolution and Channel Time Lag Requirement of Optical Satellite Sensors for Ocean Wave Monitoring

High-resolution optical satellite sensors, such as the multispectral instrument (MSI) and the operational land imager (OLI), show excellent performance in capturing fine-scale sea surface wave motion and spatial patterns. Their interband time lag offers the potential to resolve wave directional ambiguity and parameter estimation. Here, we investigate the spatial resolution and channel time lag of optical sensors, based on cross-spectral analysis of multichannel imagery, to clarify their requirement in ocean wave monitoring. The analysis, validated by matched buoy data and optical imagery, demonstrates that the minimum detectable time lags for 180° directional ambiguity removal are 0.47, 0.52, and 0.74 s for MSI 10-m, 20-m, and OLI 30-m resolution data, respectively. All three resolutions effectively detect wave system wavelengths ranging from 60 to 300 m, with minimum detection limits of 20, 40, and 60 m, respectively. Additionally, the optimal statistics window size for consistent wave detection is about 8 km. These findings not only highlight the strengths of current satellite sensors, but also provide References for future high-resolution optical sensor design in ocean wave monitoring.