Experimental Study on Doppler Characteristics of Sea Echoes at Different Radar Bands

The Doppler properties of sea echoes play a crucial role in ocean dynamic parameter inversion and target detection. However, these characteristics vary significantly across different radar frequency bands. To investigate the Doppler characteristics of multi-band sea echoesat low grazing angle, the joint observation experiment of L-, S- and X-band sea echo was carried out in Lingshan Island, Qingdao. Experimental results indicate that, when the radar is oriented along the up-wave direction, both the Doppler shift and spectral bandwidth of sea echoes increase with the frequency of the incident electromagnetic wave across different radar bands. We also found that the Doppler shift and spectral bandwidth of HH-polarized signals are greater than those of VV-polarized signals. Comparison results across different sea conditions reveal that both the Doppler shift and spectral bandwidth tend to rise with increasing significant wave height.