Research on Sea Surface Elliptical Current Remote Sensing With Single-Station Wide-Beam High-Frequency Sky–Surface Wave Radar

Abstract

This article describes a new elliptical current (${\overset{\scriptscriptstyle\rightharpoonup}{v}}_{E - \text{ssw}}$) retrieval scheme for single-station wide-beam high-frequency sky–surface wave radar, which focuses on solving the problem of locating scattering patches on the sea surface. To start with, the measured data of the Digisonde portable sounder are exploited to correct the international reference ionosphere (IRI) model, which is capable of realizing the precise application of the IRI model to a certain extent. Subsequently, the scattering patches are located by combining the 3-D ray tracing and the corrected IRI model, and the radio wave incidence angles are obtained to calculate the theoretical Bragg frequency. Finally, the large-area elliptical currents are retrieved on the basis of the correction of sea echoes with ionosphere phase contamination extracted from direct waves. The effectiveness of this scheme is verified by comparing ${\overset{\scriptscriptstyle\rightharpoonup}{v}}_{E - \text{ssw}}$ with surface wave radar current products and by comparing with a location algorithm under the plane ionosphere assumption. The main achieved results are as follows. The predicted value of ${\overset{\scriptscriptstyle\rightharpoonup}{v}}_{E - \text{ssw}}$ by the location algorithm proposed in this article is more accurate than that obtained from the plane ionosphere location algorithm. The directions of ${\overset{\scriptscriptstyle\rightharpoonup}{v}}_{E - \text{ssw}}$ are in good agreement with the surface wave radar current product, and the root-mean-square error of ${v}_{E - \text{ssw}}$ is about 11.70 cm/s. In the detection core area, such an error is about 7.76 cm/s, and the scattering patches with smaller group paths exhibit higher retrieval accuracy of ${v}_{E - \text{ssw}}$. The relative error of ${v}_{E - \text{ssw}}$ in the core area demonstrates an ascending trend in the local time interval of 9:32–10:29, revealing that the effectiveness of this scheme could be affected by the ionosphere disturbance.

Keywords

• International reference ionosphere (IRI) model correction
• scattering patch location
• sea surface current retrieval
• wide-beam high-frequency hybrid sky–surface wave radar