Spatial Range of GNSS-R Detection of Evaporation Duct in the Coastal Waters of China

Objectives The evaporation duct has a significant impact on shore based radar, shipborne radar, and 5G communication due to its refractive effect. Global navigation satellite system reflectometry (GNSS-R) has the application potential of detecting evaporation duct due to the characteristics of all weather, passive reception and high spatial and temporal resolution. However, spatial range of GNSS-R detection of evaporation duct is closely related to the evaporation duct height, and whether it has practical value in complex evaporation duct environment near the coast of China still needs to be studied.

Methods Thus, meteorological data measured from coastal meteorological observation stations and sea surface temperature released by European Centre for Medium-Range Weather Forecasts are used to obtain the spatiotemporal distribution pattern of the spatial range of GNSS-R detection of evaporation duct, with the evaporation duct model and GNSS-R evaporation duct detection range model.

Results The spatial range of GNSS-R detection of evaporation duct based on Chinese coastal meteorological data first increases and then decreases during the day. It reaches the maximum value from 5:00 to 7:00 UTC, and then gradually decreases and stabilizes at night. In terms of seasonal changes, the highest value is in summer and autumn, and the lowest value is in winter. The detection range of the Bohai Sea and the Yellow Sea are greatly affected by seasons, while the detection range of the East China Sea and the South China Sea is large and remains relatively stable throughout the year. Especially in the South China Sea, it can maintain a detection range of about 130 km throughout the year. Further analysis shows that during the high incidence period and the quiet period of the evaporation duct, the average spatial range of GNSS-R detection of the evaporation duct is 145 km and 103 km, respectively. In addition, regional differences have an influence on the detection range. For example, the average spatial range of GNSS-R detection of evaporation duct on the western side of Liaodong Peninsula and Hainan Island is greater than that on the eastern side. As a high incidence area for evaporation duct, the Taiwan Strait has a larger spatial range of GNSS-R detection of evaporation ducts than the surrounding waters.

Conclusions The analysis results can expand the application areas of meteorological data, improve radar detection efficiency in relevant areas, and provide the warning information for communication.