A study of internal solitary waves in the Northern South China Sea using the Geo High-Speed Imager of the FY-4B satellite

Abstract

ABSTRACT The FY-4B satellite is the first operational satellite of China’s new generation of geostationary-orbit meteorological satellites in the Fengyun-4 series. This study is the first to analyse the changes in the dynamic processes of internal solitary waves (ISWs) in the northern South China Sea using FY-4B Geo High-Speed Imager (GHI) data with a 250 m spatial resolution. By calculating the propagation direction, wave crest line length, distance between ISW packets and other characteristics of ISWs and comparing them with FY-3D and MODIS optical images, the feasibility and reliability of using the FY-4B GHI to observe ISWs are verified. This study analyses the dynamic processes of ISW propagation at a high temporal resolution of up to 1 minute and observes ISW propagation processes at different sea depths, ISW evolution dynamics, ISW interaction processes, and the change processes of ISWs as they pass islands and reefs. A comparison between these results and in situ measurements obtained in the northern South China Sea demonstrates that the FY-4B GHI has the unique advantage of continuously tracking and observing ISWs in the northern South China Sea and can provide new tracking observations for the study of ISWs in the South China Sea.