Ma, W.; Wang, Y.; Yang, S.; Wang, S., and Xue, Z., 2018. Observation of internal solitary waves using an underwater glider in the northern South China Sea.

Internal solitary waves (ISWs) are frequently observed in the ocean, in particular in the South China Sea. Petrel-II, the autonomous underwater glider developed by Tianjin University, conducted ISW observations in the northern South China Sea in August 2017. With the payload conductivity, temperature, and depth, Petrel-II can obtain the repeating thermohaline profiles from the surface to nearly 1500-m depth. Combined with the analysis of a moderate-resolution imaging spectroradiometer true-color image, it is verified that the thermohaline fluctuation is caused by the ISWs. The features of the ISW are estimated by calculation of vertical velocity using a glider flight model. The ISW captured by Profile-46 of the glider was a depression wave, with a period of about 24 minutes and an amplitude of about 127 m. The application of underwater gliders will contribute to studies on the features, generation, propagation, and evolution of ISWs in the South China Sea.