Monitoring of the Surface Ocean Environment under A Passing Typhoon Using A Wave Glider

Abstract

A wave glider was launched in the south of Jeju, Korea and Typhoon Talim (September 9-18, 2017) passed through the East China Sea (ECS) at the same time. It is used to monitor the effect of Typhoon Talim, which had a low pressure center of 940 hPa and a maximum wind speed of 47 m/ s. It made its closest approach to the typhoon around September 16-17. During this time, the atmospheric pressure dropped to 995 hPa, the wind speed was 25 m/s, and the significant wave height was 9.1 m. Satellite images showed two hot spots. One was an upwelling event in the southern part of the ECS and the other was a horizontal movement of the water column in the middle of the ECS. When the typhoon was approaching, the wave glider measured the lowest sea surface temperature and salinity, whereas the chlorophyll levels and turbidity increased, which could not be explained by local observations. However, satellite data could compare the trends before and after the typhoon's approach, where the data indicated that the vertical mixing and upwelling events near the typhoon's center were responsible for the low temperature and high chlorophyll levels in the surface layer.