The dynamic responses of flow and near-bed turbidity to typhoons on the continental shelf of the East China Sea: field observations

Typhoons are commonly occurring disastrous events in the Western Pacific and have become more severe as the result of global climate changes, increasingly affecting the ocean and seafloor throughout the Western Pacific. However, studies on the influences of typhoon processes and dynamic mechanisms on the continental shelf remain rather limited because of insufficient observational data in the area. This paper uses observational records at a water depth of 110m on the continental shelf of the East China Sea in the periods when the No. 1323 typhoon 'Fitow' and No. 1324 typhoon 'Danas' passed the East China Sea to study changes in the water temperature, salinity, current and turbidity. Observation results show that typhoon Fitow had limited effects on the measurement site because of the long distance to the centre of the typhoon, but during typhoon Danas, the measured surface current speed reached 2.95m/s, and the turbidity of the sea water increased rapidly due to the vertical mixing of sea water. Typhoon Danas causes both near-inertial oscillations (NIOs) and diurnal currents to increase, which is considered to be the major factor that contributes to bottom water temperature changes and the suspension of bottom sediments after the passage of the typhoon. Typhoons can also cause the Kuroshio Current to shift towards the continental shelf, which may affect the Tsushima Current.