Mixing process of the Changjiang Diluted Water typhoon Muifa (1109)

摘要

This study examined the mixing process of the Changjiang Diluted Water (CDW) by typhoon Muifa (1109) using a three dimensional high resolution ocean forecasting system driven by real time assimilated atmospheric forcing. We focused on the vertical distribution change of seawater temperature and salinity between the Changjiang and Jeju Island in order to see how vertical mixing occurs. In the temperature fields, seawater over 28 °C appeared in the upper 10-m depth along the section before the typhoon. However it decreased 4 °C over 300 km from the Changjiang mouth by the typhoon. In the salinity fields, low-salinity water of 24 psu appeared as two isolated patches in the mid-shelf between the Changjiang river mouth and area west of Jeju Island. The ocean mixed layer (OML) depth that is calculated by vertical profile of temperature and salinity is lower as the typhoon approaches. The boundary of unstable mixed layer is lower as the typhoon approaches.