Inversion of temperature vertical structure by ocean acoustic tomography data in the Luzon Strait

Abstract

Luzon Strait is the key channel which connects the western Pacific and the South China Sea(SCS). It is very important to monitor the exchanges of materials and energy between the western Pacific and the SCS, which are caused by the Kuroshio and eddy's variability. The Kuroshio can intrude into the SCS through the Luzon Strait in various manners and significantly affects the oceanic variability of the SCS. A deep-sea acoustic tomography experiment was conducted at the northern part of the Luzon Strait during April 2008 to October 2008. Three 800Hz acoustic systems were deployed at depth about 800m on the subsurface mooring line, and the distance between the systems was about 40km. The four-month reciprocal acoustic transmission data between a pair systems were successfully obtained. The three groups of acoustic arrival peak were distinctly separated. The temperature vertical structure along the transmission line are inversed by using the Matched-Mode Processing method. The inversion results are in good agreement with the temperature field observations and HYCOM results. The 17-day and 23-day period signals are found in the inversion result, which correspond to the frequency of occurrences of cold eddy in the Luzon Strait. (Work supported by NBRPC 2007CB411803, NSFC 41176033 and ONR)