A coastal acoustic tomography experiment in the Qiongzhou Strait
An experiment for synchronous mapping of current velocity (V CAT ) and temperature (T CAT ) distributions was successfully carried out using four coastal acoustic tomography (CAT) systems, from March 17 to April 1, 2013, in the Qiongzhou Strait, China. During the CAT observation period, shipboard acoustic Doppler current profiler (ADCP) surveys were also performed to observe the current velocity (V ADCP ) and temperature (T ADCP ) for the purpose of comparison with the CAT data. Position offsets, including a long-time averaged offset and a short-period fluctuation offset, were corrected for temperature estimation. The horizontal distribution of V CAT and T CAT was reconstructed by an inverse technique using the CAT data. V CAT was nearly parallel to the strait while T CAT was higher in the southern area than in the northern area. During the whole observation period, T CAT gradually increased by approximately 2°C, indicating seasonal warming. V CAT was in good agreement with V ADCP , while the root-mean-square differences (RMSDs) between V CAT and V ADCP for eastward and northward velocities were 0.10 m/s and 0.08 m/s, respectively. T CAT was in approximate agreement with T ADCP , with an RMSD of 0.30°C.