Warm-core eddy effects on sound propagation in the South China sea

•We used an automatic detection method to locate and track a warm mesoscale eddy from satellite data.•We deployed hydrophone and temperature-sensor arrays in the center and outside the eddy.•We recorded acoustic signals from explosive sources and chirped signals from a transceiver.•We combined the measured hydrological data to create a spatially and temporally dependent empirical model of the eddy.•We compared the simulations with and without an eddy to investigate the effects of the eddy on sound propagation.•We utilized the measured data to analyze the effects of the eddy on transmission losses to the two hydrographic arrays.•We employed recordings of the chirped signals to study the effects of the eddy on sound-energy fluctuations.