US Naval Surface Warfare Center with Office of Naval Research (ONR) & academia, is participating in a multi-country, acoustic scattering experiment in the Gulf of Mexico until June 2013. The test event dubbed TREX is a Target Reverberation Experiment with the key objective to understand how undersea environments impact the acoustic signature of a target. The collected data will be compared to sophisticated, physic-based, propagation and target scattering models. TREX is also being referred to as Gulf of Mexico Exercise 2013, or GULFEX13.