Surface wave energy modulation is observed over near-inertial time scales following the passage of tropical cyclone Lili (2002). Sea surface depressions, known as the barotropic trough in the wakes of tropical cyclones, are a result of the wind stress and surface Ekman divergence. The relaxation of mass and momentum after the tropical cyclone passage is associated with interactions between the density and current fields responding to the tropical cyclone-induced vertically integrated mass divergence field. The resulting weak barotropic near-inertial current oscillation, similar to a long wave with rotation, provides a physical mechanism for the eventual breakup of the sea surface depression. These free-surface wave energy modulations may play an important role in the air-sea interaction problem and thus, need to be considered in coupled interactions during and subsequent to extreme wind events such as tropical cyclones.