Ocean surface gravity waves are mechanical water waves propagating along the sea interface, with heights from centimeters to more than 10 m. They are one of the most significant dynamic processes in the upper ocean which have received a lot of attention in the fluid mechanics and ocean science community, starting from Stokes (1847) and peaking about half a century ago (e.g., see Yuan and Huang (2012) for a review). When moderate-to-strong wind blows over the sea surface, most of the energy and momentum are first transported to surface waves, to support their growth (e.g., Kudryavtsev & Makin, 2001), before those are passed to the ocean through wave breaking and wave-turbulence interactions (Babanin, 2011). That is, the waves are the "sink" of the energy and momentum flux for the low atmosphere and the "source" for the upper ocean, and play an important role in redistribution of the air-sea energy and momentum fluxes at the space-time scale of the storms. Moreover, such energy and momentum balance is not quite dependent on the instantaneous and local wind, because the waves are integral of the wind over large scales. Furthermore, in large areas dominated by swells, the waves can be unrelated to the local wind altogether, and in fact can be responsible for generating the local winds (e.g., Hanley et al., 2010).