The transfer of heat and water vapor from the ocean
to the air above it depends on a disequilibrium at the
interface of the water and the air. Within about a
millimeter of the water, air temperature is close to that of
the surface water, and the air is nearly saturated with
water vapor. But the differences, however small, are
crucial, and the disequilibrium is maintained by air near
the surface mixing with air higher up, which is typically
appreciably cooler and lower in water-vapor content.
The air is mixed by means of turbulence that depends
on the wind for its energy. As wind speed increases, so
does turbulence, and thus the rate of heat and moisture
transfer. Detailed understanding of this phenomenon
awaits further study.