Advection

In the term’s strictest sense, advection is the transfer of any atmospheric property—be it heat, moisture, or motion—through horizontal movement. In a more general sense, advection refers to one of two meteorological processes (the other being convection) that creates wind.

In a hurricane, typhoon, or cyclone, advection results in the destructive winds that scour the surface of the land or sea—the flow of air that results when the cool, dense air that is descending toward Earth’s surface on one side of a convective cell is suddenly moved horizontally across the system’s bottom, only to be lifted up on the cell’s opposite side by rapidly rising or by convective currents of warm, light air.

This cyclical motion, which results from the uneven heating of the air by unequal surface temperatures, in turn serves to power the convective cell and will remain in continuous motion as long as the two contrasting surface temperatures persist. In tandem with the convective process, advection forms one of the principal mechanisms by which all atmospheric circulations, from global weather systems, to tropical cyclones, to localized supercell thunderstorms, are sustained.