The summertime marine fog that occurs along coastal areas with Mediterranean climate such as California, Chile, Peru, South Africa, and the Canary Islands is a result of complex air, land, and sea interactions that occur along the eastern edge of ocean basins. One common air-land-sea marine fog forming combination is an anticyclonic high pressure, which is a descending air mass 1000’s of km wide that brings northwest winds to California, compressing the thin air mass called the marine layer, which in turn causes the marine layer to heat slightly filling with even more water vapor from the cold ocean beneath it that recently arrived from more polar regions or upwelled from the deeper ocean. The marine layer advects (drifts) onshore as the interior land areas heat up but gets trapped over the colder ocean condensing into fog droplets. When the tops of clouds cool and turbulence mixes the air masses, the shallow inversion-trapped marine layer thickens but the inversion pressure lessens. Fog pushes against, over, and through gaps in the coastal mountains, transporting water and other aerosol materials into coastal ecosystems. If the temperature or pressure differences (gradients) are too strong, winds will be generated and the additional turbulent mixing will dissipate the fog. If the coastal mountains are higher than the bottom of the subsiding air mass the fog will flow through gaps like the Golden Gate. [links]