Ocean
The Pacific Ocean contributes to the frequency of fog by providing atmospheric moisture and by its temperature. It is also the major source of nuclei for the condensation of moisture from vapor into cloud droplets.
Moisture evaporated from the ocean surface over hundreds, even thousands of miles of the open Pacific is carried to California from various directions. This water vapor contributes to the development of what is called a marine layer near the surface of the ocean.
Along the California coast, the prevailing current flows from the northwest and is cool owing to its origin in the North Pacific. Additional cooling occurs due to strong upwelling of cooler subsurface waters, especially along the immediate coastline and near various promontories. Sea surface temperatures along the coast are generally in the mid to upper 50s F, year-round.
When the marine layer encounters the colder waters along the California coast, it cools to its dewpoint, and if small particles called condensation nuclei are present, liquid water drops will form. Condensation nuclei in coastal fog are mostly composed of salt from surf and spray, with lesser amounts of iodine from kelp. These nuclei are so effective that condensation can occur even before the dewpoint is reached.
Read more about this topic: San Francisco Fog
Famous quotes containing the word ocean:
“A great proportion of the inhabitants of the Cape are always thus abroad about their teaming on some ocean highway or other, and the history of one of their ordinary trips would cast the Argonautic expedition into the shade.”
—Henry David Thoreau (1817–1862)
“They commonly celebrate those beaches only which have a hotel on them, not those which have a humane house alone. But I wished to see that seashore where man’s works are wrecks; to put up at the true Atlantic House, where the ocean is land-lord as well as sea-lord, and comes ashore without a wharf for the landing; where the crumbling land is the only invalid, or at best is but dry land, and that is all you can say of it.”
—Henry David Thoreau (1817–1862)
“And such the trust that still were mine,
Though stormy winds swept o’er the brine,
Or though the tempest’s fiery breath
Roused me from sleep to wreck and death.
In ocean cave, still safe with Thee
The germ of immortality!
And calm and peaceful shall I sleep,
Rocked in the cradle of the deep.”
—Emma Hart Willard (1787–1870)