tag:blogger.com,1999:blog-7778441.post114623056844421469..comments2023-12-19T06:54:20.572-05:00Comments on Answer Girl: Marine layerEllen Clair Lambhttp://www.blogger.com/profile/14944288413332520719noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-7778441.post-1146367557925311672006-04-29T23:25:00.000-04:002006-04-29T23:25:00.000-04:00Ahem.Advection fog and the "marine layer" are not ...Ahem.<BR/><BR/>Advection fog and the "marine layer" are not remotely the same thing.<BR/><BR/>Advection fog is the kind of fog you find in San Francisco, London, and Boston, where the water temperature is higher than the dew point temperature of the atmosphere immediately above the surface, leading to thick persistent fog that can last for days. It is also common at sea.<BR/><BR/>The marine layer is an instance of an "inversion layer", where atmospheric temperatures are greater at higher altitudes than they are at the surface. This is the condition that leads to smog layers in cities such as L.A., Denver, and New York (even though Denver is nowhere near the sea). In L.A., it's called the "marine" layer because the lower temperatures at lower altitudes come from an on-shore flow originating in Santa Monica Bay. Advection fog is almost unknown in Los Angeles.<BR/><BR/>The other two kinds of fog are "radiation" fog, common in San Diego, where the ground temperature is higher than the atmospheric temperature immediately above it, leading to an afternoon burn-off, and "arctic smoke", common in higher latitudes like the Alaskan Gulf, based on a similar condition to radiation fog, except that the surface temperature is from the water instead of the land, where the fog eerily only reaches a few feet into the air. A sight to behold.<BR/><BR/>I know. I'm an insufferable pedant.James Lincoln Warrenhttps://www.blogger.com/profile/09666160495434980653noreply@blogger.com