■ Advection fog Clouds and Fog 207 Valley fog 雾(fog) FIGURE 8-8 Valley fog. s in the valleys of the Appalachian Mountains.chilling FIGURE 8-6 the air to the dew point and forming a valley fog IPhoto hy author.l Advection fog. San Francisco's Golden Gate Bridge shrouded by an invading adection fog characteristic of summer conditions along a western u过.to by author Radiaf of og Evaporation fog FIGURE 8-7 Evaporation fog. 雾（fog） Advection fog Evaporation fog Valley fog Radiation fog