Atmospheric Moisture

Geographical Patterns of Fog

There is a definite geographical pattern to the formation of fogs. Figure 7.16 shows the spatial pattern of fogs over the United States. First note that radiation fog is pretty common over much of the country as no special landscape features like mountains or ocean currents are needed to create it. Advection fog is common along coasts where air originating over warm water travels over cooler water or land surfaces to induce condensation and cloud formation near the ground. Upslope fog is common through the western Great Plains and eastern slope of the Rocky Mountains as warm and moist air, often originating in the Gulf of Mexico, works its way toward higher elevation. The gentle uplift provided induces adiabatic cooling and saturation of the air with subsequent condensation and fog formation.

Figure 7.17 Geographical distribution of fogs over North America.

Previous | Continue