Fog

Definition

Fog is a low-lying cloud that forms when water vapor condenses into tiny water droplets suspended in the air near the Earth's surface. This phenomenon occurs under specific atmospheric conditions and is closely linked to processes such as condensation and evaporation, cloud formation, dew point, and humidity levels. Fog can significantly impact visibility, especially during flight, making it crucial for safe aviation operations and flight planning.

5 Must Know Facts For Your Next Test

1. Fog typically forms when the air temperature cools to the dew point, leading to condensation of water vapor in the air.
2. There are several types of fog, including radiation fog, advection fog, and upslope fog, each formed under different conditions.
3. Fog can develop quickly and reduce visibility to less than a quarter of a mile, making it hazardous for driving and flying.
4. Coastal areas often experience advection fog when warm, moist air moves over cooler water or land surfaces.
5. Weather forecasts often include fog predictions, which are essential for transportation safety and planning.

Review Questions

• How does the process of condensation lead to the formation of fog?
  • Fog forms through condensation when warm, moist air cools to its dew point temperature. As the air cools, it can no longer hold all the moisture in vapor form, leading to the formation of tiny water droplets that hang in the air. This process is similar to how clouds form but occurs at lower altitudes, resulting in fog that reduces visibility near the ground.
• Compare and contrast the different types of fog, discussing how their formation mechanisms affect visibility.
  • Different types of fog, such as radiation fog and advection fog, have distinct formation mechanisms that affect visibility. Radiation fog occurs when the ground cools at night, causing moisture near the surface to condense. In contrast, advection fog forms when warm, moist air moves over cooler surfaces. Both types can lead to low visibility, but radiation fog typically forms during calm nights while advection fog can develop more broadly along coastlines or valleys.
• Evaluate the impact of fog on aviation safety and how pilots can prepare for flying in these conditions.
  • Fog significantly impacts aviation safety by reducing visibility to dangerous levels, complicating takeoff and landing procedures. Pilots must evaluate weather reports and use instruments for navigation when flying in or near fog. They may rely on instruments rather than visual references during approach and landing. Effective flight planning involves assessing expected fog conditions at airports and determining alternative landing options if visibility is compromised.

Related terms

Stratus Clouds: A type of cloud characterized by uniform gray color and often covering the entire sky, similar to fog, and can lead to low visibility conditions.

Radiation Fog: A type of fog that forms when the ground cools rapidly at night, causing moisture in the air close to the surface to condense into droplets.

Visibility: The distance one can clearly see, which is often reduced in foggy conditions due to suspended water droplets in the air.