Characteristics of clouds and fog

When water vapor enters the sky, it cools. Since cold air cannot carry as much water vapor as warm air, the water content in it condenses into a mass of small water droplets, which we call clouds. If ground-level air is already saturated with water vapor, the vapor can condense and form low-level clouds called fog.

Water vapor

Water always evaporates, so it rises in the air as invisible gas or vapor. Evaporation absorbs heat from the surrounding water, and if the vapor is converted back into liquid water, this heat is released. When water vapor condenses into small droplets that form clouds, heat is released into the air, which heats up so that it rises and makes clouds thicker and taller.

Drops of clouds

Clouds of water condense into fine particles, such as dust or salt particles, which are thrown into the air by sea waves. Cloud droplets become so small that it takes tens of millions to form an average raindrop. At higher, cooler heights, clouds form instead of fine ice crystals.

Fog and mist

As seen in San Francisco, clouds can evolve on land or at sea level. This usually happens when warm, moist air moves to a cold surface like the ocean. The air is cooled to the point where some of its water vapor condenses.

Cloud formation

Clouds form when moist air cools, most of the time the air rises and cools. There are three main reasons why this might happen-

Frontal clouds

Clouds form when warm, moist air is pushed into the cold air on the front of the climate. As the rising air cools, water vapor condenses in the clouds.
Convective clouds

When the sun warms the land or the sea, it warms the air above it. Warm air rises and cools, water vapor condenses, and clouds form.
Orographic Cloud

If moist air is driven on high ground, it goes upwards. It cools any water vapor in the air, so it condenses into clouds.

Fair weather clouds

When the air is hot, the air molecules separate, making the air less dense. This causes an increase in air. As it grows and cools, its molecules move closer to each other, becoming more solid, so that it stops growing. This point is often marked by a layer of fluffy fair weather clouds.

Sea fog

The Golden Gate Bridge over San Francisco Bay in California is covered in fog from the Pacific Ocean.

Stormy weather

When hot sunlight produces plenty of water vapor and warm air, the mixture expands, expands, and cools. Vapors condense in large vascular clouds. These clouds release heat, which heats the air and carries it to higher altitudes, along with more water vapor. The clouds then solidify and release more heat. This process can create huge cumulonimbus storm clouds up to 10 miles high.

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