Water in the Atmosphere Ch20 EarthScience

Cirrus Clouds

Because these clouds are thin, light can easily pass through them.

cirrostratus cloud

A halo may appear around the sun or moon when either is viewed through a _______________

Lifting

Air can be forced upward when a moving mass of air meets sloped terrains, such as mountains ranges. This process is called _______.

decreases

As a mass of air rises, the surrounding atmospheric pressure ___________.

Absolute humidity the mass of water unit volume of air that contains the water vapor. Relative Humidity is the ratio of the amount of water vapor in the air to the amount of water vapor needed to reach saturation at a given temperature.

Compare relative humidity with absolute humidity.

Humidity is water vapor in the atmosphere.

Define humidity.

Water droplets form on surfaces below the dew point.

Describe what happens when the temperature of air decreases to the dew point or below the dew point.

Most water vapor enters the air through evaporation.

Explain how most water vapor enters the air.

water vapor

For clouds to form, the air must be "saturated" with ___________.

condensation

For water vapor to form a cloud, a solid surface on which _________ can take place must be available.

Cumulonimbus Clouds

High, dark storm clouds known as _______, or thunderheads, are often accompanied by rain, lightning, and thunder.

Electrical Hygrometer, Psychrometer, Dew Cell and Hair Hygrometer.

Identify four instruments that are used to measure relative humidity.

Water vapor usually comes from oceans near the equatorial area.

Identify the principal source from which most water vapor enters the atmosphere.

Sublimation is when a solid changes directly in to a gas.

Identify the process by which ice changes directly into a gas.

clouds, fog

If the air cools below its dew point, _______ or ________ will form

cirrostratus clouds

Long, thin clouds called ___________ form a high, transparent veil across the sky.

cloud formation

Mixing may cool the combined air to below its dew point, which results in __________________

clouds

Some _________ form when one body of moist air mixes with another body of moist air that has a different temperature.

troposphere

The _________ contains millions of suspended particles of materials that serve as solid surfaces.

nimbostratus and altostratus

The two variations of stratus clouds are known as _____ and _____.

Cirrus Clouds

These clouds are made of ice crystals.

High Clouds Middle Clouds Low Clouds

What are the three altitude cloud groups?

Stratus Clouds Cumulus Clouds Cirrus Clouds

What are the three basic cloud forms?

Because it is warmer at the equator and warmer air can hold more water vapor, the absolute humidity would be higher at the equatorial region.

Which region of Earth would you expect to have a higher absolute humidity: the equatorial region or the polar regions?

Clouds

______ are classified by their shape and their altitude.

Cirrus

______ means "curly."

Stratus

______ means "sheet-like' or "layered."

Cirrocumulus clouds

_______ commonly appear just before a snowfall or a rainfall.

Cumulus

_______ means "piled" or "heaped."

cirrus cloud

a feathery cloud that is composed of ice crystals that has the highest altitude of any cloud in the sky

stratus clouds

a gray cloud that has a flat uniform base and that commonly forms at very low altitudes

cumulus cloud

a low-level, billowy cloud that commonly has a top that resembles cotton balls and has a dark bottom

condensation nucleus

a solid particle in the atmosphere that provides the surface on which vapor condenses

Dew Point

at constant pressure and water vapor content, the temperature at which the rate of condensation equals the rate of evaporation

Latent Heat

the heat energy that is absorbed or released by a substance during a phase change

Absolute Humidity

the mass of water vapor per unit volume of air that contains the water vapor; usually expressed as grams of water vapor per cubic meter of air

adiabatic cooling

the process by which the temperature of an air mass decreases and the air mass rises and expands. (and air pressure decreases)

advective cooling

the process by which the temperature of an air mass decreases as the air mass moves over a cold surface

Sublimation

the process in which a solid changes directly into a gas (the term is sometimes also used for the reverse process)

Relative Humidity

the ratio of the amount of water vapor in the air to the amount of water vapor needed to reach saturation at a given temperature