PHS 1010 earth science ch. 17 terms

Humidity

the amount of water vapor in the air

Vapor pressure

pressure in water vapor

Relative humidity

ratio of the air's actual water vapor content compared with the amount of water vapor required for saturation at that temperature (and pressure)

Saturated air

means the water vapor content equals the capacity that air can hold at that temperature

Dew point temperature

temperature to which a parcel of air would need to be cooled down to in order to be saturated

Condensation level

where the air is saturated at that temperature

Dry adiabatic rate

the rate at which air cools as it rises when the air is not saturated

Wet adiabatic rate

the rate at which air cools when the air is saturation-it only cools at this rate above the condensation

Condensation

gas to a liquid

Condensation nuclei

possible condensation surfaces in the atmosphere are tiny bits of particulate matter (dust, smoke, ash, salt, etc.)

Lifting mechanism

a process that forces warmer, less dense air to rise higher in altitude

Orographic lifting

as the air rises, it cools and condenses on the windward side of the mountain, as it goes down the opposite mountain side, the air warms but has less water vapor

Rainshadow effect

more rainfall on the windward side of a mountain and less rain on the leeward side

1 multiple choice option

Rainshadow desert

a desert on the leeward side of a mountain range

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Frontal wedging

occurs along fronts where cool air acts as a barrier to warm air causing the warm air to rise (less dense)

1 multiple choice option

Convergence lifting

where air from different directions is flowing together and rising (happens at low pressure points in the atmosphere)

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Convective lifting

occurs where unequal surface heating causes pockets of air to rise

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Stable air

resists vertical displacement because the air is cooler and denser than surrounding air, so it wants to sink rather than rise higher in the atmosphere

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Conditional instability

occurs when the atmosphere is stable for an unsaturated parcel (dry adiabatic rate) of air but unstable for a saturated parcel (wet adiabatic rate)

1 multiple choice option

Absolute instability

Rising air acts like a hot air balloon

3 multiple choice options

Clouds

Made of millions and millions of microscopic water droplets or ice crystals

Cirrus

High clouds that are thin and/or wispy

1 multiple choice option

Cumulus

globular cloud masses

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Stratus

sheets or layers that cover much of the sky

1 multiple choice option

Cirro

high clouds—above 6000 meters

3 multiple choice options

Alto

middle clouds—2000 to 6000 meters

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Nimbus

low clouds—below 2000 meters; means "rainy" and can occur at any level

3 multiple choice options

Cumulonimbus

exist in all levels of altitude simultaneously

2 multiple choice options

cloud examples

Fog

clouds with its base at or near the ground; form through radiation cooling or movement of air over a cold surface

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Rain

droplets that have at least a 0.5 mm diameter

Drizzle

droplets have less than a 0.5 mm diameter

Snow

ice crystals, or aggregates of ice crystals

Sleet

small particles of ice that fall to the ground

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Freezing rain

falls as liquid (but cold) and freezes on impact with a surface

Glaze

a very thin layer of water that has frozen, generally overnight when temperatures drop close to or below freezing

Hail

concentric shells or layers of ice; range from 1-5 cm

3 multiple choice options