Unit 2: Atmosphere, Clouds, Humidity (Rugg 25-26)

Capacity

the maximum amount of water that can be present in the air at a certain temperature; increases with increasing temperature.

Cloud

a collection of small water droplets or ice crystals suspended in the air

Condensation

the change from water vapor to liquid water

Condensation Nuclei

microscopic particles on which water vapor condenses to form cloud/fog droplets.

Convergence

as air is drawn together at the surface, like when there is a surface low pressure, it causes an upward movement of air.

Deposition

phase change from gas to solid

Dew

tiny drops of water that form on cool surfaces when water vapor condenses

Dew Point

the temperature at which condensation occurs because the air is saturated

Evaporation

the change from liquid water to water vapor

Fog

a cloud in contact with the ground

Frost

feathery crystals of ice formed on surfaces when water vapor in the air deposits at a temperature below freezing

Latent Heat

heat absorbed or radiated during a change of phase

Orographic Lifting

mountains acting as barriers to the flow of air, forcing the air to rise.

Relative Humidity

a comparison of the actual amount of water vapor in the air with the maximum amount of water vapor that can be present in the air. (Specific Humidity/Capacity)

Saturation

the condition in which the air is holding as much water vapor as possible at a given temperature and pressure.

Specific Humidity

the amount of water vapor in the air at a given time and place; expressed as the number of grams of water vapor per kilogram of air.

Transpiration

the emission of water vapor into the atmosphere from the leaves of plants

Water Vapor

water in its gaseous form

Mesosphere

The layer of the Earth's atmosphere that extends from the stratosphere to the thermosphere, characterized by decreasing temperatures.

Ozone

a form of oxygen that has three oxygen atoms in each molecule instead of two. In the stratosphere it protects us from dangerous ultraviolet radiation. In troposphere it is considered a pollutant as it is a main ingredient in photochemical smog and damaging to plants and people.

Stratosphere

The layer of Earth's atmosphere that extends from the troposhere to the mesosphere; concentration of ozone in this layer causes the temperature to rise as you go up.

Thermosphere

The layer of Earth's atmosphere above the mesosphere, characterized by increasing temperatures with altitude.

Troposphere

The lower layer of the atmosphere where we live. The temperature decreases with altitude

Meteorology

is the branch of science concerned with the phenomena of the atmosphere, specifically with respect to weather and climate

Weather

The state of the atmosphere at a given place in time with respect to "weather variables" such as cloud cover and type, wind direction and speed, humidity, temperature etc.

Climate

statistically averaged weather conditions over a 30+ year period that helps describe the "typical" weather of a region.

Outgassing

The process of gases contained within the Earth being put into the atmosphere by volcanic eruptions.

Tropopause

The boundary between the troposphere and the stratosphere.

atmosphere

The gaseous envelope of air surrounding the Earth

leeward side

Protected side; the direction opposite from which the wind is blowing.

windward side

the side or direction from which the wind is blowing.

rain shadow

a region with dry conditions found on the leeward side of a mountain range

adiabatic cooling

cooling due to expansion as when air rises or is lifted and expands due reduced pressure on it

variable components

componants of the atmosphere that can change from place to place or day to day such as water vapor, ozone, pollution, aerosols.

aerosols

Tiny solid and liquid particles suspended in the atmosphere such as sea salt, dust, ash, smoke, pollen

Cyanobacteria

Photosynthetic bacteria that produce oxygen.

Chloroflourocarbons

Widely used, man-made chemical containing chlorine that destroys stratospheric ozone and lasts a long time in the stratosphere

Montreal Protocol (1987)

An agreement on protection of the ozone layer in which states pledged to reduce and then eliminate use of chlorofluorocarbons (CFCs). It is the most successful environmental treaty to date.

ozone hole

the area of lowered ozone concentration over Antarctica

Sublimation

the process in which a solid changes directly into a gas

temperature

a measure of the average kinetic energy of the particles in an object.

heat

a measure of the total kinetic energy of all the particles of a substance

Ionisphere

the part of the earth's atmosphere that contains a high concentration of ions and free electrons and is able to reflect radio waves.

alto

prefix added to clouds forming at the middle altitude of the troposphere

cirro

prefix added to clouds forming at the top altitude of the troposphere

cumulus

the family of clouds that has a heaped, puffy, often flat bottomed shape.

stratus

The family of clouds that form in flat layers and often cover much of the sky.

cirrus

The family of clouds that are wispy, feathery clouds made of ice crystals that only form at high levels.

nimbo/nimbus

Prefix/suffix added to a cloud to indicate it is one that brings rain.