aerosols
	Minute particles or liquid droplets suspended in the air.
albedo
	A description of a surface's reflective properties.
climate
	A description of the long-term pattern of weather in a particular area.
cold front
	A moving boundary of cooler air displacing warmer air.
convection currents
	Rising or sinking air currents that stir the atmosphere and transport heat from one area to another. Convection currents also occur in water; see spring overturn.
Coriolis effect
	The influence of friction and drag on air layers near the earth; deflects air currents to the direction of the earth's rotation.
El Niño
	A climatic change marked by shifting of a large warm water pool from the western Pacific Ocean towards the east. Wind direction and precipitation patterns are changed over much of the Pacific and perhaps around the world.
greenhouse gas
	Gases added to the atmosphere by human actions that trap heat and cause global warming.
hurricanes
	Large cyclonic oceanic storms with heavy rain and winds exceeding 119 km/hr (74 mph).
ionosphere
	The lower part of the thermosphere.
jet streams
	Powerful winds or currents of air that circulate in shifting flows; similar to oceanic currents in extent and effect on climate.
mesosphere
	The atmospheric layer above the stratosphere and below the thermosphere; the middle layer; temperatures are usually very low.
Milankovitch cycles
	Periodic variations in tilt, eccentricity, and wobble in the earth's orbit; Milutin Milankovitch suggested that it is responsible for cyclic weather changes.
monsoon
	A seasonal reversal of wind patterns caused by the different heating and cooling rates of the oceans and continents.
stratosphere
	The zone in the atmosphere extending from the tropopause to about 50 km (30 mi) above the earth's surface; temperatures are stable or rise slightly with altitude; has very little water vapor but is rich in ozone.
thermosphere
	The highest atmospheric zone; a region of hot, dilute gases above the mesosphere extending out to about 1,600 km (1,000 mi) from the earth's surface.
troposphere
	The layer of air nearest to the earth's surface; both temperature and pressure usually decrease with increasing altitude.
warm front
	A long, wedge-shaped boundary caused when a warmer advancing air mass slides over neighboring cooler air parcels.
weather
	Description of the physical conditions of the atmosphere (moisture, temperature, pressure, and wind).

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