| A | B |
|---|
| aa | A Hawaiian tem for sharp and pointy basaltic lava flow. This flow is rough versus pahoehoe, which is smooth |
| abrasion | The erosion of rock by being eiter carried along a stream or sandblasted by wind.This process wears down a rock |
| abyssal plain | A large flat area of the deep-ocean floor |
| acid rain | Rain that contains acid whcih can cause serious environmnetal damage,including killing plant and animal life as well as deteriorating buildings.The acid is caused by pollution,especially fron the burning of coal car exhaust and smoke from factories |
| aellian | Any wind related process. Refers to things carried deposited or eroded by the wind. Named after Aelous, the Greek God of wind. Also spelt as eolian |
| aftershock | a shock (i.e) earthquake) that occurs after a large earthquake. After extremely large earthquakes,aftershocks may occur for several years |
| air mass | A body of air that has similar characteristics such as temperature,pressure and moisture content. |
| air pressure | The weight of the air above any point. Air pressure decreases as altidtufdeincreases. For example,the cabins of airplanes must be pressurized while flying because air pressure at that elevation is much lower than at ground level |
| albedo | The percentage of a sun's radiation that is reflected off a surface. For examople, the albedo of snow is very high because white color is very reflective; tus,remember to wear your sunglasses when skiing |
| alluvial fan | Fan shaped deposits of sediment found at the foot of a mountain range brought there by mountain streams on their way from the mountains to the valley below |
| alpine glacier | A glacier that forms in the mountains |
| anemometer | An instrument that measures the speed of wind |
| anticyclone | An area of high pressure with winds that rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemispher |
| anitpode | Two points or regions on opposite sides of the planet from each other, For example, if you were able to dig a hole through the earth from the US,you would reach the Indian Ocean - not China -because the antipode of the US is a region in the Indian Ocean |
| aphelion | The Point in the earth's orbit when the Earth is farthest from the sun. Opposite of perheilon |
| apogee | The point in the Earth's orbit where the moon is fathest from the sun.Opposite of perigee |
| aquaclude | An underground rock layer that groundwater cannot enter or pas through |
| aquifer | A rock layer that holds ground water |
| Arctic circle and Antartic Circle | The Arctic circle lies at 66.30 North and the Antartic Circle lies at 66.30 South. the entire area North of the Arctic circle is light for a full 24 hours on June 21 and the entire area South of the Antartic Circle is dark for a full twenty-four hours on June 21. On Dec 22 it is the opposite |
| arid | Dry. Dry due to limited precipitation |
| arroyo | A spanish term meaning a dry streambe that fills with water following heavy rains. Similar to wadi and a wash |
| artesian well | A well from which water rises due to underground pressure |
| ash | Colcanic ash are tiny particles ejected from a volcano during an eruption |
| atmosphere | One of the four sphers of the Earth. The layer of gas that surrounds the earth,where weather and climate take place. Oftern referred to as air. The other three spheres are biosphere,hydrosphere and lithospher |
| atoll | A ring of coral reef that encloses a lagoon |
| aurora | Colorful lights in the night sky. Also know in the Northern Hemisphere as the Norther Lights |
| avalanche | The rapid falls of snow,ice or rocks from a mountainside |
| axis | An imaginary line that runs from the North Pole to the South Pole around which the Earth turns. The axis is angled 23.5 whch causes the seasons |
| barometer | An instrument that measures atmospheric pressure |
| Barrier Island | An island parallel to the shoreline,typically formed by sand deposited by waves |
| Bay | A body of water formed by a curved indentation of a coastal shoreline,larger than a cove and smaller than a gulf |
| Beaufort Scale | A scale developed by British Admiral Francis Beaufort to measure wind speed using visual clues. The scale runs from 0 to 12 with 0 being calm and 12 being hurrican force winds |
| Biodiversity | The variety of living things in a given area. |
| Biosphere | One of the four spheres of the Earth. The areas of the Earth that are home to all living things. The other three spheres are the lithosphere,hydrosphere and atmosphere |
| Butte | A flat topped hill with steep sides. Larger than a pinnacle and smaller than a mesa. |
| Caldera | A large circular cavity that remains after the explosion and collapse of a volcano |
| Calving | The breaking off of large chunks of ice from a glacier or an ice sheet sometimes forming icebergs |
| Canyon | A deep valley with steep sides carved by a river |
| Cascade | Rapids or a waterfall that flows down multiple steps |
| Cataract | A series of rapids especially those along the Nile River, or a large waterfall with a single drop |
| Celsius | A system for the measurement of temperature with 0 Celsius as the temperature at which water freezes and 100 deg Celsius at which water boils |
| Chinnok winds | A warm and dry wind that blows down the easst slope of the Rocky Mountains |
| Chlorofluorocarbons | Chemicals that destroy ozone inthe atmosphere |
| Cirque | A circular basin in the high mountains carved by a glacier |
| Cirrus | A very high feathery-looking clounds made up of ice crystals |
| Climate | The average weather for a place over a long period of time. Typically determined by thirty years of daily records |
| Cloud | A collection of water moisture and ice crystals in the atmosphere |
| Cold front | The boundary between a mass of cold air and a mass of warm air where the cold air is pushing the warm air upward creating a storm |
| Condensation | The transformation of water from gas (vapor) to liquid |
| Confluence | The place where two rivers or streams meet |
