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Ch 1 Earth and Space
Definitions from Earth and Space Science BJU Press Ch 11
Term | Definition |
---|---|
air mass | a body of air with horizontally uniform temperature, humidity, and pressure that covers a ton of area |
source region | an air mas that forms as it slowly moves of the earth surface where temperature and humidity are fairly uniform |
warm air mass | air masses that are warmer than the surface they pass |
cold air mass | air masses that are colder than the surface they pass |
stationary front | a front that is not moving |
warm front | if warm air front is replacing cold air front |
cold front | if cold air front is replacing warm air front |
squall line | a line of violent thunderstorms |
occluded front | when two cold fronts trap a warm front in between them, the warm air mass rises and loses contact with ground |
monsoon | a seasonal prevailing wind in the region of South and Southeast Asia, blowing from the southwest between May and September and bringing rain (the wet monsoon ), or from the northeast between October and April (the dry monsoon ). |
pressure gradient force | when and air mass has a higher pressure on one side than another it will be pushed in the direction of the lower pressure |
geostrophic wind | a wind whose direction and speed are determined by a balance of the pressure-gradient force and the force due to the earth's rotation. |
cyclone | low pressure areas in the atmosphere |
anticyclone | high pressure areas in the atmosphere |
jet stream | rapid currents of air high above the earth |
sea breeze | winds from the sea- shore |
land breeze | shore to sea breezes |
valley breeze | valley to mountain |
mountain breeze | mountain to valley |
trade winds | a wind blowing steadily toward the equator from the northeast in the northern hemisphere or the southeast in the southern hemisphere, especially at sea. Two belts of trade winds encircle the earth, blowing from the tropical high-pressure belts to the low- |
prevailing westerlies | the portion of upper and lower elevation air that flow toward the pole from 30 degrees latitude are deflected toward the east |
prevailing easterlies | the portion of upper and lower elevation air that flow toward the pole from 30 degrees latitude are deflected toward the west |
doldrums | a low pressure zone caused by the rising of warm air |
horse latitudes | zones of high pressure circling the earth |
subpolar low | pressure belt. A band of low pressure located, in the mean, between 50° and 70° latitude. In the Northern Hemisphere, this belt consists of the Aleutian low and the Icelandic low. In the Southern Hemisphere |
polar high | The polar highs are areas of high atmospheric pressure around the north and south poles |
thunderstorms | most common type of storm |
thunderhead | cumulonimbus cloud |
lightning | an electrical discharge |
stepped leader | faint stream of electricity when a lightning bolt first begins to form |
return stroke | is the very bright visible flash that we see as lightning, caused by the rapid discharge of electricity. Once the step leader makes contact with a streamer, the negative charge that has accumulated along the leader channel flows rapidly to ground |
forked lightning | formed when a stepped leader branches |
tornado | a narrow funnel cloud |
waterspout | tornadoes in the sea |
hurricane | cyclone windstorms |
typhoon | hurricane in the water in the western pacific area |
cyclone | hurricane in the water in the Indian ocean area |
eye | the center of a hurricane |
storm swell | huge waves produced by high wind |
storm surge | higher than normal water level |
lightning rod | a metal rod or wire fixed to an exposed part of a building or other tall structure to divert lightning harmlessly into the ground. |
heat lightning | lightning that is seen even though the thunder isn't heard |
intercloud lightning | cloud to cloud lightning |
intra-cloud lightning | lighting that stay in a cloud |