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JC GEOG
weather and atmosphere
| Term | Definition |
|---|---|
| what is air | nitrogen 78% oxygen 21% water vapour, carbon dioxide,ozone and other gasses 1% |
| radiation | air close to the ground is heated by heat waves |
| convection | warm air rises |
| conduction | cool air is heated by contact with warm air |
| warm winds | winds that blow towards the pole |
| cold winds | winds that blow towards the equator |
| prevailing winds | winds that blow regularly over a region |
| high pressure | air that has cooled and gets heavier -presses down on the earth |
| low pressure | air is heated and expands -becomes lighter less weight |
| the water cycle | evaporation ,condensation,precipitation , runoff |
| convectional rainfall | sun heats the ground,air expands gets lighter and rises,it cools condenses and forms clouds,=heavy showers of rain during hot spells |
| relief rainfall | sea winds full of moisture,forced to rise over mountains , moisture cools, condenses and falls as rain |
| cyclonic rainfall | cold polar air meets warm tropical air ,warm air is forced to rise quickly,it condenses forms clouds along warm and cold fronts ,rain falls |
| precipitation | rain ,hail, sleet, snow |
| winds | moving air.air moves from areas of high pressure to areas of low pressure |
| cause of ocean currents | unequal heating of the sea at different latitudes - at the the poles the sea is cold -at the equator the sea is warm-water moves between warm and cold sea areas |
| atmospheric pressure | the weight of air |
| to measure humidity | hygrometer |
| to measure temperature | thermometer maximum and minimum |
| to measure sunshine | Cambell-Stokes recorder |
| to measure pressure | mercury barometer, aneroid baremeter and a barograph |
| to measure rainfall | rain guage |
| to measure the direction of wind | wind vane |
| to measure the speed of wind | anemometer |
| wind strength is measured by the | Beaufort scale |
| a stephenon screen is used for | holding a maximum and minimum thermometer and a wet and dry bulb thermometer |
| hectopascals/millibars | measurment for pressure |
| isobar | lines joining places of equal pressure |
| isotherm | lines joining places of equal temperature |
| isohel | lines joining places of equal sunshine |
| isohyet | lines joining places of equal rainfall |
| Hurricane/Typhoon | rototing masses of cloud |
| cyclones | create warm and cold fronts over Ireland and Western Europe |
| a cold current | Labrador current |
| a warm current | north Atlantic drift |
| weather | condition of the atmosphere over a short period of time |
| climate | the condition of the atmosphere over a long period of time e.g 35 years |