| A | B |
|---|
| troposphere | part of atmosphere where most weather happens |
| thermometer | measures temperature |
| isotherms | isolines on a weather map that shows temperature |
| insolation | incoming solar radiation - the sun's energy that reaches the earth |
| sun | the main source of heat energy |
| conduction | moves heat from earth into the atmosphere as air touches the earth's surface |
| aerosol | any liquid or solid particle in the atmosphere [droplets, smoke, etc.] that absorbs heat |
| direct absorption of insolation [sun's heat] by gasses & aerosols | moves heat into the atmosphere |
| global warming | the more aerosols, CO2 particles & pollution in the atmosphere, the more heat is trapped |
| greenhouse gasses | methane, carbon dioxide, water vapor all absorb more heat in the atmosphere |
| convection currents | cells that move air and heat in circular patterns in the earth's troposphere |
| cause of convection currents | differences in air pressure |
| planetary winds | parts of the convection currents that are parallel to the earth's surface |
| cooling of air | when air rises in the atmosphere, it expands, its temperature decreases |
| heating of air | when air descends, it is compressed and its temperature decreases |
| atmospheric pressure | the pressure due to the weight of the atmosphere above pushing down on an area |
| density | the denser the atmosphere, the greater its weight and the air pressure it exerts |
| barometer | measures air pressure |
| barometric trend | how the magnitude of the air pressure has changed over the past three hours |
| isobars | show air pressure on a weather map |
| effect of temperature on air pressure | as temperature increases, the air expands & its density and air pressure decrease |
| effect of water vapor on air pressure | Since a water molecule weighs less than an air molecule, the greater the amount of water vapor in the air, the lower the density and pressure |
| altitude's effect on air pressure | As altitude or elevation increase, atmospheric density and air pressure decrease |
| air pressure gradient | the difference in air pressure for a specific distance |
| air pressure gradient effect on wind speed | the closer together the isobars on a weather map, the steeper the gradient and the faster the wind speed |
| anemometer | measures wind speed |
| effect of air pressure on wind | air [wind] moves from high pressure areas to low pressure areas |
| wind name | a wind is named for the direction from which it comes |
| wind blowing towards the southeast from the northwest is named | northwest because it is coming from the northwest |
| Coriolis effect | Caused by the Earth's rotation - deflects winds to the right in the Northern Hemisphere & to the left in the Southern Hemisphere |
| waves | Waves are caused by the wind blowing over bodies of water |
| Circulation of air in the troposphere | Unequal insolation [solar heat] on Earth causes differences in air pressure. Cooler, less dense air sinks toward Earth under the influence of gravity, causing less dense. warmer air to rise. The result is a series of convection cells around Earth at various latitudes. |
| Jet Stream | bands of easterly moving air at the top of the troposphere; helps steer air masses & low pressure centers |
| Effect of jet streams on air travel | Saves 1/2 hour of flight from West Coast US to East Coast; but can delay flight time an hour if going from East Coast to West Coast. |
| prevailing wind belts | Belts around the earth from which winds move in generally the same direction, caused by the movement of these winds away from high pressure areas & deflected by the Coriolis effect. |
| Coriolis effect on prevailing winds | Winds moving away from high pressure zones are deflected to the right in the Northern Hemisphere & to the left in the Southern Hemisphere |
| Effect of the seasons on prevailing winds | Differences in insolation [solar heat] during winter & sumer can cause differences in air pressure which will change the directions of winds |
| monsoons | seasonal wind caused by the shifting of wind and pressure belts |
| prevailing winds in US | Most wind patterns that effect US weather blow from the southwest to the northeast & are called the southwesterly winds |
| Ocean currents | are part of the same circular pattern that winds take due to the Coriolis effect - they spin clockwise in the Northern Hemisphere & counterclockwise in the Southern Hemisphere |
| Effect of sun's radiation on ocean currents | Some surface currents seasonally shift as do the prevailing winds - following the motions of the sun's vertical rays |
| water vapor | water as a gas in the atmosphere |
| evaporation | process by which water changes to a gas |
| transpiration | process by which plants release water vapor |
| evapotranspiration | evaporation & transpiration - how most water vapor gets into the atmosphere |
| sublimation | process by which ice changes directly to water vapor without first becoming a liquid |
| effect of insolation on evaporation | The more heat energy from the sun, the more & faster the evaporation rate |
| dynamic equalibrium | The rate at which water becomes a vapor = the rate at which it turns back into a liquid |
| condensation | process by which water vapor becomes a liquid |
| evaporation rate is increased by | heat, the greater the surface area of the water, the lower the degree of vapor already in the air, and the faster the wind speed over the water surface |
| humidity | water vapor content of the atmosphere |
| absolute humidity | the mass or amount measured in grams in each unit volume of air |
| relative humidity | the ratio of the amount of water vapor in the air to the maximum amount it can hold - measured in % |
| saturation | 100% relative humidity - the total capacity of water vapor that the air CAN hold |
| effect of temperature on relative humdity | If the temperature of the air goes up, but the amount of water vapor [absolute humidity] remains the same, the relative humidity decreases |
| Dew point | the temperature at which air is filled with water vapor & will reach saturation |
| effect of temperature on Dew point | If the temperature of the air decreases & the amount of water vapor [absolute humidity] remains the same, the temperature will eventually equal the dew point temperature |
| When Air temperature = Dew Point Temperature | there is 100% relative humidity & precipitation will occur |
| precipitation | falling liquid or solid water from clouds |
| psychrometer | instrument to measure relative humidity; contains both a wet-bulb thermometer & a dry-bulb thermometer |
| forms of precipitation | rain, drizzle, snow, sleet, freezing rain, hail |
| cloud formation | If the temperature of the air cools to dew point temperature, water vapor will condense to a liquid or sublimate to a solid forming a cloud of either water droplets or ice crystals |
| cloud cover | the fraction of the sky covered by clouds |
| fog | a cloud on the Earth's surface |
| haze | low density of water droplets or ice crystals - not enough to form a cloud |
| Requirements needed for condensation forming a cloud | the air needs to be saturated & condensation surfaces must be available from particles in the air like aerosols, dust, volcanic ash |
| dew | condensation occurs on Earth's surfaces such as grass & leaves |
| level of clouds in atmosphere | level in the troposphere where the air temperature and dew point are the same |
| atmospheric transparency | how easily the sun's radiation can pass through the atmosphere to the earth's surface |
| effect of pollution on atmospheric transparency | The more pollutants, aerosols, etc. in the air, the less transparent, the more of the sun's energy is absorbed or reflected, resulting in less insolation reaching the Earth's surface |
| smog | a brownish haze caused by decreased transparency |
| effect of precipitation on atmospheric transparency | Falling rain or snow will collect aerosols on the way down, thus cleaning the atmosphere, lowering pollution & increasing transparency |
| visibility | how far you can see along the Earth's surface in miles |
| Cause of sea breezes | Land heats up faster than the water during the day-resulting in warm, less dense, low-pressure rising over land. The cooler, denser, high-pressure air from the sea flows in to replace the rising warn air over land |
| Cause of land breezes | Land cools down at night faster than water-resulting in colder, more dense air over land falling; moving in to replace the less dense, warmer air rising over the sea. |
