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meteorology3
| Question | Answer |
|---|---|
| How long does it take the earth to revolve around the sun? | 365 days |
| How long does it take the earth to complete one spin on its axis? | 24 hours |
| WHat is the average distance from the sun to the earth? | 150 million km |
| Why does the actual distance from the sun to the earth vary? | because the earth's orbit is an ellipse |
| What two factors determine the amount of solar energy received at the earth's surface? | angle at which sunlight strikes the surface, and how long the sun shines on any latitude |
| In what way does sunlight have to strike the earth to be most intense? | perpendicularly |
| In what way must sunlight hit the earth in order to penetrate more atmosphere and be more scattered and absorbed? | slanted from the perpendicular |
| What is the earth's angle of tilt? | 23.5 degrees |
| On the summer solstice, where and when is the sun in its highest position? | in the noonday sky directly above the Tropic of Cancer |
| How would day and night be different if the earth's axis were not tilted? | the noonday sun would always be directly overhead at the equator, and there would be 12 hours of daylight and 12 hours of darkness everywhere every day |
| The farther north we go, the _____the daylight hours. | longer |
| How long does the sun stay out in the North Pole? | from March 20 to September 22 |
| insolation | incoming solar radiation |
| Why are the amount of insolation at the top of the earth's atmosphere and the amount of radiation that eventually reaches the earth's surface on the same day different? | once sunlight enters the atmosphere, fine dust and air molecules scatter it, clouds reflect it, and some of it is absorbed by atmospheric gases. |
| The greater the ____ of atmosphere that sunlight must penetrate, the greater the chances that it will be scattered, reflected, or absorbed. | thickness |
| Why are northern cities that experience 24 continuous hours of sunlight on the summer solstice colder than cities farther south? | They receive less radiation at the surface, and what they do receive does not effectively heat the surface. |
| When is the summer solstice? | June 21 |
| Why does more radiation fall on 30 N latitude than the Tropic of Cancer? | at the Tropic of Cancer, the climate is more moist and cloudy, causing more sunlight to be scattered and reflected. Day length is longer at 30 N than at the Tropic of Cancer on June 21. |
| When is the autumnal equinox? | September 22 |
| What happens at the North Pole on the autumnal equinox? | the sun appears on the horizon for 24 hours and then disappears for 6 months |
| What happens in the northern hemisphere after the fall equinox? | There are fewer hours of daylight every day, and the noon sun is lower in the sky. |
| Indian Summer | an unseasonably warm spell in the eastern two thirds of the US around mid autumn |
| Why do Indian summers occur? | A large high pressure area stalls near the southeast coast, and the clockwise flow of air around this system moves warm air from the Gulf of Mexico into the central or eastern US |
| When is the winter solstice? | December 21 |
| How many hours of daylight do latitudes above 66.5 N receive in winter? | 0 |
| Where does the sun shine directly above on the winter solstice? | Tropic of Capricorn |
| cold wave | a rapid drop in temperature in winter |
| Why do cold waves happen? | cold arctic air periodically pushes down into the northern US |
| When is the vernal equinox? | March 20 |
| What path does the sun take in December in the middle latitudes? | rises in the southeast, reaches its highest point at noon, and sets in the southwest |
| What path does the sun take in June in the middle latitudes? | rises in the northeast, reaches a much higher position in the sky at noon, and sets in the northwest |
| lag in seasonal temperature | the situation in which the warmest weather in middle latitudes occurs in July or August although sunlight is most intense on June 21 |
| When incoming solar energy and outgoing earth energy are in balance, the ___ average temperature is attained. | highest |
| When outgoing energy exceeds incoming energy, the average temperature ___. | drops |
| How much greater is the energy that strikes the top of the earth's atmosphere on January 3 than July 4? | 7 percent |
| ___ percent of the surface is water in the northern hemisphere, and ___ percent is water in the southern hemisphere. | 61, 81 |
| Why do spring in summer in the northern hemisphere last about a week longer than spring and summer in the southern hemisphere? | because the earth's path is elliptical |
| In which direction must objects face in the Northern Hemisphere to receive more sunlight in a year? | south |
| Why are south facing hillsides usually warmer and drier than north facing hillsides? | higher temperatures mean greater rates of evaporation and drier soil |
| Where should trees be planted in relation to a house? | the south side |
| Why does the heating process in the air only take place within a few centimeters above the ground? | air is a poor heat conductor |
| What happens to the air in contact with the ground when the sun rises higher in the sky ? | The air in contact with the ground becomes even warmer, and a thermal boundary separating the hot surface air from the cooler air above exists. |
| What happens to the hot air molecules that cross the boundary? | bring greater kinetic energy to the cooler air |
| What happens to the cool air molecules that cross the boundary? | they bring a deficit of energy to the hot surface air |
| forced convection | the process by which turbulent eddies are able to mix hot surface air with the cooler air above. |
| Why is there a temperature lag between the time of maximum solar heating and the time of maximum air temperature several meters above the surface? | Even though incoming solar radiation decreases after noon, it still exceeds outgoing heat energy from the surface for a time. |
| When does the maximum temperature occur? | between 3 and 5 |
| Why, when soil is a poor heat conductor, does the surface get warmer? | heat energy does not readily transfer into the ground, allowing the surface area to reach a higher temperature |
| What happens to the air above if the soil is moist and covered with vegetation? | Much of the available energy evaporated water, leaving less heat to the air. |
| Why are nights cooler than days? | As the afternoon sun lowers, its energy is spread over a larger area, which reduces the heat available to warm the ground. |
| radiational cooling | the process by which the ground and air above cool by radiating infrared energy at night |
| Why is the coldest air found next to the ground by late night or early morning? | The ground and air in contact with it continue to cool more rapidly than the air a few meters higher, and the warmer upper air transfers some heat downward. |
| radiation inversion | the measured increase in air temperature just above the ground at night |
| Why is it called a radiation inversion? | Because it forms mainly through radiational cooling of the surface |
| What is another name for a radiation inversion? | nocturnal inversion |
| What are the ideal conditions for a strong inversion? | calm air, long night, dry and cloud free air |
| Why is a windless night essential for a strong inversion? | a stiff breeze tends to mix the colder air at the surface with the warmer air above |
| What happens when the breeze mixes the cold and warm air? | It causes a vertical temperature profile that is almost isothermal in a layer several meters thick. |
| isothermal | same temperature |
| How does a long night contribute to a strong inversion? | The longer the night, the longer the time of radiational cooling and the better the chances that the air near the ground will be much colder than the air above. |
| What kind of nights provide the best conditions for a strong inversion? | winter nights |
| Why are a clear sky and dry air essential for a strong inversion? | Under these conditions, the ground is able to radiate its energy to outer space and thereby cool rapidly. |
| WHat happens on a cloudy and moist night? | Much of the outgoing infrared energy is absorbed and radiated to the surface, retarding the rate of surface cooling. Condensation in the form of fog or dew will release latent heat, warming the air. |
| What happens to the temperature at night if the surface is wet or covered with vegetation? | it adds water vapor to the air, retarding nighttime cooling. |
| What happens to the temperature at night if the soil is a good heat conductor? | Heat ascending toward the surface during the night adds warmth to the air, which restricts cooling. |
| What happens to the temperature at night if there is snow on the ground? | Snow prevents heat stored in the soil from reaching the air. It radiates energy away rapidly at night, helping to keep the temperature low. |
| Why can the cooling of the ground and surface air continue beyond sunrise for a half hour or so? | Light from the early morning sun passes through a thick section of atmosphere and strikes the ground at a low angle. |
| thermal belts | warmer hillsides around cold valley bottoms |
| What happens to cold surface air at night? | It drains downhill and settles in low lying basins and valleys. |
| Why are valley bottoms more polluted than hillsides? | Smoke and other pollutants get trapped in the cold dense air and are unable to rise. |
| How do you protect small plants or shrubs from low temperatures at night? | cover them with straw, cloth, or plastic sheeting. |
| freeze | a cold period that occurs over a widespread area for a long period of time and damages crops |
| orchard heater | a device that warms the air around fruit trees by setting up convection currents close to the ground. |
| How can fruit trees by protected from a freeze? | increase air temperature close to the ground, or mix the cold air at the ground with the warmer air above, irrigation |
| wind machine | power driven fan that resembles airplane propellers |
| Why does irrigation protect trees? | Water has a high heat capacity, so it cools more slowly than dry soil. Also wet soil has a higher thermal conductivity than dry soil. |
| How can crops be protected if the air temperature at both the surface and above fall below freezing? | turn on an orchard's sprinkling system |
| diurnal range of temperature | the difference between the daily maximum and minimum temperature |
| Where is the diurnal range of temperature greatest? | next to the ground |
| What kind of day is the diurnal range of temperature greatest on? | clear days |
| Where does the largest diurnal range of temperature occur? | high deserts where the air is fairly dry, cloud free, and there is little water vapor |
| Why do deserts have such a large diurnal range of temperature? | In daytime clear summer skies allow the sun's energy to quickly warm the ground, which warms the air above. At night, the ground cools rapidly by radiating infrared energy to space, and the minimum temperature occasionally dips blow 7 C. |
| How do clouds lower the diurnal range of temperature? | They prevent much of the sun's energy from reaching the surface, lowering daytime temperature. They keep nighttime temperatures higher because they emit infrared radiation. |
| How does humidity affect the diurnal range of temperature? | haze and clouds lower the maximum temperature by preventing the sun's energy from reaching the surface. At night, moist air absorbs the earth's infrared radiation and radiates a small portion to the ground. |
| Why do cities near large bodies of water have smaller diurnal temperature ranges than cities farther inland? | Water warms and cools much more slowly than land. |
| Why do cities whose temperature readings are taken near airports have larger diurnal temperature ranges than those whose readings are obtained in downtown areas? | nighttime temperatures in cities tend to be warmer than those in outlying rural areas because the sun's energy is absorbed by urban structures such as concrete and slowly released into the city air. |
| urban heat island | nighttime city warmth |
| mean daily temperature | average of the highest and lowest temperature for a 24 hour period. |
| controls of temperature | main factors that cause variations in temperature from one place to another |
| What are the main controls of temperature? | latitude, land and water distribution, ocean currents, and elevation |
| isotherms | lines connecting places that have the same temperature |
| Why are cities at very high elevations much colder than sea level cities? | air temperature normally decreases with height |
| Locations in the same latitude receive ___ amount of solar energy. | the same |
| the annual solar heat that each latitude receives ____ from low to high latitudes. | decreases |
| What does a tighter gradient represent? | a rapid change in temperature over a given distance |
| January temperatures in the Northern hemisphere are much ___ in the middle of continents than they are near the oceans, and in July the ___ is true. | lower, reverse |
| What are some reasons that temperatures in the middle of continents are different from temperatures near the oceans? | unequal heating and cooling properties of land and water, it takes a great deal more heat to raise the temperature of water by one degree than to raise temperature of land by one degree. |
| Why do isotherms bend when they approach an ocean-continent boundary? | because of unequal heating and cooling properties of land and water, and ocean currents. |
| annual range of temperature | the difference in average temperature between the warmest month and coldest month |
| Where are annual ranges of temperature higher? | over interior continental landmasses, inland cities, in middle and high latitudes |
| mean annual temperature | the average temperature of any station for the entire year |
| heating degree day | a form of the degree day used as an index for fuel consumption, determined by subtracting the mean temperature for the day from 65 F. |
| cooling degree day | the opposite of the heating degree day, found by subtracting 65 F from the mean temperature for the day |
| growing degree day | for a particular crop, a day on which the mean daily temperature is one degree above the minimum temperature required for growth of that crop. |
| How does the body lose and gain heat? | by emitting and absorbing infrared energy, conduction and convection |
| sensible temperature | the temperature we perceive |
| wind chill index | how cold the wind makes us feel |
| liquid in glass thermometer | a thermometer with a sealed glass tube attached to a glass bulb filled with liquid |
| maximum thermometer | a liquid in glass thermometer with a small constriction within the bore just above the bulb |
| How does a liquid in glass thermometer work? | a liquid in the bulb is free to move from the bulb up into the tube. When air temperature increases, the liquid expands, and when air temperature decreases, the liquid contracts. |
| How does a maximum thermometer work? | The constriction keeps the mercury from moving back into the bulb, keeping the thermometer at the maximum temperature. |
| minimum thermometer | thermometer that measures the lowest temperature reaches during a given period. |
| electrical thermometers | thermometers that take highly accurate temperature measurements and use electricity |
| Why are liquid in glass thermometers being replaced with electric thermometers by scientists? | the response of electrical thermometers is faster |
| What are three types of electric thermometers? | electrical resistance thermometer, thermistors, and thermocouples |
| radiometer | a device that measures air temperature by measuring emitted radiation |
| bimetallic thermometer | a thermometer that consists of two dissimilar metals that expand and contract as the temperature changes |
| thermograph | an instrument that measures and records temperature |
| Why are thermographs being replaced with data loggers? | Data loggers are more responsive to air temperature and less expensive. |
| instrument shelter | a shelter that encloses a thermometer to protect it from rain snow, and the sun's direct rays. |
Created by:
22oblina