Weather Test Flashcards

Atmosphere Key Terms:

Atmosphere-The mixture of gasses that surrounds the Earth.

Troposphere- The lowest layer of the Earth’s atmosphere, where most weather occurs.

Stratosphere-The second-lowest layer of Earth’s atmosphere, the ozone layer is

located in the upper part of this layer.

Mesosphere-The middle layer of the Earth’s atmosphere; the coldest layer in which

most meteoroids burn up.

Thermosphere-The outermost layer of the atmosphere. The air is extremely thin and

very hot.

Ozone Layer-The layer of the atmosphere that contains a higher concentration of

ozone than the rest of the atmosphere. This layer that is found in the stratosphere

blocks out many harmful ultraviolet rays from the sun.

Other important weather terms to know:

Altitude- Elevation above sea level.

Weather- The condition of the Earth’s atmosphere at a particular time and place.

Air Pressure- A force that is the result of the weight of a column of air pushing down on

an area

Nitrogen -This gas makes up about three fourths of the air.

Radiation- The direct transfer of energy through open space by electromagnetic

waves.

Solar energy- This energy travels to Earth’s atmosphere from the sun in

electromagnetic waves. The forms of energy are ultraviolet radiation, visible light, and

infrared radiation.

Ultraviolet Radiation - UV is a type of electromagnetic radiation; energy from the sun

that can cause damage to living tissue.

Absorption- Thermal energy from the Sun that is retained by Earth’s land surfaces and

atmosphere.

Reflection-The bouncing back of light rays from a surface. The Earth’s surfaces and

atmosphere reflect some of the Sun’s energy away from the Earth.

Earth’s energy budget -Earth’s energy budget accounts for the balance between energy Earth

receives from the sun, and energy Earth radiates back into outer space.

Greenhouse effect- The greenhouse effect is the natural process of Earth’s atmosphere

trapping heat near Earth’s surface.

Weather: Weather refers to a short-term condition that varies from day to day.

Climate: Climate refers to a long-term pattern in a certain region.

Also know…

● Air is a mixture of gaseous elements (gases) and compounds.

● Air exerts pressure, and air pressure decreases with increasing altitude, and

increases with decreasing altitude through all atmosphere layers.

● Temperature decreases as altitude increases in the troposphere and

mesosphere.

● Temperature increases as altitude increases in the stratosphere and

thermosphere.

● Nitrogen makes up the largest proportion of air.

● Most air in the atmosphere is in the troposphere.

Air Density

Air becomes denser (heavier) as it cools because air molecules lose energy and move together. Air also becomes less dense (lighter) as it warms since air molecules gain energy and move farther apart.

Air Masses

A large area of air that has a similar temperature and humidity is called an air mass. Air masses that originate over the ocean are usually moist and ones that begin over land are dry.  Air masses that originate in the north are generally cold and ones that begin more to the south are usually warmer.

Weather Fronts

Cold and warm fronts move in the direction of their symbols and name the type of air moving in that direction.

Cold fronts are when dense, cold air moves into and wedges under warmer air.  The lighter, warmer air and the water vapor in it rises.  As this air rises into the atmosphere it cools and some of the water vapor in it condenses and forms clouds and often results in rain or snow.

Warm fronts form when lighter, warmer air moves over heavier, colder air. Warm fronts tend to move slowly and can bring rainy, cloudy or foggy weather for several days.

A cold front will bring colder air and a warm front will bring warmer air to an area. Clouds, rain, and snow often occur at fronts between two different air masses.

The experiment we observed concluded that sand (land) heats and cools faster than water.  Because of this, cities that are inland have greater temperature changes than cities located along the coast. The temperature of the ocean and nearby cities remain fairly constant and do not change very much.

Convection currents occur when warm, less dense air expands and rises, and cooler, denser air falls.  This process causes sea and land breezes, cloud formation, and global wind currents.

Air movement or wind is caused by differences in temperature and pressure.  When warm, less dense air rises, cooler more dense air will flow (as wind) underneath the rising warm air.  A sea breeze is formed when the air warms during the day and rises near the coast and cooler air from the sea rushes in (as a breeze) to replace the rising air.

●      Falling air pressure (Low Pressure) usually means that clouds may be forming and a storm or rain could be approaching, and rising air pressure (High Pressure) usually means the weather is clearing (fair weather).

●      Air pressure changes usually mean weather is changing.

●      Thunderstorms form over heated land. They can result in cumulonimbus clouds, rain and hail, and thunder and lightning.

●      Tornadoes develop in low, heavy cumulonimbus clouds---the same clouds that bring us thunderstorms. Many tornadoes form in Tornado Alley.

●      Hurricanes form over warm tropical waters often just north of the equator.  Hurricanes’ strength usually decreases when they move over a continent since they lose the energy the warm water provides.  Hurricanes rarely form over cold water in the high latitudes.