atmosphere basics webquest
ATMOSPHERE NOTES
ATMOSPHERE BASICS
- combination of gases, dust, water droplets, and ice crystals
- Surrounds the earth
- extends from the earths surface to outer space
- Earth’s atmosphere consists mainly of nitrogen (78 percent) and oxygen (21 percent).
- The amounts of nitrogen and oxygen in the atmosphere are fairly constant over recent time.
VARIABLE ATMOSPHERIC GASES
Contains variable amounts of solids in the fABOVE THE STorm of tiny particles, such as dust, salt, and ice
- The concentrations of some atmospheric gases are not as constant over time.
- The amount of water vapor, ozone, and carbon dioxide vary significantly from place to place.
- During the past 150 years, the concentration of atmospheric carbon dioxide has increased, due primarily to the burning of fossil fuels.
- Currently 0.039% (up by 0.028%)
- Mostly in ozone layer (20 – 50 km above)
- Only 0.0012% but plays important role in blocking out harmful rays from the sun
- Concentration has decreased due to CFCs which are now banned
- Scientists estimate it should fully recover by the 2100
Contains variable amounts of solids in the fABOVE THE STorm of tiny particles, such as dust, salt, and ice
- Contains variable amounts of solids in the form of tiny particles, such as dust, salt, and ice
- Closest to the earths surface
- contains most of the atmosphere's mass
- weather occurs in this layer
- air temperature decreases with altitude
- Top is called tropopause
- above tropopause
- contains the ozone layer
- Air temperature increases with altitude since the ozone layer absorbs the sun’s energy
- ends at the stratopause
- above the stratopause
- Air temperature decreases with altitude since very little solar radiation is absorbed
- ends at mesopause
- meteors burn up and shooting stars are located
- low density so temperature rises (can be over 1000 C)
- Contains the ionosphere (made up of charged particles)
- ends at thermopause
- outermost layer
- transitional region between the Earths atmosphere and outer space
- Remember – all matter is made of particles in constant, random motion!
- These moving particles contain kinetic energy.
- The total kinetic energy of the moving particles is called thermal energy.
- Heat is the transfer of thermal energy from regions of higher temperature to regions of lower temperature
- In the atmosphere thermal energy is transferred by:
–Radiation
–Conduction
–Convection
- Transfer of thermal energy by electromagnetic waves
- Thermal energy is transferred from the Sun to Earth by radiation
- Incoming solar radiation is either reflected back into space or absorbed by Earth’s atmosphere or its surface.
- 30% reflected
- 20% absorbed by atmosphere and clouds
- 50% absorbed by Earth’s surface
- Depends on physical characteristics of the surface and the amount of solar radiation
- Examples – water heats and cools more slowly; dark colors absorb energy faster
- Transfer of thermal energy when objects at two different temperatures are in contact
- Occurs between the Earth’s surface and lowest part of the atmosphere
- Remember – convection is the transfer of thermal energy by the movement of heated material from one place to another
- Near the Earth’s surface air becomes heated, expands, and rises then as it rises it cools, contracts, and sinks.
- This creates convection currents in the atmosphere.
STATE OF THE ATMOSPHERE
- Describe the various properties of the atmosphere and how they interact
- Explain why atmospheric properties change with changes in altitude
- Temperature is different from heat
- temperatures measure the average speed of the particles of substance
- heat describes a transfer of energy
- temperature scales
- Fahrenheit
- Celsius
- Kelvin
- Dew Point (condensation temp.)
- this varies depending on water content of the air
- when temperature reaches dew point, condensation can occur
- vertical temperature changes
- air cools as elevation increases
- dry air cools at about 10 degrees C / 1000 m
- if you travel high enough, the air cools to the dew point. This is called the lifted condensation level (LCL)
- moist air cools at about 6 degrees C/ 1000 m
- The air near the earths surface is denser than air further up
- the high you go, the lower the pressure because
- Temperature-Pressure relationship
- as the temperature goes up, the pressure goes up
- this relationship is called a direct relationship
- Temperature- density relationship
- as the temperature goes up, the density goes down
- This relationship is called an inverse relationship
- temperature inversions
- the temperature of the air increases the high the elevation
- These layers act like a lid, holding in gases below
A.Results from differences in temperature.
B.Warm air has a lower density and rises causing low pressure
C.Cooler air has a higher density and falls, causing high pressure
RELATIVE HUMIDITY
- relative humidity depends on
- how much moisture is in the air
- how much moisture could be in the air
- note--- warm air holds more moisture
- If the humidity is 100% this mean the atmosphere is fully saturated
- Explain how clouds are formed
- Identify the basic characteristics of different cloud groups
- Describe the water cycle
- steps to making clouds
- warm, moist air rises
- this air expands and cools
- the air reaches it dew point
- water droplets condense around condensation nuclei
- surface on which water droplets can form. Smoke or dust particles can act as condensation nuclei
- causes for warm air to rise
- orographic lifting: Cloud formation as a result of wind moving air into a mountain. This moves the air upward.
- warm air encounters cold air
- atmospheric stability
- A stable atmosphere has no clouds, or thin, layers of clouds.
- An unstable atmosphere will have vertical development. Thunderstorms indicate an unstable atmosphere.
- Latent Heat
- energy required to evaporate water is stored in the water vapor
- when the water vapor condenses this heat is released
- types of clouds
- cirrus: Form high in atmosphere, made of ice crystals, appear as thin, white, feathery clouds
- Cumulus: Flat-based, puffy white clouds with cauliflower appearance on top. Extends vertically several thousand ft.
- Stratus: Layered cloud that covers most of the sky. Forms at low altitudes. Often gray.
- Cirrostratus: High, thin clouds that give sky a milky white appearance.
- Cirrocumulus: Delicate clouds forming in bands a ripples. These rare clouds form when cirrus clouds degenerate.
- Altostratus: Clouds of intermediate height, having blue-gray appearance. Composed of ice crystals and water.
- Altocumulus: Have oval shapes, colored white with gray undersides. May produce mild precipitation.
- Nimbostratus: Often associated with steady precipitation. Can occur in thick, continuous layers.
- Stratocumulus: Often associated with steady precipitation. Can occur in thick, continuous layers.
- Cumulonimbus: Puffy, white cloud. Towering clouds that extend upward to heights of 2-5 miles. Cause thunderstorms