Atmosphere - layer of gases that surrounds a planet or moon held by gravity (ocean of air)
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Transcript of Atmosphere - layer of gases that surrounds a planet or moon held by gravity (ocean of air)
Atmosphere - layer of gases that surrounds a planet or moon held by gravity
(ocean of air)
Composition• Atmosphere is a
Mixture of– Gases– Dust– Water vapor• clouds and
precipitation (rain)• Absorbs heat and
energy from the sun
• changes by time and place
Ozone (O3) – very rare and less stable type of oxygen molecule that combines 3 atoms
of oxygen• Thin layer is found in
the Stratosphere– 3 ozone for every
10,000,000 air molecules
• Protects living things from harmful UV sun rays
• Manmade chemicals destroy ozone. Humans have thinned the layer above the Antarctic
Carbon Dioxide (CO2) - naturally occurring gas in our atmosphere
• Needed for photosynthesis to occur during the Carbon Cycle
• (photosynthesis) -plants take in (CO2),
solar energy, and water and produce carbohydrate energy (sugars) and Oxygen
Water Vapor - water in the atmosphere
• Key to understanding atmosphere processes• Water vapor is the source of all precipitation• Examples– Clouds– Fog– Rain– Snow– Sleet– hail
Changing state of matter• changing matter
requires energy is transferred in the form of heat
• Latent heat – heat used doesn’t cause temperature change
How water changes states of matter in the atmosphere
• All water passes through the atmosphere as water vapor
• Water changes from one state of matter to anothero Solid to liquido Liquid to gaso Solid to gas
Greenhouse Effect – The warming of Earths surface and lower atmosphere when carbon dioxide, water vapor and
other gases absorb and reradiate (heat) energy
The atmosphere is divided into 4 main layers by temperature
• Troposphere (bottom layer)• Stratosphere (where important weather
occur)• Mesosphere• Thermosphere (top layer)• It generally gets colder as altitude increases• Layers of the atmosphere are divided by
temperature and height
Layers of the atmosphere
Weather – the state of the atmosphere at any given time and
place• Climate – average weather conditions in an
area over a long period of time
Earth-Sun relationship• Almost all energy that causes Earth’s weather
and climate comes from the sun• Unequal heating of Earth causes weather
Heat transfer
• Heat transfers in 3 ways
1. Conduction – transfer of heat through molecular activity (high to low temp)
2. Convection – transfer of heat by mass movement or circulation within something
3. Radiation – transfer of heat in all directions
Solar radiation – when radiation strikes an object, 3 things happen
1. Energy is absorbed by the object
2. Energy is transmitted and doesn’t add to the object
3. Energy is reflected or bounced off the object
• Reflection – when light bounces off an object
Scattering – when a large number of weaker rays are produced traveling in different direction
Other factors that influence energy coming into the atmosphere
• Earth’s rotation – spinning
• Earth’s revolution – orbit around sun
• Earth’s orientation – how Earth is tilted on it’s axis in relation to the sun
Humidity – the amount of water vapor in the air• Relative humidity – the
amount of water in the atmosphere. % of how much the air can hold
• Saturation – when the atmosphere has reached it’s maximum amount of water vapor it can hold at a temperature and pressure
Dew point
• The temperature when water vapor in the air condenses (changes) into a liquid from a gas
Cloud Formation
• As air rises in the atmosphere it expands and cools
• When air reaches it’s dew point, clouds begin to form
Air compression• When air
pressure increases, air temperature rises
• Motion of the gas molecules increases
• When air pressure decreases, air expands and temperature cools•Motion of the gas molecules slows
Orographic Lifting• when air is
forced to rise and cool due to terrain features such as hills or mountains
Frontal Wedging
• When cold dense air acts as a barrier and causes warmer, less dense air to rise
Convergence• When air masses
flow together from more than 1 direction, air rises.
Low pressure is the result
Localized convective heating
• Unequal heating of Earth’s surface causes pockets of air to be warmed more than surrounding air
• Causes pockets of air to rise, forming thermals
Clouds – 3 basic types are classified on form and height
Cirrus
Cumulus
Stratus
High Clouds
a) cirrusb) cirrostratus c) cirrocumulus• Thin and white• Low precipitation• May warn of
approaching stormy weather
cirrocumulus
Middle Clouds - alto
a) Altocumulus – large and dense
b) Altostratus – white or gray sheet covering sky
c) Cumulonimbus - • Infrequent light
snow or drizzlealtocumulus
Low clouds
a) Stratus – fog like layer covering sky
- Occasionally produce light precipitation
b) Stratocumulus – rainy clouds
c) Nimbostratus – main precipitation maker
d) Cumulus - clouds with vertical development
Stratocumulus
Fog – cloud with base at or near the ground
• Form by 1.Cooling – air
over a cold surface
2.Evaporation – when cool air moves over warm water (steaming)
How precipitation forms
• Tiny cloud droplets grow in volume by about 1,000,000 times.
Cold cloud precipitation• Ice crystals
contact with cloud droplets causing them to freeze
• Causes ice to grow into snowflakes
• Rain often begins as snow high in the clouds
Warm cloud precipitation
• Large droplets moving through the clouds collide and join (coalesce) with smaller droplets
The type of precipitation that reaches Earth’s surface depends on
temperature in the lower atmosphere
• Rain• Snow• Sleet• Glaze• Hail
1. Earth’s atmosphere is made up of a combination of gases. The major components of nitrogen, oxygen, and argon remain constant over time and space, while trace components like CO2 and water vapor vary considerably over both space and time.
2. The atmosphere is divided into the thermosphere, mesosphere, stratosphere and troposphere
3. boundaries between these layers are defined by changes in temperature and height
4. Pressure decreases exponentially with altitude in the atmosphere.
5. Our knowledge about the atmosphere has developed based on data from a variety of sources, including direct measurements from balloons and aircraft as well as remote measurements from satellites.
Atmosphere key ideas