Atmospheric Composition and Structure
What is in the Atmosphere?
• The other gases include...
Neon Krypton Methane Helium Xenon Hydrogen Ozone
• The atmosphere is mostly air, which is a mixture of gases.
• There is also water vapor and small particles in the atmosphere.
Layers of the Atmosphere
Troposphere
Thermosphere
Stratosphere
Exosphere
Mesosphere
Key Facts: Troposphere• Lowest level of the atmosphere
– Experiences the highest air pressure. – Contains most of the atmosphere’s mass. – Most dense layer – Heated by the Earth through conduction.
• According to the temperature profile, as altitude increases, temperature decreases. – Allows for the creation of
convection currents.
The Troposphere is characterized by weather!
Key Facts: The Stratosphere
• According to the temperature profile, as altitude increases, temperature increases. – There is a temperature
inversion, which means warm air is on top of cold air!
– Air CANNOT rise because it is colder than its surroundings, and cold air sinks!!
Ozone Layer!
Key Facts: The Mesosphere• The mesosphere is colder because
the gases CANNOT absorb the sun’s radiation. – Continues through to the surface
where it is absorbed. – Top of this layer is somewhere
between -90°C and -100°C.
• The thermosphere contains gases that absorb the sun’s radiation. – Blocks the x-rays and some UV-
radiation. – The temperature depends on the
sun’s activity.
Factors that Affect Climate• Climate greatly affects
the species that exist in an ecosystem. – Climate is the average
weather of an area over a long period of time.
Temperature Precipitation
• Two main climate factors that influence life in an ecosystem are: