Atmosphere - Composition + Energy Processes (p1) Flashcards
(27 cards)
What is the natural composition of the atmosphere?
Fairly constant with variations due to regular cycles and human activities
What causes changes in the composition of the atmosphere?
Direct emissions from human activities, changes in natural processes that release or absorb gases
Define dynamic equilibrium in the context of the atmosphere.
A combination of active processes that cancel each other’s effects so that there is no overall change.
What are the key processes that might change atmospheric gases?
- Changes in the sun’s activities
- Geological processes
- Human actions
What are the two important processes affecting gas concentrations in the atmosphere?
Photosynthesis and aerobic respiration
How do photosynthesis and respiration affect gas concentrations?
They roughly balance each other, but their rates vary over different timescales.
List ways how the atmosphere supports life on Earth.
- Provides gases for natural and human processes
- Absorbs electromagnetic radiation from the sun
- Delays the escape of infrared energy
- Distributes heat and water vapor
- Creates ocean currents
- Affects liquid water availability
What gases are primarily found in the atmosphere?
- Nitrogen (N2)
- Oxygen (O2)
- Carbon Dioxide (CO2)
- Water vapor (H2O)
What is the role of the ozone layer?
Absorbs UV radiation from the Sun.
How does the atmosphere delay the escape of infrared energy?
Atmospheric gases absorb infrared energy, convert it to heat, and increase atmospheric temperature.
What drives the distribution of heat in the atmosphere?
Warm winds transport heat from tropical regions to higher latitudes.
What is the structure of the atmosphere based on altitude?
- Troposphere
- Stratosphere
- Mesosphere
- Ionosphere (upper mesosphere and thermosphere)
What characterizes the troposphere?
Heated by re-radiation from the ground; contains our weather.
What is the significance of the stratosphere?
Contains the ozone layer which absorbs UV radiation, causing temperature to increase with altitude.
What happens in the mesosphere?
No gases or particles to absorb solar radiation.
What is the role of the ionosphere?
Contains ions that reflect radio signals, enabling transmission.
How is the troposphere heated?
By infrared energy radiated from the Earth’s surface.
What is insolation?
The amount and duration of incoming solar radiation.
What is the greenhouse effect?
Trapping of heat by gases in the atmosphere.
What are the types of ultraviolet radiation?
- UVA (320-400nm)
- UVB (280-320nm)
- UVC (100-280nm)
What can prolonged exposure to UVB cause?
- Sunburn
- Skin cancer
- DNA mutations
- Cataracts
What is albedo?
The ratio of solar radiation reflected by a surface to the total solar radiation reaching that surface.
What are the characteristics of high and low albedo surfaces?
- High albedo: Very light colored and shiny surfaces (e.g. 90%)
- Low albedo: Very dark surfaces (e.g. 10%)
What is the primary composition of the Sun?
- 70% Hydrogen (H)
- 30% Helium (He)
