Solar Radiation and the Atmosphere Flashcards
What is the Sun made of?
Dense hydrogen gas
What are the reactants and products of nuclear fusion?
hydrogen + hydrogen —> helium + energy
How much of the solar system’s matter is present in the Sun?
99.8%
What two things enable nuclear fusion to occur in the Sun?
heat and pressure
Protons, neutrons and electrons in most common isotope of hydrogen
protons = 1
neutrons = 0
electrons = 1
What are the two other isotopes of hydrogen called?
deuterium
tritium
Define insolation
the amount of solar radiation reaching a given area
Define albedo
a measure of how reflective a surface is
What is energy?
the ability to do work
Where does most of the energy on Earth come from?
the Sun
The majority of Solar radiation is in what wavelength?
infra-red
Where on Earth do the Sun’s rays hit most directly?
the equator
Where on Earth do the Sun’s rays hit least directly?
the poles
Wavelength of UV
100-350 nm
shorter
Environmental Importance of UV
important for the production of vitamin D
inhibits photosynthesis in plants and algae (phytoplankton = 1/2 O2 in atmosphere)
dissolves dead organic matter - useful for cleaning water
kills bacteria
Wavelength of Visible Light
380-700 nm
Environmental importance of Visible Light
photosynthesis in plants
regulates animal behaviour
degrades organic pollutants
enables us to see
Wavelength of Infra-red
700-1000 nm
longer
Environmental importance of Infra-red
keeps a stable temperature and climate
causes climate change
affects range of tolerance
What is conduction?
when heat moves from areas of more heat to areas of less heat by DIRECT CONTACT
What is convection?
where heat is transferred by movement of heated materials
cooling and rising effect
What is a convection cell?
rising of warm air and sinking of cool air
How much of the Sun’s energy is filtered out by the atmosphere?
50%
What happens to most of the energy that reaches the surface?
absorbed
warms soil/water/rock
What happens to the rest of the energy that reaches the surface?
re-radiated back into the air as heat (3%)
What is the Earth’s energy budget?
the difference between the energy entering and exiting the atmosphere
usually in balance
What happens when the Earth absorbs more energy than it emits?
warms up
What happens when the Earth emits more energy than it absorbs?
cools down
What is the greenhouse effect?
the warming of the atmosphere due to insulation by greenhouse gases
How is the greenhouse effect helpful for life on Earth?
maintains a stable temperature - within our range of tolerance
important for photosynthesis
What human activities are enhancing the greenhouse effect?
burning fossil fuels and deforestation - release CO2
grazing livestock, rice fields, landfill sites (anaerobic breakdown of organic material) - release methane
fertilisers and vehicles - release nitrous oxides
How do human activities enhance the greenhouse effect?
increase levels of C02 (by 50% since 1750), methane and nitrous oxides cause global warming
