topic 1 Flashcards
What are the three types of circulation cells in the atmosphere?
- Polar cell (poles)
- Ferrel cell
- Hadley cell (equator)
Outline the process that causes circulation cells to distribute warm air:
1) Warm moist air rises at the equator, creating a low pressure belt
2) Cool air condenses and moves out 30° North and South before sinking, creating a high pressure belt
3) The cool air either moves back to the equator or towards the poles
4) At 60° warm and cold winds meet, causing the warm air to rise and the cold air at the poles (high pressure) to return to the equator as surface winds.
What are ocean currents and what to they do? Give 1 named example:
Convection currents which drag cold surface water down and draw warmer salty water from the equator over it in a cycle.
They transfer heat energy around the ocean.
Warm current: North Atlantic Drift or Gulf Stream
What is the Coriolis Effect?
A phenomenon that causes fluids (water and air) to curve as they travel across the Earth’s surface.
Why does the equator spin faster than the poles?
The Earth spins on an axis and is a sphere. The equator is where it is the widest so it has to travel further in a the same amount of time.
Which direction do hurricanes spin in?
Northern Hemisphere= Anti-clockwise
Southern Hemisphere= Clockwise
Which direction does the Earth spin in?
West to East
Why do hurricanes spin?
Areas of high pressure rush towards areas of low pressure (the eye) but are constantly deflected because the Coriolis effect pushes them slightly off path.
Where are jet streams found on Earth?
Troposphere
What types of jet streams are there?
Polar streams (7-12 km) Subtropical streams (10-16 km)
What causes the ITCZ (intertropical convergence zone)?
It forms within the tropics when two masses of low pressure air (trade winds) converge and rise before cooling (high pressure) and sinking in the upper troposphere. This repeats as the land in the Sahara and the Gulf of Guinea is very warm, heating the cool air.
What are orbital changes and how do they effect the climate?
The milankovitch cycles are the different ways which the Earth moves around the Sun.
- Eccentricity= the changing path of the Earth’s orbit; either circular (interglacial) or elliptical (glacial)
- Axial Tilt= the angle which the Earth’s axis is tilted at
- Precession= the wobbling of the axis of the Earth
These affect the amount of radiation reaching the Earth
What is volcanism and how does it affect the climate?
Large scale volcanic eruption eject huge volumes of ash and dust, partially blocking/ reflecting the suns rays and causing cooler periods
What is solar variation and how does it affect the climate?
A changing amount of radiation that the sun produces over time.
- Glacial= lower solar activity
- Interglacial= higher solar activity
What are surface impacts and how do they affect the climate?
Asteroid collisions impacting the Earths surface, ejecting large amounts of ash and dust and rapidly cooling the Earths surface by blocking out sunlight.
E.g. the comet that wiped out the dinosaurs
What evidence is there for natural climate change?
Ice cores- water isotopes and CO2 levels
Tree rings- the warmer the temperature, the thicker the ring
Historical sources- diaries, religious records and other historical documents can check the accuracy of other records
Name 3 greenhouse gases:
- Carbon dioxide
- Methane
- Nitrous oxides
Outline the natural greenhouse effect:
1) Short wave radiation comes from the sun
2) Some long wave radiation is lost to space
3) Other long wave radiation is absorbed by greenhouse gases so is trapped in the atmosphere
(This is the greenhouse effect)
