Topic 1 - Hazardous Earth Flashcards
What causes difference in air pressure
The sun heats up the earth’s surface unevenly (the equator is heated up than the poles)
The difference in temperature causes air pressure
Name the three cells and their location
Hadley cells: either side of the equator (0-30 degrees)
Ferrel cells: in between both (30-60 degrees)
Polar cells: at the end touching the poles (60-90 degrees)
Describe the air pressure on the earth from the equator up
The sun warms the Earth which transfers heat to the air, causing it to rise, so is a low pressure zone.
The cool, dry air moves up 30 degrees
At 30 degrees, the cool air sinks, causing a high pressure zone. This cool air either heads to the equator (trade winds) or to the poles (westerlies)
At 60 degrees, the cool air meets cold air from the poles, and is forced to rise, causing a low pressure zone and frontal rains
This air heads towards the poles, where it falls, causing high pressure
What causes a low pressure zone
Useful image on showbie
When air is heated it rises as it is less dense. As the air rises heat is transferred from the air to the atmosphere. The air then cools, condenses and usually creates clouds and rain.
As the air is heading up, there is low pressure on the surface. It is therefore a low pressure point
What causes a high pressure zone
Useful image on showbie
When air cools it becomes more dense. This causes it to fall, which causes it to transfer heat to the ground. It heats up as it falls, causing clear skies and little/no rain
Because there is more pressure on the surface, this is a high pressure zone
Why is there different temperatures across the globe
Three points
The earth is at an angle, so some areas such as the poles get less daylight as others
The equator is closer to the sun, so less heat is transferred to the atmosphere. The suns rays also hit the surface at less of an angle, so the suns ray is distributed in a smaller area
What are trade winds and westerlies
Trade winds: surface winds blowing towards the equator
Westerlies: surface winds blowing to the poles
How is heat transferred by ocean currents
Surface currents are directed by winds. Warmer water can bring heat from warmer areas such as the equator to the poles and other colder areas, warming the up
When water freezes at the poles, the surrounding water gets saltier, increasing its density, causing it to sink
As this water sinks, warmer water flows in to take its place
This warmer water does the same, continuing the cycle
Compare Tindouf (Algeria) and Singapore
Tindouf:
Desert
5-10mm of precipitation
14 - 36 degrees all year round
Singapore:
Rainforest
150+ precipitation
25 - 28 degrees all year
Why is Tindouf’s and Singapore’s temperatures so different?
Tindouf is in a very high pressure zone
Therefore no clouds and little rain all year round
With no rain clouds, the suns radiation is very intense
The high pressure causes winds to head outwards. This blocks all moist, cooler areas coming in from areas
Give 3 orbital changes which are natural causes for climate change
An Eccentricity:
An Eccentricity is what happens every 99-100,000 years where the earths orbit changes to a much longer course, causing a ice age. It becomes an oval shape
Tilt of the earth:
The earths axis is not perfect, but tilts at a 22.1 - 24.5 angle. Although the average is 23, minor changes can have huge effects. A 22,000 year cycle
Precession (wobble):
As the earth rotates for night and day, it wobbles slightly. This changes the direction of the axis, changing seasons. A 24,000 year cycle
Give 3 non-orbital natural causes of climate change
Asteroid collisions:
When large cosmic materials, such as asteroids and comets. collide with the earth, lots of dust is kicked up, blocking the suns rays, changing the climate. For example, the asteroid that hit 65 million years ago did not wipe out the dinosaurs, but the dust and change of climate probably did
Volcanic activity:
Big volcanic eruptions produces ash and sulphur dioxide. If these rise enough, they can block sunlight
Solar output variation:
The suns output is not constant, black areas on the sun called sunspots differentiate, shifting the suns output
What is an ITCZ
Inter-Tropical-Convergence-Zone
A permanent zone of low pressure
Evidence for climate change
Tree rings:
Trees grow a ring every year. The shape and size of the tree ring shows conditions e.g warmer and wetter weather shows bigger tree rings
Ice cores:
Ice contains bubbles of air from every year. These can be analysed to see how much co2 was in the air, showing different temperatures
Historical sources:
Paintings, written records, diaries and harvest records show different temperatures e.g the Thames froze over in the 1700’s, we know through paintings
Human causes of climate change:
Farming:
Cattle farming
Deforestation for more space to grow crops
Transport:
Cars and flights are more affordable and common every day
More traffic every day
Energy:
Growing population : growing demand for energy
30% increase of CO2 since 1850
Industry:
Al levels of disposable income rises,increase of demands for consumer goods rise
Industrial growth
Industrial waste ends up in landfill
