Component 1 - Hazardous Earth Flashcards
What are the 3 cells?
1.Hadley
2.Ferrel
3.Polar
How does air move around the Earth due to cells?
1.The sun warms the Earth at the equator, which causes air to rise. This creates a low pressure belt. As the air rises, it cools and condenses and forms clouds and rain.
2.The cool, dry air moves out to 30° N and S of the equator
3.Here the cool air sinks, creating a high pressure belt, with cloudless skies and very low rainfall.
4.The cool air then moves as wind back to the equator, forming a Hadley cell, or towards the poles.
5.At 60° N and S of the equator, the warmer surface winds meet colder air from the poles. The warm air is less dense so is forced to rise, creating low pressure and frontal rain.
6.Some of the air moves back towards the equator, forming a Ferrel cell, some goes towards the poles.
7.At the poles, the cool air sinks creating high pressure. The high pressure air is drawn back to the equator as wind, forming a polar cell.
What is frontal rain?
rain that forms where the warm and cold air masses meet
What are trade winds?
surface winds which blow towards the equator
What are westerlies?
surface winds blowing towards the poles.
What is thermohaline circulation?
The cycle of cooling and sinking of water, which moves water around the earth in a big loop
How are surface currents made and what do they do?
- caused by winds
- They transfer heat away from the equator, eg the gulf stream
How do deep ocean currents work?
1.When water freezes at the poles, surrounding water gets saltier and denser
2.This makes it sinking, causing warmer water to flow in at the surface, creating a current
3.The warmer water cools, creating a cycle
How are arid climates made?
- Sinking air from the Hadley and Ferrel cells causes high pressure.
- This means rainfall is low, and termperatures are warm for most of the year.
How are polar climates made?
1.Sinking air from the polar cells creates an area of high pressure at the poles.
2.This means temperatures are low all year round and there’s very little rainfall.
How are tropical climates made?
1.Rising air from the 2 Hadley cells meeting causes low pressure.
2.This results in high rainfall and high temperatures all year round.
How has the Earth’s climate changed in the period before and during the Quarternary period?
- Before, it was warmer and quite stable.
- During, global temp has shifted between glacial periods, that last 100,000 yrs, and warmer interglacial periods, lasting 10,000 yrs
- The last glacial period ended 15,000 yrs ago, the Earth is currently warming
What are the 3 orbital changes which can change the climate?
1.Eccentricity - where the Earth’s orbit goes between circular and eliptical every 96k years
2.Tilt - where the Earth’s tilt changes angle over 41k yrs
3.Precession - where the axis of the Earth wobbles every 22k yrs
How do the 3 orbital changes affect the climate?
The cycles change the amount of solar radiation the Earth gets.
What are the 4 natural causes of climate change?
- Orbital changes
- Volcanic activity
- Solar output
- Asteroid collision
How does volcanic activity affect the Earth’s climate?
1.Major eruption eject large amounts of material like ash into the atmosphere
2.Some of these particles reflect the sun’s energy back into space, so the Earth cools
3.This causes a short term cooling in the climatge, eg - Mount Tambora in 1815, which led to the year without summer in 1816
How do asteroid collisions affect climate?
1.Asteroids hitting the Earth throw up huge amounts of dust into the atmosphere
2.These particles prevent the Sun’s energy from reaching the Earth, causing temperatures to fall for several years
How does solar output affect climate?
1.The sun’s output of energy changes in short cycles of 11yrs, and longer cycles of hundereds of years
2.Sunspot activity/solar flares result in more energy from the sun, raising temperatures/
What are 3 pieces of evidence for past climate change?
1.Tree rings
2.Ice cores
3.Historical records
How can we detect past climate change through tree rings?
1.The thickness of each ring depends on the climate that year
2.If it is warmer then the rings are thicker, else they’re thinner.
How can we detect past climate change through ice cores?
1.1 layer of ice is formed every yr in ice sheets
2.We drill in to the ice sheets to get long cores
3.By analysing the gases, eg CO2, trapped in the layers of ice, we can tell what the temperature was like that year.
How can historical records tell us about past climate change?
1.Since the 1850s global temp has been measured with thermometer
2.Historical diaries can show what the climate was like in the past, by giving the dates of harvests and days of rain/snow.
3.Paintings and news articles of fairs and markets on a frozen Thames show that winters in Europe were colder back then
What was the medieval warm period?
1.A period of relatively high temps between 900-1300AD
2.Harvest records show England was warm enough to grow large amounts of grapes
What was the Little Ice Age?
1.A period of cooling after the medieval warm period
2.Paintings from the 17th centure show the London Frost Fairs on the Thames.
3.Historical records show Arctic Ice reaching Scotland.