Topic 1 - Cylcones + Case Study + Climate Changes (set A)✔️ Flashcards
Where is most radiation received and why?
Earth is largely spherical so more radiation received at the equator - hottest part of earth
Why is the equator the hottest part of earth?
Because the earth is spherical - most radiation is received at the equator - suns rays are concentrated over a small area - strikes at a right angle - also at the poles radiation as to pass through more atmosphere resulting in most energy being absorbed
What is low pressure? What causes it?
Low pressure is a result of less air at the surface and caused when air is heated and it rises (because it is less dense) - when rising it transfers energy to the atmosphere - cools, condenses and form clouds - causing rain
What is high pressure? What causes it?
High pressure is when there is more air at the surface - caused when air cools and becomes more dense - it falls transferring heat to the ground -leaves clear sky’s and little/no rainfall
What is atmospheric pressure?
Is the weight of the air and the force it exerts on the ground
What causes winds?
Winds caused when air moves from high to low pressure across the earths surface transferring heat away from the equator
What is the Coriolis effect?
The deflection of winds from the right in the northern hemisphere and left in the southern hemisphere - caused due to the earths rotation
What are the three cells in each hemisphere?
-Hadley
-Ferrell
-Polar
Explain global atmosphere circulation cells ?
1) equator warmed by sun - causes air to rise - creating a low pressure belt (high rainfall)
2) cool dry air moves out to 30 degrees north and south of equator
3) at 30 degrees - cool air sinks creating high pressure belt (low rainfall)
4) cool air reaches ground surface and moves as surface winds back to equator or towards the poles
What are surface winds that blow towards the equator called?
Trade winds blow from SE in southern hemisphere and NE in northern hemisphere - meet at equator and are heated by the sun - causing them to rise and form clouds
What are westerlies?
Surface winds that blow towards the poles - blow from NW in southern hemisphere -and SW in northern hemisphere
What are ocean currents? Give an example of an ocean current?
Large scale movements of water that transfer heat energy from warmer to cooler regions (can be surface currents or deep ocean currents) - example of current is golf stream heats Europe with warm water from Caribbean
What happens to colder and freezing water? What does it cause?
Cold water freezes at the poles - surrounding water gets saltier increasing its density - it sinks causing warmer water to flow at the surface - creating a current - warmer water cools and sinks continuing cycle
What is thermohaline circulation?
The cycle of cooling and sinking water moving in a big loop round the earth
What are ITCZ - Inter tropical convergence zones?
Permanent zones of low pressure with high rainfall - occur near equator between Hadley cells
Why do ITCZ have high rainfall?
They occur near the equator between two Hadley cells - where warm tropical air flows to the equator from the north and south - intense radiation from sun causes air to rise, expand and become less dense - resulting in low pressure and lots of rainfall
What are orbital changes and what do they cause?
Changes and variations in the way the earth moves around the sun (orbit) - changes may have caused glacial and interglacial periods
What is stretch/eccentricity and what does it cause?
Changes in the earths orbit - happens over a long period (100,000 years) - sometimes earths cycle is more circular around the sun making it warmer (interglacial) - sometimes its more elliptical making earth cooler(glacial)
What does changes in Axial tilt cause?
Earth is tilted which creates our seasons - about every 40,000 years - tilt changes - earth is tilted further from sun (makes difference in seasons more pronounced) - tilted closer, difference in seasons is less
what is precession? What does it cause?
Earth wobbles when it rotates - direction axis is facing changes - affects our seasons creates either small or greater differences between summer and winter - happens over a period of 24,000 years
What is a glacial period?
Glacial period - caused when summers are cooler than they usually are - snow/ice does not melt
How can asteroid collisions cause change in the climate?
When asteroids impact with the earth the eject large volumes of dust into the atmosphere partially blocking out solar radiation - causing a decline in temperature
How can volcanic eruptions cause climate change?
Volcanic eruptions send ash and sulphur dioxide into the earth stratosphere stopping some of the suns rays heating the planet - as they are reflected of the large blanket of ash and gas
How can sunspots cause climate change?
Lots of spots on the sun indicates it is more active than usual - more solar energy being fired out - less spots shows the sun is less active and could cause cooler temperatures on earth
How are tree rings - evidence for climate change?
Each ring shows a year of growth - changes in shape and size of rings shows changes in condition that year - bigger tree ring show warmer and wetter conditions