Global atmospheric circulation and climate change Flashcards
How does the equator getting more solar radiation create air pressure
The equator gets most of the suns radiation, causing a difference in temp creating air pressure.
How does air pressure effect wind
Wind goes from areas of high pressure to areas of low pressure, which transfers heat from the equator
What is global atmospheric circulation cells
They are loops which have warm air rising creating a low pressure belt, and cool air falling, creating a high pressure belt.
What are the names of the three belts
1 Hadely, 2 Ferrel and 3 Polar cells
Why do some parts of the Earth get more solar radiation than others
The thickness of the atmosphere
The size/area of what is getting heaten up (less distrupution)
What happens to the air at low pressure
As air heats it rises and becomes less dense as it cools and condenses. As the air leaves the surface, it causes low air pressure (rainfall and clouds)
What happens to air at high pressure
When air cools it becomes more dense meaning it falls, transfering heat to the surface (clear skiesand wind)
Direction of air through the cells
From the equator (low pressure belt) the air rises to 30° north and south (high pressure belt), then 60° (low pressure belt)
What happens at 30° of the equator
Cool air sinks, creating a high pressure belt. As it reaches the ground it moves as surface winds to the equator or pole with cloudless skies
Trade winds
Surfaces winds blowing to the equator. They blow from the SE in the south hemisphere and the NE in the north hemisphere
Westerlies
Surface winds blowing towards the Pole. They blow from the NW in the south hemisphere and the SW in the north hemisphere
What happens at 60° from the equator
Warmer surface winds meet colder air from the poles. The warm air is less dense so it rises, creating low pressure and frontal rain
What happens at the poles to air
Cool air sinks creating high pressure which is drawn back to the equator as surface winds
How do ocean currents transfer heat
They are large scale movements that transfer heat energy from warmer areas to cooler areas by surface currents and deep ocean currents
Surface currents
Caused by winds, they help transfer heat away from the equator
Example of surface currents
Gulfstream brings warm water to the Carrabisn keeping Western Europe warm
Deep ocean currents
They are driven by differences in water density. As water freezes at the poles, the surrounding water gets saltier, increaing in density. This thermohaline circulation
What is thermohaline circulation
water sinks causing warmer water to rise creating a current and cycle called thermohaline circulation
Arid climate
Sinking air from hadely and ferrel cells meeting causes high pressure climate
Location of Arid areas
Approx close to the 30°
Tropical climate
Rising air from Hadely cells meeting caises low pressure
Tropical loaction
Inbetween 30°
Polar
Sinking air from polar cells creates area of high pressure
Location of Hadely cell
From equator to 30°
Loaction of Ferrel cell
30° to 60°
Location of Polar cells
Above 60°
Quanternary period
Most recent geological period from 2.6 mill years ago to now
How long to glacial periods usually last
100,000 years (lasr one 15000 years ago).
How long do interglacial periods last
10,000 years
What are orbital changes
Ways the Earth moves round the sun:
Stretch
Tilt
Wobble
Stretch (eccentricity)
Path of the Earth’s orbit from an almost perfect circle to an ellipse and back (every 96000 years)
Tilt
Earth’s axis tilting at an angle of approx 23° (every 41,000 years) further from the Sun meaning more extreme and pronounced seasons. If it is tilted closer to the Sun less of a difference in seasons
Wobble (precession)
The axis of Earth wobbles ever 22,000 years
Volcanoc activity
Dust and particles from erruptions reflect the sun’s rays like in Mount Tambora where there was a year without summer
Solar output
Every 11 years or longer the sun’s output changes, causing periods where solar output could be reduced like the Mauder Minimum where there was a little ice age
Asteroid collisions
If one hit the Earth’s surface it could cause dust to rise into the atmosphere reflecting the Sun’s solar radiation
Evidence of natural climate change
Tree rings
Ice cores
Historical records
Tress rings
Most tres produce a ring a year showing the climate by its thickness.
Ice cores
Ice sheets form one layer a year. The ice core contains gases like CO2 so you can see what temp the year was
Historical record examples
Historical diaries, records and paintings like images of orange vines and warm crops show the medievsl warm period in 900 to 1300 AD or the little ice age in England at 1700 century
Wave radiation structure
Incoming of short-wave radiation
Outgoing of long-wave radiation (trapped by insulating layer of gasses)
How has farming causes climate change
Livestock produce methane
Rice paddies emitt methane
Deforestaion of trees
How has industry causes climate change
Requires lots of energy which is usually fossil fuels
Processes like cement is made of limestone which contains CO2
Industrial waste decays releasing methane
Energy
Requires fossil fuels
Transport
Most vechiles run on fossil fuels and as car ownership is rapidly rising from its avordability its increases congestion meaning cars run for longer
Evidence of climate change
Decline in artic ice
Global temp rise
Sea levels and temp rise
Extreme weather events
Declining ice
Sea ice froms in temps of -1.8°c. The extents of artic sea ice in winter has decreased by over 3% each decade for 35 years
Global temp rise
Temps have increases by nearly 1°c since 1880. The top ten warmest years have occured since 2000
Sea level and temp rise icreases (0.1°c)
Since 1901 sea levels have risen almost 0.2 m from:
Eustatic sea level rise-Warmer temps cause glaciers and ice sheets to melt
Thermal exapnsion- water expands as it gets hotter
Extreme weather events
Since 1950 there has beens higher frequence of heat waves. In the UK more rainfall records were broken in 2010-2014 than in any decade.
What senarios have the IPCC come up with
Use projection graphs to predict changes in temp and sea level by 2100
4 senarios
Senario 1 Minimum emmissions
This is the best outcome, in which levels of greenhouse gases peak then reduce
Scenarios 2 + 3- stabalising
In which greenhouse gas levels continue to increase but eventually level off
Scenario 4- maximum emissions
This is worst case where the rate of production of emissions continues to increase in greenhouse gasses
What is difficult to predict to create uncertanties
Emissions-due to pop change and economic development
Complexity-the exact climate changes like unclear natural processes
Management-what attempts will be made to manage greenhouse gases
