Global atmospheric earth (Topic1)

Question 1

What is wind?

Answer 1

wind is the movement of air caused by the uneven heating of the earth by the sun and the earths own rotation

Question 2

What is the coriolis effect?

Answer 2

the coriolis effect is that circulating air is deflected towards the right in the northern hemisphere and towards the left in the southern hemishphere

Question 3

How does air move around the world?

Answer 3

Air rises at the equator, leading to low pressure and rainfall
When air reaches the edge of the atmosphere, it cannot go any further and so it travels to the north and south
As a result, the air becomes colder and denser and falls, creating high pressure and dry conditions at around 30• north and south of the equator

large cells of air are created in this way

Question 4

Hadley cell

Answer 4

The first cell is called the hadley cell. At the equator, the ground is intensely heated by sun which causes air to rise which creates a low pressure zone

As air rises, it cools and forms thick storm clouds

Air continues to rise until it cannot go any further so it travels to the north and south

As a result, the air becomes colder and denser and falls creating high pressure and dry conditions at 30• north and south of the equator. This is where deserts are found

The hadley cell is then complete. The air completes the cycle and flows back towards the equator.

Question 5

Ferrel cell

Answer 5

The ferrel cell occurs at 30-60• N&S of the equator

Air on the surface is pulled towards the poles forming warm south westerly winds in the northern hemisphere and north westerly winds in the southern hemisphere

These winds pick up moisture as they travel over the oceans

At around 60•N&S they meet cold air. the warmer air is lighter then the dense cold polar air and so it rises as the 2 meet

The uplift in air causes low pressure at the surface and unstable weather conditions. This determines a lot of our wet windy weather

Question 6

Polar cell

Answer 6

At the poles, air is cooled and sinks towards the ground forming high pressure (polar high)

It then flows towards the lower latitudes. At about 60•N&S, the cold air mixes wiht the warmer tropical air and roses upwards creating a zone of low pressure (subpolar low)

The boundary between the warm and cold air is called the polar front.

Question 7

What is an area of low pressure called?

Answer 7

A depression

Question 8

What does areas of low pressure cause?

Answer 8

clouds and rainfall to form (unsettled weather)

Question 9

What happens to winds in a depression and how is it shown?

Answer 9

winds are normaly stronger

shown by isobars being closer together

Question 10

Where do depressions normally form and what direction do they move in?

Answer 10

over the atlantic ocean and are carried across britain by westerly winds and move in an anticlockwise direction

Question 11

How can we recognise depressions on a weather chart?

Answer 11

the isobars are below 1000mb and are packed closer together

a warm front (red line) is followed by a cold front (blue line)

Question 12

What is an area of high pressure called?

Answer 12

an anticyclone

Question 13

What does areas of high pressure cause in summer and winter?

Answer 13

summer: clear skies and a gentle breeze
fine weather

winter: clear skies and colder conditions

Question 14

What happens to winds in a high pressure area and how is it shown?

Answer 14

less winds as the isobars are further apart

Question 15

what direction do anticyclones move in?

Answer 15

clockwise

Question 16

How can we recognise anticlyclones on a weather chart?

Answer 16

isobars are above 1000mb and spread further apart

Question 17

What lasts longer and anticyclone or a depression?

Answer 17

anticlyclones - 2 weeks
depressions 2-3 days

Question 18

Order the layers of the earth

Answer 18

inner core
outer core
mantle
crust

Question 19

Describe the inner core

Answer 19

centre of the earth and is the hottest part of the earth

a solid made up of iron and nickel

temps up to 5500•

Question 20

Describe the outer core

Answer 20

the layer surrounding the inner core

a liquid layer made of nickel and iron

Question 21

Describe the Mantle

Answer 21

the thickest section of the earth approximately 2900km

made of semi molten rock called magma

Question 22

Describe the crust

Answer 22

is the outer layer of the earth

a thin layer between 0-60 km thick

a solid layer and is either continental or oceanic , we live on the crust

Question 23

What is the athenosphere

Answer 23

the upper part of the mantle is called the asthenosphere

made of semi molten rock called magma

Question 24

What was originally believed about plate movement?

Answer 24

The earths crust is broken into tectonic plates, it was once believed that convection currents in the mantle caused the plate to move. However it is now recognised to be more complicated than this

Question 25

what actually causes plate movement?

Answer 25

Mechanism called slab pull and ridge push are believed to move tectonic plates

Question 26

Ridge push

Answer 26

Is where the new crust formed at the divergent plate margins is less dense than the surrounding crust and so it rises to form oceanic ridges

The older sea floor either side of the ridge slides away and this moves the seafloor apart – moving the tectonic plates

Question 27

Slab pull

Answer 27

occurs where older denser tectonic plates sink into the mantle at subduction zones

as these older plates sink newer less dense sections of plate are pulled along behind sinking in one place leads to plates moving apart in other places

Question 28

Conclusion of plate movement theory

Answer 28

therefore instead of tectonic plates moving because of the convection currents, evidence suggests that it is the plates that drive the convection

Question 29

Natural causes of climate change

Answer 29

orbital changes - milankovitch cycles are variations in the tilt/orbit of the Earth around the Sun, causing natural warming and cooling periods

volcanic eruptions - carbon dioxide is released into the atmosphere during eruptions

Solar output - the amount of radiation omitted by the Sun fluctuates. High level is a radiation lead to an increase in earth temperature

Question 30

Human causes of climate change

Answer 30

Deforrestation- (cutting down trees) trees absorb CO2. One trees are cut down less CO2 will be absorbed leading to increased concentrations of it in the atmosphere

Burning fossil fuels - when coal, gas and oil are burned, carbon dioxide is released into the atmosphere

Agriculture - increased animal/pastoral farming leads to more methane being released into the atmosphere

Dumping waste in landifill - as waste decomposes it releases methane

Question 31

Evidence for natural climate change

Answer 31

ice cores - are cylinder samples extracted from ice sheets and glaciers. These cores contain layers of ice that have gathered over thousands of years of years each layer representing a year or season

Tree rings - when a tree trunk has been cut each ring represents one year of growth and the thickness of the ring reflects the environmental conditions that year. (wider rings =warm wet and narrow rings = cold dry)

Historical sources - offer qualitative data on past climate conditions eg. written records, paintings, archeological findings

Question 32

Evidence for human climate change

Answer 32

Thermometer readings

Glacier retreats - photographs of glaciers taken years apart show that many of the worlds glaciers are melting and retreating

Ice cores

Rising sea levels

Question 33

Predictions for global sea level

Answer 33

rise by 2100 vary from 20 cm to over 100cm

Question 34

Predictions for average global temp

Answer 34

increase by 1• to 5•

Question 35

Why are we uncertain about rises from human and natural contributions?

Answer 35

we can’t certainly predict future global temperature because earths climate system may respond to increased emmisions in the future

Question 36

Human factors contributing to uncertainty

Answer 36

the future global population is uncertain

emmisions per person are tied to wealth and predicting future wealth is hard

uncertainty about wether humans will change their emissions or if they will continue to pollute

Question 37

Natural factors contributing to uncertainty

Answer 37

the ice sheets in greenland and antarctica could melt faster in the future significantly raising global sea levels

the oceans capacity to absorb co2 might reach a limit

a warmer earth may lead to increased cloud cover, these clouds could reflect more solar radiation back into space, offseting some warming