A & W xtra

Question 1

Define energy budget

Answer 1

An energy budget refers to the amount of energy entering a system, the amount leaving the system and the transfer of energy within the system.

Question 2

Define albedo

Answer 2

The proportion of energy reflected back to the atmosphere.

Question 3

Explain how albedo varies with colour.

Answer 3

Light materials are more reflective than dark materials. Grass has an average albedo of 20-30%, meaning that it reflects about 20-30% of the radiation it receives.

Question 4

Energy that reaches the Earth’s surface has the potential to heat it. Explain how to depends on the nature of the surface.

Answer 4

If the surface can conduct heat to lower layers, the surface will remain cool. If the energy is concentrated at the surface, the surface warms up.

The heat transferred to the soil and bedrock during the day may be released back to the surface at night. This can partly offset the night-time cooling at the surface.

Question 5

Define Sensible heat transfer

Answer 5

Sensible heat transfer refers to the movement of parcels of air into and out of the area being studied. For example, air that is warmed by the surface may begin to rise (convection) and be replaced by cooler air. This is known as convective transfer.

Question 6

Explain sensible heat transfer affects the day-time and night-time energy budget.

Answer 6

Air that is warmed by the surface may begin to rise (convection) and be replaced by cooler air. This is known as convective transfer. It is very common in warm areas in the early afternoon.

Sensible heat transfer is also a part of the night-time energy budget: cold air moving into an area may reduce temperatures, whereas warm air may supply energy and raise temperatures.

Question 7

Define long-wave radiation

Answer 7

Long-wave radiation refers to the radiation of energy from the Earth (a cold body) into the atmosphere and, for some of it, eventually into space.

Question 8

Explain how radiation affects the day-time energy budget.

Answer 8

The difference between radiation of energy from the Earth (a cold body) into the atmosphere, and for some of it, eventually into space & the downward movement of long-wave radiation from particles in the atmosphere is known as the net long-wave radiation balance.

During the day, outgoing long-wave radiation transfer is greater that incoming long-wave radiation transfer, so there is a net LOSS of energy from the surface.

Question 9

Explain how long-wave radiation affects the night-time energy budget.

Answer 9

During a cloudless night, there is a large loss of long-wave radiation from the Earth. There is very little return of long-wave radiation from atmosphere, due to the lack of clouds. Hence there is a net loss of energy from the surface.

In contrast, on a cloudy night the clouds re-radiate long-wave radiation to the surface, hence the overall net energy loss is reduced. Thus, in hot desert areas, where there is a lack of cloud cover, the loss of energy at night is maxmised.

Question 10

Explain how latent heat transfer effects the day-time and night-time energy budget.

Answer 10

When water is present at a surface, a proportion of energy available will be used to evaporate it, and less energy will be available to raise local energy levels and temperatures.

During the night, water vapour in the air close to the surface can condense to form water, since the air has been cooled by the surface. When water condenses, latent heat is released.

Question 11

Define Dew.

How does dew affect the energy budget.

Answer 11

Dew refers to condensation on a surface.

The air becomes saturated generally because the temperature of the surface has dropped enough to cause condensation.

Occasionally, condensation occurs because more moisture is introduced, for example by a sea breeze, while the temperature remains constant.

Question 12

Explain how greenhouse gases affect the energy budget.

Answer 12

The insolation received by the Earth will be reradiated as long-wave radiation. Some of this will be absorbed by water vapour and other greenhouse gases, thereby raising the temperature.

Question 13

Explain how ground-surface temperatures can vary in the between day and night.

Answer 13

During the day, the ground heats air by radiation, conduction, and convection. The ground radiates energy and the air received more radiation than it emits, the air is therefore warmed.

Air close to the ground is also warmed through conduction.

Air movement at the surface is slower due to friction with the surface, so there is more time for it to be heated. The combined effect of radiation and conduction is that the air becomes warmer, and rises as a result of convection.

At night, the ground is cooled as it emits long-wave radiation.

Question 14

Define radiation.

Answer 14

The emission of electromagnetic waves such as X-ray, short- and long-wave; as the Sun is a very hot body, radiating at a temperature of about 5700oC, most of its radiation is in the form of very short wavelengths such as ultraviolet and visible light.

Question 15

Define convection.

Answer 15

The transfer of heat by the movement of a gas or liquid.

Question 16

Define conduction.

Answer 16

The transfer of heat by contact.

Question 17

Describe how incoming radiation is absorbed by the atmosphere.

(The Earth’s energy budget)

Answer 17

Of incoming radiation, 19% is absorbed by atmospheric gases, especially oxygen and ozone at high altitudes, and carbon dioxide and water vapour at low altitudes.

Question 18

Describe how incoming radiation is reflected by the atmosphere

Answer 18

Reflection by the atmosphere account for a net loss of 8%, and clouds and water droplets reflect 23%. Reflection from the Earth’s surface (planetary albedo) is generally about 6%.

About 36% of insolation is reflected back to space.

Question 19

What percentage of insolation at the top of the atmosphere actually gets through the Earth’s surface.

Answer 19

46%

Question 20

Describe the variations in the receipt of solar radiation with latitude and season.

Answer 20

There is an excess radiation (+ve budget) in the tropics; a deficit of radiation (-ve balance) at higher latitiudes. However, neither region is getting progressively hotter or colder.

This is because of the horizontal transfer of energy from the equator to the poles takes place by winds and ocean currents. The horizontal transfer between low latitudes and high latitudes to compensates for the differences in global insolation.

Question 21

Explain why areas close to the equator receive more heat than area that are close to the poles.

Answer 21

-Incoming solar radiation (insolation) is concentrated near the equator, but dispersed near the poles. At the equator, the overhead sun is high in the sky, so the insolation received is of a greater intensity. At the poles, the overhead sun is low in the sky, so the quality of the energy received is poor.

-Insolation near the poles has to pass through a greater amount of atmosphere and there is more chance of it being reflected back out to space. In addition, albedo is higher in polar regions as snow and ice are very reflective, and low-angle sunlight is reflected from water surfaces.

Question 22

There is much more land in the northern hemisphere compared to the southern hemisphere.

Use statistics to show this.

Explain how this affects temperatures

Answer 22

Oceans cover about 50% of the Earth’s surface in the northern hemisphere but about 90% in the southern hemisphere.

Land heats and cools more quickly than water (it has a lower specific heat capacity). It takes five times as much heat to raise the temperature of water by 2Oc as it does to raise land temperature.

Therefore, a large volume of water is heated for every unity of energy than the volume of land, so water takes longer to heat up.

Question 23

Why does water heat more slowly?

Answer 23

-Water is clear, so the Sun’s rays penetrate to great depth, distributing the energy over a wider areas.

-Tides and currents cause heat to be further distributed.

Question 24

What are ocean currents caused by?

Answer 24

Surface ocean currents are caused by the influence of prevailing winds blowing steadily across the sea.

Question 25

Explain the pattern of ocean currents.

Answer 25

The dominant pattern of surface ocean currents (know as gyres) is roughly a circular flow. The pattern of these ocean currents is CLOCKWISE in the northern hemisphere and ANTI-CLOCKWISE in the southern hemisphere. Within the circulation of the gyres, water piles up into a dome. The effect of the rotation of the Earth causes the water in the oceans to push westward; this piles up water on the western edge of ocean basins. The return of flow is often narrow, fast-flowing currents such as the Gulf stream.

Question 26

Explain how the Gulf Stream effects temperatures.

Answer 26

The Gulf Stream transports heat northwards and and then eastwards across the north Atlantic; the Gulf Stream is the main reason that the British isles have mild winters and relatively cool summers.

Question 27

Explain how warm ocean currents effect temperature.

Answer 27

Warm currents from equatorial regions raise the temperature of polar areas (with the aid of prevailing westerly winds). However, this effect is only noticeable in the winter. For example, the North Atlantic Drift raises the winter temperature of north-west Europe.

Question 28

Explain how cold ocean currents effect temperature.

Answer 28

Cold currents such as the Labrador Current off the north-east coast of North America may reduce summer temperatures, but only if wind blows from the sea to the land.

Question 29

Explain how ocean currents affect pressure.

Answer 29

In the Pacific Ocean, there are two main atmospheric states. The first is warm surface water in the west with cold surface water in the east; the other is warm water surface in the east with cold in the west. In both cases, warm air causes low pressure. As air blows from high pressure to low pressure, there is movement of water from colder areas to the warmer area. These winds push warm surface water into the warm region, exposing colder deep water behind them and maintaining the pattern.

Question 30

Explain how the ocean conveyer belt effects the transfer of energy.

Answer 30

In the oceanic conveyor-belt model, surface currents bring warm water to the North Atlantic from the Indian and Pacific Oceans. This water then sinks and starts the reverse convection of the deep ocean current. The amount of heat given about of the third energy that is received. This pattern is maintained by salt; the North Atlantic is warmer than the North Pacific, so there is proportionally more evaporation there. The water left behind by evaporation is saltier and therefore much denser, which causes it to sink. Eventually, the water is transported into the Pacific where it picks up more water and density is reduced.

Question 31

Explain the cause of air motion? (Factors affecting air movement).

Answer 31

The basic cause of air motion is the unequal heating of the Earth's surface. The major equalising factor is the transfer of heat by air movement. Variable heating causes variation in pressure and this in turn sets the air in motion. There is thus a basic correlation between winds and pressure.

Question 32

Explain how the pressure gradient affects air movement.

Answer 32

This driving force is the pressure gradient; that is, the difference in pressure between any two points. Globally, very high pressure conditions exist over Asia in winter due to low temperatures. Cold air contracts, leaving room for adjacent air to converge at high altitude, adding to weight and pressure of the air. By contrast, the mean sea-level pressure is low over continents in summer. High surface temperatures cause atmospheric expansion and therefore a reduction in air pressure. High pressure dominates at around 25oC-30oC latitude. The highs are centred over the oceans in summer and over the continents in winter - whichever is cooler.

Question 33

Define the Coriolis force.

Answer 33

The Coriolis force is the deflection of moving objects caused by the easterly rotation of the earth.

Question 34

Explain the Coriolis force affects air movement.

Answer 34

Every point on the Earth completes one rotation every 24 hours. Air near the equator travels a much greater distance than air near poles. Air that the originates near the equator is carried towards the poles, taking it with a vast momentum. The Coriolis force deflects moving objects to the right of their path in the northern hemisphere and to the left of their path in the southern hemisphere. The balance of forces between the pressure gradient and the Coriolis force is known as the geostrophic balance and the resulting wind is known as geostrophic wind. The centrifugal force acts at right angles to the wind, pulling objects outwards, so for given pressure, airflow is faster around a high pressure.

Question 35

How does friction effect the Coriolis force.

Answer 35

Friction decreases wind speed, so it decreases the Coriolis force, hence the air is more likely to flow to low pressure.

Question 36

Briefly explain the general circulation model.

Answer 36

-warm air is transferred poleward and is replaced by cold air moving towards the equator. -air that rises is associated with low pressure, whereas air that sinks is associated with high pressure. -low pressure rain; high pressure produces dry conditions.

Question 37

Explain the role of the Hadley cell.

Answer 37

There is direct heating over the equator. This air here is forced to rise by convection, travels polewards and then sinks at the subtropical anticyclone (high-pressure belt).

Question 38

Explain how the ITCZ affects air movement.

Answer 38

At the ITCZ, convectional storms lift air into the atmosphere, which increases air pressure near the tropopause, causing winds to diverge at a high altitudes. The winds move out of the equatorial regions towards the poles, gradually losing heat by radiation. As they contract, more air moves in and the weight of the air increases so the air pressure at the subtropical high-pressure zone. The denser air sinks, causing subsidence (stability)

Question 39

Define jet streams.

Answer 39

Jet streams are strong, regular winds that blow in the upper atmosphere about 10km above the surface; they blow between the poles and tropics (100-300km/h). There are two jet streams in each hemisphere - the polar jet is located between the 50°-60° latitude lines in both the northern and southern hemispheres. The subtropical jet is located around the 30° latitude line. In the northern hemisphere, the polar jet and subtropical jet flow eastwards.

Question 40

Define Rossby waves.

Answer 40

Rossby waves are 'meandering river of air' formed by westerly winds. There are three to six waves in each hemisphere. They are formed by major topographic barriers such as the Rockies and the Andes, by thermal differences and uneven land-sea interfaces.

Question 41

Explain the formation of jet streams.

Answer 41

The jet streams result from differences in equatorial and sub-tropical air, and between polar and sub-tropical air. The greater the temperature difference, the stronger the jet stream.

Question 42

When does evaporation occur?

Answer 42

Evaporation occurs when vapour pressure of a water surface exceeds that in the atmosphere.

Question 43

What is vapour pressure and when does the maximum vapour pressure occur? What does evaporation aim to equalise?

Answer 43

Vapour pressure is the pressure exerted by the water vapour in the atmosphere. The maximum vapour pressure at any temperature occurs when the air is saturated. Evaporation aims to equalise these pressures.

Question 44

What three main factors does evaporation depend on?

Answer 44

Evaporation depends on: -the initial humidity of the air, if is very dry then strong evaporation occurs; if air is saturated very little occurs. -Supply of heat, the hotter the air, the more evaporation that takes place. -Wind strength, under calm conditions the air becomes saturated rapidly.

Question 45

When does condensation occur?

Answer 45

Condensation occurs when either enough water vapour is evaporated into an air mass for it to become saturated or when the temperature drops to dew point (the temperature at which the air is saturated) is reached.

Question 46

How may cooling (one of the causes of condensation occur)?

Answer 46

-radiation cooling of air. -contact cooling of air when it rests over a cold surface. -Adiabatic cooling of air when it rises.

Question 47

What does condensation require to occur?

Answer 47

Condensation requires tiny particles or nuclei onto which the vapour can condense.

Question 48

Define freezing.

Answer 48

Freezing refers to the change from a liquid to a solid, namely ice, once the temperature falls below 0oC.

Question 49

Define melting.

Answer 49

Melting is the change from a solid to a liquid when the air temperature rises above 0oC.

Question 50

Define Sublimation. When does sublimation occur?

Answer 50

The conversion of a solid into a vapour with no intermediate liquid state. Sublimation occurs under conditions of low humidity, snow can be evaporated directly into water vapour without entering a liquid state.

Question 51

According to the Bergeron theory, how does rain form?

Answer 51

-Water and ice must exist in clouds at temperatures below 0oC. -Indeed, the temperature in clouds may be as low as -40oC. -At such temperatures, water and ice droplets form. -Ice crystals grow by condensation and become big enough to overcome turbulence and cloud updrafts, so they fall. -As they fall, crystals coalesce to form larger snowflakes. -These generally melt and become rain as they pass into warm air layers near the ground. Therefore, according to Bergeron, rain comes from clouds where the coexistence of water and ice is possible.

Question 52

Rain comes from clouds that are not so cold. What do these mechanisms include?

Answer 52

-Condensation on extra-large hydroscopic nuclei. -Coalescence by sweeping, whereby falling droplet sweeps up others in its path. -The growth of droplets by electrical attraction.

Question 53

Define Snow. Define Sleet.

Answer 53

Snow is a single flake of frozen water. Sleet is partially melted snow.

Question 54

Explain how convectional rainfall occurs.

Answer 54

When land becomes very hot, it heats the air above it. This air expands and rises. As it rises, cooling and condensation takes place. If it continues to rise, rain will fall. Convectional rainfall is very common in tropical areas and is associated with the permanence of the ITCZ.

Question 55

Explain how frontal rainfall occurs.

Answer 55

Frontal rain occurs when warm air meets cold air. The warm air, being lighter and less dense, is forced to rise over the cold, denser air. As it rises, it cools, condenses and forms rain. It is most common in middle and high latitudes where warm tropical air and cold polar air converge.

Question 56

Explain how orographic rainfall occurs.

Answer 56

Air may be forced to rise over a barrier such as a mountain. As it rises, it cools, condenses and forms rain, There is often a rainshadow effect, whereby the leeward slopes receives a relatively smally amount of rain. In general, there are increases of precipitation up t about 2km. Above this level rainfall decreases because the air temperature is so low.

Question 57

Define Thunderstorms.

Answer 57

Thunderstorms are special cases of rapid cloud formation and heavy precipitation in unstable air conditions.

Question 58

How are clouds classified?

Answer 58

-form or shape: such as stratiform (layers) and cumuliform (heaped type). -Height, such as low (<2000m), medium or alto (2000-7000m) and high (7000-13000m)/

Question 59

What does the vertical development of a cloud suggest?

Answer 59

Vertical development suggests upward movement.

Question 60

Cumulus cloud are...

Answer 60

flat-bottomed and heaped. They indicate bright brisk weather.

Question 61

Cumulonimbus clouds produce...

Answer 61

heavy rainfall and often thunderstorms.

Question 62

What occurs with clouds in unstable conditions.

Answer 62

In unstable conditions, the dominant form of uplift is convection and this may cause cumulus clouds.

Question 63

What clouds form in stable conditions?

Answer 63

Stratiform clouds occur.

Question 64

Where fronts are involved...

Answer 64

a variety of clouds exist.

Question 65

What is the effect of relief on clouds?

Answer 65

Relief causes stratiform or cumuliform clouds, depending on the stability of air.

Question 66

Explain the formation of banner clouds.

Answer 66

Banner clouds are formed by orographic uplift under stable air conditions. Uplifted moist air stream reach condensation only at the very summit, and form a small clouds. Further downwind the air sinks, and the cloud disappears.

Question 67

Define rain.

Answer 67

Rain refers to liquid drops of water with a diameter between 0.5 mm and 5mm. It is heavy enough to fall on the ground,

Question 68

Define Hail. Explain the formation of hail.

Answer 68

Hail is alternate concentric rings of clear opaque ice. As the raindrops are carried high up in the cumulonimbus cloud they freeze. The hailstones collide with droplets of supercooled water, which freeze on impact and a layer of opaque ice around the hailstone. As the hailstone falls, the outer layer may be melted but may freeze with further uplift. Freezing and partial melting may occur several times before the pellet finally falls to the ground, this occurs when its weight is great enough to overcome the strong updraughts of air.

Question 69

Define Snow. Explain the formation of snow.

Answer 69

Snow is frozen precipitation. Snow crystals form when the temperature is below freezing and water vapour is converted into solid. However, very cold air contains a limited amount of moisture, so the heaviest snowfall tends to occur when warm moist air is force over very high mountains or when warm moist air comes into contact with very cold air at a front.

Question 70

Define Dew. When does dew occur?

Answer 70

Dew is the direct deposition of water droplets onto a surface. It occurs in clear, calm anticyclonic conditions (high pressure) where there is rapid radiation cooling by night. The temperature reaching dew point, and further cooling causes condensation and direct precipitation onto the ground and vegetation.

Question 71

Define Fog.

Answer 71

Fog is cloud at ground level.

Question 72

Explain the formation of radiation fog.

Answer 72

Radiation fog is formed in low-lying areas during calm weather, especially during the spring and autumn. The ground radiates away heat (i.e. the ground loses heat by thermal radiation) at night and therefore cools rapidly. The colder ground then cools the surrounding air. This air then flows into hollows by gravity and is cooled to a dew point (the temperature at which condensation occurs). Ideal conditions for radiation fog include a surface layer of moist air and clear skies, which allow RAPID radiation cooling. The decrease in temperature of the lower layers of the air cause air to go below dew point. With fairly light winds, the fog forms close to the water surface.

Question 73

Explain how a temperature inversion occurs.

Answer 73

Under cold anticyclonic conditions in late autumn and winter, fog may be thicker and more persistent, and around large towns smog may develop under an inversion layer. An inversion means that cold air is found at ground level, whereas warm air is above it.

Question 74

Explain the formation of Advection fog.

Answer 74

Advection is formed when warm moist air flows horizontally over a cooler land or sea surface.

Question 75

Describe how much carbon dioxide levels have risen by.

Answer 75

Carbon dioxide levels have risen from about 315ppm (parts per million) in 1950 to over 424ppm in 2024 and are expected to reach over 600ppm by 2050.

Question 76

How do paddy fields emit methane?

Answer 76

Paddy fields emit up to 150 million tonnes of methane annually. As global warming increases, bogs trapped in permafrost will melt and release vast quantities of methane.

Question 76

How many tonnes of methane do cattle alone give off?

Answer 76

Cattle alone give off between 65 million and 85 million tonnes of methane per year.

Question 77

Since the industrial revolution...

Answer 77

the combustion of fossil fuels and deforestation have led to an increase of 26% of carbon dioxide concentration in the atmosphere.

Question 78

How does deforestation contribute to global warming?

Answer 78

When forest are cleared or burnt, stored carbon is released into the atmosphere, mainly as carbon dioxide. Also, trees remove carbon dioxide from the atmosphere and convert it into oxygen through photosynthesis.

Question 79

Give two real life examples of impact of global warming.

Answer 79

-There has been a rise in sea levels due to the melting of the polar ice caps, causing flooding in low-lying areas such as the Netherlands, Egypt and Bangladesh. This has led to 200 million people at risk of being displaced from their homes by flood or drought in 2050. -Reduced rainfall over the USA, southern Europe and the Commonwealth of Independent States, leading to widespread droughts. -Carbon emission have already increased global temperatures by more than 0.5oC.

Question 80

According to the Stern review, what is a nice way putting an argument for tackling climate change

Answer 80

According to the report, climate change poses a threat to the world economy and it will be cheaper to address the problem than to deal with the consequences. Global warming could deliver an economic blow between 5 to 20% of GDP to world economies because of natural disasters and creation of hundreds of million of climate refugees displaced by sea-level rise. Dealing with the problem, will cost just 1% of GDP, equivalent of £184 billion.

Question 81

Why is there a relative lack of moisture in urban areas? What is the effect of this?

Answer 81

-a lack of vegetation means that there is little energy for evapotranspiration, so more is available to heat the atmosphere. -a high drainage density (sewers and drains), which removes water. Thus there is a decrease in the relative humidity in urban areas due to lack of available moisture and high temperatures.

Question 82

In urban areas, the release of heat by buildings...

Answer 82

offset the cooling process.

Question 83

Urban climates occur as a result of extra sources of heat released from industry etc. What is the effect of this?

Answer 83

There are more intense storms, particularly during hot summer evenings and nights, owing to greater instability and stronger convection above built up areas.

Question 84

What is the heat-island effect caused by?

Answer 84

-Changes in the energy balance, buildings have a high thermal capacity in comparison to rural areas; up to six times greater than agricultural land. -there are less bodies of open water, so less evaporation and fewer plants, therefore less transpiration. -Urban surface tends to be rough, this means that there is a reduction in heat diffusion due to changes in air flow patterns. -The may be a pollution dome which act as a lid on pollutant and prevent them from dispersing. By night, the pollutants may absorb some long-wave radiation, thereby keeping urban areas warmer than surrounding areas.

Question 85

Describe surface pressure belts effect atmospheric transfers.

Answer 85

-The subtropical high-pressure belts (STHP) belts, especially over ocean areas in the southern hemisphere are almost continuous at a 30oC, although ins summer over South Africa and Australia they tend to be broken. Generally pressure is about 1036mb. -In the northern hemisphere, by contrast, at 30oC the belt is much more discontinuous because of land. High pressure only occurs in areas such as discrete cells such as the Azores and Pacific high. Over continental areas such as southern Asia and the Sahara, there is a high pressure gradient: high pressure in winter, and summer lows because of overheating.

Question 86

What is the intertropical convergence zone and what is the effect it has on atmospheric transfers?

Answer 86

The intertropical convergence zone (ITCZ) is a convergence zone a few 100km wide, into which trade winds of the northern and southern hemisphere blow inwards and subsequently rise, thereby forming an area of low pressure. The rising air releases vast quantities of latent heat, which in turn stimulates convection. The air that is forced to rise along the ITCZ moves towards the poles and it is cooled. As the air is cooled it becomes denser and heavier so it slowly descends leading areas of high pressure in the sub-tropics, bringing largely benign weather conditions to places like the Azores.

Question 87

What is the effect of low-latitude winds between 10oC and 30oC? What is the effect of Westerly winds?

Answer 87

Low-latitude winds between 10oC and 30oC are mostly easterlies; that is, they flowing towards the west. These are reliable trade winds; they blow over 30% of the earth's surface. The weather in this zone is fairly predictable: warm, dry mornings and showery afternoon, caused by the continuous evaporation from tropical seas. Westerly winds dominate between 35oC and 60oc of latitude, which accounts for about a quarter of the world's surface. However, unlike steady trade winds, these contain rapidly evolving and decaying depressions, bringing wet weather.

Question 88

How can pressure variations cause monsoons?

Answer 88

Monsoons are influenced by the reversal of land and sea temperatures between Asia and the Pacific during summer and winter. In winter, surface temperatures in Asia may be as low as -20oC. By contrast surrounding oceans have temperatures of 20oC. During summer, the land heat up quickly and may reach 40oC. By contrast, the sea remains cooler at about 27oC. This initiates a land sea-breeze blowing from cooler sea (high pressure) in summer to warmer land (low pressure), whereas in winter air flows out of the cold land mass (high pressure) to the warm water (low pressure).

Question 89

Why do temperature inversions happen?

Answer 89

During the day the ground is heated by the sun's short wave radiation, and then after a short time, the surface heats the air above when it emits long wave radiation. At night the ground surface and the air lose the heat energy they have absorbed during the day. However, the ground loses heat energy faster than the air as it is a more efficient conductor of heat. By the end of the night the ground surface is therefore very cold, and the air will be cooled due to close proximity to the surface. However, the air layer above this, will be still warmer as it has cooled at a slower rate than the ground surface, causing a temperature inversion.

Question 90

How is the night time energy budget different to the daytime energy budget?

Answer 90

There is a long wave radiation loss at night (terrestrial radiation) as often nights are cloudless so there so there is nothing to re-radiate long wave radiation back to the surface. However, on cloudy nights energy loss is reduced. At night, water vapour in the air is close to the ground so it can condense to form dew because the air is cooled by the cold surface. Heat is released during this process. Heat transferred by the sun to the surface during the day, may be released back to the surface at night which can off set the night time cooling at the surface. Sensible heat transfer still occurs and cold air moving into an area may reduce temperatures whereas warm air moving in will raise temperatures.

Question 91

Define and explain Latent Heat (evporation)

Answer 91

The turning of a liquid water into vapour (evaporation), it consumes a considerable amount of energy. When water is present at the surface, a proportion of the incoming solar radiation will evaporate it. Consequently, that energy will not be available to raise local energy levels and temperatures.

Question 92

What is a land breeze?

Answer 92

A land breeze occurs at night when the land cools faster than the sea at night. This created a situation which is the opposite to day time - where the air above the sea is actually warmer at night than the air above the land. In this case, it is air above the warmer surface water that is heated and rises, pulling in air from the cooler land surface.

Question 93

Explain what is meant by a sea breeze?

Answer 93

On a warm summer day along the coast, this differential heating of land and sea leads to the development of local winds called see breezes. The land is heated at a faster rate than the sea and so the air above the land is warmer than the air above the sea during the day. As the air above the land surface is heated by radiation from the Sun , the air begins to expand and rise, being lighter than the surrounding air. To replaced the rising air, cooler air is drawn in from the above the surface of the sea. This is the sea breeze, and can offer a pleasant cooling influence on hot summer afternoons.

Question 94

Explain circulation in the Polar cell?

Answer 94

At the equator the sun shines directly and warms the earth' surface. Warmer air rises at lower latitudes and moves pole wards. When the air reaches the polar areas, it has cooled considerably, and descends as a cold, dry high pressure area. This circulation is known as the polar cell.

Question 95

Explain circulation in the Ferrell cell.

Answer 95

The cell lying between the Polar cell and the Hadley cell is called the Ferrell cell. It only exists due to other two cells and it mirrors the other cells' movements. It transfers warm air to high latitudes and shifts cold air back to the subtropics, where it is water.

Question 96

Explain the green house effect.

Answer 96

-The green house effect is a natural process. Without the green house effect, temperatures would be too low for life on earth to exist. The earth is surrounded by a thin layer of greenhouse gases. Short wave radiation from the sun travels through the layer. It is re-adiated by the earth as long wave radiation. Some of the long wave radiation is re-emitted by the layer of greenhouse gases. Some of the long wave radiation is allowed to escape back out to space through the layer, this stops the atmosphere from overheating.

Question 97

Explain the Human Enhanced Greenhouse Effect.

Answer 97

The Human Enhanced Greenhouse effect is caused by humans. It happens when humans produce extra greenhouse gases. This makes the amount of greenhouse gases in the earth's atmosphere more concentrated. This layer therefore stops more of the long-wave radiation escaping into space. Also, more long-wave radiation is re-emitted towards the earth's surface. This causes the global average temperature to increase.