past paper questions Flashcards
1
Q
explain why there is excess energy at lower
latitudes
A
- Occurs due to radiation input being greater than outgoing radiation. This results in a positive balance at these latitudes.
- This is because the incoming solar radiation is greater at these latitudes because of the high angle of the sun (concentrated at lower latitudes)
- Rays have to pass through less atmosphere because of their high angle resulting in higher levels of solar radiation reaching the Earth’s surface
- At lower latitudes there tends to be lower albedo rates thus less is reflected
2
Q
define convection
A
Air warmed (during the daytime) (1) and rises in pockets (1).
3
Q
define wind belts
A
Global bands of wind (uniform temperature and moisture) (1) blowing in a predominant direction (1) over a seasonal/long time period (1)
4
Q
Briefly describe how solar radiation may be reflected
A
- Reflected by clouds
- Dust particles in the atmosphere/pollution dome
- Reflected by the Earth’s surface
5
Q
Explain how human activity can affect the temperature of an urban area
A
- concrete and tarmac absorb heat
- industrial and residential building release heat
- vehicles releases gases that retain long wave radiation and are CCNs
- smog forms a pollution dome which traps radiation, thus heat, further
6
Q
With the aid of examples, assess the extent to which human activity is the main cause of global warming
A
- focusing on the sources of greenhouse gases
- there is a combination of natural and anthropogenic (human) causes
- natural: volcanic eruptions or variations relating
to the sun - the burning of fossil fuels, releasing nitrous oxides from vehicles, CFCs from aerosols and methane from
agriculture and deforestation - human activity causing global warming in the present compared with the past
7
Q
briefly explain the formation of hail
A
- Produced through turbulence and convection in cumulonimbus clouds.
- Results in condensation on cooling, which can lead to freezing and the formation of hail.
- Repeated strong uplift and down-draughts of moving air allowing growth as they get coated with more ice (sublimation is a relevant process)
8
Q
Explain why the type of precipitation may vary in one location
A
- Stability of air means a lack of uplift and adiabatic cooling limits the development of clouds and rainfall.
- Discussion about the moisture content of air, or anti cyclonic conditions compared with cyclonic conditions changing over time at any one location.
- Diurnal variations of heating and cooling or seasonal variations with reasons given.
- Cause of rainfall can give rise to characteristically different types of precipitation – convectional rainfall leading to short heavy outbursts, frontal rainfall leading to continuous rain.
- Passage of fronts can cause changes in the type of precipitation in one location.
- Cooler conditions / freezing (leads to snow)
9
Q
Describe two ways incoming (shortwave) solar radiation can be reflected
A
- Clouds with reference to type of clouds, colour, etc.
- Surfaces (e.g. snow, ice, water, various vegetation and crop types, building, road surfaces) with different albedos.
- Scattering by particulate matter
10
Q
Explain how ocean currents influence surface temperatures on land
A
- transfer heat from warmer equatorial areas north and south
- Other currents bring cooler water back in a continuous cycle
- This is a horizontal transfer of energy, ensuring a more even distribution of temperature
- The sea temperatures and ocean currents influence the development of winds which transfer heat to land, with areas nearest to the coast being most affected
- occasionally condensation occurs when more moisture is introduced for example by a sea breeze while the temperature remains constant
- surface ocean currents caused by prevailing winds dominant patterns of gyres, roughly circular flows
- The Gulf Stream: fast flowing return current that transports heat northwards and then eastwards across the North Atlantic: the main reason the British Isles have mild winters and relatively cool summers
- The cold Labrador current reduces the temperatures of the western side of the Atlantic
-The North Atlantic drift raises temperature on the eastern side - only if the wind blows from the sea to the land
11
Q
‘The most significant effect of human activity on urban climates is on humidity.’
With the aid of examples, how far do you agree?
A
- Humidity, which is lower in urban areas, needs to be discussed and explained
- due to: lack of vegetation and high drainage density
- discuss temperature, winds and precipitation in order to evaluate the significance of humidity
-rainwater in cities is unable to be absorbed into the ground to be released into the air by evaporation, and transpiration occurs much less since cities contain little vegetation relative to rural areas - evaporation instead of dew formation at night where there are local sources of heat
- less energy used for evaporation and more for heating of the atmosphere
12
Q
briefly explain the formation of fog
A
- Air cooled close to Earth’s surface.
- Saturated air leads to condensation and water droplets.
- Tiny droplets remain suspended in the air.
- Condensation nuclei present allow water droplets to coalesce and grow.
- Advection fog (warm moist air going over colder surface such as body of water).
- Radiation fog (forming at night – cold calm conditions with radiation away from Earth’s surface).
13
Q
Explain how orographic uplift of air can lead to precipitation
A
- Barrier forces air to rise (mountains).
- Air expands and cools.
- Dew point is reached leading to condensation around hygroscopic nuclei.
- Once saturated, air cools at a lower rate causing instability.
- Collision or Bergeron processes create larger raindrops.
14
Q
define evaporation
A
the process of a change of state from a liquid to a gas (1) by heat (1)
15
Q
Briefly explain the latitudinal radiation surplus in the global energy budget
A
- Located approximately between 40 degrees N and 40 degrees S where incoming solar radiation exceeds outgoing radiation.
- The angle of the sun’s rays below 40 degrees N and S means heat is spread over a smaller land surface.
- Less heat is also lost when rays pass at a low angle through the atmosphere
16
Q
Explain the seasonal variation in global pressure belts
A
- seasonal shift and migration of the ITCZ and LP zones
- due to passage and position of overhead sun
- high pressure is observed during the cold season and low pressure is observed in warm season
- temperature of the air, altitude and moisture
- high latitude and polar region, variation in the pressure is not that great in comparison to tropical region
- Once the mass remains the same but the volume is increased, it lead to decrease in density. Lower dense air has tendency to rise
- Addition of water vapour in the atmosphere causes the air pressure to fall
- equatorial trough: well north of the equator in July whereas in January just south of the equator as land masses are not of sufficient size to displace it southwards ( ocean areas are more equable in terms of pressure and temperature
- In the northern hemisphere there are strong winter low-pressure zones over Icelandic and oceanic areas but in Canada and Siberia there is high pressure due to coldness of the land,in summer high pressure is reduced
- in polar areas pressure is relatively high throughout the year owing to the coldness of the landmass
17
Q
‘The most significant effect of human activity on urban climates is on wind.’
A
- Their main findings showed that calm winds and clear skies result in increased means of urban heat island values. In summer, it was found that an increase of wind speed by 1 m/s causes a 0.14 °C reduction in the intensity of heat island
- winds decrease in urban areas than in suburbs or rural areas
- winds are deflected over high buildings. Buildings affect the winds due to their size, shape and spacing.
- reduction in heat distribution by winds
- large building can cause eddying
18
Q
explain formation of altocumulus clouds
A
- Uplift of air
- Causes of the air rising (orographic / frontal / convection)
- Adiabatic cooling
- Dew point and condensation
- Reference to clear skies / no rain
- Evaporation / transpiration
19
Q
Briefly explain the formation of frontal precipitation
A
- Uplift of air caused by meeting of two air masses
- Warm air rises over colder air at a warm front
- Cold air undercutting warm air at a cold front
- Warm air cools as it rises, condenses (dew point), leads to water droplets which, when of sufficient size, fall as rain
20
Q
define melting
A
Change of state from solid (ice) to liquid (water) (1) if temperature sufficiently high (1)
21
Q
define reflected solar radiation
A
- The energy from the sun as shortwave radiation (1) that is not absorbed but reflected by the surfaces (1)
22
Q
Briefly explain one way solar energy absorbed into the surface affects
A
- The more that is absorbed, the less that is reflected.
- Absorbed solar energy leads to a warming of the surfaces.
- These warm surfaces radiate longwave radiation at night, leading to heat loss which will affect sensible heat transfer and latent heat transfer.
- The role of albedo in the process
23
Q
Explain the seasonal variation in global wind belts
A
- Winds are created by differences in atmospheric pressure
- Atmospheric pressure is affected by heating from the sun
- overhead position of the Earth in relation to the sun, especially between 30 and 45 degrees
- Winds blow from the sub-tropical high pressure areas to the equatorial low pressure areas (doldrums)
- In higher latitudes, winds blow from the sub-tropical high pressure areas to the sub-polar low pressure areas; south west to north east in the northern hemisphere and north west to south east in the southern hemisphere
- These pressure systems move north and south according to the relative position of the sun. This accounts for seasonal variations
- Landmasses also affect the position of the belts, especially due to the differential heating and cooling of land and sea
- low latitude winds (10-30) are mostly easterlies that form reliable trade winds
- 35-60 lat westerlies dominate that contain rapidly evolving and decaying depressions
- monsoon:reverse: continent of Asia: causes winds to blow outwards from high pressure in the winter but pulls the southern trades into low pressure in the summer
- summer in the southern hemisphere means cooling in the northern thereby increasing differences between polar and equatorial air, consequently high level westerlies are stringer in the northern hemisphere in winter
24
Q
‘The most significant effect of human activity on urban climates is on temperature.’
A
- consideration of day and night, as well as location of the urban area
25
Q
define radiation cooling
A
Radiation cooling is the emission of longwave (infrared) radiation (1) from the (Earth’s) surface/at night time (1)
26
Q
Briefly describe how ocean currents affect the atmospheric transfer of energy
A
Ocean currents transfer heat (1) towards poles (1) and vice versa. It is a horizontal energy transfer (1) that affects the air above the sea and influences wind, which leads to atmospheric transfer of energy (1)
27
Q
Explain how frontal uplift of air and orographic uplift of air cause precipitation
A
- in both cases air is forced to rise
- uplift of air causing decrease in pressure, cooling and condensation of air
- Air being forced to rise because of undercutting of warm air by a mass of cooler air (frontal) or because of relief (orographic)
- explanation of adiabatic cooling
- rising relative humidity levels and thus condensation
