Atmosphere and Weather

Question 1

Incoming solar radiation

Day time energy budget

Answer 1

• The main energy input
• Affected by latitude, season and cloud cover
• The less cloud cover there is and/or the higher the cloud, the more radiation reaches the earth’s surface

Question 2

Reflected solar radiation

Day time energy budget

Answer 2

• Varies with colour – light materials are more reflective than dark materials
• Amount of incoming solar radiation that is reflected by the surfaces
• Lighter surfaces e.g. fresh snow has an avg. albedo of 75-90%
• Darker surfaces e.g. grass has an avg. albedo of 20-30% and dry concrete albedo is 17-27%
• Solar energy (shortwave radiation) is reflected from earth back into space

Question 3

Surface absorption

Day time energy budget

Answer 3

• Energy arriving at the surface has the potential to heat that surface, as heat is absorbed by it
• Nature of the surface has an effect e.g. surfaces can conduct heat rapidly into lower layers of the soil, its temperatures will be low
• If heat is not carried away quickly, it will be concentrated at the surface and result in high temperatures

Question 4

Sensible heat transfer

Day time energy budget

Answer 4

• Used to describe the transfer of parcels of air to or from the point at which the energy budget is being assessed
• If relatively cold air moves in, energy may be taken from the surface, creating an energy loss
• If warm air rises from the surface to be replaced by cooler air, a loss will occur – the process is convection transfer
• During the day it is responsible for removing energy from the surface and passing it to the air

Question 5

Long wave radiation

Day time energy budget

Answer 5

• Emitted by the surface and passes into the atmosphere, and eventually into space
• Downward-directed stream of long-wave radiation from particles in the atmosphere
• Difference between two streams is known as net radiation balance
• During the day, since outgoing stream is greater than incoming one, there is a net loss of energy from the surface

Question 6

Latent heat transfer (evaporation)

Day time energy budget

Answer 6

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

Question 7

Long wave radiation

Night time energy budget

Answer 7

• Loss at night (terrestrial radiation) as nights are often cloudless and there is nothing to return the long wave radiation back to the surface.
• On cloudy nights, energy loss is reduced

Question 8

Latent heat transfer (condensation)

Night time energy budget

Answer 8

• At night water vapour in the air close to the ground can condense to form dew as the air cooled by the cold surface
• Heat is released during this process

Question 9

Sub surface supply

Night time energy budget

Answer 9

• Heat transferred by the sun to the surface during the day

* May be released back to the surfaces at night which can off set the night time cooling at the surface

Question 10

Sensible heat transfer

Night time energy budget

Answer 10

•Cold air moving into an area may reduce temperatures whereas warm air moving in will raise temp.

Question 11

Mist and fog

Answer 11

• Cloud at ground level
• Mist occurs when visibility is between 1000m and 5000m
• Fog occurs where visibility is below 1000m
• Fog is thicker cloud cover than mist
• They form at ground level because air can only hold a certain amount of water
• Colder air can hold less moisture than warmer air
• Once this maximum amount of moisture is reached, air is saturated and water vapour in air turns to liquid
• This is when clouds form as condensation of water vapour to water droplets occur

Question 12

Advection fog

Answer 12

• Warm air passes over a cold surface it is chilled
• Condensation takes place as the temp. of air is reduced and the air reaches dew point (the temp. at which relative humidity is at 100%)

Question 13

Radiation fog

Answer 13

• Occurs when the ground loses heat at night by long wave radiation
• Occurs during high pressure conditions associated w/ clear skies

Question 14

Temperature inversions

Answer 14

• Occurs when warm air meets a cold surface and rapid condensation occurs
• During the day the ground is heated by the sun’s short wave radiation
• After a short time it heats the air above it 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

Question 15

Sea breeze

Answer 15

• On a warm day along the coast, differential heating of land and sea leads to the development of local winds known as sea breezes
• Land is heated quicker than the sea and so the air above the land is warmer than the air above the sea during the day
• As air above land surfaces is heated by radiation from the sun, it expands and begins to rise, being lighter than the surrounding air

Question 16

Land breeze

Answer 16

• Occurs at night when the land cools faster than the sea at night
• Creates 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