Atmosphere and weathering (content)

Question 1

Define “climate”

Answer 1

long term average conditions in the atmosphere (temperature, humidity, precipitation)

Question 2

What determines the Earth’s energy budget?

Answer 2

The inputs, throughputs and outputs of heat energy in the atmosphere together determine Earth’s energy budget. It’s the energy budget that governs Earth’s temperature and therefore drives our weather & climate.

Question 3

What is convection?

Answer 3

Convection is a heat transfer process involving the movement of fluids, whether liquids or gases.

When a fluid is heated, particles become more energetic, expand, and become less dense, creating an ascent.

Colder and denser particles then fill the vacant space, creating a continuous flow.

Question 4

What is insolation?

Answer 4

During the day, the sun makes energy in the form of shortwave solar radiation.

This solar radiation is either reflected or absorbed.

Question 5

what affects the amount of insolation an area receives?

Answer 5

The angle of incidence of the suns rays

which is in turn affected by:

Latitude
Time of day
Season
Cloud cover

Question 6

What is Albedo, and how does it affect levels of insolation?

Answer 6

the ratio of reflected to incoming solar radiation, measured as a percentage.

It is expressed from 0, the lowest to 1, the highest

It can also be expressed as a percentage.

Question 7

What is specific heat capacity?

Answer 7

The rate of solar absorption different surfaces have.

e.g the oceans have really high specific heat capacities, as they take ages to warm up.

Question 8

What is surface absorption?

Answer 8

Once the sun’s rays hit a surface, what energy is not reflected is absorbed by that surface and heats up.

Question 9

What dictates the amount of HEAT that is absorbed through surface absorption?

Answer 9

Heat has the potential to be conducted downwards from Earth’s surface into the soil/rock and stored.

How much this happens is controlled by the nature of the material and its Thermal conductivity

Question 10

Rock is a poor thermal conductor, what will this mean for surfaces covered in rock?

Water is a great thermal conductor, what will this mean for surfaces covered in ocean? Also, why is water such a good conductor?

Answer 10

Rock will rapidly heat up in the day/summer, and release all their heat at night/winter, not storing any.

Water will take a long time to heat up during the day/summer, and stores more heat in the winter/night.

Water is a good conductor because it is subject to convection and is a fluid.

Question 11

What is outgoing radiation/long wave radiation?

Answer 11

As the ground warms, due to insolation, heat is re-radiated as relatively weak, long wave ‘thermal’ radiation back into the atmosphere.

This is caught by gases, particularly greenhouse gases like carbon dioxide, water vapour and methane

As a result, much of the heat energy in the lower atmosphere is the result of LW terrestrial radiation, rather than direct heating from the sun.

This goes some way to explaining why temperatures drop with altitude.

some long wave radiation does escape into space.

Question 12

What is sensible heat transfer?

Answer 12

The transfer of warmer and cooler parcels of air through convection and winds.

Question 13

What is sensible heat?

Answer 13

sensible heat is heat given off or absorbed by a surface.

it is predominately given off from the surface and pulled up into the air through convection, producing thermals.

Question 14

What are thermals

Answer 14

thermals are parcels of warm, rising air.

Thermals move heat up vertically, but wind can move the thermals horizontally, influencing the local energy budget.

Question 15

What is Latent heat?

Answer 15

As water evaporates through insolation, it takes up energy from its surroundings to change state. This creates “latent heat”

This heat is released from the water when it condenses into a cloud.

absorption of energy during evaporation causes a drop in temperature in its surroundings.

The opposite occurs when condensation occurs, increasing the temperature of the surrounding atmosphere.

This therefore affects the amount of energy available to raise local energy levels and temperatures.

Question 16

What components are there of the 4 factor night model?

Answer 16

• Long wave radiation
• subsurface supply
• sensible heat transfer
• latent heat (condensation)

Question 17

How does long wave radiation change in the night model?

Answer 17

The ground reradiates heat back into the atmosphere (LW radiation) and if there is cloudless sky then the majority of this heat is lost into space and cools.

If clouds are present then much of the LW radiation is reradiated downwards and temperatures do not change significantly.

Question 18

How does sub surface supply work in the 4 factor night model?

Answer 18

The heat stored in the soil and subsoil during the day can be transferred to the cooled surface during the night.

This energy supply can offset overnight cooling, and reduce the size of the night-time temperature drop on the surface.

Question 19

How does sensible heat transfer change at night?

Answer 19

Warm air moving to a given point (wind + convection) will contribute energy and keep temperatures up.

By contrast, if cold air moves in, energy levels will fall, with a possible reduction in temperature.

Question 20

How does latent heat (condensation) change at night?

Answer 20

The radiation of heat from the Earth’s surface at night causes it to cool down at night.

Water vapour in the air close to the ground is cooled as a result, and it can condense to form dew.

The condensation process liberates latent heat, and supplies energy to the surface, resulting in a net gain of energy.

However, it is possible for evaporation to occur at night. If this happens on a significant scale a net loss of energy might result.

Question 21

Overall summary of nighttime energy budget

Answer 21

There is long wave radiation loss at night (terrestrial radiation)
However on cloudy nights energy loss is reduced

Heat transferred by the sun to the surface during the day, may be released back to the surface at night, increasing temperatures.

Sensible heat transfer still occurs and cold air moving into an area may reduce temperatures whereas warm air moving in will raise temperatures

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

Question 22

How does latitude affect insolation?

Answer 22

1) Due to the earth’s curvature, insolation is more concentrated at lower latitudes.

2) Due to the earth’s curvature, insolation has to go through more atmosphere in the polar regions, leading to significant energy being lost there to reflection.

Thus an energy and temperature imbalance is created as the equator holds significantly more radiation than the polar regions.

Question 23

If the poles are in deficit and the equator is in surplus, why are both locations not exponentially hot/cold?

Answer 23

Winds and ocean currents carry heat from the equator, to the poles

Firth:
A balance is achieved by the horizontal transfer of energy from the equator to the poles by winds and ocean currents to compensate for differences in global insolation

Question 24

Where is the Thermal Equator?

Answer 24

The Thermal Equator is the hottest region of the planet.

It moves depending on the time of year.

In December/ January it is over the Tropic of Capricorn (23.5 south)
In June/ July it is over the Tropic of Cancer (23.5 north)

Question 25

How does the Tri-Cellular Model impact the global energy budget?

How is the global energy budget rebalanced?

Answer 25

Convection in the atmosphere redistributes heat from the thermal equator to polar regions

The surplus of energy at the equator causes the lower atmosphere to heat. The warm gas expands and rises.

As it rises, it cools and its rise slows down. But buoyant air still rising below pushes the air out of the way, forcing it sideways.
With the cooling air moving horizontally away from the equator and the rising air below, it cools, regains density and sinks.

Finally, the resulting high pressure at the Earth’s surface means air is again pushed sideways, it will head towards the area from where it originally rose, or towards where there is low pressure (the next cell).

Therefore, heat makes its way from the equator to the polar cells, rebalancing the global energy budget

Question 26

What is the Coriolis effect?

Answer 26

A phenonemon which causes fluids (liquid/air) to spin as they travel along the earth’s surface.

The slow rotation of the earth toward the east causes the air to be deflected toward the right in the northern hemisphere and toward the left in the southern hemisphere, creating the coriolis effect.

https://www.youtube.com/watch?v=1Y1Qi821n-s

Question 27

How does the coreolis effect create winds, and how do they impact heat transfer?

Answer 27

The coriolis effect creates wind as air in the tri cellular model is diverted from its linear path due to the earths spin. This creates wind belts, which carry warm air in the directions shown on the image below. (towards the convergence zones).

Winds also drive oceanic currents, which contribute to the reheating of descending cold air, allowing the conveyor to work, as cold air coming from the hadley cell is reheated and supplied to the ferrel cell and then polar cell.

https://rwu.pressbooks.pub/app/uploads/sites/7/2019/05/figure8.2.4.png

Question 28

How do the world’s continental land masses affect the global energy budget?

Answer 28

• They have different albedo values.
• The thermal properties of rock and water are different (i.e. specific heat capacity).
• They determine the pathways of ocean currents.

Question 29

How does Temperature and salinity affect water.

Answer 29

Cold water has a higher density than warm water, leading to it sinking.

Saline water has a higher density than fresh water, leading to it sinking.

Question 30

How do Ocean currents affect the global energy budget?

(how does the oceanic conveyor belt form)

Answer 30

• Warm water at the equator flows towards the poles. This heats the atmosphere above it, causing it to lose heat. significant amounts of water also evaporate, leading to salt being absorbed by the remaining, already salty water.
• This leads to the (originally) equatorial waters to sink at the poles, and circulate back to the equator, creating the oceanic conveyor belt.

https://youtu.be/C0ck2njRe9Y

Question 31

How do winds drive ocean currents?

Answer 31

The winds blow surface water causing ocean currents to form. These ocean currents GENERALLY move towards the polar cells, causing warm water to move from the equator to the poles.

Question 32

What are Gyres?

Answer 32

Gyres are “cogs” in the “oceanic conveyor.

They are ciclical currents which are driven by winds. The proximity of gyres to each other helps balance the global energy deficit.

Question 33

What are the most significant impacts of the distribution of land and sea?

Answer 33

• Ocean and coastal areas tend to have more limited diurnal and annual temperature ranges
• There is better heat redistribution by ocean currents in the Atlantic and Pacific oceans than in the Indian Ocean.

Question 34

Why are the east coasts of continents generally more wet than the west?

Answer 34

Wind currents tend to blow west, leading to significant evaporation (as the waters in these currents are warm equatorial waters), leading to increased condensation and precipitation.