Atmosphere and weather

Question 1

what is the energy input in the earths energy budget system?

Answer 1

incoming solar radiation / insolation

Question 2

what affects insolation in an area?

Answer 2

• amounts and type of cloud cover
• the sun’s angle
• earth’s orbit
• earth’s tilt
• latitude

Question 3

how much of insolation is scattered by the atmosphere

Answer 3

5%

Question 4

how much is reflected into space

Answer 4

24%

Question 5

how much is absorbed by atmospheric gasses

Answer 5

23%

Question 6

how much is absorbed by earth’s surface and heats it (surface absorption)

Answer 6

48%
Energy arriving at the surface has the potential to heat that surface, as heat is absorbed by it.
The nature of the surface has an effect, e.g. If the surface can conduct heat rapidly into the lower layers of the soil its temperature will be low. If the heat is not carried away quickly it will be concentrated at the surface & result in high temperatures there.

Question 7

Reflected Solar Radiation-

Answer 7

The proportion of reflected solar radiation varies greatly with the nature of the surface.
The degree of reflection is expressed as either a fraction on a scale of 0 to 1, or as a percentage.

This fraction is referred to as the albedo of the surface. This is simply the proportion of sunlight reflected from a surface.

Fresh snow & ice have the highest albedos, reflecting up to 95% of sunlight.
Ocean surfaces absorb most sunlight, and so have low albedos.

Question 8

define the term albedo and state which material have a higher albedo value

Answer 8

proportion of energy that is reflected back to the atmosphere

lighter materials have a higher albedo value, therefore they reflect more radiation energy

Question 9

what is planetary albedo

Answer 9

proportion of insolation scattered and returned to space by earth

Question 10

subsurface absorption

Answer 10

since darker surfaces absorb more radiation, the energy has potential to be transferred to lower layers via conduction. If conduction is possible, the surface will remain cool as heat is transferred to the soil/bedrock. Conduction is encouraged when moisture is present. This heat is released back to the surface at night, offsetting night-time cooling.

Question 11

what is long wave radiation

Answer 11

sensible heat

This is emitted by the surface, and passes into the atmosphere, and eventually into space.

There is also a downward-directed stream of long-wave radiation from particles in the atmosphere

The difference between the 2 streams is known as the net radiation balance.

During the day, since the outgoing stream is greater than the incoming one, there is a net loss of energy from the surface.

Question 12

formula for daytime budget

Answer 12

insolation – (reflected insolation + surface absorption + sensible heat transfers + latent heat transfers + longwave radiation)

Question 13

formula for nigh-time energy budget

Answer 13

stored energy – (latent heat transfers + sensible heat transfers + longwave radiation)

Question 14

cloud effecf during the day

Answer 14

clouds have a net cooling effect due to their albedo value, causing insolation to be reflected to space.
Cirrus clouds allow insolation to pass through, but not longwave radiation.
Cumulonimbus clouds do not heat or cool well.
Low, thick stratus clouds reflect 80% of insolation, keeping Earth’s surface cool.

Question 15

effect of clouds during the night

Answer 15

thick clouds acts as an insulating layer, absorbing and reradiating longwave radiation which keeps nights warm. Warm clouds can also emit longwave radiation out to space.

Question 16

define sensible heat transfer

Answer 16

This term is 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 also occur.
This process is best described as convective transfer, and during the day it is responsible for removing energy from the surface and passing it to the air.

Question 17

what is the atmopshere

Answer 17

The atmosphere is an area of transparent gases surrounding the earth
The gases stretch to 500-1000km above the earth’s surface
There are several layers to the atmosphere
The area between layers is called a pause
Weather occurs only in the lowest part of the earth’s atmosphere called the troposphere.

Question 18

define weather and climate

Answer 18

The atmosphere is an area of transparent gases surrounding the earth
The gases stretch to 500-1000km above the earth’s surface
There are several layers to the atmosphere
The area between layers is called a pause
Weather occurs only in the lowest part of the earth’s atmosphere called the troposphere.

Question 19

layers of the atmosphere

Answer 19

• troposphere
• stratosphere
• mesosphere
  -thermosphere
• exosphere

Question 20

what is the area between the layers called?

Answer 20

pause

Question 21

define insolation

Answer 21

short wave radiation that comes directly from the sun

Question 22

scattering

Answer 22

radiation diverted by gas molecules

Question 23

latent heat energy

Answer 23

occurs when water evaporates to water vapour, or ice melts into water vapour. Heat required to change state is absorbed from the air, leaving less energy to heat the surface. Latent heat of condensation increases the speed and extent of convection.

The turning of 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 be used to evaporate it.
Consequently, that energy will not be available to raise local energy levels and temperatures.

Question 24

examples of latent heat transfer

Answer 24

a. Evaporation: water molecules gain enough energy from surrounding air to change state to a gas, and leave the surface. This leaves overall energy less at the surface, so the surface and air cool.

Dew: water saturated air comes into contact with an object with a temperature cooler than the airs dew point. Water vapour condenses into liquid form. Latent heat is released during condensation, adding heat to the ground.

Absorbed Energy returned to Earth: greenhouse gasses absorb reradiated longwave radiation and atmosphere warms.

Question 25

features of the day-time energy budget

Answer 25

the budget assumes that the ground is horizontal and covered in grass

• insolation
• reflection by clouds
• scattering by greenhouse gases
• absorption by the surface
• sensible heat transfer
• latent heat transfer
• long wave radiation

Question 26

features of the night time energy budget

Answer 26

• longwave radiation
  -sensible heat transfer
• heat supply to surface
• condensation : supply of heat as dew forms of surface

There is long wave radiation loss at night (terrestrial radiation) as often nights are cloudless so there is nothing to return the long wave radiation back to the surface.
However on cloudy nights energy loss is reduced
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
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 27

convection

Answer 27

thin air layer heated above surface (poor conductor), molecules vibrate more, gas is less dense so rises. Air cools, becomes denser and falls, to replace rising air. At night, air might sink at night in higher latitudes. Some advection may occur.

Question 28

conduction

Answer 28

heat transfer between the ground and the air when they are in contact.

Question 29

Surface Temperature Changes

Answer 29

during the day, the surface is heated by radiation, conduction, and convection. Surface air moves slow due to friction, is heated, and rises as a result of convection. At night, ground is cooled by lack of radiation, heat from soil and rocks rises to heat the surface.

Question 30

excess

Answer 30

positive radiation budget in the tropics. Occurs because insolation is so concentrated.

Question 31

deficit

Answer 31

negative radiation budget at higher latitudes. Insolation has a larger amount of atmosphere to pass through, there is more chance of reflection back to space, and rays are less concentrated.

Question 32

balance

Answer 32

neither regions are getting warmer/colder, horizontal transfer from the tropics to higher latitudes compensate to global insolation differences.

Question 33

vertical rays

Question 34

oblique rays

Question 35

temperature patterns

Answer 35

little seasonal variation at the equator, but great variation in mid/high latitudes. A lag time exists between overhead sun and maximum insolation, as the atmosphere is heated from below, not above. Coldest period is after winter solstice, as ground continues to lose heat despite resumed insolation. Greater lag time over ocean due to high specific heat capacity compared to land.

Question 36

evaporation

Answer 36

occurs when vapour pressure of a water surface exceeds that in the atmosphere. Sped up by: low initial air humidity, heat and strong wind.

Question 37

absolute humidity

Answer 37

actual amount of water vapour in a given volume of air.

Question 38

relative humidity

Answer 38

actual moisture content*100 / saturation moisture content at the same temp press

Question 39

condensation

Answer 39

further cooling below dew point temperature, or when an air mass reaches saturation – turns water vapour into a liquid water. When hygroscopic condensation nuclei are present.

Question 40

conduction cooling

Answer 40

leads to condensation when moist air contacts a cold object.

Question 41

expansion cooling

Answer 41

air rises and expands due to reduced pressure in atmosphere. Expansion causes a temperature drop.

Question 42

radiation cooling

Answer 42

heat lost to space by longwave radiation from clouds and gases in atmosphere.

Question 43

define freezing

melting

deposition

sublimation

Answer 43

Freezing: liquid water changes into a solid once temperature falls below 0°C.

Melting: the change of state from solid to liquid above 0°C.

Deposition: transition from water vapour to ice, with no intermediate stage. May deposit on surfaces.

Sublimation: transition from ice to water vapour, with no intermediate stage. Might occur in low humidity.

Question 44

what is precipitation ?

Answer 44

all forms of deposition of moisture from the atmosphere in either solid or liquid states. It includes rain, hail, snow, sleet and dew.

Question 45

what are the causes of precipitation

Answer 45

Water vapour in the air is condensed into tiny water droplets forming clouds. If these droplets join together (coalesce) to form large droplets they get heavier. When they are heavy enough to overcome ascending air currents they fall as rain. The droplets must get large enough to form rain drops and there are several theories on how this happens.

-Coalescence( joining) by sweeping where a falling droplets sweeps up others in its path
-Growth of droplets by electrical attraction to each other
-Condensation around nuclei e.g. dust particles

Question 46

collision theories

Answer 46

droplets in clouds collide together (after rising and falling at different rates based on their size) to from a larger droplet.
Coalescence: two droplets combine to form rain.
Aggregation: two ice crystals collide to form snow.
Accretion: ice crystal collects a water droplet, forming hail.

Question 47

explain the Bergen-Findeisen Theory

Answer 47

air is saturated with ice before water is added. When air temperature is between -12°C and -30°C, air can only be saturated over ice, so water droplets must evaporate. Ice particles grow when the air has a mix of ice and water, as a result of sublimation. Water vapour deposits on ice crystals. Precipitation occurs once ice crystals have aggregated into a large enough snowflake to fall. When falling, ice may melt into rain.

Question 52

what are the causes of

Question 53

what are the causes of

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