Week 5

Question 1

What happens if F>0

Answer 1

the earth needs to warm in order to emit more infrared energy to space and re-establish radiative balance

Question 2

What is λ? and what are the measurments?

Answer 2

w/m^2/oC

determines how efficiently the earth cools to space per unit of global warming

Question 3

Why does the atmosphere circulate?

Answer 3

fuelled by solar energy
- it works to redistribute heat horizontally (eddy currents circulate circularly and correolis effect) and vertically (convection)

• more energy is focused in the tropics and less in high latitudes therefore there is more heating in some areas

Question 4

What is the meriodional distribution of radiative heating?

Answer 4

Idea that there is an uneven distribution of solar radiation = there is more heating near the equator than at the poles - the beam is spread over a larger area which decreases the flux of energy per unit of area

Question 5

What is the consequence of meridional distribution of radiative heating?

Answer 5

in the tropics the atmosphere recieves more heat than it can radiate away

the excess radiative energy in the tropics is transported to higher latitudes by the circulation of the atmosphere and the ocean

this varies depending on the season

Question 6

what would a net short or long wave mean?

Answer 6

Net short = net solar radiative heating

net long = net infrared radiative cooling

Question 7

What is the biggest source of energy transport?

Answer 7

the atmosphere but oceans are also important for energy transport

Question 8

Can you describe the energy transport between the poles and the tropics?

Answer 8

Northward is defined as postive so the transport is positive to the NH

negative in the SH - but oceans also important for transport especially in the tropics

the graph for this is a flipped S with a line down the middle for the southern hemisphere it is negative for the northern is it positive

Question 9

What are the two ways that meriodional energy is transported?

Answer 9

The mean meridional circulation - north south

eddy (turbulent) motions - spinning motion or turbulence

Question 10

Can you explain how heat and convection work?

Answer 10

Air is heated from the surface, it becomes less dense than the air above it and start to rise = convection

air will stop rising when it is sufficiently cooled by radiation

the air has to be replenished from the surface and this created cells - due to the rotation of the earth the cells break up –> 3x per hemisphere
this is further influenced by the trade winds, westerlies and polar easterlies

rising air is warm, sinking air is cool - contributes to the transport of heat in the tropics to the polls

Question 11

Tell me about the Hadley cell?

Answer 11

tropical cell - profound impact on the climate - important for rainfall and cloud distribution

Question 12

What are the three kind of winds and where do they move to and how?

Answer 12

Trade winds - equator to the west - bend in both hemispheres

westerlies - west to east

easterlies - east to west

Question 13

Why are the winds not straight?

Answer 13

The rotation of the earth deflects the waves therefore the turn in a different direction

Question 14

What is the Coriolis force?

Answer 14

the force that affects flow in a rotating frame of reference

• we are spinning around an axis - at the poles there is a small circle at the equator it is a much bigger circle in terms of distance travelled

Question 15

What is the effect of the coriolis force?

Answer 15

the velocity at which the earth’s surface rotates varies with latitude

this has an impact on the atmosphere and ocean circulation

this can be more noticeable in some regions compared with others due to this idea of the distance travelled in each rotation being different at the poles compared to the equator

Question 16

What is the impact of the coriolis effect on deflection?

Answer 16

Northern - to the right
Southern- to the left

there is low pressure in the middle - therefore a lack of air there and air likes to flow to low pressure therefore the air surrounding it starts to go inwards

correolis force happens and the air moving to the centre will bend to the right (n)/left(s) depending on the hemisphere - therefore the air flows inwards and bends creating a spiralling motion around the area of low pressure

they are counter clockwise in the north and clockwise in the south in a spinning motion

Question 17

What are low and high pressure systems associated with?

Answer 17

Low pressure is associated with storms - low pressure has weak descent and as it cools it causes condenssation and cloud formation

high pressure has less clouds - high pressure has descent and the air is dry

Question 18

What do storms contribute to energy mixing?

Answer 18

They are a large source of energy transport or heat transport in the atmosphere

they mix cold and warm air

Question 19

What gives rise to the jet stream?

Answer 19

the difference in temperature - warmer regions on one side and cold on the other - drives winds

add the effect of rotation

Question 20

What is the jet stream?

Answer 20

belts of strong eastward winds in the mid-latitudes of each hemisphere in the upper atmosphere of about 10km

• coincident with strong temperature gradients - typically warm air is in the south and cold air is in the north

get their energy from the temperature difference between tropics and high latitudes

Question 21

What drives ocean currents?

Answer 21

• surface winds
• temperature and salinity differences - both of which control density

Question 22

What is the relationship between denisty and temperature of the ocean?

Answer 22

Density increases with decreasing temperatures and increasing salinity

the densiest waters are found near the sea ice margins, very cold water and high salinity - because salt is left behind when ice forms

density reduces with temperature as water increases it expands and the same mass of water takes up more volume

Question 23

Why is water density important for the heat transfer in the ocean ?

Answer 23

Dense water sinks - it is cold so cold water sinks - this is critical for the overturning of water as it mixes things

Question 24

What is the Atalantic meridional overturning circulation

Answer 24

ocean circulation that transports heat from low to high latitudes on average

• very complicated pattern of deep water formation and surface level warm currents

Deep water formation near the poles as close to sea ice - heat is being released to the atmosphere warm waters are flowing towards the norm - heat release thus transport

Question 25

What percentage of extra heat in the climate goes into the ocean? why?

Answer 25

90%

have a high heat capacity and can take a lot of energy to heat water by a certain amount compared to the low heat capacity of air and land

this means it will take a long time for oceans to reach an equilibrium even if we stopped emitting Co2 today the oceans would continue to warm

Question 26

What is the difference between an ice sheet and an ice shelf?

Answer 26

Ice sheet = large mass of continental ice - flow on long timescales - idea of ablation and accumulation for growth

ice shelf = a thick floating platform of ice that forms where a glacier or ice sheet flows onto the sea

Question 27

What is the relationship between ice sheets and ice shelves?

Answer 27

ice sheets can become unstable when ice shelves disappear

potential for accelerated sea level rise if this happens

• ice shelves are floating - holds the ice sheet back due to this bouyancy - if this is gone, the flow of the ice sheet into the ocean will increase potential for ACC. melting and sea level rise

warming of ocean melts the ice sheet from below - lubricant to accelerate flow into warm oceans - ACC. warming

Question 28

What is the issue with ice sheets?

Answer 28

They are non-linear - the only way to build an ice sheet is accumulation over years and can be lost v quickly - tipping point

Question 29

Briefly describe the water cycle?

Answer 29

It is the exchange of water over reseviours, laakes, vegetation etc. water is transported from the oceans/bodies of water to land as vapour

flows back to the ocean/water bodies through runoff - surface and groundwater

formation of clouds and rainfall - exchange of water

Question 30

What determines global wet and dry regions?

Answer 30

The distribution is determined by the circulation of the atmosphere which transports heat and moisture

• idea of the circulation cells - warming and cooling air and differing amount of cloud and rainfall - peaks at mid-latitiudes - cell convergence

Question 31

What are the future changes for the water cycle?

Answer 31

on average - wet gets wetter and dry gets drier - wind patters are exacerbated - more moisture away from the sub tropics and brinign more into the mid-lat

direct consequence of the higher oisture content in the atmosphere - Clausius- Clayperson

important for future water management in the sub-top, med regions

Question 32

How will precipitation change in the future?

Answer 32

Projected to decrease over the Med, South Africa and Aus

more precp - Equitorial regions and at high lat

pattern is not symmetrical - what happens is dependenton winds and this is a great uncertainty

Question 33

Can you briefly describe the carbon cycle? like what are the major components? and how have humans messed this up?

Answer 33

Atmosphere, ocean, land and geological reservoirs

rapdi cycling btween land, atmosphere and ocean reservoirs

much slower cycling between geological and other reservoirs

without human activity the fluxs are in balance - the size of each reservoir stays constant

HUMANS…
- perturbed the cycle - extracting carbon from the geological res. in ff.
- land use - deforestation

this cannot be balanced easily because it takes a long time to put carbon back into the geological res.

Question 34

How much of the total carbon budget has gone into the ocean and the land?

Answer 34

the ocean accounts for 25% of ALL the CO2

25% in the land

the remaining has gone into the atmosphere

Question 35

What is the impact of the biosphere?

Answer 35

Plants take up Co2 and emit oxygen in photosynthesis

plants required CO2 for respiration - grow better with more co1

Question 36

What is the role of the ocean in terms of CO2?

Answer 36

the ocean takes up Co2 in two ways

• the biological pump - tiny organisms take up C02 as they grow and deposit on sea floor as they die and sink
  = form ff
• the solubility pump - Co2 is directly taken up by seawater

Question 37

Describe the process of ocean acidification?

Answer 37

When Co2 disolves in water - it forms Carbonic Acid

this lower the pH - makes it more acid

Question 38

What are the white cliffs of dover made out of?

Answer 38

Carbonate

formed by the sedimentation of tiny organisms at the bottom of the ocean over millions of years

Question 39

What is the relationship between carbonate and ocean acidification?

Answer 39

carbonate tends to dissolve as water becomes more acidic

organisism that rely on carbonate eg. coral or mollusks - struggle to build their shells

ocean acidification interuprs this biological cycle

Question 40

Why does global warming cause sea level rise?

Answer 40

• water expands as it warms - thermal component
• glaciers melt
• ice sheets melt

NB MELTING SEA ICE DOES NOT CAUSE SEA LEVEL RISE - THIS IS BECAUSE IT IS FLOATING THINK ABOUT A GLASS WITH ICE IN IT

Question 41

What sort of time scale will oceans warm?

Answer 41

Long time scales - idea of the high heat capacity of oceans - even if we stop emitting carbon the seas will continue to warm

there is a delayed ocean waring in response to present and past emissions

Question 42

Can you briefly outline the different time scales of the climate spheres? Fastest–>slowest

Answer 42

response to forcing occur at different scales
FAST
- atmosphere
- oceans - decades (top layer) to thous (deep ocean)
- ice sheets - tho to adjust

Question 43

What is the imapct of the different climate sphere time scales for climate models?

Answer 43

Makes it very difficult to predict the long term impacts of GHG emissions

Question 44

What are the five spheres?

Answer 44

Lithosphere

Cryosphere

Biosphere

Hydrosphere

Atmosphere