Atmospheric and Ocean Circulation

Question 1

Natural and anthropogenic CO2 increase

Answer 1

• More than 1/2 of the observed temperature
  since 1951 is caused by human forcing
• Oceans observing twice as much heat since
  1997

Question 2

ENSO

Answer 2

El Niño Southern Oscillation

• El Niño and La Niña alternate every 2 to 7
  years

Question 3

Normal El Niño conditions

Answer 3

• Pacific Ocean absorbs a large volume of
  solar heat = fall in atmospheric pressure
  around the western tropical pacific
• Trade winds flow in an east to west direction
  causing a westward migration of warm water
  = warm pool along the coast of countries
  located in the west Pacific
• Upwelling in the east as colder water, from
  deep within the ocean, rises up to replace
  the loss of the warmer water from the
  western coasts
• A temperature difference occurs between
  the east and west pacific
• Increase in surface temperature of the ocean
  in the east results in the warm air to rise up
  into the atmosphere more vigorously =
  powerful storms in the west

Question 4

El Niño

Answer 4

• Rising air in the east causes the
  thunderstorms that were experienced in
  western Pacific countries to affect those
  located in the south
• Normal weather conditions is reversed during
  an El Niño with warm water being present in
  the east
• Drought = Australia, Indonesia
• Heavy rains normally occur along the west
  coast of South America due to warm air
  rapidly rising up into the atmosphere

Question 5

La Niña

Answer 5

• Higher atmospheric pressure and much
  cooler temperatures in comparison to the
  normal conditions
• Colder temperatures shift from being in the
  west to the east; therefore the conditions
  experienced during a La Niña is the opposite
  of what occurs during an El Niño
• Droughts typically occur in areas such as
  South America
• Heavy rainfall in the western countries such
  as Indonesia
• Colder temperatures cover the majority of
  equatorial areas in comparison to the other
  conditions.

Question 6

Atmospheric structure

Answer 6

• All weather occurs in the troposphere
• Extends 12km above surface
• 80% mass

Question 7

Energy in the atmosphere - conduction

Answer 7

• Heat energy is transferred via contact to
  neighbouring particles
• Air is poor conductor so conduction occurs at
  the surface

Question 8

Radiation

Answer 8

Transfer of heat energy without the physical substance e.g. the Suns electromagnetic wave

Question 9

Convection

Answer 9

Heat energy transferred by movement of molecules with a substance. Both water and air transport heat by moving energy particles

Question 10

Heat capacity

Answer 10

Heat energy required to change the temperature of an object by a given amount. Water has a higher capacity than land

Question 11

Latent heat

Answer 11

Is the transfer of heat (also through convection) but the energy is hidden in the form of water.

Water has a higher heat capacity - can hold 4 x more gas in the atmosphere

The amount of water vapour air can hold depends on temperature

Question 12

Saturation vapour density

Answer 12

Measure of how much H2O air can hold

Question 13

Latent heat energy more explained

Answer 13

• Air much better at transporting
  energy in medium to high
  latitudes
• higher latitudes = takes the bulk
  of the heat
• Warm tropical air (30 degrees
  Celsius) holds 10 x more water
  than in the poles

Question 14

Lower latitude energy

Answer 14

Surplus

Question 15

Higher latitude energy

Answer 15

Deficit

Question 16

Transport of heat

Answer 16

Ocean is most important in transporting heat out of the tropics

Question 17

Circulation patterns controlled by

Answer 17

• Heating by solar radiation
• Pressure gradient force
• Coriolis force

Question 18

Coriolis force

Answer 18

The force that causes a deflection of objects as they move across a rotating surface

Question 19

Model 1: single cell, non rotating

Answer 19

• non rotating
• no Coriolis force
• pressure gradient force

Question 20

Model 2: single cell rotating sphere

Answer 20

• rotating and so a Coriolis force

Question 21

Model 3: three cell rotating sphere

Answer 21

Three cells:

• Hadley cell (0-30*)
• Ferrel cell (30-60*)
• Polar cell (60-90*)

Coriolis force

Hot air continues to rise at 30* and not at the poles

Question 22

Doldrums

Answer 22

Belt of low pressure that forms around the equator

Question 23

Ocean gyres

Answer 23

Result of the initial drag of the winds. Largely driven by atmospheric system

Question 24

Ekman transport

Answer 24

Results in major direction of ocean movement to be 90* to the direction of the wind

Centre of gyres are 2m higher in Atlantic

Occurs at the coast

Question 25

Feedbacks

Answer 25

Processes that alter climate changes already underway, either amplifying (positive) them or suppressing (negative) them

Question 26

Water vapour

Answer 26

POSITIVE and REVERSIBLE

Most efficient ghg trapping radiation - triples the amount of warming

Initial change
          |
         \/
Climate warming
          |
         \/
Increased atmospheric water vapour
          |
         \/
Increase ghg trapping of radiation
          |
         \/             
Increased warming

Question 27

Albedo

Answer 27

POSITIVE
Important for glacial = cooling

Instant change
          |
         \/
Climate cooling
          |
         \/
Increased snow and ice: higher reflectivity
          |
         \/
Less solar radiation absorbed at surface
          |
         \/
Greater cooling

40% amplification

Question 28

Vegetation

Answer 28

POSITIVE and REVERSIBLE

Forest replacing grassland increasing water vapour in the atmosphere - increasing moisture for precipitation

Initial change
          |
         \/
Increased precipitation
          |
         \/
Forest replaces grassland
          |
         \/
Increased transpiration of water vapour
          |
         \/
Additional precipitation

Initial change
          |
         \/
Warmer climate
          |
         \/
Increased temperature, precipitation and vegetation
          |
         \/
Increased chemical weathering 
          |
         \/
Increased CO2 removal by weathering
          |
         \/
Reduction of initial warming