Atmospheric and Ocean Circulation Flashcards

1
Q

Natural and anthropogenic CO2 increase

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

ENSO

A

El Niño Southern Oscillation

  • El Niño and La Niña alternate every 2 to 7
    years
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3
Q

Normal El Niño conditions

A
  • 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
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4
Q

El Niño

A
  • 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
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5
Q

La Niña

A
  • 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.
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6
Q

Atmospheric structure

A
  • All weather occurs in the troposphere
  • Extends 12km above surface
  • 80% mass
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7
Q

Energy in the atmosphere - conduction

A
  • Heat energy is transferred via contact to
    neighbouring particles
  • Air is poor conductor so conduction occurs at
    the surface
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8
Q

Radiation

A

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

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9
Q

Convection

A

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

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10
Q

Heat capacity

A

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

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11
Q

Latent heat

A

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

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12
Q

Saturation vapour density

A

Measure of how much H2O air can hold

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13
Q

Latent heat energy more explained

A
  • 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
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14
Q

Lower latitude energy

A

Surplus

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15
Q

Higher latitude energy

A

Deficit

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16
Q

Transport of heat

A

Ocean is most important in transporting heat out of the tropics

17
Q

Circulation patterns controlled by

A
  • Heating by solar radiation
  • Pressure gradient force
  • Coriolis force
18
Q

Coriolis force

A

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

19
Q

Model 1: single cell, non rotating

A
  • non rotating
  • no Coriolis force
  • pressure gradient force
20
Q

Model 2: single cell rotating sphere

A
  • rotating and so a Coriolis force
21
Q

Model 3: three cell rotating sphere

A

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

22
Q

Doldrums

A

Belt of low pressure that forms around the equator

23
Q

Ocean gyres

A

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

24
Q

Ekman transport

A

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

25
Feedbacks
Processes that alter climate changes already underway, either amplifying (positive) them or suppressing (negative) them
26
Water vapour
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 ```
27
Albedo
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
28
Vegetation
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 ```