Physics of the Climate System part 2

Question 1

Clouds

Answer 1

More Warming => more evaporation => more clouds => clouds cool the earth => less
warming

Question 2

Chemical
weathering

Answer 2

Iniianl change — warmer climate — increased temperature, precipitation, vegetation — increased chemmical weathering — increase c02 removal by weathering — reduction of initail warming

Question 3

Clouds in the Climate
System

Answer 3

• The process of condensation results in the
  formation of clouds.
• Reflect incoming solar radiation
• cools the surface
• Absorb outgoing terrestrial radiation
• warms the surface

Question 4

Cloud Types

Answer 4

• High Clouds (cirrus)
• low reflection
• high absorption
  ‣ net warming effect at surface
• Low Clouds (e.g. stratus)
• high reflection
• high absorption
  ‣ net cooling effect at surface

Question 5

Cloud Feedbacks

Answer 5

Initial warming —- More high clouds
/More low clouds —– more longwave absorption —- more shortwave reflection —- Initial warming

Question 6

Seasonal Radiation Changes

Answer 6

As the season changes into winter, the net radiation becomes negative across much of the Northern Hemisphere and positive in the Southern Hemisphere.

Question 7

Seasonal temperature
changes

Answer 7

• What influences seasonal temperature
  changes?
• Heat capacity
• measures the ability of a substance to absorb heat
• specific heat = amount of energy needed to
  raise 1 gram of something by 1 °C ‣ (Water’s specific heat: 1 calorie = 4.2 Joules; Air 1.0 joules, soil 0.8 joules)
• Heat capacity ratio:
  ‣ Water : Ice : Air : Land = 60:5:2:1

Question 8

Sensible Heat

Answer 8

• Sensible Heat = Heat you
  can sense
• product of the temperature
  of the air and its heat
  capacity
• Sensible heat can be transported
  upwards by convection

Question 9

Water in the Climate System

Answer 9

• High heat capacity
• seasonal temperature change
• long response time of oceans
• Absorbs longwave radiation
• Can absorb and transfer heat through
  phase changes
• => Latent Heat = “hidden” energy

Question 10

Water vapour feedback

Answer 10

Initial change — climate change — increased atmospheric water vapor — increase greenhouse trapping of radiation —increased warming

Question 11

Heat Transport

Answer 11

• More energy received in the tropics
• Atmosphere and ocean circulation
• ~2/3 heat transport in lower atmosphere
• redistribute heat from tropics to the poles
• General circulation

Question 12

Adiabatic Motion

Answer 12

• Adiabatic:
• no energy transfer
  with surrounding
  air
• rising air cools due
  to pressure changes
• Lapse Rate
• temperature change
  with altitude

Question 13

Vertical Atmospheric Forces

Answer 13

• Downward Force:
• Upward Force:
• Hydrostatic balance = Vertical force
  balance in the atmosphere

Question 14

Horizontal Forces

Answer 14

• Pressure gradient force
• air flow from H to L pressure
• Friction
• particularly for surface flow
• Coriolis
• “apparent” force on a rotation sphere

Question 15

The Coriolis Effect

Answer 15

Because the Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere. This deflection is called the Coriolis effect.

Question 16

What is geostrophic balance?

Answer 16

As the air mass starts to move, it is deflected to the right by the Coriolis force. The deflection increases until the Coriolis force is balanced by the pressure gradient force. At this point, the wind will be blowing parallel to the isobars. When this happens, the wind is referred to as the “geostrophic wind”.

Question 17

General Circulation of the Atmosphere

Answer 17

The general circulation of the atmosphere. Hot air rises in the tropics, moves north or south, descends and returns in the equatorial “Hadley cells”. Its path along the surface is bent into the trade winds by the Earth’s rotation (Coriolis Effect). Two other cells in each hemisphere work similarly.

Question 18

General Circulation of the
Atmosphere

Answer 18

What drives the Hadley Cell?
* What is the Inter-Tropical Convergence
Zone?
* Why do desert belts occur around 30
°N/S?
* Why do the Trade Winds blow E to W?
* What direction are the prevailing winds in
the mid-latitudes?

Question 19

Mid-latitude Circulation

Answer 19

• Prevailing winds
  ‣ Persistent H pressure in subtropics (from Hadley Cell)…
• Frontal zones
  ‣ Between subtropical and polar air masses…
  ‣ Cyclones and such like
• Jet stream
  ‣ Carries warm air N and cold air S
• Orographic precipitation
  ‣ Common feature along frontal zones

Question 20

Monsoons

Answer 20

A monsoon is a seasonal change in the direction of the prevailing, or strongest, winds of a region. Monsoons cause wet and dry seasons throughout much of the tropics. Monsoons are most often associated with the Indian Ocean. Monsoons always blow from cold to warm regions.

Seasonal heat transfer between continent
and oceans
* What drives monsoonal circulations?
* Where do they occur?