Chapter 6 AirSea Interaction

1
Chapter 6 AirSea Interaction
2
Uneven Solar Heating

• Horizontal Solar Rays

• Equator, rays are perpendicular to surface
• High latitudes, rays are directed at an angle
• Energy gets spread out over larger area

3
Earths seasons

• Earths axis is tilted 23º from vertical
• Tilts Northern (Southern) hemisphere closer to
  the Sun
• Northern and Southern Hemispheres alternately
  tilt toward and away from the Sun
• Seasons
• Causes longer days and more intense solar
  radiation during summer
• Causes shorter days and less intense solar
  radiation during winter

4
Earths seasons
5
Uneven Temperature
6
Temperature

• Troposphere is
• Lowermost part of the atmosphere
• Where most weather occurs
• Temperature of troposphere cools with increasing
  altitude

7
Composition (dry air)
8
Water vapor

• Cool air cannot hold much water vapor, typically
  dry
• Warm air can hold more water vapor, typically
  moist
• Water vapor decreases the density of air
• Relative Humidity
• Amount of Water Vapor in Air divided by Maximum
  Amount of Water Vapor that could be in Air
• Typical Southern California R.H. is 50, Boston
  R.H. is 80

9
Pressure

• A column of cool, dense air causes high pressure
  at the surface, which will lead to sinking air

10
Pressure

• A column of warm, less dense air causes low
  pressure at the surface, which will lead to
  rising air

11
Wind

• Air always moves from high-pressure regions
  toward low-pressure regions
• Moving air is called wind

High Pressure
Low Pressure
12
Density

• Warm, low density air rises (it is buoyant)
• Cool, high density air sinks
• Creates circular- moving loop of air (convection
  cell)

Figure 6-5
13
Earths Convection Cell
14
The Coriolis effect
Different latitude bands
r1
r2
Which spot on earth moves the fastest?
15
The Coriolis effect on Earth

• As Earth rotates, different latitudes travel at
  different speeds
• The change in speed with latitude causes the
  Coriolis effect

16
Air Movement

• Two air parcels are moving toward New Orleans in
  the Northern Hemisphere
• Both air parcels curve to the right
• If this were in the Southern Hemisphere they
  would turn left

17
Coriolis effect

• To an observer above the merry-go-round, objects
  travel straight
• To an observer on the merry-go-round, objects
  follow curved paths

18
The Coriolis effect

• The Coriolis effect
• Is a result of Earths rotation
• Causes moving objects to follow curved paths
• In Northern Hemisphere, curvature is to right
• In Southern Hemisphere, curvature is to left
• Changes with latitude
• No Coriolis effect at Equator
• Maximum Coriolis effect at poles

19
Circulation Cells

• Hadley Cell
• Rises at equator
• Descends at 30N/S
• Ferrel Cell
• Rises at Arctic / Antarctic circle
• Descends at 30N/S
• With Hadley Cell
• Polar Cell
• Rises at Arctic / Antarctic circle
• With Ferrel Cell
• Descends at pole

20
Wind Belts

• Surface portion of circulation cells are effected
  by Coriolis
• Hadley Cell
• Surface wind, north to south
• Bent right in NH, left in SH
• NE Trade winds, SE Trade winds
• Ferrel Cell
• Surface wind, south to north
• Bent right in NH, left in SH
• Prevailing westerlies
• Polar Cell
• Polar easterlies

21
Wind belts and boundaries
22
Real World
23
Uneven Heating

• Heat Capacity, Hcap
• Amount of energy to raise 1 g of material 1C
  higher
• Hcap of water, high
• Hcap of rock, low

24
Cyclonic, Anticyclonic Flow

• Northern Hemisphere winds curve to the right as
  they move from high to low pressure
• Causes wind to circulate
• Clockwise around high-pressure regions
• Counterclockwise around low-pressure regions

25
Origin and paths of tropical cyclones

• Tropical cyclones are intense low pressure storms
  created by
• Warm water
• Moist air
• Coriolis effect
• Includes
• Hurricanes
• Cyclones
• Typhoons

26
Hurricane structure

• Hurricanes have
• Circular cloud bands that produce torrential rain
• The ability to move into the mid-latitudes
• A central eye

27
Hurricanes produce storm surge

• Storm surge
• Is a rise in sea level created by hurricane
  coming ashore
• Can be up to 12 meters (40 feet) high
• Causes most destruction and fatalities associated
  with hurricanes

Figure 6-18
28
Oceanic heat flow

• A net heat gain is experienced in low latitudes
• A net heat loss is experienced in high latitudes
• Heat gain and loss are balanced by oceanic and
  atmospheric circulation

29
How a greenhouse works

• Sunlight (visible and UV) passes through the
  clear covering of a greenhouse
• It is converted to longer wavelength heat energy
  (IR)
• Heat (and IR) cannot pass through the covering
  and is trapped inside

30
The heating of Earths atmosphere
31
Anthropogenic gases that contribute to the
greenhouse effect
32
Carbon dioxide is increasing in the atmosphere
33
Earths average temperature is rising

• Earths average surface temperature has risen at
  least 0.6C (1.1F) in the last 130 years
• May be related to increase in atmospheric carbon
  dioxide
• Arctic ice sheet breaking up
• Glaciers throughout the world melting

34
Predicted changes with increased greenhouse
warming

• Higher than normal sea surface temperatures that
  could affect world climate
• More severe droughts or increased precipitation
• Water contamination and outbreaks of water-borne
  diseases
• Longer and more intense heat waves
• Shifts in the distribution of plants and animals
• Potential melting or enlargement of polar ice caps

35
Dissolved gasses