Ocean and Atmosphere
Earth’s Heat Budget and
Atmospheric Circulation
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Atmospheric properties
Earth’s Energy Budget
Vertical Atmospheric Circulation
Surface Atmospheric Circulation
Atmospheric Temperature
Water vapor saturation pressure
How much water
vapor the air can
“hold”
Density of Air
• Which is more dense, DRY air or
HUMID air?
– Air:
N2 (14*2=28)
O2 (16*2=32)
– Water: H2O (2+16=18)
Light molecules displace heavier molecules…
Density of Air
• Humid air is light, and rises
• Dry air is heavy, and sinks
Water vapor, convection, condensation
1. Adiabatic Expansion  Cooling
2. Condensation  Release latent heat of vaporization
Water Budget
Earth’s Heat Sources
• Geothermal = 0.1 cal/cm2/day
• Solar = 2880 0.1 cal/cm2/day
BALANCED BUDGET!
– Wavelength (μm) = 2900 / T (Ko)
• SUN = 2900/5600 ≈ 0.5 μm (visible light)
• Earth = 2900/290 ≈ 10 μm (infrared)
Sun’s Radiation
Earth’s Heat Budget
Earth’s Heat Budget
Atmosphere reflection and
absorbance
Global Warming: Increased heat
absorption in the atmosphere
Seasonal variability in solar
radiation
Latitudinal variability in solar
radiation
Latitudinal Heat Budget
So what are the effects of
uneven heating?
• Less Dense Air:
– HOT
– HUMID
• More Dense Air:
– COLD
– DRY
Atmospheric Convection in a
NON-Rotating Earth
•HIGH Surface Air
Pressure
•LOW Surface
Air Pressure
Low & High Pressure
But…
The Earth Spins!
FLASH NEWS:
The US attempts to
stop the axis of Evil
by bombing Quito
(Ecuador), using
cannons located in
Buffalo (NY)!
Bombing of Quito from Buffalo
Bombing of Quito from Buffalo
Bombing of Quito from Buffalo
Earth Rotation: Coriolis Effect
• Apparent deflection force due to Earth’s
rotation
• Acts on freely moving objects
• North Hemisphere: Deflection to the right
• South Hemisphere: Deflection to the left
• C = (2Ωsin(lat))v
– V=velocity of a particle in motion
– Ω=constant (angular velocity of Earth)
• So:
– High v = high C ; High latitude = high C
– No Coriolis at equator, maximum at poles
Figure 6.16
Figure 6.17
Atmospheric Convection Cells
Figure 6.19
Global atmospheric generalities
• Hadley Cells (subtropical) are quite
stable
• Pressure systems:
– Equator: LOW (Doldrums or ITCZ- Inter
Tropical Convergence Zone)
– 30’s: HIGH (Horse Latitudes)
– 60’s: LOW
Figure 6.21
Horse latitudes
Doldrums
Global atmospheric generalities
• Hadley Cell is quite stable
• Pressure systems:
– Equator: LOW (Doldrums or ITCZ- Inter
Tropical Convergence Zone)
– 30’s: HIGH (Horse Latitudes)
– 60’s: LOW
• In between Pressure systems:
– WIND!!
• Trade Winds
• Westerlies: (Roaring Forties, Screaming
Fifties)
Figure 6.19
Seasonal Wind Variation
Seasonal Wind Variation
Monsoons (Indian Ocean)
Precipitation / Evaporation
Surface Ocean Salinities
Land – Ocean Temperatures
Local Winds: Sea Breeze
Local Winds: Coastal Fog
Local Winds: Mountain or
Island Effect