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Ocean and Atmosphere
Earth’s Heat Budget and Atmospheric Circulation
• 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
•LOW Surface Air Pressure
•HIGH 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
