Transcript Slide 1

Energy balance at the Earth’s
surface

Dependent on

Solar insolation


All incoming radiation that is intercepted by the Earth
Changes throughout the year and throughout the day
1
Simplified surface radiation budget
+SW -SW +LW –LW = NET R
Incoming
solar
radiation
Outgoing
solar
radiation via
reflection
Incoming
infrared
radiation
Outgoing
infrared
radiation
Net
radiation
2
3
4
Atmospheric Energy Balance
5
Total idealized insolation during 24
hours (daily radiation curve)
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A single day’s radiation budget
875
700
Insolation
+SW
525
350
175
+LW
0
NET R
-175
-SW
-350
–LW
-525
midnight
noon
Surface albedo value
midnight
7
8
Net radiation

Expended from the Earth’s surface three ways

Latent heat of evaporation (more common in moist areas)



Sensible heat (more common in dry areas)


Latent heat is absorbed when water evaporates
Latent heat is released when vapor liquefies
Transfer of energy via conduction, convection, and advection
Ground heating and cooling (greatest between the tropics)
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10
What happens to the energy?

Latent heat



The same energy it takes to melt 1g of ice could heat
1 g of water 80°C.
Sensible heat
Ground heat
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Sensible Heat flux
Latent Heat flux
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13
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Theoretical vs Actual Insolation
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Global Insolation
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