The Global Heat Budget

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The Global Heat Budget

• Air-sea exchanges of heat ( freshwater) create
  deep water masses drive the conveyor belt
• Heat source into the ocean is solar radiation
• There are several heat loss terms
• latent, conduction, longwave radiation,
  reflected solar
• Ocean circulation moves heat (advection)

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Solar Radiation
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Solar Radiation
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The Heat Budget

• Total heat flux (Qt) Solar radiation (Qs)
• - Latent heat loss (Qe)
• - Conductive heat loss (Qh)
• - Longwave radiation (Qb)
• Qt Qs - Qe - Qh - Qb

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Heat Loss Terms

• Latent heat flux (Qe)
• Energy required to evaporate water
• Most important in tropics midlatitudes
• Conductive (or sensible) heat flux (Qh)
• Loss to turbulent exchange with atmosphere
• Typically small
• Longwave radiation (Qb)
• Net thermal IR emission from ocean

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Global Heat Budget
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Net Solar Radiation
Typical Jan Tropics 200 W/m2 Mid-latitudes
100 W/m2 High-latitude 10 W/m2
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Latent Heat Loss
Typical Jan Tropics 120 W/m2 Mid-latitudes
100 W/m2 High-latitude 20 W/m2
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Conductive Heat Loss
Typical Jan Tropics 0-10 W/m2 Mid-latitudes
0-40 W/m2 High-latitude 0-30 W/m2
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Net Longwave Radiation
Typical Jan Tropics 40-50 W/m2 Mid-latitudes
60-70 W/m2 High-latitude 30-50 W/m2
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Total Heat Flux
Typical Jan Cool NH Heat - SH WBCs -200
W/m2 SH Subtropics 70 W/m2 NH Subtropics
gt -80 W/m2
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Total Heat Flux
Typical July Heat NH Cool SH NH Subtropics
100 W/m2 SH Subtropics -40 W/m2
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Global Heat Budget
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Global Heat Transport
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Global Heat Transport
1015 W 1 Petawatt
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Hydrographic Inverse Models

• WOCE hydrographic sections are used to estimate
  global circulation material transport
• Mass, heat, salt other properties are conserved
  
• Air-sea exchanges removal processes are
  considered
• Provides estimates of basin scale circulation,
  heat freshwater transports

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Global Heat Transport
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Global Heat Transport
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Global Heat Transport
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The Global Heat Budget

• Heat source into the ocean is solar radiation
• There are several heat loss terms
• latent, conduction, longwave radiation,
  reflected solar
• Ocean circulation moves heat (advection)
• Large scale heat budget can be closed by
  analyzing hydrographic sections