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Topic: Oceanic Heat Budget

Theme: Interactions

Key Concepts:

Ocean/Atmosphere Interface

  • The oceans transport about one-half of the heat needed to warm higher latitudes, the atmosphere transports the other half.
  • Most of the heat absorbed by the oceans in the tropics is released as water vapor which heats the atmosphere when water is condensed as rain. Most of the heating is in the Tropical Convergence Zone.
  • Heat released by rain and absorbed long-wave radiation from the ocean are primary drivers for the atmosphere.
  • The atmospheric wind field nearest the ocean/atmosphere interface is driven by convection. These winds pull the surface waters of the ocean along with them as surface currents. As the winds pass over the ocean surface, they aid in mixing the surface waters.

Human-Induced (Greenhouse Effect)

  • The global heat budget also involves outgoing heat by radiation. This is when Earth radiates heat back into space. This radiative loss balances heat absorbed from the sun. Earth is just hot enough--the input (sun's heat) exactly balances loss (radiation).
    • One of the important factors aiding or hindering in this process is the amount of cloud cover in the atmosphere.
    • Carbon dioxide in the atmosphere is very efficient at absorbing radiation from the surface. This traps heat at the surface.
      • This is why anthropogenic (man-made) sources of carbon dioxide emission, such as fossil fuel burning, worry scientists.
  • While a certain amount of carbon dioxide is necessary in the atmosphere to help insulate Earth and prevent too much heat from escaping, by the same token, trapping too much heat could have many disastrous effects to Earth's biosphere.
    • Excessive carbon dioxide concentrations on Venus have made it extremely hot (855 degrees F).
    • Mars has very little carbon dioxide in its atmosphere and the temperatures may vary by as much as 144 degrees F between day and night.
  • Why is the ocean important in the research on global warming due to carbon dioxide build up? It is estimated that the ocean absorbs approximately half of the carbon dioxide emissions. Scientists are worried what might happen if the ocean was incapable of providing a sink (center of accumulation or storage) for the carbon dioxide. Plus, carbon dioxide (CO2) absorbed in the oceans may eventually come back out many centuries later.