Slide 9: The oceans
They are divided into two distinct layers:
The upper, seasonal layer of warm mixed water that stretches up to 100m deep in the tropics, and interacts with the atmosphere.
The lower deeps, which contain more than 80% of the water in the oceans.
The oceans are vital for the climate, because they hold far more energy than the atmosphere. This is because the oceans have a higher heat capacity (4.2 times that of air), and much higher density (1000 times more than air).
The seasonal layer alone contains more than 30 times as much energy as the entire atmosphere. Thus, a change in the energy of the climate system will affect the atmosphere 30 times more than the ocean. Clearly a very small perturbation of the oceanic system can affect the atmosphere in a large way.
Other heat transfers are through the evaporation of water vapour, which passes on its energy to the atmosphere when it condenses into clouds or precipitates.
Vertical energy transfer is largely at the poles - as sea water freezes, the salt remains in the unfrozen water, this dense saline water tends to sink to the bottom of the ocean despite it's relative warmth, and takes its energy with it.
Oceans also are involved in transfer of heat. Warm water flows towards the poles, raising the temperature of polar areas, and cold water flows below towards the tropics, carrying nutrients from the seabed.
The world therefore has extensive global thermohaline circulation, which has been hypothesized to drive millennia-long climate changes.