The Climate Machine: Heat Reservoirs

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Reservoir	Volume (km3)	Mass  (Gt)	Temperature (oK)	Heat capacity (J /gram oK)	Energy content* (J)
Atmosphere	5.0 x 109	5.0 x 106	260	1.0	1.3 x 1024
Land Surface	5.0 x 103	1.0 x 104	290	4.0	1.2 x 1022
Land Subsurface	1.0 x 105	2.0 x 105	280	4.0	2.2 x 1023
Surface Ocean	3.8 x 107	3.8 x 107	280	4.0	4.3 x 1025
Deep Ocean	1.4 x 109	1.4 x 109	275	4.0	1.5 x 1027

*The energy content of each reservoir is equal to its mass times its temperature times its temperature.

• Reservoirs that can exchange heat on short timescales include the atmosphere, land surface, and surface ocean.
• The deep ocean can only exchange heat with the atmosphere on a slow timescale but the deep ocean is also the most massive heat reservoir in the Earth system (by a factor of almost 20).
• Thus to predict changes in temperature for long-term climate changes, the processes that exchange heat with the deep ocean must be well resolved.

Details of the exchanges of energy among the reservoirs can be found here.

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