28 | The ocean, a climatic heat pump |
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Despite a “pause” on the rise in average temperature of the Earth from 1999 to 2008, the ocean has not ceased to store heat during the last decade. This is what an international team (USA, Germany, Japan) in the columns of the journal Nature (1), which took over all the data available since 1993 to monitor the energy stored in all the oceans of the world.
The amount of energy involved are enough to dim the energy producers. Just between 2000 and 2009, the energy stored in the oceans have gone up the equivalent of one trillion tons oil equivalent, about one hundred times the annual energy consumption of the whole humanity. And over the period 1993 and 2009, is the double!
To achieve this, researchers have relied on two types of data. First measures bathythermograph immersed in scientific field. Very fragmentary data-dependent and conditions of use of these probes, John Lyman and his colleagues patiently corrected using calibration data available to establish a pattern of development of the stored heat from the surface a depth of 700 meters (black curve). And if the period 2003-2008 is marked by a more modest, changes from 1993 to 2009 confirms that the ocean captures more and more heat in the atmosphere. With an estimated average capture power at 0.64 watts per square meter (total land surface, red curve), between zero and seven hundred meters deep.
The reading of these results suggests that the rate of uptake of energy in the oceans has decreased in recent years. But only after 2003, while the temperature of the atmosphere had begun his break in 1999. A sign which confirms the thermal inertia of the ocean.
To be sure of what they say, Lyman and his colleagues have taken over the great harvest of temperature information gathered by three miles Argo buoys since 2003, and published this year by another researcher Kevin Trenberth. These buoys dip regularly up to two thousand feet deep, measuring temperature, currents and salinity of water (2). They are there as an increase of the energy captured by the oceans, even if it is lower (0.54 watts per square meter, blue curve) than that deduced from the other set of data. Invited by Nature to comment on the work of his colleagues, Kevin Trenberth, is the similarity of the results, even if it stresses that progress is still required in the evaluation of heat stored in the oceans. Progress is essential for the ocean becomes a reliable indicator of climate change.
Source:science-et-vie
| Category: Environment | Tags: annual energy consumption, atmosphere, store heat |