Ocean currents in the Atlantic remain stable for the time being

Researchers predict no climate-related slowdown until 2014

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One of the most important factors for the European climate will not change significantly in the near future: ocean currents in the Atlantic, which transport warm water to Europe's shores, will not weaken over the next four years. Report Hamburg researchers in the journal "Science". For their calculations, they had prepared a prognosis model of the Atlantic circulation and checked this on the basis of measured data.

"For all calculated variants, predictions point to a generally stable circulation until at least 2014, " the researchers write. There will be no change apart from the usual ups and downs over the seasons. The scientists thus dispel fears that the flow in the North Atlantic has already subsided due to climate change.

"We can now also say with certainty that a weakening of the Atlantic circulation in March 2010 was only a short-term phenomenon, " says first author Daniela Matei from the Max Planck Institute for Meteorology in Hamburg. During the spring of 2010, the current had eased slightly and probably contributed to the exceptionally frosty winter of 2009/10.

Influence on the global climate

The course and strength of ocean currents have a major impact not only on the European but also on the global climate. The global ocean circulation brings warm water to the polar regions. There it cools down, sinks into deeper sea layers and flows back there in moderate and tropical latitudes.

Forecasts for the Atlantic circulation are therefore also important for the prediction of the climate. "The fact that we can now predict the Atlantic circulation for several years means great progress for climate forecasts over a few years, " says Jochem Marotzke, director at the Max Planck Institute for Meteorology and head of the study. It is the world's first prediction of the evolution of this ocean current. display

Predictive model calibrated with data from past years

The predictive value of their prediction, the researchers owe mainly to the fact that now measurement data on the strength of the Atlantic circulation are available. This is so far the case for no other of these ocean movements, and even here they exist only at a latitude of 26.5 degrees North, approximately at the height of the Canary Islands. This area is being continuously monitored by scientists at the National Oceanography Center in Southampton, UK.

For their study, the researchers initially developed a model of the Atlantic circulation. For this they adapted an ocean climate model of the Max Planck Institute to their requirements. This model takes into account numerous climatic and physical factors that influence the movements of the ocean, such as winds, air pressure or temperatures.

In order to check the accuracy of their forecasting model, they first made forecasts for the past few years. These results then compared them with the measurements of the British researchers. The simulation for the past was in good agreement with the data, says Matei. Therefore, it can be assumed that the model also provides useable forecasts for the future.

However, the comparison between model calculation and measurement data also showed that the simulation can not reliably look into the future beyond the fourth year. The Hamburg scientists now want to improve their simulations so that they can make reliable predictions for more than four years. (Science, 2012; doi: 10.1126 / science.1210299)

(Max Planck Institute for Meteorology / Science, 06.01.2012 - NPO)