Long-range weather forecasts are notoriously difficult, but a new paper in the journal Weather and Climate Dynamics suggests that the melting rate of the Greenland ice sheet can predict next summer’s weather in Europe.
The chain of events is complex and other factors can interfere. But according to Dr Marilena Oltmanns from the UK National Oceanography Centre, lead author of the study, it goes more or less as follows:
Warm conditions in Greenland brings more glacial meltwater into the Atlantic Ocean. Because it is lighter than seawater, this meltwater sits on top of the ocean and reduces the heat exchange between the air and the ocean. This leads to stronger winds around the meltwater region. In winter, the winds cause a northward shift in the North Atlantic Current, an extension of the Gulf Stream.
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The following summer, winds follow the direction of the current and are redirected north. This helps shape the type of large-scale atmospheric circulation conditions that bring warmer and drier weather over Europe.
Oltmanns says the location, extent and strength of freshwater events can be used to estimate the subsequent pattern of warm and dry weather across Europe.
“Based on the identified chain of events, we expect the ocean-atmosphere conditions to be favorable for an unusually warm and dry summer over southern Europe this year,” says Oltmanns.
