While much of Europe experienced a summer of warmth and extensive drought, Greenland had a cold and rather snowy one — culminating with a violent storm that dumped monster amounts of snow in late August.
This “see-saw” pattern is a feature of the North Atlantic Oscillation (NAO), a source of variability over the Atlantic Ocean.
If it is relatively warm over central and northern Europe, temperatures are often below normal in Greenland – and vice versa.
This weather pattern persisted for several weeks this summer, and was one of the reasons why the Greenland ice sheet was colder than usual and accumulated far more snow than average.
The DMI calculated a total SMB of 517bn tonnes this year, which is almost 150bn tonnes above the 1981-2010 average, ranking just behind the 2016-17 season as sixth highest on record.
— Diablobanquisa (@diablobanquisa) September 1, 2018
Good news for the Greenland ice sheet! The SMB over Sep 2017-Aug 2018 has been the highest since 20 years thanks to exceptional snowfall in winter 2017-2018 and normal melt in summer 2018! pic.twitter.com/FDHM9NK5HL
— Xavier Fettweis (@xavierfettweis) August 31, 2018
In recent days, Greenland has been trending towards warmer than average temperatures (though warmer to Greenland is still well-below zero) and as a consequence, arctic air has been plunging further and further south into Europe, bringing with it record cold and early snow.
This is exactly what’s expected during a Grand Solar Minimum.
Looking at NASA’s Maunder Minimum temperature reconstruction map, there are regions that actually warm during periods of global cooling.
The North Atlantic and Southern Greenland are two of these regions. The Arctic and Alaska are others.
NASA’s Maunder Minimum Temp Change Map
Research shows blocking persistence increases when solar activity is low, causing weather patterns to become locked in place at high and intermediate latitudes for prolonged periods of time.
During a solar minimum, the jet stream’s usual Zonal Flow (a west–east direction) reverts to more of a Meridional Flow (a north-south direction).
This is exaggerated further during a Grand Solar Minimum, like the one we’re entering now, and explains why regions become unseasonably hot or cold and others unusually dry or rainy, with the extremes lasting for an extended period of time.
Mikhaël Schwander, et al, 2017 — “The zonal flow characteristic of westerly types is reduced under low solar activity as the continental flow for easterly and northerly types is enhanced. This is also confirmed by the higher blocking frequency over Scandinavia under low solar activity.”
And the paper goes further:
“The 247-year-long analysis of the 11-year solar cycle impact on late winter European weather patterns suggests a reduction in the occurrence of westerly flow types linked to a reduced mean zonal flow under low solar activity. Based on this observational evidence, we estimate the probability to have cold conditions in winter over Europe to be higher under low solar activity than under high activity.”— Mikhaël Schwander, et al, 2017
Last winter a blocking high over Scandinavia lead to bitterly cold air funnelling in over the UK from eastern Europe/Russia — the ‘Beast from the East’.
It lasted for months and led to record snow in Ireland and Britain.
With the sun slipping into a Grand Solar Minimum, these blocking highs are only going to become more prevalent.
We can expect future European winters to be evermore brutal, with record cold temperatures and snow accumulations.