The Danish Meteorological Institute has confirmed on a preliminary basis that the Nuuk measurement would replace the previous record of 73.8 degrees (23.2 Celsius), which was set in Kangerlussuaq on June 15 in 2014. That temperature was also recorded in southwest Greenland about 200 miles (320 km) north of Nuuk.
John Cappelen, a senior climatologist at the DMI, told The Washington Post that the warm weather was brought on by winds from the east that set up between high pressure over northeast Greenland and low pressure south of Greenland. When winds come from the east over Nuuk, they blow downhill, which leads to an increase in temperature. This is the result of adiabatic warming, where air is compressed from low pressure (at the top of a mountain) to high pressure (at sea level). It’s the same kind of dry warmth that occurs as a result of Santa Ana winds in Southern California.
Thursday’s toasty reading in Nuuk marks the second exceptionally warm temperature recorded in southwest Greenland since April, when the ice melt season began about a month prematurely.
On April 11, Kangerlussuaq hit a record high of 64.4 degrees (17.8 Celsius). “This was the warmest April temperature on record at that location, and it nearly set an all-time warm temperature record for Greenland as a whole,” reported Mashable’s Andrew Freedman.
At the time, so much ice was melting that scientists at the DMI couldn’t believe what they were seeing. “We had to check that our models were still working properly,” said Peter Langen, a climate scientist.
This week, the institute announced that Greenland’s ablation season, the period when its ice sheet loses more mass from melting along its edges than it does from snowfall in its interior, started on June 6. The DMI defines the start of this season when Greenland loses more than one gigaton of ice to the ocean. On the first three days of the month, Greenland lost 1.6, 2.2 and 2.4 gigatons of ice, the institute reports.
“This is the sixth earliest onset of ice loss in our 27-year record, although there isn’t really a large difference from one year to the next in the top-ranking 17 years,” said climate scientist Peter Langen.
Greenland’s exceptional warmth in 2016 piles on to other record-warm milestones established in recent years. In 2012, the temperature in Narsarsuaq, on the southern coast, soared to 76.6 degrees in May — a new monthly record, according to Jeff Masters at Weather Underground.
The next year, on July 30, 2013, the temperature at the observing station in Maniitsoq, on Greenland’s southwest coast, soared to 78.6 degrees (25.9 Celsius) becoming Greenland’s warmest July temperature and warmest of any month.
(Official weather records in Greenland only date to 1958, and historical records indicate that on June 23, 1915, the temperature may have reached 86 degrees (30.1 C) in Ivigtut.)
The temperatures and early ice melt in Greenland are consistent with a pattern of exceptional warmth in the Arctic. Temperatures have frequently averaged well over 10 degrees above normal on the icy continent, and the extent of Arctic sea ice has set record lows most months.
It was also the warmest winter on record across the Arctic, says the National Snow and Ice Data Center, which reported that large areas recorded their “warmest conditions in 67 years of weather model data, including the northern half of the Greenland ice sheet.”