More record-warm Antarctica temperatures recorded in September
By Summit Voice
FRISCO — While scientists recently pinpointed areas with all-time record low temperatures in Antarctica, the South Pole is not immune to global warming — scientists based at the bottom of the world say the past winter was the warmest since record-keeping started in 1957.
In August, for example, the average temperature for the month was more than 11 degrees Fahrenheit above average, at minus 63.9 degrees Fahrenheit.
The trend continued into the Austral spring, with September 2013 also ending up as an all-time record warm month, including four daily maximum temperature records, according to the Antarctic Sun.
That’s not to say the weather was balmy — the average annual temperature at the South Pole is about minus 56.9 degrees Fahrenheit. The coldest reading on record was minus 117 degrees Fahrenheit, set June 23, 1982, while the warmest temperature recorded since 1957 was just a few years ago, Christmas Day, 2011, when the official high was 9.9 degrees Fahrenheit.
The interior Antarctic heatwave are likely linked with weaker westerly winds between August and October, a climate shift that may also be responsible for the record expanse of sea ice around Antarctica, according to the National Snow and Ice Data Center.
The weakened flow of westerlies allows more north-south flow into Antarctica, occasionally bringing relatively warm air masses into the interior. Between September 11 and September 15, usually a time of unimaginable cold, four daily maximum temperature records were set, in one case by more than 15.3 degrees Fahrenheit. On September 13, the temperature reached minus 17.9 degrees Fahrenheit, a reading more typical of early summer conditions at the South Pole.
Researchers with the NSIDC said strong westerly flow favors ice growth in autumn and early winter, and this was the case; however, as sea ice approached a maximum, the westerly wind pattern abated, allowing ice to drift even further north than usual, in some places urged on by southerly winds.
At the beginning of summer in the southern hemisphere, sea ice extent was above average around the Antarctic Peninsula, the Amundsen Sea, and the Wilkes Land sectors, but has retreated in the northern Ross Sea region. In total sea ice extent in November averaged 6.63 million square miles, compared to the average of 6.29 million square miles.
In its monthly update, the NSIDC said that recent cool conditions and extensive ice around the Antarctic Peninsula strongly contrast with the past few decades’ shift to a more ice free Peninsula and extensive surface melting there.
Palmer Station, the U.S. Antarctic research base, was once again briefly surrounded by sea ice this winter, as it was in 2012.