Planet’s most frigid region is colder than scientists thought
For several years, scientists have known that the coldest weather on Earth was tucked in the valleys near the top of Antarctica’s ice sheet. Weather satellites had detected temperatures there that could tumble as low as -93 C.
But a new analysis of satellite data finds the planet’s coldest spot is even more frigid, and can see temperatures plunge as low as nearly -100 C at night during Antarctic winter.
The authors of the new study, published in Geophysical Research Letters, found “approximately 100” sites that posted low temperatures of around -98 C during the winters of 2004-2016. Most frequently, these temperatures, colder than the average temperature on Mars (around -60 C), were observed in dips and hollows near the top of the East Antarctic Ice Sheet. They occurred at elevations of about 12,500 to 13,000 feet, mostly during July and August.
Prior to analysis of satellite data, the coldest temperature measured on Earth had been -89 C, recorded on the East Antarctic Plateau at Russia’s Vostok Station in July 1983. The satellite data analysis published in 2013 analyzed 32 years’ worth of data to find that colder temperatures were present, closer to -93 C. This latest study recalibrated satellite data using more up-to-date weather station data and concluded that the coldest temperatures were five degrees lower than that.
The locations where the -98 C air was analyzed shared similar characteristics. “(T)hey occurred in small hol- lows two to three meters deep in the surface of the ice, on the southern side of high ridges on the plateau,” the study’s news release explained.
Remarkably, the lowest temperatures observed at all of these hollows on the ice sheet was right around -98 C, even though some of them were spaced tens of miles apart. In other words, the scientists found that -98 C seemed to represent the floor or the theoretical minimum for how cold it can get.
Such a frigid temperature reading is possible only to occur under very specific weather conditions, the study found. The sky must be clear and winds calm to allow for any residual heat to radiate away from the Earth’s surface back into space. They must also be as dry as possible, as water vapour, which is a greenhouse gas, can retain heat in the atmosphere.