The coldest place on Earth is even colder than thought, a new study has found.
Researchers discovered tiny valleys near the top of Antarctica’s ice sheet reach temperatures of nearly minus 100 degrees Celsius (minus 148 degrees Fahrenheit) in the winter.
The results could change scientists’ understanding of just how low temperatures can get at Earth’s surface, according to the researchers.
The coldest place on Earth: Blowing snow conditions at a camp site near Vostok Station in Antarctic summer.
Scientists used satellite data between 2004 and 2016 to come up with the minus 144 degrees Fahrenheit figure, as the eastern plateau of Antartica is a barren, snowy region where surface-based weather instruments aren’t available .
Small low-lying dips in the Antarctic ice sheet had the most frigid temperatures, they found.
Because cold air is dense, it funnels into the dips where it may stay trapped for several days when skies are clear and winds are light.
This is similar to how cold air drains into valley locations at night elsewhere in the world.
Dry air is also key to the ultracold temperatures, the study found.
This allows the snow surface and the air above it to cool further, until the clear, calm, dry conditions change and the cold air mixes with warmer air higher in the atmosphere.
‘In this area, we see periods of incredibly dry air, and this allows the heat from the surface of the snow to radiate into space more easily,’ said Ted Scambos, a senior research scientist at the National Snow and Ice Data Center at the University of Colorado-Boulder and lead author of the new study in Geophysical Research Letters, a journal of the American Geophysical Union.
The record of minus 98 degrees Celsius is about as cold as it is possible to get at Earth’s surface, according to the researchers.
For the temperature to drop that low, clear skies and dry air need to persist for several days.
Temperatures could drop a little lower if the conditions lasted for several weeks, but that’s extremely unlikely to happen, Scambos said.
With remote-sensing satellites, scientists have found the coldest places on Earth, just off a ridge in the East Antarctic Plateau. The coldest of the cold temperatures dropped to minus 135.8 F (minus 93.2 C) – several degrees colder than the previous record.
‘There’s a limit to how long the conditions persist to allow it to cool to these ultra-low temperatures, and a limit to how much heat you can actually get through the atmosphere, because water vapor has to be almost nonexistent in order to emit heat from the surface at these temperatures,’ he said.
Scientists first announced in 2013 they had found the lowest temperatures on Earth’s surface in the area.
Sensors on several Earth-observing satellites measured temperatures of minus 93 degrees Celsius (minus 135 degrees Fahrenheit) in several spots on the East Antarctic Plateau, a high snowy plateau in central Antarctica that encompasses the South Pole.
But the researchers revised that initial study with new data and found the temperatures actually reach minus 98 degrees Celsius (minus 144 degrees Fahrenheit) during the southern polar night, mostly during July and August.
When the researchers first announced they had found the coldest temperatures on Earth five years ago, they determined that persistent clear skies and light winds are required for temperatures to dip this low.
The new study found not only are clear skies necessary, but the air must also be extremely dry, because water vapor traps some heat in the air.
Persistent winds shape the surface of East Antarctica?s snow into small dune forms called ‘sastrugi’. The coldest spot on Earth was found on the East Antarctic Plateau, a high snowy plateau in central Antarctica that encompasses the South Pole.
The high elevation of the East Antarctic Plateau and its proximity to the South Pole give it the coldest climate of any region on Earth.
The lowest air temperature ever measured by a weather station, minus 89 degrees Celsius (minus 128 degrees Fahrenheit), was recorded there at Russia’s Vostok Station in July 1983.
But weather stations can’t measure temperatures everywhere.
In the new study, they analyzed satellite data collected during the Southern Hemisphere’s winter between 2004 and 2016.
They used data from the MODIS instrument aboard NASA’s Terra and Aqua satellites as well as data from instruments on NOAA’s Polar Operational Environmental Satellites.
The researchers initially saw a broad region of the plateau more than 3,500 meters (11,000 feet) above sea level where temperatures regularly dropped below minus 90 degrees Celsius (minus 130 degrees Fahrenheit) at the snow surface.
The lowest temperature they observed was minus 93 degrees Celsius (minus 135 degrees Fahrenheit).
However, after NASA calibrated its system with more up-to-date weather station measurements, the researchers reanalyzed the temperature data.
The weather conditions on the plateau did not change, but the adjusted satellite data gave the researchers a more accurate picture of what the actual lowest temperature was.
They found the record low was about 5 degrees Celsius (9 degrees Fahrenheit) colder than they originally reported, about minus 98 degrees Celsius (minus 144 degrees Fahrenheit).