What is the coldest place on Earth? It is a high ridge in Antarctica on the
East Antarctic Plateau where temperatures in several hollows can dip below minus
133.6 degrees Fahrenheit (minus 92 degrees Celsius) on a clear winter night.
Scientists made the discovery while analyzing the most detailed global
surface temperature maps to date, developed with data from remote sensing
satellites including the new Landsat 8, a joint project of NASA and the U.S.
Geological Survey (USGS). Ted Scambos, lead scientist at the National Snow and
Ice Data Center in Boulder, Colo., joined a team of researchers reporting the
findings Monday at the American Geophysical Union meeting in San Francisco.
The coldest place on earth is in the East Antarctic
Plateau, but not at the highest peak. Rather, the coldest spots develop just
downhill from a ridge that runs from Dome A to Dome Fuji. Data from NASA-USGS
Landsat 8 satellite, and NASA's MODIS sensor on the Aqua
satellite.
Image Credit: NASA's Goddard Space Flight
Center
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Researchers analyzed 32 years' worth of data from several satellite
instruments. They found temperatures plummeted to record lows dozens of times in
clusters of pockets near a high ridge between Dome Argus and Dome Fuji, two
summits on the ice sheet known as the East Antarctic Plateau. The new record of
minus 136 F (minus 93.2 C) was set Aug. 10, 2010.
That is several degrees colder than the previous low of minus 128.6 F (minus
89.2 C), set in 1983 at the Russian Vostok Research Station in East Antarctica.
The coldest permanently inhabited place on Earth is northeastern Siberia, where
temperatures in the towns of Verkhoyansk and Oimekon dropped to a bone-chilling
90 degrees below zero Fahrenheit (minus 67.8 C) in 1892 and 1933,
respectively.
"We had a suspicion this Antarctic ridge was likely to be extremely cold, and
colder than Vostok because it's higher up the hill," Scambos said. "With the
launch of Landsat 8, we finally had a sensor capable of really investigating
this area in more detail."
The quest to find out just how cold it can get on Earth -- and why -- started
when the researchers were studying large snow dunes, sculpted and polished by
the wind, on the East Antarctic Plateau. When the scientists looked closer, they
noticed cracks in the snow surface between the dunes, possibly created when
wintertime temperatures got so low the top snow layer shrunk. This led
scientists to wonder what the temperature range was, and prompted them to hunt
for the coldest places using data from two types of satellite sensors.
This narrated animation shows the process by which
the coldest place on Earth develops its extreme low
temperatures.
Image Credit: NASA's Goddard Space Flight
Center
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They turned to the Moderate Resolution Imaging Spectroradiometer (MODIS)
instruments on NASA's Terra and Aqua satellites and the Advanced Very High
Resolution Radiometer (AVHRR) on several National Oceanic and Atmospheric
Administration satellites. These sensitive instruments can pick up thermal
radiation emitted from Earth's surface, even in areas lacking much heat.
Using these sensors to scan the East Antarctic Plateau, Scambos detected
extremely cold temperatures on a 620-mile stretch of the ridge at high
elevations between Argus and Fuji, and even colder temperatures lower elevations
in pockets off the ridge. Then, with the higher resolution of the Thermal
Infrared Sensor (TIRS) aboard Landsat 8, the research team pinpointed the
record-setting pockets.
The team compared the sites to topographic maps to explore how it gets so
cold. Already cold temperatures fall rapidly when the sky clears. If clear skies
persist for a few days, the ground chills as it radiates its remaining heat into
space. This creates a layer of super-chilled air above the surface of the snow
and ice. This layer of air is denser than the relatively warmer air above it,
which causes it to slide down the shallow slope of domes on the Antarctic
plateau. As it flows into the pockets, it can be trapped, and the cooling
continues.
"By causing the air to be stationary for extended periods, while continuing
to radiate more heat away into space, you get the absolute lowest temperatures
we're able to find," Scambos said. "We suspected that we would be looking for
one magical site that got extremely cold, but what we found was a large strip of
Antarctica at high altitude that regularly reached these record low
temperatures."
The study is an example of some of the intriguing science possible with
Landsat 8 and the TIRS instrument, which was built at NASA’s Goddard Space
Flight Center in Greenbelt, Md. Since its launch Feb. 11, Landsat 8 has captured
approximately 550 scenes per day of Earth's land surface. USGS processes,
archives and distributes the images free of charge over the Internet.
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.
Image Credit: Ted Scambos, National Snow and Ice Data
Center
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"With Landsat 8, we expect to see more accurate and more detailed maps of the
landscape than we've ever been able to see," said James Irons, the mission's
project scientist at Goddard. "If change is occurring, I think we'll be able to
detect it earlier and track it."
Researchers also are eager to see what new results come out of Landsat 8,
both from icy plateaus and Earth's warmer regions.
"What we've got orbiting Earth right now is a very accurate and consistent
sensor that can tell us all kinds of things about how the land surface of Earth
is changing, how climate change is impacting the surface of Earth, the oceans of
Earth, and the icy areas of Earth," Scambos said. "Finding the coldest areas on
Earth is just the beginning of the discoveries we're going to be able to make
with Landsat 8."
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Text issued as NASA Headquarters release No. 13-364
NASAGuillermo Gonzalo Sánchez Achutegui
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