SAN FRANCISCO -- Last July the surface temperature dropped to minus 135.3 degrees Fahrenheit in an icy trough on a south-facing ridge in western Antarctica. According to Ted Scambos at the National Snow and Ice Data Center in Boulder, Colo., that and another day during Antarctica's polar night are the coldest surface temperatures yet recorded on Earth.
"It's more like what you would see on Mars on a summer day," Scambos said during a press conference here at the Fall Meeting of the American Geophysical Union. Scambos is one of more than 20,000 scientists who will attend the weeklong gathering of Earth and space scientists.
Scambos noticed the unearthly temperatures while looking at data from remote sensing satellites, including the new Landsat 8, launched last February. The satellite orbits over Antarctica (and Alaska) and has a sensitive temperature sensor onboard.
With it, Scambos saw the cold temperature from this July and an even lower minus 136 degrees Fahrenheit on Aug. 10, 2010.
The official world record is the minus 128.6 Fahrenheit recorded at the Russian Vostok Research Station in East Antarctica in 1983. Scambos said the satellite records won't be official because the Vostok record was from a thermometer mounted about 6 feet off the ground, as is the standard for meteorologists.
"The air would probably be 1 or 2 degrees warmer at two meters," he said. If someone were to install a similar weather station at the sites the satellite measured, its temperature sensor would probably knock off the Vostok record.
"I'm confident these places are the coldest pockets on Earth," he said. "We're talking about temperatures 50 degrees colder than anything seen in Alaska or Siberia."
Scambos wants to know if there's a physical limit to how cold Earth can get. The Antarctic cold spots are just off Dome A at about 15,000 feet elevation. The coldest air forms when already chilled air slides down the mound and settles in pockets, where it cools further.
Because the satellite also passes above Alaska in its orbit, Scambos said it might be possible to use it to find Alaska's cold spots, though he's going to concentrate on Greenland and Antarctica.
Alaska's all-time low of minus 80 degrees Fahrenheit, recorded Jan. 23, 1971, at Prospect Creek, is just 1 degree off North America's all-time low. Canadian meteorologists measured minus 81 degrees Feb. 3, 1947, at a now-defunct airstrip at Snag in the Yukon Territory, just 15 miles from where the Alaska Highway passes near Beaver Creek in the Yukon.
Alaska has come close to that number, making meteorologists think 81 below could be bested if a thermometer sat in the right spruce bog. Weather observers Dick and Robin Hammond of Chicken recorded minus 72 degrees Fahrenheit during their 8 a.m. thermometer check on Feb. 7, 2008. Two days later, Larry and June Taylor -- also official observers for the National Weather Service -- recorded the same temperature at O'Brien Creek off the Taylor Highway.
Ned Rozell is a science writer for the University of Alaska Fairbanks Geophysical Institute.