From: Andy Soos, ENN
Published May 5, 2010 01:53 PM

How Cold Can It Go?

Here we are in global warming but there are still places that can be outright cold. Antarctica, of course, comes to mind as well as Siberia. The lowest recorded air temperature on Earth was a measurement of −89.2C (-128.6 F) made at Vostok station, Antarctica, at 0245 UT (Universal Time or Greenwich Mean Time) on 21 July 1983. What could have caused it? What sort of freak weather pattern made it so frigid?

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Antarctica is uninhabited except for a few hardy scientists. In the more human populated sections of the world such as Siberia, there are a few cold spots such as Verkhoyansk that once hit -72 C (-97.6 F)with an average January temperature of -49 C (-56 F). Back in the US lower 48 states the cold champion is International Falls, Minnesota, where the average winter temperature is a balmy 36 F.

Vostok Research Station is located about 800 miles from the Geographic South Pole, at the center of the East Antarctic Ice Sheet.

The station is over 11,000 feet above sea level and is the most isolated established research station on the Antarctic continent. The station typically contains 25 scientists and engineers in the summer. In winter, their number drops to 13.

A team of British and Russian scientists have presented the first detailed analysis of this super cold event using meteorological reanalysis fields, in situ observations and satellite imagery. Surface temperatures at Vostok station in winter are highly variable as a result the effects of the Southern Ocean.

The record low temperature happened following a cooling of over 30 C over a 10 day period from approximately average July (which is winter in Antarctica) temperatures. The event occurred because of five specific weather conditions:

(1) A cold front of air at a near record low temperature was present.

(2) The cold front stalled and did not move from the vicinity of the station.

(3) An almost circular flow regime persisted around the station for over a week resulting in very little warmer air intrusion.

(4) Little wind was evident.

(5) There were no clouds or diamond dust (tiny particles of ice suspended in the air)above the station for a week, promoting the loss of surface heat.

The team further estimated that temperatures might drop as low as -96 C if the cold front had stalled longer. A nearby slightly higher elevation (Dome Argus) is normally a bit cooler than Vostok and might break even the Vostok record under the right weather conditions.

For further information: http://nora.nerc.ac.uk/9656/

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