1991 data reveals Northern Hemisphere's coldest recorded temperature
The World Meteorological Organization (WMO) has uncovered the coldest temperature ever recorded in the Northern Hemisphere. Based on historical readings from an automatic weather station in Greenland, on December 22, 1991, Klinck, located on the summit of the Greenland ice sheet, plunged to -69.6 °C (-93.3 °F).
In order to understand the incredibly complex system that is the Earth's climate, scientists rely on a globe-spanning network of weather stations as well as data from satellites, ships, and aircraft. Part of this vast task of information gathering is keeping track of extreme record events, such as the hottest and coldest spots in various regions of the world.
As part of this, the WMO established the Archive of Weather and Climate Extremes in 2007 to go over the historical records for the highest and lowest temperatures and rainfall, the heaviest hailstone, the longest dry period, the maximum gust of wind, the longest lightning flash and weather-related mortalities. As part of this effort, teams of "climate detectives" not only look at modern climate events, but also go through historical archives in search of overlooked records.
In this case, the record low Northern Hemisphere temperature was observed by an automated weather station set up in the early 1990s that was operated for two years by the University of Wisconsin-Madison to study meteorological conditions around the Greenland Crest during the Greenland Ice Sheet Project. The station was of a particularly rugged build because it had to remain calibrated when transported across the ice by snowmobile.
After it completed its Greenland mission in 1994, the station was removed, tested, and then sent to Antarctica. This testing and retesting is important because one danger of weather station records is that the equipment might be faulty, uncalibrated, or subject to unusual local conditions, such as an airport weather station that suddenly starts giving very high temperature readings because jet aircraft start taxiing past it.
In the case of the new record, the WMO established a blue-ribbon international panel of polar scientists to seek out the original team as it pursued analysis of the equipment, observation practices, and the weather situation in December 1991. The panel ended up commending the project scientists for their careful maintenance of the calibrations and metadata.
The previous Northern Hemisphere record cold temperature was a tie of -67.8 °C (-90 °F) at the Russian sites Verkhoyanksk in February 1892 and Oimekon in January 1933. The coldest ever recorded world cold temperature, -89.2 °C (-128.6 °F), was recorded on July 21, 1983, at the high-altitude Vostok weather station in Antarctica.
"In the era of climate change, much attention focuses on new heat records," says WMO Secretary-General Professor Petteri Taalas. "This newly recognized cold record is an important reminder about the stark contrasts that exist on this planet. It is testimony to the dedication of climate scientists and weather historians that we are now able to investigate many of these older records and secure a better global understanding of not only current, but also historical, climate extremes."
The research was published in the Quarterly Journal of the Royal Meteorological Society.
Source: British Antarctic Survey