ASU climate expert refutes reports of new coldest temperature record

Several news media yesterday reported on a finding presented at the American Geophysical Union scientific meeting currently taking place in San Francisco. Ice scientist Ted Scambos of the National Snow and Ice Data Centre in Boulder, Colo. announced that he’d used NASA satellite data to identify a temperature of -94 C (-135.8 F) at a location in Antarctica – colder than the official record of -89.2 C (-128.6 F) set in 1983.

However, the statement that this is a new record – not made by Scambos, but by news media – is incorrect. In a USA Today news story, ASU’s Randy Cerveny, President’s Professor in the School of Geographical Sciences and Urban Planning, explains why.

First, official temperature measurements must be taken at precisely 1.5 meters above the ground. While satellite measurements can target general elevation ranges, they don’t have the ability to measure at such a precise distance from the ground.  

“Think of the temperature of Sun Devil Stadium bleachers on a summer day, as compared with the air temperature a few feet away,” points out Cerveny. Small differences in elevation can make a drastic difference in temperature – thus the need for a consistent elevation to compare temperatures and establish records.

This need for consistency applies to all aspects of temperature measurement. Thus, the World Meteorological Association (WMO), which establishes climate records, requires that to become an official record, a temperature must be measured with a thermometer (not a satellite), at an officially recognized WMO weather station, with "length-of-record" measurements to establish the validity of the value.

Cerveny is very well-qualified to explain the WMO’s rules for establishing records: Cerveny is the WMO’s rapporteur of climate extremes, which means he’s responsible for coordinating investigations into world and continental climate records. Additional records are documented at the WMO’s World Weather/Climate Extremes Archive web site.

The School of Geographical Sciences and Urban Planning is an academic unit of the College of Liberal Arts and Sciences.