If you think this summer was hot, it's nothing compared to the summer of 1913, when the hottest temperature ever recorded was a searing 134 degrees Fahrenheit in Death Valley, Calif. But while that reading was made 99 years ago, it is only being recognized today by the World Meteorological Organization (WMO) as the most extreme temperature ever recorded. That's because an international team of meteorologists（气象学家） recently finished an in-depth investigation of what had been the world-record temperature extreme of 58 degrees Celsius (136.4 F), recorded on Sept. 13, 1922, in El Azizia, Libya. The group found that there were enough questions surrounding the measurement and how it was made that it was probably inaccurate, overturning the record 90 years to the day it was recorded.

"We found systematic errors in the 1922 reading," said Randy Cerveny, an ASU President's Professor in the School of Geographical Sciences and Urban Planning. "This change to the record books required significant sleuthing（侦查） and a lot of forensic records work," added Cerveny, who also is the Rapporteur of Climate and Weather Extremes for the WMO, the person responsible for keeping worldwide weather records.

Officially, the "new" world record temperature extreme is 56.7 C (134 F), recorded on July 10, 1913, at Greenland Ranch in Death Valley, Calif.

"In the heart of every meteorologist and climatologist beats the soul of a detective," said Cerveny. In this case the weather detectives had to work around an unfolding revolution in Libya.

Cerveny said the El Azizia temperature had long been thought as dubious（可疑的）. It was recorded in 1922 at what then was an Italian army base.

The international meteorological team -- which included experts from Libya, Italy, Spain, Egypt, France, Morocco, Argentina, the United States and the United Kingdom -- identified five major concerns with the El Azizia temperature record. They included the use of antiquated（过时的） instrumentation, a likely inexperienced observer, an observation site which was not representative of the desert surroundings, poor matching of the extreme to other nearby locations and poor matching to subsequent temperatures recorded at the site.

The WMO evaluation committee concluded the most compelling scenario for the 1922 event was that a new and inexperienced observer, not trained in the use of an unsuitable replacement instrument that could be easily misread, improperly recorded the observation. The reading was consequently in error by about 7 degrees Celsius (12.6 F).

The detective work Cerveny describes included finding and examining the original log sheet, which he said was very useful. In reconstructing the events, Cerveny describes a person new to making temperature measurements being asked to make the measurements with a "Six-Bellini thermometer," which even by 1922 standards was an obsolete piece of technology. By reviewing the logs, it became apparent that the person who recorded the temperature was transposing what he read from the thermometer, consistently scoring the readings in the wrong column of the log.