THE ASAHI SHIMBUN
June 10, 2024 at 16:45 JST
A woman uses a parasol to shield herself from the sun’s rays and avoid heatstroke in Osaka in July 2023. (Asahi Shimbun file photo)
Unofficial data from weather authorities suggests that summers around the turn of the 21st century in Japan may have been hotter than recorded when the temperatures taken every 10 minutes are included.
An analysis by The Asahi Shimbun found that 158 locations had maximum temperatures that were 0.1 to 1.3 degrees higher than the official records, and that these temperatures occurred on a total of 226 days between 1994 and 2002.
The Japan Meteorological Agency recorded hourly temperatures at approximately 760 unstaffed observation points until 2002.
Additionally, the JMA collected temperatures every 10 minutes between 1994 and 2002. However, these 10-minute readings were not included in the official records and remain unofficial.
According to this unofficial data, Ikomayama in Osaka Prefecture recorded a high temperature of 35.6 degrees on Aug. 6, 1994. This is 1.3 degrees higher than the official record.
Similarly, Ezarugi in Saga Prefecture recorded a high of 37.3 degrees on Aug. 10, 1994, which is also 1.3 degrees higher than the official record.
Unofficial data from Hirakata, Osaka Prefecture, indicates a high temperature of 40.3 degrees at 3:10 p.m. on Aug. 8, 1994. This is 0.5 degree higher than the official record, marking the first time the prefecture exceeded 40 degrees.
These unstaffed locations in the Automated Meteorological Data Acquisition System (AMEDAS) currently collect temperature data every 10 seconds.
While significant, these findings will not affect Japan's official yearly average temperatures. These averages have been consistently calculated using data taken by 15 main observation stations every 10 seconds.
Similarly, the official count of hot summer days exceeding 30 or 35 degrees won't change either, as they are compiled based on the same data as yearly averages.
“Unearthing and utilizing old data is a crucial research technique,” said Masahiro Watanabe, a professor of climate science at the University of Tokyo's Atmosphere and Ocean Research Institute. “It helps to improve the transparency and accessibility of archived data.”
However, Watanabe cautions against using these and similar findings to dismiss concerns over climate change as deniers are wont to do.
Potentially hotter summers in the past by no means translate to “it's been hot since the old days, so there's no global warming,” said Watanabe.
(This article was written by Takaoki Yamamoto, Kanato Ishii and Ryo Oyama.)
Okinawa seen as ‘summer retreat’ as it stays cool amid heat waves
August 23, 2022
Sea temperatures around Japan hit record high for third year
April 16, 2024
Early pressure patterns causing record-setting heat in Japan
June 30, 2022
Sweltering Japan suffered hottest September ever recorded
October 2, 2023
Earth hit an unofficial record high temperature this week--and stayed there
July 7, 2023
Temperature hits a 100-year high in November in central Tokyo
November 8, 2023
Stories about memories of cherry blossoms solicited from readers
Cooking experts, chefs and others involved in the field of food introduce their special recipes intertwined with their paths in life.
A series based on diplomatic documents declassified by Japan’s Foreign Ministry
A series on the death of a Japanese woman that sparked a debate about criminal justice policy in the United States
A series about Japanese-Americans and their memories of World War II
Here is a collection of first-hand accounts by “hibakusha” atomic bomb survivors.
