Sprinkling Water Lowers Road Temperatures by 9 Degrees

August 28, 2018

Tokyo- The Tokyo metropolitan government saw road surface temperatures drop by over 9 degrees Celsius in a test to see the effects of "uchimizu" water sprinkling Monday.

The traditional Japanese practice is being considered as a measure to ease scorching heat during the 2020 Tokyo Olympics and Paralympics.

The metropolitan government carried out the test on a street along the Imperial Palace that is included in the marathon and race walk courses.

The test, the second of its kind, produced better results than the previous one, which was carried out Aug. 13.

"It was cloudy during the previous test, but it's sunny today. So we can say we've seen greater effects this time," an official said.

This time, the metropolitan government measured heat stress by using an index based on factors such as humidity, sunlight and temperatures. It plans to release the results of its analysis as early as mid-September.

On Monday, water was sprinkled from tubes with tiny holes for agriculture and melting snow. Temperatures were measured after water was sprinkled.

At 10:00 a.m., the temperature in the unsprinkled area reached as high as 44.6 degrees, while the temperature was lower at 35.0 degrees in the sprinkled area where the agricultural water tube was used and 35.2 degrees in the area where the snow-thawing tube was used.

In the previous test, road surface temperatures dropped 3 to 4 degrees after the water was sprinkled. Jiji Press