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  2. Climate Change & Energy
  3. Urban Heat Island
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Urban Heat Island

A page number:101-441-008

Last updated date:2018/2/9

The term "Urban Heat Island phenomenon" in which the air the temperature of a city part increases more markedly in the inner city than that in the suburbs comes from the isothermal line that forms an “island”.

The heat island and its effect on human health, such as heat stroke and sleep disorders, resulting from the increased number of tropical days and tropical nights has been reported.

It is said that heat island phenomenon is also a contributing factor to the increased occurrence of torrential rain in the urban area.

In Tokyo, because of the global warming and the heat island phenomenon, the annual mean temperature has increased by about 3°C over the past 100 years.

Urban heat island effects have continued in Tokyo as urbanization progresses. In the context of the Tokyo 2020 Olympic and Paralympic Games, measures to reduce heat for citizens and tourists have become a critical challenge.

Creation of Cool Spots

In collaboration with business operators and municipalities ready to install fine mist generation equipment or plant more flowers and trees, Tokyo has been creating cool spots for heat mitigation to allow citizens and tourists to stroll comfortably during midsummer.

“Uchimizu”(Water Sprinkling)

Sprinkling water is part of the traditional Japanese culture. Sprinkling water in front of houses or stores lowers the temperature of the hot ground surface, helping mitigate the summer heat.
TMG is making efforts to promote Uchimizu activities by working with citizens and businesses in Tokyo.

Laying Solar Heat-Blocking Pavements

TMG lays solar heat-blocking pavements and water retaining pavements to mitigate road surface temperature rise during daylight hours.
As of the end of March 2017, we completed approximately 106 km in total, controlling temperature rise caused by road surface heat.

Maintenance and Management of Trees

TMG continues ensuring the shade of trees blocking the blaze of the sun in summer and reducing temperature rise further through a mass of greenery by properly maintaining trees along Tokyo metropolitan roads as well as those in parks.



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