Temperatures in built-up areas of the Tel Aviv metropolitan area can reach up to 4°C (7.2°F) higher than in surrounding open areas in summer, and up to 9°C in winter, according to new research on so-called urban heat islands, an issue of growing concern for planners in an era of global warming.

The study, led by Prof. Oded Potchter of the central Holon Institute of Technology along with Tel Aviv University scientists Moshe Mandelmilch, Amit Goldberg and Prof. Yitzhak Omer, reveals microclimatic variations between specific parts of the metropolis and its greener hinterland, depending on the season, the time of day, and the type of urban landscape.

Differences in air temperatures where humans walk—the space between the ground and tree canopies—vary more in the summer (up to 4°C) than in winter (up to 2°C, or 3.6°F).

However, when looking at heat trapped on the surface of the ground, the reverse happens: surface temperature variations between the city and the countryside are more significant in winter (up to 9°C, or 16.2°F) than in summer (up to 4°C).

This happens because winter weather suppresses strong daytime heat accumulation, while clear or breezy winter nights allow rural ground to radiate heat away and cool rapidly compared to the city.

The........

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