ESA helps make summer in the city more bearable

When it comes to excitement and non-stop activity, cities are the place to be. However, summer in the city is often far from cool. Heat waves are quite common across southern Europe and cities such as Athens are notorious for their sweltering conditions. The Greek capital suffers particularly from high summer temperatures because of its densely packed buildings, narrow streets, limited green space and air pollution.

While the number of days that exceed 38ºC appears to be increasing dramatically, the temperature remains high even at night. This is because Athens is an example of an urban heat island. The built-up environment acts like a giant storage heater, soaking up the heat during the day and releasing it at night. As a result, the night-time temperature in the city can be up to 10ºC higher than in the surrounding countryside.

In order to find out more about the Athenian heat island, a team of experts from Greece and Spain has been carrying out detailed mapping of urban temperatures. The ESA-sponsored campaign, called Thermopolis 2009, involved ground-based measurements at various sites in and around the Greek capital. At the same time, aircraft equipped with sensitive instruments flew overhead and satellites, such as ESA’s ERS and Envisat, looked down on the city from space.

These data will increase awareness of the city areas most likely to be hit by extreme heat. By placing ambulances nearby, transport times to the hospitals will be shortened, reducing suffering and saving lives. The new maps should also help to reduce the effects of heat waves by improving future urban planning.