Predicting Urban Heat Island Effects from Space

Architects seeking to improve the aspect of cities could soon be informed in their decisions by data relayed to Earth by satellites belonging to the European Space Agency (ESA). A new study suggests that specialized spacecraft could detect urban heat island effects before they actually form.

Forecasting the locations at which these effects may develop is essential towards designing those spaces in such a manner that they can no longer support the phenomenon. Such an effect occurs when temperatures in a particular area spike well above those in its surroundings.

In large cities, this can happen for a variety of reasons. The most important is that black pavement stores a lot of heat during the day, and then releases it during the night. Darker buildings also capture heat, contributing to the effect.

On average, the central areas of large metropolises can be tens of degrees warmer than suburbs. Experts say that global warming will contribute to exaggerating these effects in the near future, and that authorities therefore need to be prepared to handle this.

Designing cooler, more comfortable cities is obviously the way forward, experts agree. Health problems, higher energy demand, air pollution and water shortages are just some of the consequences of the current situation in any major city.

At a recent meeting, the ESA Center for Earth Observation (ESRIN) Urban Heat Islands and Urban Thermography team presented the results of a new analysis, indicating that remote Earth-sensing conducted from orbit could allow scientists to keep a constant eye on urban thermal radiation levels.

“Monitoring thermal radiation can help city planners to design more ‘livable’ cities, assist civil protection authorities in taking adequate measures during heat waves and create maps of energy efficiency,” an ESA press release says.

“The new urban climate models show a muggy outlook for the future. During the summer of 2003, large portions of Europe were struck by a major heat wave,” the document goes on to reveal.

“Paris was affected severely as the urban heat island effect prevented the city from cooling during the night, leading to thousands of heat-related deaths,” it concludes. Data used to compile this assessment were collected over a period of 10 years.

The team focused on 10 major European cities – Athens, Bari, Brussels, Budapest, Lisbon, London, Madrid, Paris, Seville and Thessaloniki. All of them could suffer from heat waves such as the one recorded in 2003, which may occur once every 3-4 years, the team reports.