Dubai: If you are in Bur Dubai or Deira and think it's hotter here than other areas of the city - you're probably right.
Dubai's first high-resolution thermal map - shared by Dubai Municipality with XPRESS - reveals that built-up areas are emitting more heat than other less densely populated areas of the city, because of lack of vegetation and heat absorption by concrete, a senior municipality official said.
The thermal mapping scheme, which was incidentally undertaken in the winter month of December 2009, showed some areas were witnessing a phenomenon known as urban heat island effect (UHI) - thus necessitating more air-conditioning in these areas.
Green ideas
The results have prompted authorities to draw up a raft of measures including ‘green roofs', urban vegetation and covered parking to cool things down.
Engr Ahmad Mohammad Al Jasmi, Head of Environmental Planning & Studies Section at Dubai Municipality said: "Definitely, a range of options to mitigate UHI is being studied, one of which includes green roofs, while other options on the table include ‘cool pavement', urban vegetation, shaded parking and reducing the usage of highly absorptive materials in construction, etc."
The thermal map of Dubai covering 700 square kilometres of the city's urban landscape (little bigger than the size of Singapore) showing a snapshot of ‘hot spots' — including high-rises on Shaikh Zayed Road — was released in July.
"It also shows the differences between the [relatively] cooler parts and the hottest part of Dubai which can be associated with heat radiation from the materials used in buildings and pavements, HVAC (heating, ventilation and air conditioning) units in buildings and other ground and water surface features."
Even during winter, the "urban heat island" effect is a "concern" and this was confirmed by findings from the study that was done in winter. "Dubai Municipality is committed to sustainable development of Dubai," the municipality official said.
"The intention of thermal mapping is to understand and map the prevalence of urban heat island effect in Dubai.
"Based on the thermal map data, mitigation options and overall intervention through best practices to reduce UHI can be suggested in the city with the participation of the stakeholders such as developers, building owners, utilities, industries and other concerned parties," he said.
"The result of the study indicated and identified areas in Dubai subject to surface ‘heat-island effect' aside from the overall thermal map given to the media," said the official.
The thermal imaging mission was conducted over four nights by an aircraft equipped with thermo graphic sensor. The missions took place on December 1, 2, 3 and 6.
Verification
Field verifications are currently being conducted by Dubai Municipality's Environment Department to verify areas subject to high heat to include identification of type of materials used and local conditions that contribute to UHI concerns in these areas.
Water bodies
Why do water bodies generate more heat?
In the daytime heat, the evaporative effect of water bodies cool and refresh the surrounding air with their vapour since the surface water goes on evaporating, thus taking heat from the water. Water evaporation depends on wind, atmospheric stability and humidity. But during the night, even as the adjacent land cools down, the water bodies (as shown in the thermal map taken during the night) continue to retain heat. This shows how water bodies maintain a fairly constant temperature day and night due to its high heat-retaining capacity.
Source: Dubai Municipality
