Weather condition at the time of the measurements Time of day: 12:20-12.30 pm
Sky condition: clear
Ambient air temperature: 30.5°C Location: Colombo, Sri Lanka
Climate zone: Tropical rainforest climate
Following are the surface temperature measurements on different surfaces at the same time period (within a 10 min span)
Figure 1: Bare soil surface mixed with gravel, under moderate shade (under a tree)
Surface Temperature= 28.9°C
Gridlock paving (light gray color) exposed to sun
Surface Temperature = 49.4°C
The same gridlock paving, but an adjacent area under moderate shade (under a tree)
Surface Temperature = 38.9°C
Asphalt road exposed to sun
Surface Temperature = 54.5°C
The same asphalt road, but an adjacent area under moderate shade (under a street tree)
Surface Temperature = 35.3°C
Grid lock paved sidewalk adjacent to the asphalt road mentioned above (color- red and black)-Exposed to sun
Surface Temperature = 50.9°C
Baseline condition: Figure 1
A shaded (under a tree) soil surface behind a wall separating the asphalt road (minimum exposure to radiant heat from the road). This is closer to a natural condition found in a highly urbanized area.
|Surface Temperature (Exposed to sun)
|Surface Temperature (Under moderate shade)
|Surface Temperature Difference (shaded vs. exposed)
|Surface Temperature Difference from the Baseline (28.9°C)
|Grid Lock Paving Behind a wall separating the road (color: light gray)
Asphalt road 54.5°C 35.3°C 19.2°C 25.6°C
- Since the heat transfer from the exposed paved areas to adjacent shaded paved areas, primarily through conduction, if the whole paved area was shaded the temperature drop could be even more significant.
- The temperature measurements were taken around noon. However the highest temperatures occur in between 2pm-3pm in Colombo area. Therefore, surface temperatures could get higher during that time period.
|Gridlock sidewalk pavement adjacent to asphalt road (color: red & black)
Divantha is an Urban Planning Enthusiast who currently works as a Sustainability Consultant. He thinks that urban planning is the best tool we have to achieve sustainable development goals and should be at the forefront of sustainability and climate discussions.
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