I want to be able to determine if changing the colour of the roofs in a suburb will change the average temperature of the suburbs.

E.g. if the roofs in a suburb were changed from black to white would that reduce the average temperature and by how much.

Is there a way to calculate this has it been worked out

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    $\begingroup$ I think you have to define the area of effect you want to analyze more clearly. $\endgroup$ – J. Ari Nov 28 '20 at 0:10

Yes, but probably no

If we're feeling a bit pedantic, the answer is obviously yes: a suburb of white roofs will have a higher albedo than one with black roofs. It'll therefore reflect more light instead of absorbing it as heat, resulting in lower temperatures.

The question is whether the change is significant, but it's impossible to give a solid answer to that, since there's an infinity of variables which will change the outcome: how dense is this suburb (if roofs only cover 10% of the area, they'll have a lower impact than if they're 50%), how humid is the air, what's the cloud cover, is it windy, what material are the roofs made of, etc.

That being said, I'd wager the roofs aren't going to have a noticeable impact on the temperature in a suburb, since suburbs tend to be low-density areas, so roofs will be a small fraction of the surface area.

If you're looking for an objective answer, you won't get it without getting your hands dirty with modeling.

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    $\begingroup$ white roofs are useful in hot climates and are required as LEED code in some cities. they help lowering the energy cost of the building. as for lowering the ambient temperature in a neighborhood landscaping is the most effective way. $\endgroup$ – kamran Nov 28 '20 at 4:00
  • $\begingroup$ Worth remembering that allowing solar energy into the building helps with winter heating - there are other climates / countries... $\endgroup$ – Solar Mike Nov 28 '20 at 5:47
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    $\begingroup$ If the buildings are surrounded by lots of tall trees then the roof color may not be relevant. $\endgroup$ – Solar Mike Nov 28 '20 at 5:54
  • $\begingroup$ As important as the color is the character of the white . From steel oil tank studies ; you want a self cleaning ,chalking white for lowest heat gain. A high gloss brilliant white ,like a urethane , is great at first but it holds dirt and soon is gaining more heat than the chalking white. $\endgroup$ – blacksmith37 Nov 28 '20 at 16:59

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