http://www.urbanplacemaking.com/urban-places/what-are-some-places-which-experiences-urban-heat-islandeffect-and-ywat-caused-it/ Fri, 16 Apr 2010 14:21:59 +0000 hourly 1 http://wordpress.org/?v=3.2.1 http://www.urbanplacemaking.com/urban-places/what-are-some-places-which-experiences-urban-heat-islandeffect-and-ywat-caused-it/#comment-1181 rSy Thu, 12 Nov 2009 08:25:59 +0000 http://www.urbanplacemaking.com/urban-places/what-are-some-places-which-experiences-urban-heat-islandeffect-and-ywat-caused-it#comment-1181 Probably the best-known effect of urban areas on heat islands is the so-called "microclimate" created in city centres. Even though city centres receive up to 30 per cent less solar radiation than rural areas—because the large amounts of dust and pollution in the air not only reflect radiation themselves, but also provide nuclei around which water condenses and clouds form—they are on average 1° to 8° C (1.8° to 14.4° F) warmer. Buildings store and generate heat more efficiently than soil, rocks, or vegetation. The heat they emit combines with the heat generated by the people living and working in the city, by city traffic, by industry, and by the heating of the interiors of buildings to raise temperatures. Most importantly, heat loss at night, when buildings give out most of the heat stored during the day, is reduced because the dust and clouds act like a blanket to keep it in. Higher average temperatures mean that city centres experience less snow and fewer frosts than either their suburbs or the surrounding rural area. The higher levels of cloud cover and of dust pollutants in the atmosphere mean that city centres also have higher rainfall levels and more fogs than adjacent rural areas.<br><b>References : </b><br> Probably the best-known effect of urban areas on heat islands is the so-called "microclimate" created in city centres. Even though city centres receive up to 30 per cent less solar radiation than rural areas—because the large amounts of dust and pollution in the air not only reflect radiation themselves, but also provide nuclei around which water condenses and clouds form—they are on average 1° to 8° C (1.8° to 14.4° F) warmer. Buildings store and generate heat more efficiently than soil, rocks, or vegetation. The heat they emit combines with the heat generated by the people living and working in the city, by city traffic, by industry, and by the heating of the interiors of buildings to raise temperatures. Most importantly, heat loss at night, when buildings give out most of the heat stored during the day, is reduced because the dust and clouds act like a blanket to keep it in. Higher average temperatures mean that city centres experience less snow and fewer frosts than either their suburbs or the surrounding rural area. The higher levels of cloud cover and of dust pollutants in the atmosphere mean that city centres also have higher rainfall levels and more fogs than adjacent rural areas.
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