The downtown that densely crowded population and buildings appears its temperature higher than other regions in general. In this way, heat island is the region that represents specially higher temperature than the temperature of the surroundings. the heat island phenomenon is clear in autumn and spring that diurnal range is greater or winter than summer and appear badly at night than daytime.
The meteorologist W. Schmidt of Austria confirmed the fact that the temperature is higher when go to the urban center by investigating the temperature distribution of the capital Vienna in 1927. Thereafter, climate of downtown was found to have a unique phenomenon that different from the surrounding.
In the city, ① changing in the ground surface heat balance with increasing construction, paving ② increasing emissions of artificial heat, the pollutant due to fuel consumption ③ greenhouse effect by atmospheric pollution ④ making so many high-rise buildings ventilation is difficult affect heat island phenomenon. Because ground covered roads, buildings, concrete plays the role of the reflector which absorbs and stores solar heat and reflects more than soil contained water.
In particular, the smoke of the city is the main substance that causes heat island phenomenon so it is also called as "island of pollution". The velocity of the wind, the amount of the clouds, the size of city also influence on heat island phenomenon. If density of building increases 10%, temperature of downtown increase 0.16°C. Most tropical night also appears in heat island.
No comments:
Post a Comment