Uploaded on 2015-11-02 by LamWY1997

The UHI effect is significant at US cities, especially for cities situated inland. For example, at summer, Las Vegas has a large average daily urban-rural temperature difference of 7.3°F, which is the highest among all US cities recorded. 2. UHI effect is very obvious in my place Hong Kong, a well-developed city, with especially high density urban areas and intensive pieces of rural land. According to the data and information given by HK Green Power, a local NGO, the city center of Hong Kong has a temperature 1.1-5.5 Celsius degrees higher than Hong Kong’s urban fridges. Walking from HK’s urban fridges to HK’s city center, every 1 km equals to temperature rise of 2 to 6 Celsius degrees. (1) ![此处输入图像的描述][1] *Sheung Wan (Western Market)* ![此处输入图像的描述][2] *Sai Kung* (taken from Google) The urban area (Sheung Wan) has obivious UHI effect. In terms of heat loss via buoyancy effect, Sheung Wan (urban area) is densely packed with all buildings. Affected by monsonn throughout the year, average wind speed is quite high, thus diminishing the effect of buoyancy effect. Heat is trapped in Sheung Wan, as a result. In the opposite, Sai Kung, the rural area, has scattered built up areas and buoyancy effect is obivious. Heat can be lost easily. In terms of heat source, road vehicles are a main source of emission of heat (via combustion of fuel), and Sheung Wan (urban area) has well-developed road transportation networks, like Des Voeux Road Central and Connuaght Road. There are a lot of vehicles in urban area like Sheung Wan. This makes urban areas like Shueng Wan has even more heat trapped. Inversely, for Sai Kung the rural area, road network is dispersed and vehicles are rarely seen. So there are not much heat emission (from vehicles) in rural areas like Sai Kung. 3. I would urge the local government to set up a law to regulate the heights of buildings in urban areas, especially those buildings facing wind directly. By regulating the heights of these buildings, like buildings at the waterfront, it can be ensured sufficient amount of wind can enter inner parts of the city. Thus, wind velocity in the urban areas can be high enough to drive away heat in the city center, alleviating UHI effect. 4. In my area, Hong Kong, the government is starting to build public housing estates that put air ventilation as a priority in their designs. The Hong Kong Housing Authority (responsible for public housing estates) has started a scheme called Micro-Climate Studies, which tries to simulate the natural ventilation of housing buildings, thus designing a housing estate with the best ability for natural ventilation. This helps heat in urban areas to be driven away by wind and thus reduces the impact of the UHI effect. The most recognized example is Choi Ying Estate situated in Kai Tak Development Area, built in 2009.(2) (1) Greenpower.org.hk,. (2015). Green Power. Retrieved 21 October 2015, from http://www.greenpower.org.hk/html/eng/job_weather_03.shtml (2) Housingauthority.gov.hk,. (2015). Hong Kong Housing Authority - Our Environmental Performance. Retrieved 21 October 2015, from https://www.housingauthority.gov.hk/hdw/en/aboutus/publication/sr0809/our-environmental-performance.htm#part2 [1]: https://farm1.staticflickr.com/594/22189631079_82ac9d6a1a_k.jpg [2]: https://c2.staticflickr.com/6/5592/15112283307_7d2720b6eb_b.jpg