Urban heat island effect occurs when the temperature in the urban areas is significantly higher than the neighboring rural areas nearby due to anthropogenic factors.

• Reduced natural landscapes in urban areas (Physics F3) (STEM Education)

  Trees, vegetation, and water bodies cool the air by providing shade, transpiring water from plant leaves, and evaporating surface water through evapotranspiration.

  Hard, dry surfaces in urban areas, such as roofs, sidewalks, roads, buildings, and parking lots, provide less shade and moisture than natural landscapes. Therefore, higher temperature in urban areas than in areas is found.

• Urban material properties (Physics F3) (STEM Education)

  Conventional building materials used in urban environments such as pavements or roofing tend to reflect less solar energy, absorb and emit more of the sun’s heat when comparing to trees, vegetation, and other natural surfaces.

  Materials, such as bitumen, steel, and brick have dark colours, absorb more heat from the sun.

  Often, heat islands are built throughout the day and become more pronounced after sunset due to the slow release of heat from urban materials.

• Urban geometry (Physics F3) (STEM Education)

  The dimensions and spacing of buildings within a city can influence wind flow and urban materials’ ability to absorb and release solar energy.

  In densely-developed areas, surfaces and structures obstructed by neighbouring buildings become large thermal masses that cannot release their heat readily.

  Narrow streets and tall buildings in the cities become urban canyons, which can block natural wind flow that induce cooling effects.

• Heat generated from human activities (Physics F5) (STEM Education)

  Vehicles, air-conditioning units, buildings, and industrial facilities all emit anthropogenic heat into the urban environment, which results in heat island effects.

• Weather and geography (Physics F3) (STEM Education)

  Calm and clear weather conditions result in more severe heat islands by maximizing the amount of solar energy reaching urban surfaces and minimizing the amount of heat that can be carried away.

  Conversely, strong winds and cloud cover suppress heat island formation. Geographic features can also impact the heat island effect.

  For example, mountains nearby can block the wind from reaching a city, or create wind patterns that pass through a city.

  

• Higher energy consumption

  The temperature in the cities is higher, especially on summer nights. This raises the demand for energy to power air-conditioning units, which also drives up the price of electricity.

  Example: Li et al. (2019) suggests that the global heat island effect reduces the heating energy consumption of buildings by 18.7% and raises cooling energy consumption. This further creates a vicious cycle of energy consumption.

• Impact on health

  High temperatures can adversely affect the health of city dwellers, causing widespread discomfort, respiratory problems, sunstroke, dehydration, tiredness and even increasing mortality rates due to heatstroke.

• Greater atmospheric contamination (Chemistry F6) (STEM Education)

  Heat islands worsen air quality the increased consumption of fossil fuels they add to the emission of carbon dioxide (CO₂) and other contaminants, such as sulphur dioxide (SO₂) and nitrogen oxides (NO_x), which are to blame for the intensification of greenhouse effect and global warming.

• Impact on the economy

  Estrada et al. (2017) indicates that the effects associated with the warming caused by urban heat islands could double the foreseen economic losses of climate change.

• Bioclimatic architecture (Physics F6) (STEM Education)

  Installation of renewable energy, such as solar panels, to encourage photovoltaic self-consumption or green roofs to mitigate heat absorption, as well as other passive cooling elements to create more energy efficient houses.

• Eco-neighbourhoods

  New urban developments reduce the environmental impact by changing the life habits of their inhabitants. This could be done by incorporating more green areas, regenerating public spaces and promoting environmental education.

  

• Sustainable infrastructure

  Cities need to renew their buildings, roads, bridges, pavements, stations, street lights, fight against climate change. They are essential for underpinning green economic growth.

  Under green economy, income and employment growth is driven by economic activities and infrastructure that minimize carbon and pollutant emissions through enhancing energy efficiency.

• Sustainable mobility

  Land traffic is a main cause of urban pollution, which in turn contributes to rises in temperatures. It is for this reason that mobility must look to the future and, hand-in-hand with the new technologies, drive initiatives such as Mobility as a Service (MaaS).

  1. MaaS requires a widespread penetration of smartphones on mobile wireless network (4G / 5G) for transmission of real-time data and seamless payments, e.t.c. (STEM Education)

  Example 1: Sharing economy and shared mobility in Helsinki

  1. Using an app named "Whim" to allow users to conduct convenient door-to-door trips with shared bycycle (green mobility) and cars.
  2. Digital connectivity in this case links users and suppliers seamlessly to make good use of under-utilized assets to produce economic benefits for the society as a whole. (STEM Education)

  Example 2: Proposed environmentally friendly transport system in Hung Shui Kiu New Development Area, Hong Kong. (Physics F6) (STEM Education)

  1. MaaS requires a widespread penetration of smartphones on mobile wireless network (4G / 5G) for transmission of real-time data and seamless payments, e.t.c. (STEM Education)

• Green corridors

  These areas, which have different social, cultural or sporting uses, enable natural areas in a city to be connected via extensive swathes of vegetation. It is also worth mentioning elements such as urban gardening.

  Example: Kai Tak River Green Corridors

  1. Used to be one of the most polluted river with serious pharmaceutical pollution. (Chemistry in University) (STEM Education)
  2. Recreational and cultural uses are now found there, such as public participation in different participatory art projects along the river in the 2011 Green Arts Festival.

The Community Weather Information Network (Co-WIN) serves as a platform for providing real-time weather data to the public.

Step 1: We can compare recent weather data using "Time-series" page.

Step 2: Tick the checkbox to choose the second weather station. Although some stations are not active every day, there are still other stations to choose. After choosing two weather stations, click "Plot" button to plot the data.

Step 3: To examine and visualize the urban heat island effect directly, it is suggested to use the real-time data from one station in rural area and one station from urban area with the same weather element, i.e. "Air Temperature". Form the above example, the blue and orange line indicates the temperature of a weather staton in Tai Po, while the green and red line is the temperature in Kowloon respectively. The graph illustrates the existence of heat island effect by showing the temperature difference of two weather stations. In this case, the regional temperature difference can range up to two degree Celcius, which demonstrates the existence of urban heat island effect in Hong Kong.

Data can be download in a bulk using "Present Year Data Download" and "Historical Data Download" pages.