What is an Urban Heat Island? Just from the name of this term, make a guess at what it means. Write the answer in your green book. Explain what this picture shows. Improve your definition of Heat Island. The term "heat island" refers to urban air and surface temperatures that are higher than nearby rural areas. What factors can cause a Heat Island? Brainstorm in your books. Think about it! Explain how these factors work to promote a heat island. Concrete and man made surfaces Less water in the soil and environment Excess energy from buildings The principal reason for the nighttime warming is that buildings block surface heat from radiating into the relatively cold night sky. Tar, asphalt, brick and concrete absorb insolation and release it as heat, rather than reflecting it (without heat) like soil does. During the day in rural areas, the solar energy absorbed near the ground evaporates water from the vegetation and soil. Thus, causes evaporative cooling. In cities, where there is less vegetation, the buildings, streets and sidewalks absorb the majority of solar energy input. What about the buildings and the people in them? Make a list of the heat/pollution producing activities that humans take part in that would be more common in a city…. Remember, the way the heat island effect works, is that it increases the overall temperature of the city. (a bit like greenhouse effect) But in particular, it raises night time temperatures (not always day time) by the slow releasing of heat. Which makes an overall increase Design an experiment so that we could measure if Hong Kong has a heat island. *Write on paper, be ready to present. Individual work! Also, an experiment to see if the heat island is related to urbanization.