The urban environment can generate its own climate and even smaller scale micro-climates are possible, depending on the building materials and design. High air temperatures caused by heat convected or conducted from the surface of the building are the most obvious source of error. Also, the physical and radiative properties of the building fabric are important, for example, in determining heat loading. The impervious nature of an urban surface compared to surrounding rural areas, together with the efficient channelling of water as surface run-off, leads to a generally drier environment. However, the ponding of water that occurs, for example, on flat roofs, can also lead to local areas of high relative humidity.
Wind speeds are generally lower in urban areas compared to more exposed rural locations.
However, aspects of city design and building geometry can combine to create areas of high or low wind speeds because of the funnelling of air. Get free updates by email Copyright Campbell Scientific Ltd. 1996, 2001. Best viewed with Internet Explorer 4.0 or higher.