Sol-air temperature and daylight illuminance profiles for the UKCP09 data sets

To provide information on climate change, the UK Climate Impacts Programme (UKCIP) provided the latest UKCP09 data to a resolution of 5 km square grids for the UK. Those data sets were used in this study along with the historical measured data for two locations—Bracknell (London) and Edinburgh—to critically analyse the likely changes that may occur in the sol-air temperature and daylight illuminance profiles. These parameters have an important bearing on the design and function of buildings and building services.Drastic increment of sol-air temperature was found for the projected data sets. An increase of as much as 20.1 °C of sol-air temperature for dark-coloured surface was found for Edinburgh and 13.3 °C for Bracknell. These increments may be due to the compound effect of change in the constituent variables that are used to calculate sol-air temperature, i.e. solar radiation, wind speed and dry bulb temperature. A sensitivity test was carried out to see the effect of each variable on sol-air temperature.An increasing trend of daylight was also found in the data sets. This is attributed to the changing clarity of the sky condition. The predictions indicate a radical change in the characteristics of solar climate, i.e. from the present diffuse fraction of total irradiation of 0.37 which indicates mild turbidity to a drop of 0.13 indicating clear skies with exceptionally low turbidity.