The Urban Heat Island in Manchester 1996–2011

Abstract

The urban heat island intensity (difference between a semi-rural and urban dry bulb air temperature, urban heat island intensity) has been analysed for Manchester using data from 1996 to 2011. The semi-rural sites were airfields and the urban site was 2 km from the centre of Manchester. Although the urban site was not as developed as the city centre it showed a significant urban heat island intensity. A stochastic model developed from the data showed that the maximum mean daily value would be about 6℃ which compared well with more detailed measurements. However, there was a highly significant trend of increasing urban heat island intensity which by the end of the century could add 2.4 K to the predicted climate change increase. An analysis of the urban morphology showed that the urban site had indeed become more urban over 9 years of the study, losing green spaces which mitigate against the urban heat island intensity. Practical application: The results from this paper will allow building and HVAC designers to consider the increase in the urban heat island in their designs when using future weather data. Although the results are for Manchester, similar trends may well apply to other similar-sized cities. Designers should consider the future weather data available, as their buildings will last for a considerable time so they should be as future-proofed as possible.