The London Heat Island: results from summertime monitoring

This paper reports results from a study investigating the variation of air temperature across London. The paper focuses on the description of temperature measurements in summer 1999 and the analysis of the results. The intensity of the London Heat Island has been assessed using a radial grid of 68 stations recording simultaneous hourly air temperatures. The urban heat island has been found to be predominantly a nocturnal phenomenon and its intensity reaches 7 K on occasion. It was found that the thermal centre is in the City of London which is characterized by tall buildings and high anthropogenic heat emissions. The night-time temperature pro” le of London tends to follow a simple pattern with contours arranged roughly circularly around the centre; it is found that 77% of the variance of the mean night-time temperature across London is related to distance from the thermal centre. The more complicated pattern in the daytime precludes such a simple relationship.