Effect of Urban Heat Island on Heat Waves in Summer of Shanghai

Using the data of daily maximum temperature at 11 stations in summer half-year(from June to October) in 1955-2004 and hourly mean temperature derived from 6 AWS urban,suburban and rural sites in Shanghai,the effect of increased urban heat island magnitude on heat waves in summer has been analyzed.It has been found that the mean maximum temperature,extreme temperature and hot days in summer measured at the urban and sub-urban sites all appeared increasing trends,with the largest value at urban site,larger one at suburban sites and the smallest one at the rural sites.Urban heat island induced temperature increase excesses the regional warming which lead to the more hot days,higher extreme temperature and longer duration,but the wide covered high temperature did not increase so much.