Monitoring and Simulating Urban Heat Island Phenomenon During Unusual High Temperature and Drought Period in 2006 Summer in Chongqing, China

Chongqing city locates at the foothill, where the Jialing River and the Yangtze River joins. A severely high temperature and drought occurred in the summer of 2006. So, it has been very necessary and urgent to know the affection trend and extent of the urban heat island to high temperature in urban during that period. The temperature data measured at automatic weather stations was used to statistic the urban heat island. High resolute numeric model was used to simulate the urban heat island distribution and its influences to high temperature. The researches showed that there was a clear urban heat island phenomenon in Chongqing. The average of the daily urban heat island intensity in the summer was 1.0°C and the maximal reached 1.8°C. The urban heat island intensity varied clearly in a day. It was stronger in nighttime than it was in daytime. The average of night urban heat island intensity in summer was 1.4°C and the maximal reached 2.6°C. The appearance of urban heat island probably increased the high temperature harm at night. The refined temperature distribution and numerical simulating results clearly showed the temperature and the urban heat island distribution. The results indicated that the temperature and the urban heat island were affected by the city zone, hills and rivers, etc, at the same time. The highest heat island was located in Shapingba district, east of Zhongliang hill, which was mainly because of dense buildings, industries and isolated wind velocity field in it. Along the river area of Jiangbei, Yuzhong, Nanan, Jiulongpo, Dadukou formed connected high heat island areas, which were all old districts with high urbanization. The high temperature harm in night in urban increased by the urban heat island.