摘要
Although the urban heat island(UHI) is a well-documented phenomenon, relatively little information in the literature is available about its impact on summer extreme heat event(EHE). As UHI is characterized by increased temperature, it can potentially increase the magnitude and duration of EHEs within cities. Based on daily maximum temperature records from 62 observation stations in Zhejiang province from the period 1971-2011 and satellite-measured nighttime light imagery from the Defense Meteorological Satellite Program(DMSP) Operational Linescan System(OLS) during 1992-2010, we analyzed the long-term change of summer EHEs and its association with the rapid urbanization process. The results could be concluded as follows:(1) Zhejiang has experienced rapid urbanization and dramatic growth in urban areas in the past two decades, especially after 2000.(2) The summer mean maximum temperature and the 95 th percentile of summer daily maximum temperature in most of its stations have increased, with the most significant increase occurring in the highly urbanized areas including the city belt around Hangzhou Bay, Taizhou-Wenzhou and Jinghua-Yiwu city belts.(3) The hot days and hot-day degrees, defined by both daily 95 th percentile and the threshold of 35℃, show that the UHI effect causes additional hot days and heat stress in urban stations compared to rural stations.The results in this study suggest that the UHI effect should be determined and incorporated in preparing high temperature forecasts in cities.
Although the urban heat island（UHI） is a well-documented phenomenon, relatively little information in the literature is available about its impact on summer extreme heat event（EHE）. As UHI is characterized by increased temperature, it can potentially increase the magnitude and duration of EHEs within cities. Based on daily maximum temperature records from 62 observation stations in Zhejiang province from the period 1971-2011 and satellite-measured nighttime light imagery from the Defense Meteorological Satellite Program（DMSP） Operational Linescan System（OLS） during 1992-2010, we analyzed the long-term change of summer EHEs and its association with the rapid urbanization process. The results could be concluded as follows：（1） Zhejiang has experienced rapid urbanization and dramatic growth in urban areas in the past two decades, especially after 2000.（2） The summer mean maximum temperature and the 95 th percentile of summer daily maximum temperature in most of its stations have increased, with the most significant increase occurring in the highly urbanized areas including the city belt around Hangzhou Bay, Taizhou-Wenzhou and Jinghua-Yiwu city belts.（3） The hot days and hot-day degrees, defined by both daily 95 th percentile and the threshold of 35℃, show that the UHI effect causes additional hot days and heat stress in urban stations compared to rural stations.The results in this study suggest that the UHI effect should be determined and incorporated in preparing high temperature forecasts in cities.
基金
National Science Foundation of China(41371068)
"Strategic Priority Research Program(B)" of the Chinese Academy of Sciences(XDB05020403)
