Effect of Urbanization Process on Local Climate in Changsha City

Peng Jiadong; Zhao Hui; Chen Xiaochen

doi:10.16765/j.cnki.1673-7148.2017.04.006

Abstract：Using daily air temperature,precipitation and relative humidity observation data of Changsha and 4 nearly suburban county weather stations from 1961 to 2010,preprocessing with homogeneous adjustment and correction,the climate impact of urbanization on different stages in Changsha is analyzed through suburban stations as background field.The results are as follows.For the influence of urbanization,the increasing trend of surface air temperature in urban is much higher than suburban in recent 50 years.The urban heat island effect is significant,which contribute 30％ of the annual mean air temperature increasement in the urban area,and mainly appeared after 1990s.Among the four seasons,summer has the most contribution of urbanization,following autumn and spring,and winter has the least.The differences of precipitation between urban and suburban have an obviously increasing trend over the last 50 years.The rain island effect is significant,particularly in spring and summer.The rain island effect accelerates the polarization of precipitation structure in Changsha and increases the probability of urban waterlogging.Neither the relative humidity in urban and suburban or the differences between them show any significant trend in recent 50 years.For annual average,the dry island effect of Changsha in recent 50 years is unremarkable but significantly enhanced in recent 20 years.For seasonal,the dry island effect mainly occurs in summer in recent 50 years.