Temperature change characteristics and its influence by urbanization in the Yangtze River Delta

Abstract

With global climate change and rapid regional urbanization,temperature and eco-environment changed significantly in the Yangtze River Delta.Based on regional meteorological data from basic/reference climatological surface stations and population data,annual and seasonal temperature change characteristics,the difference of temperature change in big cities,middle cities and small towns,and the urbanization warming and its relative contribution to the total amounts of temperature change was analyzed covering the periods from 1959 to 2005 and from 1981 to 2005.The result indicates that in the past 47 years and 25 years,annual mean temperature,annual mean maximum and minimum temperature increased significantly,with the highest warming rate in winter and spring,and the lowest warming rate in summer.For all types of stations,the annual and seasonal mean temperature,mean maximum and minimum temperature generally increased in the two periods of time.The warming rate in big cities was significantly higher than that in middle cities and small towns,and urbanization warming was almost in annual and seasonal temperature in big cities.The warming rate of urbanization and its relative contribution to the total amounts of temperature change was highest in mean minimum temperature,and lowest in mean maximum temperature.From 1959 to 2005,the warming rate in small towns was close to that in middle cities,and the influence of urbanization on the temperature in middle cities was small,but from 1981 to 2005,the warming rate in middle cities was higher than that in small towns,and the warming rate of urbanization for middle cities was significant.In the Yangtze River Delta,the changing trend and warming rate of temperature,the warming rate of urbanization and its relative contribution to the total amounts of temperature change were basically consistent with that in other places.Causes for the differences between our result and those found by other researchers are likely to be related to regional extent,the criteria for defining urban and contrasting stations,the different influence of urbanization on the contrasting stations,station network density,analytical methods,time periods,and etc.